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Maximally coherent mixed states: Complementarity between maximal coherence and mixedness | Ordering states with various coherence measures | Minimizing Communication in Linear Algebra | eng_Latn | 3,800 |
Copulas checker-type approximations: application to quantiles estimation of aggregated variables | High level quantile approximations of sums of risks | 1 n-Dimensional Copulas on Quantum Logic | eng_Latn | 3,801 |
Epistemic View of Quantum Communication | On Ternary Coding and Three-Valued Logic | Improving Performance of Multiagent Cooperation Using Epistemic Planning | eng_Latn | 3,802 |
The concept of equal space commutators in quantum optics | Quantum control model for spatial propagation of electromagnetic fields in dielectrics | Synthesis of unequally spaced arrays as inverse problem | eng_Latn | 3,803 |
Disorder-induced Effects in Noisy Dynamics of Bose-Hubbard and Fermi-Hubbard Quantum Glasses | An Open Systems Approach to Quantum Optics | Absence of CCR8 does not impair the response to ovalbumin-induced allergic airway disease. | eng_Latn | 3,804 |
Bound states in the one-dimensional two-particle Hubbard model with an impurity | Interaction-induced topological states of photon pairs | Improved estimation of the size of the state space of petri nets for the analysis of reachability problems | eng_Latn | 3,805 |
Quantum key distribution with distinguishable decoy states | Bounding light source side channels in QKD via Hong-Ou-Mandel interference | Unconditional security of quantum key distribution over arbitrarily long distances | eng_Latn | 3,806 |
Relativistic quantum cryptography for open space without clock synchronization on the receiver and transmitter sides | Relativistic Quantum Cryptography | Lagrangian empirical design of variable-rate vector quantizers: consistency and convergence rates | eng_Latn | 3,807 |
Quantum fluctuations in the mazer | Optical Coherence and Quantum Optics | Technical Efficiency of Shallot Farming in Central Java Province: Stochastic Frontier Modelling | eng_Latn | 3,808 |
Bound entangled states with non-positive partial transpose exist | On a matrix inequality related to the distillability problem | Completely Stale Transmitter Channel State Information is Still Very Useful | eng_Latn | 3,809 |
High-fidelity generating multi-qubit W state via dressed states in the system of multiple resonators coupled with a superconducting qubit | Bell's theorem, quantum theory and conceptions of the universe | Oral spray wintertime vitamin D3 supplementation has no impact on inflammation in Gaelic footballers | eng_Latn | 3,810 |
On-chip quantum optics with quantum dots and superconducting resonators | Coupling Two Distant Double Quantum Dots with a Microwave Resonator | Delayed Reactive Distractor Suppression in Aging Populations | eng_Latn | 3,811 |
Evolution of Complex Emergent Behaviour in Multi-State Cellular Automata | Design of Arithmetic Circuits in Quantum Dot Cellular Automata Nanotechnology | Exogenous growth factors do not affect the development of individually cultured murine embryos | kor_Hang | 3,812 |
Understanding the measurement theory in quantum mechanics | Decoherence and the transition from quantum to classical | A Novel Optimal Design of Measurement Configurations in Robot Calibration | eng_Latn | 3,813 |
Differential calculus on quantum complex Grassmann manifolds I: Construction | The classification of differential structures on quantum $2$-spheres | Communication on the Grassmann Manifold: A Geometric Approach to the Noncoherent Multiple-Antenna Channel | eng_Latn | 3,814 |
Self-error-rejecting photonic qubit transmission in polarization-spatial modes with linear optical elements | High-efficiency three-party quantum key agreement protocol with quantum dense coding and Bell states | Generalizing Epipolar-Plane Image Analysis on the spatiotemporal surface | eng_Latn | 3,815 |
Row scaling as a preconditioner for some nonsymmetric linear systems with discontinuous coefficients | Some New Bounds on the Condition Numbers of Optimally Scaled Matrices | Unconditional security of quantum key distribution over arbitrarily long distances | eng_Latn | 3,816 |
Genuine multipartite entanglement in quantum phase transitions | Factorization and Criticality in the Anisotropic XY Chain via Correlations | Microtubule capture by CENP-E silences BubR1-dependent mitotic checkpoint signaling | eng_Latn | 3,817 |
An Computer Virus Spreading Model with Delayed Quarantine in Internet | Epidemic dynamics and endemic states in complex networks | Unconditional security of quantum key distribution over arbitrarily long distances | eng_Latn | 3,818 |
SEE spaceflight measurements are presented on various devices (SRAMs and DRAMs) in the MIR orbital station. The standard models CREAME and AP8 have been used to predict the event rates from heavy ion and proton ground data. The prediction and actual in-flight rates are compared. | We present multi-layer single event upset (SEU) flight data on solid state recorder (SSR) memories for the NASA Orbview-2 mission. Actual SEU rates are compared to the predicted rates based on ground test data and environment models. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,819 |
We fabricated an integrated patch-clamp amplifier capable of recording from pico- to tens of micro-amperes of current. The high-dynamic range of seven decades and the pico-ampere sensitivity of the instrument was designed for whole-cell patch-clamp recordings. The prototype was fabricated on a 0.5/spl mu/m silicon-on-sapphire process. The device employs an integrating headstage with a frequency-modulated output pulse ranging from 3Hz to 10MHz. A digital interface produces a 16bit output conversion of the input currents. We report on electrical measurements from the fabricated device, and measurements conducted on cells in a typical patch-clamp experiment. | A neurochemical sensor system is being developed to spatially sense and process neurotransmitters. This paper reports the design and VLSI implementation of a multichannel potentiostat that interfaces to a nitric-oxide (NO) sensor array. Picoampere to microampere input currents are range-normalized with programmable gain, and digitized by a bank of current-mode delta-sigma analog-to-digital (A/D) converters. First-order noise shaping and 4096-fold oversampling provide high signal-to-noise ratio for the low-frequency NO transients. A shift register scans the buffered decimated delta-sigma outputs in bit-serial format providing asynchronous sequential readout. An 8-channel potentiostat in 0.5 /spl mu/m CMOS measures 1.5 mm/spl times/1.5 mm, and consumes 0.5 mW power. The device is expected to serve as a valuable tool for neurophysiological research and implantable neural prostheses. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,820 |
Brain tumor segmentation from MRI data is an important but challenging task. This paper presents an efficient and fully automatic brain tumor segmentation technique. The proposed technique includes a fuzzy C-means (FCM) based preprocessing to enhance the quality of T1-weighted coronal MR images, a fast bounding box (FBB) detection algorithm to locate a rectangle around tumor, and a new dynamic snake using modified Hausdorff distance (MHD) for the final tumor extraction. | Tuberculosis (TB) is a deadly infectious disease and the presence of cavities in the upper lung zones is a strong indicator that the disease has developed into a highly infectious state. Currently, the detection of TB cavities is mainly conducted by clinicians observing chest radiographs. Diagnoses performed by radiologists are labor intensive and very often there is insufficient healthcare personnel available, especially in remote communities. After assessing existing approaches, we propose an automated segmentation technique which takes a hybrid knowledge-based Bayesian classification approach to detect TB cavities automatically. We apply gradient inverse coefficient of variation (GICOV) and circularity measures to classify detected features and confirm true TB cavities. By comparing with non hybrid approaches and the classical active contour techniques for feature extraction in medical images, experimental results demonstrate that our approach achieves high accuracy with a low false positive rate in detecting TB cavities. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,821 |
The "quantum walk" has emerged recently as a paradigmatic process for the dynamic simulation of complex quantum systems, entanglement production and quantum computation. Hitherto, photonic implementations of quantum walks have mainly been based on multipath interferometric schemes in real space. We report the experimental realization of a discrete quantum walk taking place in the orbital angular momentum space of light, both for a single photon and for two simultaneous photons. In contrast to previous implementations, the whole process develops in a single light beam, with no need of interferometers; it requires optical resources scaling linearly with the number of steps; and it allows flexible control of input and output superposition states. Exploiting the latter property, we explored the system band structure in momentum space and the associated spin-orbit topological features by simulating the quantum dynamics of Gaussian wavepackets. Our demonstration introduces a novel versatile photonic platform for quantum simulations. | Quantum random walks on graphs have been shown to display many interesting properties, including exponentially fast hitting times when compared with their classical counterparts. However, it is still unclear how to use these novel properties to gain an algorithmic speedup over classical algorithms. In this paper, we present a quantum search algorithm based on the quantum random-walk architecture that provides such a speedup. It will be shown that this algorithm performs an oracle search on a database of N items with O({radical}(N)) calls to the oracle, yielding a speedup similar to other quantum search algorithms. It appears that the quantum random-walk formulation has considerable flexibility, presenting interesting opportunities for development of other, possibly novel quantum algorithms. | We report enhancement of the mechanical stability of graphene through a one-step method to disperse gold nanoparticles on the pristine graphene without any added agent. | eng_Latn | 3,822 |
Cluster algorithms for classical and quantum spin systems are discussed. In particular, the cluster algorithm is applied to classical O(N) lattice actions containing interactions of more than two spins. The performance of the multi-cluster and single--cluster methods, and of the standard and improved estimators are compared. (Lecture given at the summer school on `Advances in Computer Simulations', Budapest, July 1996.) | We apply the Quasi Monte Carlo (QMC) and recursive numerical integration methods to evaluate the Euclidean, discretized time path-integral for the quantum mechanical anharmonic oscillator and a topological quantum mechanical rotor model. For the anharmonic oscillator both methods outperform standard Markov Chain Monte Carlo methods and show a significantly improved error scaling. For the quantum mechanical rotor we could, however, not find a successful way employing QMC. On the other hand, the recursive numerical integration method works extremely well for this model and shows an at least exponentially fast error scaling. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,823 |
Individual electron and hole quantum dot spin qubits can be coherently manipulated using picosecond modelocked laser pulses; an all-optical spin-echo was implemented that decouples slow environmental changes. While dephasing and decoherence mechanisms for electrons and holes are intrinsically different, similar qualitative results are obtained, ::: except for dynamic nuclear polarization effects that affect the controllability of electrons. In addition, we demonstrate ::: spin-photon entanglement in a charged InAs quantum dot, using an ultrafast downconversion technique that converts a single, spontaneously emitted photon at 900 nm into a 1560 nm photon with picosecond timing resolution. This ultrafast conversion technique allows quantum erasure of which-path frequency information in the spontaneous emission process. | A basic requirement for quantum information processing systems is the ability to completely control the state of a single qubit. For qubits based on electron spin, a universal single-qubit gate is realized by a rotation of the spin by any angle about an arbitrary axis. Driven, coherent Rabi oscillations between two spin states can be used to demonstrate control of the rotation angle. Ramsey interference, produced by two coherent spin rotations separated by a variable time delay, demonstrates control over the axis of rotation. Full quantum control of an electron spin in a quantum dot has previously been demonstrated using resonant radio-frequency pulses that require many spin precession periods. However, optical manipulation of the spin allows quantum control on a picosecond or femtosecond timescale, permitting an arbitrary rotation to be completed within one spin precession period. Recent work in optical single-spin control has demonstrated the initialization of a spin state in a quantum dot, as well as the ultrafast manipulation of coherence in a largely unpolarized single-spin state. Here we demonstrate complete coherent control over an initialized electron spin state in a quantum dot using picosecond optical pulses. First we vary the intensity of a single optical pulse to observe over six Rabi oscillations between the two spin states; then we apply two sequential pulses to observe high-contrast Ramsey interference. Such a two-pulse sequence realizes an arbitrary single-qubit gate completed on a picosecond timescale. Along with the spin initialization and final projective measurement of the spin state, these results demonstrate a complete set of all-optical single-qubit operations. | We report nearly complete preservation of “spin memory” between optical absorption and photoluminescence under excitation >0.2 eV above the band gap in nanometer GaSe slabs. | eng_Latn | 3,824 |
: This is the final report for our project Hybrid Techniques for Quantum Circuit Simulation . We propose new computing technologies for simulating quantum-mechanical phenomena to aid in the development of quantum computers. We contribute new algorithms and software tools to simulate certain classes of quantum circuits with improved efficiency. Such circuits arise when enriching arbitrary quantum circuits with quantum error-correction codes, and may also be generated by restructuring more generic quantum circuits to improve the efficiency of quantum simulation. The project particularly explores extensions of the so-called stabilizer formalism to allow arbitrary quantum gates. Compared to prior work, the resulting computation is more efficient and more amenable to parallel processing. Empirical results are presented on a variety of quantum circuit benchmarks. We also show how to apply stochastic logic to the simulation of quantum circuits. | were proposed in the early 1980’s [Benioff80] and shown to be at least as powerful as classical computers an important but not surprising result, since classical computers, at the deepest level, ultimately follow the laws of quantum mechanics. The description of quantum mechanical computers was formalized in the late 80’s and early 90’s [Deutsch85][BB92] [BV93] [Yao93] and they were shown to be more powerful than classical computers on various specialized problems. In early 1994, [Shor94] demonstrated that a quantum mechanical computer could efficiently solve a well-known problem for which there was no known efficient algorithm using classical computers. This is the problem of integer factorization, i.e. testing whether or not a given integer, N, is prime, in a time which is a finite power of o (logN) . ---------------------------------------------- | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 3,825 |
Qualitative researchers seek to understand the words of the people they interview and may use narrative inquiry to find meaning in the stories told by research participants. Narrative inquiry entails “overreading,” a sensitivity to unspoken or indirect statement, which is central to interpretation. Some of the tools of the literary overreader are applied to two research interviews, particularly as they direct readers to attend to inconsistencies, endings, repetitions, and silence. Because overreading is also intrusive, we conclude with some considerations about how far the overreader of the research may legitimately go. © 1997 John Wiley & Sons, Inc. Res Nurs Health 20: 551–557, 1997 | National Institute of Nursing Research of the National Institutes of Health (NIH) [F31NR014964] | We propose general methodology of deterministic single-mode quantum interaction nonlinearly modifying single quadrature variable of a continuous variable system. The methodology is based on linear coupling of the system to ancillary systems subsequently measured by quadrature detectors. The nonlinear interaction is obtained by using the data from the quadrature detection for dynamical manipulation of the coupling parameters. This measurement-induced methodology enables direct realization of arbitrary nonlinear quadrature interactions without the need to construct them from the lowest-order gates. Such nonlinear interactions are crucial for more practical and efficient manipulation of continuous quadrature variables as well as qubits encoded in continuous variable systems. | eng_Latn | 3,826 |
We simultaneously measured fine-structure state Rabi oscillations of rubidium atoms in reconfigurable single-atom tweezer traps driven by shaped ultrafast laser pulses, which are in a good agreement with the characterized laser beam profiles. | Deterministic loading of single atoms onto arbitrary two-dimensional lattice points has recently been demonstrated, where by dynamically controlling the optical-dipole potential, atoms from a probabilistically loaded lattice were relocated to target lattice points to form a zero-entropy atomic lattice. In this atom rearrangement, how to pair atoms with the target sites is a combinatorial optimization problem: brute-force methods search all possible combinations so the process is slow, while heuristic methods are time-efficient but optimal solutions are not guaranteed. Here, we use the Hungarian matching algorithm as a fast and rigorous alternative to this problem of defect-free atomic lattice formation. Our approach utilizes an optimization cost function that restricts collision-free guiding paths so that atom loss due to collision is minimized during rearrangement. Experiments were performed with cold rubidium atoms that were trapped and guided with holographically controlled optical-dipole traps. The result of atom relocation from a partially filled 7-by-7 lattice to a 3-by-3 target lattice strongly agrees with the theoretical analysis: using the Hungarian algorithm minimizes the collisional and trespassing paths and results in improved performance, with over 50\% higher success probability than the heuristic shortest-move method. | A basic requirement for quantum information processing systems is the ability to completely control the state of a single qubit. For qubits based on electron spin, a universal single-qubit gate is realized by a rotation of the spin by any angle about an arbitrary axis. Driven, coherent Rabi oscillations between two spin states can be used to demonstrate control of the rotation angle. Ramsey interference, produced by two coherent spin rotations separated by a variable time delay, demonstrates control over the axis of rotation. Full quantum control of an electron spin in a quantum dot has previously been demonstrated using resonant radio-frequency pulses that require many spin precession periods. However, optical manipulation of the spin allows quantum control on a picosecond or femtosecond timescale, permitting an arbitrary rotation to be completed within one spin precession period. Recent work in optical single-spin control has demonstrated the initialization of a spin state in a quantum dot, as well as the ultrafast manipulation of coherence in a largely unpolarized single-spin state. Here we demonstrate complete coherent control over an initialized electron spin state in a quantum dot using picosecond optical pulses. First we vary the intensity of a single optical pulse to observe over six Rabi oscillations between the two spin states; then we apply two sequential pulses to observe high-contrast Ramsey interference. Such a two-pulse sequence realizes an arbitrary single-qubit gate completed on a picosecond timescale. Along with the spin initialization and final projective measurement of the spin state, these results demonstrate a complete set of all-optical single-qubit operations. | eng_Latn | 3,827 |
We review and compare different approaches for studying the influence of quenched, random disorder in three-dimensional Ising and Potts models for ferromagnets subject to impurities. From a theoretical view point, field theoretic renormalisation gr oup studies provide quite accurate results. Experiments carried out on crystalline mixtures of compounds lead to measurements of criticial exponents as accurate as three digits. Numerically, extensive Monte Carlo simulations are shown to be of comparable accuracy. Finally, we also discuss recently generated high-temperature series expansions for the free energy and susceptibility. Wit hin this approach, using the star-graph expansion technique, quenched disorder averages can be calculated exactly while keeping the disorder strength p as well as the dimension d as symbolic parameters. | The distributions $P(X)$ of singular thermodynamic quantities, on an ensemble of $d$-dimensional quenched random samples of linear size $L$ near a critical point, are analyzed using the renormalization group. For $L$ much larger than the correlation length $\ensuremath{\xi}$, we recover strong self-averaging (SA): $P(X)$ approaches a Gaussian with relative squared width ${R}_{X}\ensuremath{\sim}(L/\ensuremath{\xi}{)}^{\ensuremath{-}d}$. For $L\ensuremath{\ll}\ensuremath{\xi}$ we show weak SA ( ${R}_{X}$ decays with a small power of $L$) or no SA [ $P(X)$ approaches a non-Gaussian, with universal $L$-independent relative cumulants], when the randomness is irrelevant or relevant, respectively. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,828 |
Multitime measurements in quantum mechanics | Leggett-Garg Inequalities Draft : 26 October 2018 | Microtubule capture by CENP-E silences BubR1-dependent mitotic checkpoint signaling | eng_Latn | 3,829 |
Sequential Machines Having Quasi-Stable States | Asynchronous sequential switching circuits | A Superior Vector Quantization Based on Steady-State Memetic Algorithm | eng_Latn | 3,830 |
The Object Distribution Problem Revisited | 2002), Choosing Wisely: a Multi-bidding Approach | Unconditional security of quantum key distribution over arbitrarily long distances | eng_Latn | 3,831 |
Enhanced cooperativity for quantum-nondemolition-measurement--induced spin squeezing of atoms coupled to a nanophotonic waveguide | Internal Spin Control, Squeezing and Decoherence in Ensembles of Alkali Atomic Spins | Eavesdropping Squirrels Reduce Their Future Value of Food under the Perceived Presence of Cache Robbers | eng_Latn | 3,832 |
Probability in two deterministic universes | How probability arises in quantum mechanics | Equivalence of deterministic one-counter automata is NL-complete | eng_Latn | 3,833 |
Equation of Motion for Estimation Fidelity of Monitored Oscillating Qubits | An Open Systems Approach to Quantum Optics | EXO0748−676 Rules out Soft Equations of State for Neutron Star Matter | eng_Latn | 3,834 |
MULTI PARTICLE STATES CALCULATIONS AND PARTICLES STORAGE IN PERTURBED NANOLAYERS | Beautiful Models: 70 Years of Exactly Solved Quantum Many-Body Problems | Completely Stale Transmitter Channel State Information is Still Very Useful | yue_Hant | 3,835 |
New generalized coherent states | `Nonclassical' states in quantum optics: a `squeezed' review of the first 75 years | On the Fundamental Limits of Recovering Tree Sparse Vectors From Noisy Linear Measurements | eng_Latn | 3,836 |
A Grid Implementation of Direct Semiclassical Calculations of Rate Coefficients | Full‐dimensional quantum mechanical calculation of the rate constant for the H2+OH→H2O+H reaction | A Universal Optimal Consumption Rate for an Insider | eng_Latn | 3,837 |
Quantum information processing in decoherence-free subspace with nitrogen-vacancy centers coupled to a whispering-gallery mode microresonator | The Investigation of WGM Effective Potential from Micro PANDA Ring Resonator | Eavesdropping Squirrels Reduce Their Future Value of Food under the Perceived Presence of Cache Robbers | eng_Latn | 3,838 |
Braess’s Paradox for Flows over Time | Nash Equilibria and the Price of Anarchy for Flows over Time | On Wavefunction Collapse, the Absence of the Einstein-Poldolsky-Rosen Paradox for the Entangled Spin-1/2 System, and Some Results for Measurement in Quantum Mechanics | eng_Latn | 3,839 |
Higher-Dimensional Bell Inequalities with Noisy Qudits | Entanglement Dynamics for Two Spins in an Optical Cavity---Field Interaction Induced Decoherence and Coherence Revival | An instrumental variable approach finds no associated harm or benefit from early dialysis initiation in the United States | eng_Latn | 3,840 |
Linear optical implementation of a single-mode quantum filter and generation of multiphoton polarization entangled states | Bell's theorem, quantum theory and conceptions of the universe | Completely Stale Transmitter Channel State Information is Still Very Useful | eng_Latn | 3,841 |
The Inseparability of Consciousness from Embodiment in the Phenomenology of Edith Stein | A Phenomenological Framework of Architectural Paradigms for the User-Centered Design of Virtual Environments | On Wavefunction Collapse, the Absence of the Einstein-Poldolsky-Rosen Paradox for the Entangled Spin-1/2 System, and Some Results for Measurement in Quantum Mechanics | eng_Latn | 3,842 |
Quantum-enhanced metrology with the single-mode coherent states of an optical cavity inside a quantum feedback loop | Non-ergodicity in open quantum systems through quantum feedback | Quantitative real-time reverse transcription polymerase chain reaction: normalization to rRNA or single housekeeping genes is inappropriate for human tissue biopsies. | eng_Latn | 3,843 |
J an 2 01 7 Probabilistic Quantum Teleportation | Complete hyperentangled-Bell-state analysis for quantum communication | A Probabilistic Approach to People-Centric Photo Selection and Sequencing | eng_Latn | 3,844 |
Extended Learning Graphs for Triangle Finding | Algorithms for quantum computation: discrete logarithms and factoring | Self-insight into emotional and cognitive abilities is not related to higher adjustment | eng_Latn | 3,845 |
Copula and s-map on a quantum logic | 1 n-Dimensional Copulas on Quantum Logic | An utter refutation of the ‘Fundamental Theorem of the HapMap’ | eng_Latn | 3,846 |
Quantum quenches and driven dynamics in a single-molecule device | Introducing molecular electronics | Evaluation of divergent N-echelon (s, nQ)-policies under compound renewal demand | eng_Latn | 3,847 |
Feedback control on geometric phase in dissipative two-level systems | Universal single-qubit non-adiabatic holonomic quantum gates in optomechanical system | An instrumental variable approach finds no associated harm or benefit from early dialysis initiation in the United States | eng_Latn | 3,848 |
Here in this study we propose an efficient entanglement concentration protocol (ECP) for separate nitrogen-vacancy (NV) centers, resorting to the single-photon input---output process of the NV center and microtoroidal resonator coupled system. In the proposed ECP, one ancillary single-photon is prepared and passed through a hybrid quantum circuit. By measuring the photon under the suitable polarization basis, maximally entangled state between the separate NV centers can be obtained with a certain success probability. The solid entanglement will be preserved during the process, which can be iterated several rounds to obtain an optimal total success probability. We also discuss the experimental feasibility of the protocol by considering current technologies, and we believe that the protocol is useful in the future applications of long-distance quantum communication and distributed quantum computation. | The concatenated Greenberger-Horne-Zeiglinger (C-GHZ) state which is a new type of logic-qubit entanglement has attracted a lot of attentions recently. We present a feasible entanglement concentration protocol (ECP) for logic-qubit entanglement. This ECP is based on the linear optics, and it does not know the initial coefficients of the less-entangled C-GHZ state. This protocol can be extended to arbitrary C-GHZ state. This protocol may be useful in future quantum information processing tasks. | Since the end of the Cold War, the study of European defence has been dominated by a ‘Common Security and Defence Policy (CSDP)-centric’ approach, while largely neglecting the comparative analysis ... | eng_Latn | 3,849 |
We utilize a 1992 survey of approximately, 2500 AIDS activists to analyze their degree of participation. Activity levels were affected by several traditional predictors, but the inclusion of contextual measures indicating the activists' connection with AIDS, especially the pain and loss incurred, led to a much fuller and more complex explanatory model. We argue that a richer comprehension of political participation requires more studies of issue-specific activists and the specification of contexual features that serve to motivate more intensive degrees of participation. | The study aims to extend the existing knowledge about the dynamics of first-time participation in protest events. To tackle that puzzle we rely on extensive and innovative protest survey evidence covering 18 separate demonstrations in eight countries across nine different issues. On the individual level, age, motivation, and non-organizational mobilization appear to be consistent and robust predictors of first-timership. On the aggregate level, demonstrations staged just after or during a protest wave, large demonstrations, and demonstrations of old or new emotional movements are attended by a relatively larger share of first-timers. We conclude that it is thus the interplay of individual- and aggregate-level determinants that produces first-time participation. | We characterise a model of universal quantum computation where the register (computational) qubits are controlled by ancillary qubits, using only a single fixed interaction between register and ancillary qubits. No additional access is required to the computational register and the dynamics of both the register and ancilla are unitary. This scheme is inspired by the measurement-based ancilla-driven quantum computation of Anders et al. [PRA 82, 020301(R), 2010], but does not require measurements of the ancillas, and in this respect is similar to the original gate based model of quantum computation. We consider what possible forms this ancilla-register interaction can take, with a proof that the interaction is necessarily locally equivalent to SWAP combined with an entangling controlled gate. We further show which Hamiltonians can create such interactions and discuss two examples; the two-qubit XY Hamiltonian and a particular case of the XXZ Hamiltonian. We then give an example of a simple, finite and fault tolerant gate set for universal quantum computation in this model. | eng_Latn | 3,850 |
Recent demonstrations of macroscopic quantum coherence in Josephson junction based electronic circuits have opened an entirely new dimension for research and applications in the established field of Josephson electronics. In this article we discuss basic Josephson circuits for qubit applications, methods of quantum description of these circuits, and circuit solutions for qubit couplings. Principles of manipulation and readout of superconducting qubits are reviewed and illustrated with recent experiments using various qubit types. | Already in the first edition of this book (Barone and Paterno,"Fundamentals and Physics and Applications of the Josephson Effect", Wiley 1982), a great number of interesting and important applications for Josephson junctions were discussed. In the decades that have passed since then, several new applications have emerged. This chapter treats one such new class of applications: quantum optics and quantum information processing (QIP) based on superconducting circuits with Josephson junctions. In this chapter, we aim to explain the basics of superconducting quantum circuits with Josephson junctions and demonstrate how these systems open up new prospects, both for QIP and for the study of quantum optics and atomic physics. | The reasons for the failure to develop a successful Josephson tunnel junction made from high-temperature superconducting cuprates is discussed. The difficulties in developing a theoretical analysis of even simple-to-make cuprate Josephson devices are pointed out. The development of alternative Josephson devices based on the fabrication of engineered microbridges is addressed, and an overview is given of successful YBCO microbridges. Emphasis is given to focused ion beam and step-edge microbridges. | eng_Latn | 3,851 |
For six decades, physicists have broken their heads over quantum entanglement. But by now we have learned to do more than break our heads over it. This review explains what is so baffling about entanglement and also what we can do with it. Entanglement is a resource for teleporting quantum states and constructing unbreakable codes, a resource that we can extract, purify, distribute and consume. The applications of entanglement lead us to develop new conceptual tools and adapt old ones—in particular, the concept of entropy, which helps us exploit entanglement efficiently. Here we define entanglement and show, via the EinsteinPodolosky-Rosen (EPR) paradox and Bell’s inequality, how it implies quantum nonlocality. We draw a parallel between reversible heat engines and reversible transformations among entangled states. This parallel leads to the “entropy of entanglement” as the measure of entanglement of bipartite pure states. We also discuss the entanglement of density matrices. | On a Theory of the Collapse of the Wave Function.- On the Measurement Problem of Quantum Mechanics.- A New Characteristic of a Quantum System Between Two Measurements - A "Weak Value".- Can the Quantum Measurement Process be put into QED?.- Chained Bell Inequalities.- From George Boole to John Bell - The Origins of Bell's Inequality.- The Logic of Quantum Nonseparability.- Bell's Theorem and Mermin's Gedanken Experiment.- Searching for Mutually Unbiased Observables.- Going Beyond Bell's Theorem.- Quantum Field Theory, Bell's Inequalities and the Problem of Hidden Variables.- What Locality Isn't: A Response to Jarrett.- Bell's Theorem: The Forgotten Loophole and How to Exploit It.- Are More Economical Escapes From Bell's Strictures Possible?.- Concerning Theories Free From Bell's Constraint.- The EPR Paradox, Actions at a Distance and the Theory of Relativity.- Conditionals, Probability and Bell's Theorem.- Relativity and Probability, Classical or Quantal.- Relativistic Probability Amplitudes and State Preparation.- Non-Linearity and Post-Bell Quantum Mechanics.- Observable Effects of the Uncertainty Relations in the Covariant Phase Space Representation of Quantum Mechanics.- Geometry of Cyclic Quantum Evolutions.- On the Computer Simulation of the EPR-Bohm Experiment.- Discrete Phase-Space Model for Quantum Mechanics.- A Possible Explanation of Quantum Mechanics Behavior by a Classical Cellular Automaton Construction.- Quantum Mechanical Information is Ubiquitous.- The Unobservability of Spinor Structure.- Teaching QM: True, Trivial, Inevitable.- Quantum Cosmology and Quantum Mechanics.- Cosmology, EPR Correlations and Separability.- Bell's Theorem: Form and Information in the Quantum Theory.- Horizons of Knowledge in Cosmology.- The Ontological Status of the Cosmological Singularity.- Quantum Cosmological Generality of Inflation in Anisotropic Spacetime.- Mass Generation in the Early Universe.- Massive Photons and Monopoles.- The Large-Scale Streaming of Galaxies.- The Numerically Simple Universe.- Size of a Least Unit.- Bell, Book and Candle: The Limning of a Mystery.- Complementarity and Space-Time Description.- Complementarity and Cosmology.- Quantum Ontologies.- Henry P. Stapp on Quantum Theory and Reality.- For Whom the Bell Tolls: A Plea for Fundamental Ontology.- The Role of Consciousness in Physical Reality.- The Significance of Human Observation in Measurement in Quantum Mechanics The Nature of the Traditional Separation Between Psychology and Physics.- The Universe in the Light of Contemporary Scientific Developments.- Name Index. | Entanglement is one of the pillars of quantum mechanics and quantum information processing, and as a result the quantumness of nonentangled states has typically been overlooked and unrecognized. We give a robust definition for the classicality versus quantumness of a single multipartite quantum state, a set of states, and a protocol using quantum states. We show a variety of nonentangled (separable) states that exhibit interesting quantum properties, and we explore the ``zoo'' of separable states; several interesting subclasses are defined based on their diagonalizing bases, and their non-classical behavior is investigated. | eng_Latn | 3,852 |
In this article we make a review on the usefulness of probabilistically cloning and present examples of quantum computation tasks for which quantum cloning offers an advantage which cannot be matched by any approach that does not resort to it. In these quantum computations, one needs to distribute quantum information contained in states about which we have some partial information. To perform quantum computations, one uses state-dependent probabilistic quantum cloning procedure to distribute quantum information in the middle of a quantum computation. And we discuss the achievable efficiencies and the efficient quantum logic network for probabilistic cloning the quantum states used in implementing quantum computation tasks for which cloning provides enhancement in performance. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 3,853 |
Quantum steering, loosely speaking the distribution of entanglement from an untrusted party, is a form of quantum nonlocality which is intermediate between entanglement and Bell nonlocality. Determining which states can be steered is important from a conceptual point of view, but also for applications, e.g. in quantum cryptography. Here we show that bound entanglement, although it represents the weakest form of entanglement, can nevertheless lead to quantum steering. This is done by noticing that steering inequalities can be derived from entropic uncertainty relations. Our result has implications on the connection between entanglement distillability and nonlocality, and shows that bound entangled states can be useful for information-theoretic tasks featuring an untrusted party. | We demonstrate the detection of bipartite bound entanglement as predicted by the Horodecki's in 1998. Bound entangled states, being heavily mixed entangled quantum states, can be produced by incoherent addition of pure entangled states. Until 1998 it was thought that such mixing could always be reversed by entanglement distillation; however, this turned out to be impossible for bound entangled states. The purest form of bound entanglement is that of only two particles, which requires higher-dimensional (d > 2) quantum systems. We realize this using photon qutrit (d = 3) pairs produced by spontaneous parametric downconversion, that are entangled in the orbital angular momentum degrees of freedom, which is scalable to high dimensions. Entanglement of the photons is confirmed via a 'maximum complementarity protocol'. This conceptually simple protocol requires only maximized complementary of measurement bases; we show that it can also detect bound entanglement. We explore the bipartite qutrit space and find that, also experimentally, a significant portion of the entangled states are actually bound entangled. | We report enhancement of the mechanical stability of graphene through a one-step method to disperse gold nanoparticles on the pristine graphene without any added agent. | eng_Latn | 3,854 |
An algebraic analysis of Grover's quantum search algorithm is presented for the case in which the initial state is an arbitrary pure quantum state $\ensuremath{\mid}\ensuremath{\psi}⟩$ of $n$ qubits. This approach reveals the geometrical structure of the quantum search process, which turns out to be confined to a four-dimensional subspace of the Hilbert space. It unifies and generalizes earlier results on the time evolution of the amplitudes during the search, the optimal number of iterations, and the success probability. Furthermore, it enables a direct generalization to the case in which the initial state is a mixed state, providing an exact formula for the success probability. | The Grover search algorithm is one of the two key algorithms in the field of quantum computing, and hence it is desirable to represent it in the simplest and most intuitive formalism possible. We show firstly, that Clifford's geometric algebra, provides a significantly simpler representation than the conventional bra-ket notation, and secondly, that the basis defined by the states of maximum and minimum weight in the Grover search space, allows a simple visualization of the Grover search analogous to the precession of a spin- $${\frac{1}{2}}$$ particle. Using this formalism we efficiently solve the exact search problem, as well as easily representing more general search situations. We do not claim the development of an improved algorithm, but show in a tutorial paper that geometric algebra provides extremely compact and elegant expressions with improved clarity for the Grover search algorithm. Being a key algorithm in quantum computing and one of the most studied, it forms an ideal basis for a tutorial on how to elucidate quantum operations in terms of geometric algebra--this is then of interest in extending the applicability of geometric algebra to more complicated problems in fields of quantum computing, quantum decision theory, and quantum information. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 3,855 |
We propose a state protection scheme of quantum feed-forward control and its reversal (QFFCR) by quantum weak measurement and quantum control to protect the arbitrary N-qubit state in amplitude-damping channel (ADC). Before the state enters the ADC, a weak measurement and an offsetting operation are made to make the state almost immune to the effect of ADC. After the state passes the ADC, the reversed offsetting operation and a correction rotation are applied to recover the state. Unlike most previous state protection schemes, ours does not use weak measurement reversal, but a correction rotation to bring back the state to its initial amount. Our protection scheme can also protect entangled states even for heavy damping probabilities effectively. Fidelity and success probability are used to evaluate the effect of the proposed scheme. The general formula for complete recovery and the total success probability of N-qubit system are derived. The effectiveness of our control scheme is demonstrated by simulation results. | We present practical GHz-clocked QKD systems, next generation entanglement QKD technologies, and QKD platform to manage the secure keys and to support a variety of applications. We then show the intrinsic limit of QKD, i.e., a key rate bound, and discuss how to realize the provable (information theoretic) security with a larger secrecy capacity over longer distances. In particular, we present a basic theory of physical layer cryptography, which characterizes the secrecy capacity, and engineers the tradeoff between the efficiency of reliable transmission and secrecy of communication. We introduce a concept to unify these schemes in photonic network, referred to as quantum photonic network. Future issues for realizing this new network paradigm are discussed. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 3,856 |
New multiple categories of health disciplines have become popular in the west and integration between the medicinal approaches has become essential.The hypothesis presented here suggests a novel integrative view that combines Western biochemistry with the Chinese medicinal concept of qi.The core for this hypothesis is that transmission of qi along the meridians is based on informational molecules that travel via an intercellular communication system. Acupuncture at specific points enhances the flow of the signaling molecules through this communication system.Nitric oxide is suggested as a prime candidate for such a signaling molecule in the meridian system. The biochemistry of nitric oxide can shed light on the biology underlying Chinese medicine while Chinese medicinal data can provide a clue to the sought after framework for nitric oxide. | "Demystifies Oriental medicine in a remarkably rational analysis of both its strengths and weaknesses". -- Science Digest | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,857 |
Although the quantum laws are time-reversal invariant, a contradiction appears if two measurements performed by a single observer, and described according to these laws, are performed in two opposite directions of time. This contradiction leads to bringing forth the concept of an observer's private time, and then to building up a temporal parameter common to several observers from their private times. Time asymmetry turns out to be a consequence of the latter construction. | We expand the time reversal symmetry arguments of quantum mechanics, originally proposed by Wigner in the context of unitary dynamics, to contain situations including generalized measurements for monitored quantum systems. We propose a scheme to derive the time reversed measurement operators by considering the Schr\"{o}dinger picture dynamics of a qubit coupled to a measuring device, and show that the time reversed measurement operators form a Positive Operator Valued Measure (POVM) set. We present three particular examples to illustrate time reversal of measurement operators: (1) the Gaussian spin measurement, (2) a dichotomous POVM for spin, and (3) the measurement of qubit fluorescence. We then propose a general rule to unravel any rank two qubit measurement, and show that the backward dynamics obeys the retrodicted equations of the forward dynamics starting from the time reversed final state. We demonstrate the time reversal invariance of dynamical equations using the example of qubit fluorescence. We also generalize the discussion of a statistical arrow of time for continuous quantum measurements introduced by Dressel et al. [Phys. Rev. Lett. 119, 220507 (2017)]: we show that the backward probabilities can be computed from a process similar to retrodiction from the time reversed final state, and extend the definition of an arrow of time to ensembles prepared with pre- and post-selections, where we obtain a non-vanishing arrow of time in general. We discuss sufficient conditions for when time's arrow vanishes and show our method also captures the contributions to time's arrow due to natural physical processes like relaxation of an atom to its ground state. As a special case, we recover the time reversibility of the weak value as its complex conjugate using our method, and discuss how our conclusions differ from the time-symmetry argument of Aharonov-Bergmann-Lebowitz (ABL) rule. | We show quantitatively that an exact solution of Einstein's conformal gravity can explain very well the galactic rotation curves for a sample of 104 galaxies without need for dark matter or other exotic modification of gravity. The metric is an overall rescaling of the Schwarzschild-de Sitter spacetime as required by Weyl conformal invariance, which has to be spontaneously broken, and the velocity of the stars depends only on two universal parameters determined on the base of the observational data. | eng_Latn | 3,858 |
A general definition and a criterion (a necessary and sufficient condition) are formulated for an arbitrary set of external factors to selectively influence a corresponding set of random entities (generalized random variables, with values in arbitrary observation spaces), jointly distributed at every treatment (a set of factor values containing precisely one value of each factor). The random entities are selectively influenced by the corresponding factors if and only if the following condition, called the joint distribution criterion, is satisfied : there is a jointly distributed set of random entities, one entity for every value of every factor, such that every subset of this set that corresponds to a treatment is distributed as the original variables at this treatment. The distance tests (necessary conditions) for selective influence previously formulated for two random variables in a two-by-two factorial design (Kujala & Dzhafarov, 2008, J. Math. Psychol., 52, 128–144) are extended to arbitrary sets of factors and random variables. The generalization turns out to be the simplest possible one: the distance tests should be applied to all two-by-two designs extractable from a given set of factors. | Similar formalisms have been independently developed in psychology, to deal with the issue of selective influences (deciding which of several experimental manipulations selectively influences each of several, generally non-independent, response variables), and in quantum mechanics (QM), to deal with the EPR entanglement phenomena (deciding whether an EPR experiment allows for a "classical" account). The parallels between these problems are established by observing that any two noncommuting measurements in QM are mutually exclusive and can therefore be treated as analogs of different values of one and the same input. Both problems reduce to that of the existence of a jointly distributed system of random variables, one variable for every value of every input (in psychology) or every measurement on every particle involved (in an EPR experiment). We overview three classes of necessary conditions (some of them also sufficient under additional constraints) for the existence of such joint distributions. | A key competitive precondition for any organization involved in any of today's multinational businesses is speed and pace in implementing strategies. Although one's organization may offer superior products or services today, it may quickly lag behind its competitors if it is not adept at implementing critical decisions. | eng_Latn | 3,859 |
We study a quantum teleportation scheme between two nanomechanical modes without local interaction. The nanomechanical modes are linearly coupled to and connected by the continuous variable modes of a superconducting circuit consisting of a transmission line and Josephson junctions. We calculate the fidelity of transferring Gaussian states at finite temperature and non-unit detector efficiency. For coherent state, a fidelity above the classical limit of 1/2 can be achieved for a large range of parameters. | Superconducting systems have a long history of use in experiments that push the frontiers of mechanical sensing. This includes both applied and fundamental research, which at present day ranges from quantum computing research and efforts to explore Planck-scale physics to fundamental studies on the nature of motion and the quantum limits on our ability to measure it. In this paper, we first provide a short history of the role of superconducting circuitry and devices in mechanical sensing, focusing primarily on efforts in the last decade to push the study of quantum mechanics to include motion on the scale of human-made structures. This background sets the stage for the remainder of the paper, which focuses on the development of quantum electromechanical systems (QEMS) that incorporate superconducting quantum bits (qubits), superconducting transmission line resonators and flexural nanomechanical elements. In addition to providing the motivation and relevant background on the physical behavior of these systems, we discuss our recent efforts to develop a particular type of QEMS that is based upon the Cooper-pair box (CPB) and superconducting coplanar waveguide (CPW) cavities, a system which has the potential to serve as a testbed for studying the quantum properties of motion in engineered systems. | This paper investigates the control and synchronization of the shunted nonlinear resistive-capacitive-inductance junction (RCLSJ) model under the condition of noise disturbance with only one single controller. Based on the sliding mode control method, the controller is designed to eliminate the chaotic behavior of Josephson junctions and realize the achievement of global asymptotic synchronization of coupled system. Numerical simulation results are presented to demonstrate the validity of the proposed method. The approach is simple and easy to implement and provides reference for chaos control and synchronization in relevant systems. | eng_Latn | 3,860 |
It is known that there exist two locally operational settings, local operations with one-way and two-way classical communication. And recently, some sets of maximally entangled states have been built in specific dimensional quantum systems, which can be locally distinguished only with two-way classical communication. In this paper, we show the existence of such sets is general, through constructing such sets in all the remaining quantum systems. Specifically, such sets including p or n maximally entangled states will be built in the quantum system of (np - 1) ⊗ (np - 1) with n ≥ 3 and p being a prime number, which completes the picture that such sets do exist in every possible dimensional quantum system. | We explicitly exhibit a set of four ququad-ququad orthogonal maximally entangled states that cannot be perfectly distinguished by means of local operations and classical communication. Before our work, it was unknown whether there is a set of $d$ locally indistinguishable $d\otimes d$ orthogonal maximally entangled states for some positive integer $d$. We further show that a $2\otimes 2$ maximally entangled state can be used to locally distinguish this set of states without being consumed, thus demonstrate a novel phenomenon of "Entanglement Discrimination Catalysis". Based on this set of states, we construct a new set $\mathrm{K}$ consisting of four locally indistinguishable states such that $\mathrm{K}^{\otimes m}$ (with $4^m$ members) is locally distinguishable for some $m$ greater than one. As an immediate application, we construct a noisy quantum channel with one sender and two receivers whose local zero-error classical capacity can achieve the full dimension of the input space but only with a multi-shot protocol. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 3,861 |
This work inquires into global climatic catastrophes of the past, presenting data not easily available outside of the Socialist Countries, and applies these results to the study of future climatic developments, especially as they threaten in case of Nuclear Warfare - Nuclear Winter. The authors discuss probable after effects from the Soviet point of view on the basis of research, stressing the need to avoid all conflict which might lead to the next and final Global Climatic Catastrophy. | The Flood/post-Flood boundary in the geologic column can be determined by investigating geophysical evidence in light of Scripture’s record of the Flood. The following evidences are investigated: (1) global sediment and post-Flood erosion, (2) volcanism and climatic impact, (3) changes in the global sea level, (4) formation of the mountains of Ararat, and (5) the formation of fossil fuels. The evidences suggest that the Flood/post-Flood boundary is very late in the Cainozoic and most likely in the Pleistocene. | We present a scheme for achieving coherent spin squeezing of nuclear spin states in semiconductor quantum dots. The nuclear polarization dependence of the electron spin resonance generates a unitary evolution that drives nuclear spins into a collective entangled state. The polarization dependence of the resonance generates an area-preserving, twisting dynamics that squeezes and stretches the nuclear spin Wigner distribution without the need for nuclear spin flips. Our estimates of squeezing times indicate that the entanglement threshold can be reached in current experiments. | eng_Latn | 3,862 |
The PENN-PET scanner consists of six hexagonally arranged position-sensitive Nal(TI) detectors. This design offers high spatial resolution in all three dimensions, high sampling density along all three axes without scanner motion, a large axial acceptance angle, good energy resolution, and good timing resolution. This results in three-dimensional imaging capability with high sensitivity and low scatter and random backgrounds. The spatial resolution is 5.5 mm (FWHM) in all directions near the center. The true sensitivity, for a brain-sized object, is a maximum of 85 kcps/microCi/ml and the scatter fraction is a minimum of 10%, both depending on the lower level energy threshold. The scanner can handle up to 5 mCi in the field of view, at which point the randoms equal the true coincidences and the detectors reach their count rate limit. We have so far acquired [18F]FDG brain studies and cardiac studies, which show the applicability of our scanner for both brain and whole-body imaging. With the results to date, we feel that this design results in a simple yet high performance scanner which is applicable to many types of static and dynamic clinical studies. | Noise equivalent counts (NEC) have been used as a measure or proxy of PET image quality for many years. It has been shown to be a useful metric, for example to determine clinical patient dosage. However, NEC should be used cautiously in evaluating image quality since it is a global data quality measure that does not take into account localized effects due to spatial resolution and image reconstruction, as well as the effect of time-of-flight (TOF) imaging on resultant images. In this work, we study the use of a numerical observer that uses a generalized scan-statistic model to estimate lesion detectability with localization in a uniform background phantom, for varying activity levels and scan times. Data were acquired on a clinical whole-body TOF PET scanner. Data show that ALROC increases as a function of NEC but at high activity levels it approaches a peak value earlier than the NEC peak. Also, the ALROC for images acquired with the same NEC, but at two different activity levels and scan times, is similar. Our results show that with TOF information we can either achieve improved clinical performance for heavy patients, or reduce the scan time or injected activity while maintaining similar ALROC value as in a Non-TOF image. | We consider the problem of quantum phase estimation with access to arbitrary measurements in a single suboptimal basis. The achievable sensitivity limit in this case is determined by the classical Cram\'{e}r-Rao bound with respect to the fixed basis. Here we show that the sensitivity can be enhanced beyond this limit if knowledge about the energy expectation value is available. The combined information is shown to be equivalent to a direct measurement of an optimal linear combination of the basis projectors and the phase-imprinting Hamiltonian. Application to an atomic clock with oversqueezed spin states yields a sensitivity gain that scales linearly with the number of atoms. Our analysis further reveals that small modifications of the observable can have a strong impact on the sensitivity. | eng_Latn | 3,863 |
We propose and analyze the implementation of a two qubit quantum gate using circular Rydberg states with maximum orbital angular momentum. The intrinsic quantum gate error is limited by the finite Rydberg lifetime and finite Rydberg blockade shift. Circular states have much longer radiative lifetimes than low orbital angular momentum states and are therefore candidates for high fidelity gate operations. We analyze the dipole-dipole interaction of two circular state Rydberg atoms and present numerical simulations of quantum process tomography to find the intrinsic fidelity of a Rydberg blockade controlled phase gate. Our analysis shows that the intrinsic gate error can be less than $9 \times10^{-6}$ for circular Cs atoms in a cryogenic environment. | Rydberg blockaded gate is a fundamental ingredient for scalable quantum computation with neutral Rydberg atoms. However the fidelity of such a gate is intrinsically limited by a blockade error coming from a Rydberg level shift that forbids its extensive use. Based on a dark-state adiabatic passage, we develop a novel protocol for realizing a two-atom blockade-error-free quantum gate in a hybrid system with simultaneous van der Waals (vdWsI) and resonant dipole-dipole interactions (DDI). The basic idea relies on converting the roles of two interactions, which is, the DDI serves as one time-dependent tunable pulse and the vdWsI acts as a negligible middle level shift, as long as the adiabatic condition is preserved. We adopt an optimized super-Gaussian optical pulse with kπ(k ≫ 1) area accompanied by a smooth tuning for the DDI, composing a circular stimulated Raman adiabatic passage, which can robustly ensure a faster operation time ∼ 80ns as well as a highly-efficient gate fidelity ∼ 0.9996. This theoretical protocol offers a flexible treatment for hybrid interactions in complex Rydberg systems, enabling on-demand design of new types of effective Rydberg quantum gate devices. | MLL1 regulates circadian promoters by depositing H3K4 trimethyl marks, whose levels are also modulated by the NAD+-dependent deacetylase SIRT1. SIRT1 is now shown to promote circadian deacetylation of MLL1, thus affecting MLL1's methyltransferase activity. | eng_Latn | 3,864 |
In this paper some necessary and sufficient conditions are obtained for a operator tensor product\(\sum\limits_k {A_{1k} \otimes A_{2k} \otimes \cdot \cdot \cdot \otimes A_{nk} } \) to be zero, compact, normal, hyponormal, subnormal, essential normal,k-quasihyponormal, etc. | The number of qubits of current quantum computers is one of the most dominating restrictions for applications. So it is naturally conceived to use two or more small capacity quantum computers to form a larger capacity quantum computing system by quantum parallel programming. To design the parallel program for quantum computers, the primary obstacle is to decompose quantum gates in the whole circuit to the tensor product of local gates. In the paper, we first devote to analyzing theoretically separability conditions of multipartite quantum gates on finite or infinite dimensional systems. Furthermore, we perform the separation experiments for $n$-qubit quantum gates on the IBM's quantum computers by the software Q$|SI\rangle$. Not surprisedly, it is showed that there exist few separable ones among multipartite quantum gates. Therefore, we pay our attention to the approximate separation problems of multipartite gates, i.e., how a multipartite gate can be closed to separable ones. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 3,865 |
We present a computer-aided design flow for quantum circuits, complete with automatic layout and control logic extraction. To motivate automated layout for quantum circuits, we investigate grid-based layouts and show a performance variance of four times as we vary grid structure and initial qubit placement. We then propose two polynomial-time design heuristics: a greedy algorithm suitable for small, congestion-free quantum circuits and a dataflow-based analysis approach to placement and routing with implicit initial placement of qubits. Finally, we show that our dataflow-based heuristic generates better layouts than the state-of-the-art automated grid-based layout and scheduling mechanism in terms of latency and potential pipelinability, but at the cost of some area. | We optimize the area and latency of Shor's factoring while simultaneously improving fault tolerance through: (1) balancing the use of ancilla generators, (2) aggressive optimization of error correction, and (3) tuning the core adder circuits. Our custom CAD flow produces detailed layouts of the physical components and utilizes simulation to analyze circuits in terms of area, latency, and success probability. We introduce a metric, called ADCR, which is the probabilistic equivalent of the classic Area-Delay product. Our error correction optimization can reduce ADCR by order of magnitude or more. Contrary to conventional wisdom, we show that the area of an optimized quantum circuit is not dominated exclusively by error correction. Further, our adder evaluation shows that quantum carry-lookahead adders (QCLA) beat ripple-carry adders in ADCR, despite being larger and more complex. We conclude with what we believe is one of most accurate estimates of the area and latency required for 1024-bit Shor's factorization: 7659 mm2 for the smallest circuit and 6 x 108 seconds for the fastest circuit. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 3,866 |
Photonic chip based time-bin entanglement has attracted significant attention because of its potential for quantum communication and computation. Useful time-bin entanglement systems must be able to generate, manipulate and analyze entangled photons on a photonic chip for stable, scalable and reconfigurable operation. Here we report the first time-bin entanglement photonic chip that integrates time-bin generation, wavelength demultiplexing and entanglement analysis. A two-photon interference fringe with an 88.4% visibility is measured (without subtracting any noise), indicating the high performance of the chip. Our approach, based on a silicon nitride photonic circuit, which combines the low-loss characteristic of silica and tight integration features of silicon, paves the way for scalable real-world quantum information processors. | We demonstrate correlated photon pair generation in a double-stripe silicon nitride waveguide with coincidence-to-accidental ratio over 10 at pair generation rate of 186 kHz, indicating this structure may be useful for on-chip quantum light sources. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 3,867 |
Papers presented at the fourth annual meeting of the Society for Medical Decision Making are discussed in the context of a review of the rapidly evolving interdisciplinary field of medical decision making (MDM). Advocates claim that probabilistic MDM techniques will incorporate diagnostic information, treatment options and outcomes, patient preferences, societal ethics, and financial considerations into a rational framework for making decisions in the face of uncertainty. | This article highlights some observations made in the American Occupational Therapy Association/American Occupational Therapy Foundation Clinical Reasoning Study, an ethnographic study of 14 occupational therapists working in a large teaching hospital. Concepts and premises that frequently appear in the clinical reasoning in medicine literature are discussed and compared and contrasted to observations and interpretations made of the practice and reasoning strategies of the occupational therapists who were participants in the Clinical Reasoning Study. It is postulated that similarities in the reasoning strategies of the members of the two professions are a result of use of the scientific model that calls for hypothetical reasoning. Differences, it is proposed, are accounted for by the difference in the particular focus, goals, and tasks of the two professions and the nature of the practice in those arenas. Five hypotheses are proposed as questions for further research in clinical reasoning in occupational therapy. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,868 |
Qudits, multiple-level quantum systems, enable more efficient scaling of physical resources in quantum computing than qubits, but they are more difficult to control. Svetitsky et al. now experimentally demonstrate a simplifying technique that converts a four-level qudit into a pair of qubits. | We consider a general unitary operator acting on two qubits in a product state. We find the conditions such that the state of the qubits after the action is as entangled as possible. We also consider the possibility of using ancilla qubits to increase the entanglement. | The authors acknowledge the financial support of the Spanish Government through Project TEC2008-02606 and Project Quantum Optical Information Technology (QOIT), a CONSOLIDER-INGENIO 2010 Project; and also the Generalitat Valenciana through the PROMETEO research excellency award programme GVA PROMETEO 2008/092. | eng_Latn | 3,869 |
This paper introduces a Tele-Management system as a part of SmartUM which is a Ubiquitous Cloud Middleware for ubiquitous city (u-city). The cloud computing platform allows users to control remote devices. The users get data from a various kinds of remote sensors and scene images about the place of sensors from remote video cameras and control remote devices seeing the scene images of the remote place. Our cloud computing platform has context-awareness and can intelligently control the remote devices according to the circumstance scenario. We used ontology for the context aware intelligence processing. | In this paper, we introduce an unified ubiquitous middleware which supports an infrastructure to provide the ubiquitous convergence services by providing not only dynamic service discovery based on context-awareness but also variety of converged services in three applications such as environment management, traffic accident management and underground fire accident management. It is composed of three layers which support the unified efficient ubiquitous computing: context-aware computing layer(framework), ubiquitous core computing layer (framework), common interface layer(framework). Therefore, It has the multilayered architecture which makes applications or services used everywhere by providing the cooperative interacting computing environment among the layers. It can provide modularity and expansibility through the design of multi-hierarchical structure, and reduces complicatedness of the system and increases reusability and flexibility of components. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,870 |
In this paper, we develop a virtual link priority mapping (LPM) approach and a virtual node priority mapping (NPM) approach to improve the energy efficiency and to reduce the spectrum usage over the converged flexible bandwidth optical networks and data centers. For comparison, the lower bound of the virtual optical network mapping is used for the benchmark solutions. Simulation results show that the LPM approach achieves the better performance in terms of power consumption, energy efficiency, spectrum usage, and the number of regenerators compared to the NPM approach. | A profit-maximized approach is proposed to reduce the network cost of virtual optical networks (VONs) mapping by considering the link importance degree. Simulation results show that the proposed approach achieves better profits than traditional mapping approaches. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,871 |
A multi-dimensional modulation scheme in inter-satellite quantum communication based on pulse position modulation and polarization encoding is put forward and designed. By this way we can send additional classical signal simultaneously when transmitting quantum signal. The basic principle of multi-dimensional modulation scheme is introduced. Simulation experiment is performed using Optisystem and Matlab simultaneously. The binary sequence before modulation and that after demodulation are compared and analyzed. The error bit rate, eye diagram and quality factor of classical optical date are obtained. Stabilities of classical optical signal during the transmission are tested. The results show that this multi-dimensional modulation scheme can decrease the numbers of information channels needed, increase information transmission efficiency and reduce the demands for power load systematic complexity in communication terminals. The proposed coexistence system is confirmed to be effective and applicable. | When elementary quantum systems, such as polarized photons, are used to transmit digital information, the uncertainty principle gives rise to novel cryptographic phenomena unachievable with traditional transmission media, e.g. a communications channel on which it is impossible in principle to eavesdrop without a high probability of disturbing the transmission in such a way as to be detected. Such a quantum channel can be used in conjunction with ordinary insecure classical channels to distribute random key information between two users with the assurance that it remains unknown to anyone else, even when the users share no secret information initially. We also present a protocol for coin-tossing by exchange of quantum messages, which is secure against traditional kinds of cheating, even by an opponent with unlimited computing power, but ironically can be subverted by use of a still subtler quantum phenomenon, the Einstein-Podolsky-Rosen paradox. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 3,872 |
Digital holographic microscopy (DHM) is a quantitative phase imaging (QPI) modality, which retrieves 3D object phase information. The quantification of subcellular features within the object is possible. Its single-shot hologram recording feature makes it suitable for real-time imaging applications. This paper discusses QPI capability of LED-based digital inline holographic microscopy (LDHM), which has gained much attention for its portability, cost-effective features. However, the twin image artifact is present in the inline setup. Though several twin image reduction and elimination methods are developed, the exact phase quantification is always a challenge. Original phase information may be lost after elimination of twin image. There is always a trade-off between twin-image elimination and QPI of inline microscopy setup. This paper discusses the QPI capability of LDHM in comparison with the conventional off-axis DHM. Further, the results of phase objects using both the methods are studied. | In this paper we review the major contributions over the past sixty years to the subject of twin reduction and twin removal in holography. We show that this collective work may be broken down into a number of categories including the well known techniques of off-axis holography and phase retrieval. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,873 |
We present a small network for the testing of the entanglement of two ballistic electron waveguide qubits. The network produces different output conditional on the presence or absence of entanglement. The structure of the network allows for the determination of successful entanglement operations through the measurement of the output of a single qubit. We also present a simple model of a dynamic Coulomb-like interaction and use it to describe some characteristics of a proposed scheme for the entanglement of qubits in ballistic electron waveguides. | We consider a system of two parallel quantum waveguides that coupled via a coupling window. The coupled waveguide system is exposed to an external magnetic field and coupled to a photon field. We take into account both the electron–electron and electron–photon interactions in the system and an exact diagonalization technique is used to treat these interactions. We investigate electron switching between the waveguides using external static magnetic field, side-dot gate, and quantized photon field. The role of the Coulomb interaction in electron switching is also presented. Furthermore, we show how a single photon can enhance electron transport between the waveguides where the photon is polarized in the same direction of electron motion. | A non-parametric framework for testing the existence of aggregates is developed. The framework is based on the notion of the maximum entropy formalism which is applied to model the size distribution of firms. The theory, once presented, is applied to the US banking industry in order to test for the existence 'of a consistent output-aggregate. The existence of an output-aggregate in banking can facilitate much of the empirical research in this industry and shed some light on the industry's long-run market structure. | eng_Latn | 3,874 |
Following a review of the physics of quantum decoherence, an instructive comparison is made between the mathematical description of qubit decoherence due to interaction with the environment, and certain aspects of the problem of Wigner's friend. | The exciting new field of quantum information science and technology is burgeoning with revolutionary new advances in the areas of quantum communication, quantum information processing, quantum computing, and quantum cryptography. Potential useful products of these advances include a wide variety of innovative qubit devices, ranging from quantum games and quantum teleporters to quantum computers and quantum robots. The major obstacle to the successful development of these devices is the phenomenon of quantum decoherence. This brief survey article gives reviews of a full gamut of potential qubit devices, alternating with expository discussions of the issue of quantum decoherence as it relates to the possible practical development of these devices. The qubit devices examined here include an interaction-free detector, a quantum key receiver, quantum games, various quantum gates, qubit entanglers, quantum dense coders, Bell-state analyzers, entanglement swappers, quantum teleporters, quantum repeaters, entangled atomic clocks, quantum copiers, various quantum computers, and quantum robots. | The physical form or design of a product is an unquestioned determinant of its marketplace success. A good design attracts consumers to a product, communicates to them, and adds value to the produc... | eng_Latn | 3,875 |
We present evidence that decoherence can produce a smooth quantum-to-classical transition in nonlinear dynamical systems. High-resolution tracking of quantum and classical evolutions reveals differences in expectation values of corresponding observables. Solutions of master equations demonstrate that decoherence destroys quantum interference in Wigner distributions and washes out fine structure in classical distributions, bringing the two closer together. Correspondence between quantum and classical expectation values is also reestablished. {copyright} {ital 1998} {ital The American Physical Society} | We explore the quantum-classical crossover of two coupled, identical, superconducting quantum interference device (SQUID) rings. The motivation for this work is based on a series of recent papers. In ~[1] we showed that the entanglement characteristics of chaotic and periodic (entrained) solutions of the Duffing oscillator differed significantly and that in the classical limit entanglement was preserved only in the chaotic-like solutions. However, Duffing oscillators are a highly idealised toy system. Motivated by a wish to explore more experimentally realisable systems we extended our work in [2,3] to an analysis of SQUID rings. In [3] we showed that the two systems share a common feature. That is, when the SQUID ring's trajectories appear to follow (semi) classical orbits entanglement persists. Our analysis in[3] was restricted to the quantum state diffusion unravelling of the master equation - representing unit efficiency heterodyne detection (or ambi-quadrature homodyne detection). Here we show that very similar behaviour occurs using the quantum jumps unravelling of the master equation. Quantum jumps represents a discontinuous photon counting measurement process. Hence, the results presented here imply that such persistent entanglement is independent of measurement process and that our results may well be quite general in nature. | Adolescent penetration into the labor market is a relatively new, and much understudied, phenomena. To date, limited empirical evidence suggests that the extensive employment of adolescents increases their offending. We bring together insights garnered from life-course criminology, which emphasizes the timing of transitional role changes; and economic sociology, which draws attention to the "social embeddedness" of development and decision-making. The objective is to test whether a youth's embeddedness within the labor market has deleterious consequences for the youth's behavior. Our results show that work embeddedness is positively related to delinquency, and that this effect is not accounted for by prior levels of delinquent involvement. These findings were replicated by use of a community sample. In total our findings suggest that being embedded in a work role as a teenager has general deleterious consequences for behavior. | eng_Latn | 3,876 |
This paper presents two approaches for the problem of multiple target tracking (MTT) and specifically people tracking. Both filters are based on sequential Monte Carlo methods (SMCM) and joint probability data association (JPDA). The filters have been implemented and tested on real data from a laser measurement system. Experiments show that both approaches are able to track multiple moving persons. A comparison of both filters is given and the advantages and disadvantages of the two approaches are presented. | This paper presents a method for moving-object tracking with in-vehicle 2D-laser range sensors (LRS). Since a sensing area of the LRS is limited in orientation, mobile robot is equipped with multi-LRS's for omnidirectional sensing. In order for moving-object tracking by multi-LRS's cooperation, the coordinate frames of the multi-LRS's are calibrated based on Kalman filter and chi-hypothesis testing. The moving-object tracking is achieved by Kalman filter, Covariance Intersection and the assignment algorithm based data association. A rule based track management system is embedded into the tracker in order to improve the tracking performance. The experimental result of three people tracking in indoor environments validates the proposed method. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,877 |
In a previously published paper Tijms and van der Duyn Schouten proposed a special-purpose policy iteration algorithm for optimal inspections and revisions in a maintenance system with partial information. In this paper we point out some shortcomings of this algorithm. We demonstrate that their algorithm, which operates on a class of control-limit rules, does not always lead to an optimal policy within that class, and present appropriate improvements. In doing so, we analyse some specific aspects of the policy iteration algorithm. | A critical factor that prevents optimal scheduling of maintenance interventions is the uncertainty regarding the current condition of the asset under consideration, as well as the rate at which deterioration takes place. However, current maintenance modeling and optimization techniques assume that the condition of the asset is either known, or assumed to have an exponential deterioration rate. In this paper, we present a novel approach to maintenance modeling that removes such assumptions. Here, we employ a Partially Observable Semi-Markov Decision Process (POSMDP) for optimizing maintenance decisions, where the condition of the asset is not fully observable, and decision epochs occur at times following any other type of distribution. This method enables a more realistic way of modeling asset deterioration and optimizing maintenance schedules. | challenge of this work is to re-define the concept of intelligent agent as a building block of social networks by presenting it as a physical particle with additional non-Newtonian properties. The proposed model of an intelligent agent described by a system of ODE coupled with their Liouville equation has been introduced and discussed. Following the Madelung equation that belongs to this class, non-Newtonian properties such as superposition, entanglement, and probability interference typical for quantum systems have been described. Special attention was paid to the capability to violate the second law of thermodynamics, which makes these systems neither Newtonian, nor quantum. It has been shown that the proposed model can be linked to mathematical models of livings as well as to models of AI. The model is presented in two modifications. The first one is illustrated by the discovery of a stochastic attractor approached by the social network; as an application, it was demonstrated that any statistics can be represented by an attractor of the solution to the corresponding system of ODE coupled with its Liouville equation. It was emphasized that evolution to the attractor reveals possible micro-mechanisms driving random events to the final distribution of the corresponding statistical law. Special attention is concentrated upon the power law and its dynamical interpretation: it is demonstrated that the underlying micro- dynamics supports a "violent reputation" of the power-law statistics. The second modification of the model of social network associated with a decision-making process and applied to solution of NP-complete problems known as being unsolvable neither by classical nor by quantum algorithms. The approach is illustrated by solving a search in unsorted database in polynomial time by resonance between external force representing the address of a required item and the response representing the location of this item. | eng_Latn | 3,878 |
The Electrochemical Machining (ECM) is widely used in machining variety of components used in aerospace, automotive, defense & medical applications. Due to low machining accuracy ECM is yet to be a best alternative process. This paper presents experimental investigation of PECM parameters such as voltage, feed rate, and pulse on time, duty cycle on MRR. Keeping pressure constant, Taguchi‟s orthogonal array L9 has been effectively used to study the effect of independent process parameters. The results show PECM has enhanced MRR. The experimental results were analyzed using analysis of variance (ANOVA) method and by plotting various graphs. | This paper presents the concept and prototype of a computer aided engineering (CAE) system that can be used to solve different task of electrochemical machining (ECM), such as: tool-electrode design, selection of optimal machining variant and input machining parameters optimization. The system uses computer simulation software that was developed for various kinds of ECM operations like: electrochemical (EC) sinking, EC milling, EC smoothing, ECM-CNC with a universal electrode and numerically controlled electrode movement, etc. The results of computer simulation of different ECM processes and results of experimental verifications are also presented in the paper. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,879 |
The purpose of this work is to investigate the material and device properties of GST-based PCM by studying relaxation oscillations [1, 2]. Our experimental results relate oscillation characteristics to applied voltage, load resistance and device thickness. | We survey progress in the PCM field over the past five years, ranging from large-scale PCM demonstrations to materials improvements for high–temperature retention and faster switching. Both materials and new cell designs that support lower-power switching are discussed, as well as higher reliability for long cycling endurance. Two paths towards higher density are discussed: through 3D integration by the combination of PCM and 3D-capable access devices, and through multiple bits per cell, by understanding and managing resistance drift caused by structural relaxation of the amorphous phase. We also briefly survey work in the nascent field of brain-inspired neuromorphic systems that use PCM to implement non-Von Neumann computing. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,880 |
Entangled light can provide a seminal improvement in resolution sensitivity even without achieving Heisenberg limit in a single channel. In this paper, based on the back-of-the-envelope type calculations, I demonstrate an alternative path to space based long-arm interferometer. Its advantage with respect to LISA is that it does not require complex satellites with many active components to achieve similar resolution. | Non-classical states of light find applications in enhancing the performance of optical interferometric experiments, with notable example of gravitational wave-detectors. Still, the presence of decoherence hinders significantly the performance of quantum-enhanced protocols. In this review, we summarize the developments of quantum metrology with particular focus on optical interferometry and derive fundamental bounds on achievable quantum-enhanced precision in optical interferometry taking into account the most relevant decoherence processes including: phase diffusion, losses and imperfect interferometric visibility. We introduce all the necessary tools of quantum optics as well as quantum estimation theory required to derive the bounds. We also discuss the practical attainability of the bounds derived and stress in particular that the techniques of quantum-enhanced interferometry which are being implemented in modern gravitational wave detectors are close to the optimal ones. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 3,881 |
We discuss the potential of long, thin “continuum” robots to enable new and more effective approaches to remote inspection. Resembling robotic cables, this new class of robots can enter and explore congested and potentially unstable environments, sending back information from sensors at their tips. This capability is of particular value in search operations in disaster relief situations. We illustrate the potential using a thin continuum robot in representative tasks. | Bringing a new robot to market is an exciting venture. When that robot is a new type of robot the venture takes on new proportions – it becomes an adventure. Dr Rob Buckingham, managing director of OCRobotics Ltd, describes the principles of a new snake arm robot that has applications in a number of industries including aerospace (engines and airframes), nuclear, space and surgery as well as a whole range of general inspection and maintenance tasks. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,882 |
We show near optimal bounds on the worst case quantum communication of single-shot entanglement-assisted one-way quantum communication protocols for the {\em quantum state redistribution} task and for the sub-tasks {\em quantum state splitting} and {\em quantum state merging}. Our bounds are tighter than previously known best bounds for the latter two sub-tasks. A key technical tool that we use is a {\em convex-split} lemma which may be of independent interest. | The Quantum Reverse Shannon Theorem states that any quantum channel can be simulated by an unlimited amount of shared entanglement and an amount of classical communication equal to the channel’s entanglement assisted classical capacity. In this paper, we provide a new proof of this theorem, which has previously been proved by Bennett, Devetak, Harrow, Shor, and Winter. Our proof has a clear structure being based on two recent information-theoretic results: one-shot Quantum State Merging and the Post-Selection Technique for quantum channels. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 3,883 |
This work proposes a quantum dialogue (QD) based on single photons, which not only allows two communicants to exchange their secret messages simultaneously via a one-step quantum transmission but also can confirm the message integrity. Moreover, the proposed QD protocol is free from information leakage. Compared with the previous QDs, the proposed QD protocol is more efficient. It is also secure against several well-known attacks. | In this paper, we present an innovative quantum dialogue protocol for multiple users to get private information from each other without leaking any information. In our protocol, a semi-honest third party (TP) is introduced to assist multiple participants for exchanging their private information. Specifically, exploiting multi-particle entangled GHZ states as the information carriers, we investigate how to implement the multi-party quantum dialogue protocol and perform the equivalence comparison. We also analyze the security of our protocol. Compared with previous quantum dialogue protocols, our protocol is more flexible and more efficient. | The oxidative polymorphism of debrisoquine (DBQ) has been determined in 89 patients with colo-rectal cancer and in 556 normal control subjects. Four patients and 34 controls, with a metabolic ratio >12.6, were classified as poor metabolisers of DBQ (n.s.). | eng_Latn | 3,884 |
The generalized rotating-wave approximation with counter-rotating interactions has been applied to a biased qubit-oscillator system. Analytical expressions are explicitly given for all eigenvalues and eigenstates. For a flux qubit coupled to superconducting oscillators, spectra calculated by our approach are in excellent agreement with experiment. Calculated energy levels for a variety of biases also agree well with those obtained via exact diagonalization for a wide range of coupling strengths. Dynamics of the qubit has also been examined, and results lend further support to the validity of the analytical approximation employed here. Our approach can be readily implemented and applied to superconducting qubit-oscillator experiments conducted currently and in the near future with a biased qubit and for all accessible coupling strengths. | Einstein's Theory of Atom-Radiation Interaction.- Atom-Field Interaction: Semiclassical Approach.- Quantization of the Electromagnetic Field.- States of the Electromagnetic Field I.- States of the Electromagnetic Field II.- Quantum Theory of Coherence.- Phase Space Description.- Atom-Field Interaction.- System-Reservoir Interactions.- Resonance Fluorescence.- Quantum Laser Theory: Master Equation Approach.- Quantum Laser Theory: Langevin Approach.- Quantum Noise Reduction 1.- Quantum Noise Reduction 2.- Quantum Phase.- Quantum Trajectories.- Atom Optics.- Measurements, Quantum Limits and All That.- Trapped Ions.- Decoherence.- Quantum Bits, Entanglement and Applications.- Quantum Cloning and Processing. | Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights. | eng_Latn | 3,885 |
This paper surveys recent advances in the monetary transmission mechanism (MTM). In particular, while laying out the functioning of the separate channels in the MTM, special attention is paid to exploring possible interrelations between different channels through which they may amplify or attenuate each others’ impact on prices and the real economy. We take stock of the empirical findings especially as they relate to countries in Central and Eastern Europe, and compare them to results reported for industrialised countries, especially for the euro area. We highlight potential pitfalls in the literature and assess the relative importance and potential development of the different channels. | This paper investigates replacing separate taxation by consolidation and formulary apportionment in a Bottom-up Federation, when a multijurisdictional firm is mobile in various respects. The reform is decided cooperatively by all the jurisdictions or by some of them, while tax rates remain within the competence of each jurisdiction. The paper sets forth the conditions for the reform to be social welfare enhancing, while not increasing tax competition. Among them, the formula should emphasize criteria that the Multijurisdictional Enterprise cannot easily manipulate and the consolidating area should protect its capacity to levy taxes by adopting a crediting system, possibly extended to accrued capital gains, vis-a-vis the rest of the world. Policy conclusions are suggested accordingly. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,886 |
By only specifying the conditional mean and variance functions of the response variable given covariates, the quasi-likelihood can produce valid semiparametric inference for regression parameter in generalized linear models (GLMs). However, in many studies, auxiliary information is available as moment restrictions of the marginal distribution of the response variable and covariates. We propose the combined quasi and empirical likelihood (CQEL) to incorporate such auxiliary information to improve the efficiency of parameter estimation of the quasi-likelihood in GLMs with missing responses. We show that, when assuming responses are missing at random (MAR), the CQEL estimator achieves better efficiency than the maximum quasi-likelihood (MQL) estimator due to utilization of the auxiliary information. When there is no auxiliary information, we show that the CQEL estimator of the mean response is more efficient than the existing imputation estimators. Based on the asymptotic property of the CQEL estimator, we also develop Wilks' type tests and corresponding confidence regions for the regression parameter and mean response. The merits of the CQEL are further illustrated through simulation studies. | In this paper, we propose an empirical likelihood-based weighted estimator of regression parameter in quantile regression model with nonignorable missing covariates. The proposed estimator is computationally simple and achieves semiparametric efficiency if the probability of missingness on the fully observed variables is correctly specified. The efficiency gain of the proposed estimator over the complete-case-analysis estimator is quantified theoretically and illustrated via simulation and a real data application. | Perfect Quantum Cloning Machines (QCM) would allow to use quantum nonlocality for arbitrary fast signaling. However perfect QCM cannot exist. We derive a bound on the fidelity of QCM compatible with the no-signaling constraint. This bound equals the fidelity of the Bu\v{z}ek-Hillery QCM. | eng_Latn | 3,887 |
Due to decoherence, realistic quantum systems inevitably interact with the environment when quantum information is processed, which causes the loss of quantum properties. As a fundamental issue of quantum properties, quantum correlations have attracted a lot of interests in recent years. Because of the importance of high dimensional systems in quantum information, in this work, we study the quantum correlations affected by the Markovian environment by considering the quantum correlations of qutrit-qutrit quantum systems measured by the negativity and the geometric discord. The local noise channels covered in this work include dephasing, trit-flip, trit-phase-flip, and depolarising channels. We have also investigated the cases where the local decoherence channels of two sides are identical and non-identical. | It has been proven that the quantum discord is a more general tool to capture non-classical correlation than quantum entanglement, because there is a non-zero quantum discord in several mixed states that could not be measured by quantum entanglement. But because of optimization part in formulating quantum discord, it is very difficult and nearly impossible to find quantum discord for some quantum states. So people proposed geometric quantum discord, which in a bipartite state could be describe as the distance of the states from the closest zero-discord state. To understand better geometric quantum discord, this paper is devoted to compare it with quantum discord and measurement induced non-locality that is in some sense dual to the geometric quantum discord. As studying the quantum correlation experimentally is one of the important thing in quantum information processing, so as our example for illustrating the difference of geometric quantum discord, quantum discord and measurement induced non-locality, our quantum system is a dimer (two spin-1/2 particles) in multiple quantum nuclear magnetic resonance. | Between 1997 and 2012, Paraguay achieved not only remarkable improvements in child nutrition, but also a surprising elimination of the rural-urban differential in child height-for-age Z score (HAZ) and stunting. Our decomposition analysis, applied to four rounds of Paraguayan National Household Surveys, allows us to directly infer not only the contributions of changes in determinants of child nutritional status to the improvements in child nutritional status in rural and urban areas, but also their contribution to closing the rural-urban gap. We find that while common determinants of child nutritional status such as income, maternal education, sanitation, and access to piped water are strongly associated with improvements in child nutrition, they have contributed little to reducing the rural-urban gap (10%, p < 0.05). Improvements in health care utilization, family planning, and demographics have been the main drivers in closing the rural-urban gap in child nutritional status in Paraguay (32%, p < 0.05). The results highlight the potential need for multipronged nutritional strategies that consider the distinct needs of rural and urban communities. | eng_Latn | 3,888 |
We present a framework for studying bosonic non-Gaussian channels of continuous-variable systems. Our emphasis is on a class of channels that we call photon-added Gaussian channels which are experimentally viable with current quantum-optical technologies. A strong motivation for considering these channels is the fact that it is compulsory to go beyond the Gaussian domain for numerous tasks in continuous-variable quantum information processing like entanglement distillation from Gaussian states and universal quantum computation. The single-mode photon-added channels we consider are obtained by using two-mode beamsplitters and squeeze operators with photon addition applied to the ancilla ports giving rise to families of non-Gaussian channels. For each such channel, we derive its operator-sum representation, indispensable in the present context. We observe that these channels are Fock-preserving (coherence non-generating). We then report two novel examples of activation using our scheme of photon addition, that of nonclassicality at outputs of channels that would otherwise output only classical states, and of both the quantum and private capacities, hinting at far-reaching applications for quantum-optical communication. Further, we see that noisy Gaussian channels can be expressed as a convex mixture of these non-Gaussian channels. We also present other physical and information-theoretic properties of these channels. | We introduce a novel measure to quantify the non-Gaussian character of a quantum state: the quantum relative entropy between the state under examination and a reference Gaussian state. We analyze in details the properties of our measure and illustrate its relationships with relevant quantities in quantum information as the Holevo bound and the conditional entropy; in particular a necessary condition for the Gaussian character of a quantum channel is also derived. The evolution of non-Gaussianity (nonG) is analyzedfor quantum states undergoing conditional Gaussification towards twin-beam and de-Gaussification driven by Kerr interaction. Our analysis allows to assess nonG as a resource for quantum information and, in turn, to evaluate the performances of Gaussification and de-Gaussification protocols. | We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero. | eng_Latn | 3,889 |
We stand by our findings in Phys. Rev A. 96, 022126 (2017). In addition to refuting the invalid objections raised by Peleg and Vaidman, we report a retrocausation problem inherent in Vaidman's definition of the past of a quantum particle. | We analyze Vaidman's three-path interferometer with weak path marking [Phys. Rev. A 87, 052104 (2013)] and find that common sense yields correct statements about the particle's path through the interferometer. This disagrees with the original claim that the particles have discontinuous trajectories at odds with common sense. In our analysis, "the particle's path" has operational meaning as acquired by a path-discriminating measurement. For a quantum-mechanical experimental demonstration of the case, one should perform a single-photon version of the experiment by Danan et al. [Phys. Rev. Lett. 111, 240402 (2013)] with unambiguous path discrimination. We present a detailed proposal for such an experiment. | The exciting new field of quantum information science and technology is burgeoning with revolutionary new advances in the areas of quantum communication, quantum information processing, quantum computing, and quantum cryptography. Potential useful products of these advances include a wide variety of innovative qubit devices, ranging from quantum games and quantum teleporters to quantum computers and quantum robots. The major obstacle to the successful development of these devices is the phenomenon of quantum decoherence. This brief survey article gives reviews of a full gamut of potential qubit devices, alternating with expository discussions of the issue of quantum decoherence as it relates to the possible practical development of these devices. The qubit devices examined here include an interaction-free detector, a quantum key receiver, quantum games, various quantum gates, qubit entanglers, quantum dense coders, Bell-state analyzers, entanglement swappers, quantum teleporters, quantum repeaters, entangled atomic clocks, quantum copiers, various quantum computers, and quantum robots. | eng_Latn | 3,890 |
Quantum simulations of a fiber squeezing experiment | We report on the excellent agreement of a first-principles, quantum dynamical simulation with the experimentally measured results of a fiber squeezer using intense, ultra-short laser pulses. | In applying reinforcement learning to continuous space problems, discretization or redefinition of the learning space can be a promising approach. Several methods and algorithms have been introduced to learning agents to respond to this problem. In our previous study, we introduced an FCCM clustering technique into Q-learning (called QL-FCCM) and its transfer learning in the Markov process. Since we could not respond to complicated environments like a non-Markov process, in this study, we propose a method in which an agent updates his Q-table by changing the trade-off ratio, Q-learning and QL-FCCM, based on the damping ratio. We conducted numerical experiments of the single pendulum standing problem and our model resulted in a smooth learning process. | eng_Latn | 3,891 |
Low-loss transmission of quantum bits by wavelets | Only one Mach-Zehnder interferometer is used in the proposed quantum bit distribution system where the two arms composing the Mach-Zehnder interferometer have been used as the transmission line. The loss of the photons due to absorption will decrease and the wavelets composing the photon are expected to transmit longer distance. The optical cable which contains many fiber belts which contain many fibers in parallel that is possible to make a Mach-Zehnder ::: interferometer with its two arms as long as possible. This transmission system uses only two couplers and physically ensures transmission security. | A purely deterministic approach to the LMS (least mean square)-Newton algorithm for adaptive filters is proposed. A QR-decomposition method for solving the algorithm's equations is described. Simulations using fixed-point arithmetic are provided, which confirm the good numerical characteristics of the method. A variable convergence factor is also discussed which is optimum in the sense that the output a posteriori error is zero. > | eng_Latn | 3,892 |
Amplitude phase-space model for quantum mechanics | We show that there is a close relationship between quantum mechanics and ordinary probability theory. The main difference is that in quantum mechanics the probability is computed in terms of an amplitude function, while in probability theory a probability distribution is used. Applying this idea, we then construct an amplitude model for quantum mechanics on phase space. In this model, states are represented by amplitude functions and observables are represented by functions on phase space. If we now postulate a conjugation condition, the model provides the same predictions as conventional quantum mechanics. In particular, we obtain the usual quantum marginal probabilities, conditional probabilities and expectations. The commutation relations and uncertainty principle also follow. Moreover Schrodinger's equation is shown to be an averaged version of Hamilton's equation in classical mechanics. | Nonlinear branches, such as saturable reactors, can generate harmonics and consequently increase the EMTP time-domain simulation time before the actual distorted steady-state is reached. This is an important initialization problem for transient analysis studies performed in steady-state operating conditions. This paper presents the implementation of a new method in the EMTP for initializing time-domain simulations. It is based on frequency domain steady-state calculations including harmonics from nonlinear branch functions. > | eng_Latn | 3,893 |
S-Matrix for AdS from General Boundary QFT | The General Boundary Formulation (GBF) is a new framework for studying quantum theories. After concise overviews of the GBF and Schrodinger-Feynman quantization we apply the GBF to resolve a well known problem on Anti-deSitter spacetime where due to the lack of temporally asymptotic free states the usual S-matrix cannot be defined. We construct a different type of S-matrix plus propagators for free and interacting real Klein-Gordon theory. | We consider the throughput performance of ARQ in interfering channels, where the signal of interest as well as the interferers are subject to independent distributed Nakagami-m block fading. The key contribution is the derivation of closedform expressions for the rate-maximized throughput. For this purpose, we employ the powerful parameterization approach from [1], allowing the problem to be solved exactly in a closedform. We also consider the scaled-power, and the interferencelimited, case. | eng_Latn | 3,894 |
Simulating B92 Protocol in Depolarizing Channel | The B92 protocol is a two quantum states protocol in quantum cryptography. It is one of the basic models of quantum key distribution (QKD) in depolarizing channel. We simulate the rate of secure key distribution in depolarizing channel on a classical computer with the method of event-by-event simulation.After the event-by-event simulation of quantum transmission, data reconciliation and privacy amplification are done to obtain the secure key. We give the simulation results of private classical capacity with respect to the depolarizing coefficient. | The paper examines an array of issues regarding the development of standard through both consensus and non-consensus processes. Key areas of inquiry included the growing importance of market-driven consortia (MDCs), potential benefits and problems from use of non-consensus processes, ANSI's review procedures for determining consensus, and OMB Circular A-119 which implements federal policy regarding regulatory use of voluntary standards. The white paper then applied the broad discussions of standards issues to the specific instance of the development, at the FCC's request, of cable modem standards by CableLabs, an MDC organization. | eng_Latn | 3,895 |
Geometro-Stochastic Quantization and Quantum Geometry | The most basic features of the geometro-stochastic method of quantization are outlined in the nonrelativistic and special relativistic regime. Their adaptation to the general relativistic regime leads to the replacement of the classical frame bundles, which underlie the formulation of parallel transport in classical general relativity, with quantum frame bundles. This gives rise to quantum geometries for quantum field theory in curved spacetime, in which quantum frames take over the role played by complete sets of observables in conventional quantum theory. The ensuing quantum-geometric mode of propagation in general relativistic quantum bundles is implemented by path integration methods based on parallel transport along broken paths consisting of arcs of geodesics of the Levi-Civita connection, and can be further extrapolated to a geometric formulation of quantum gravity. | Results on performance statistics of a single server queue fed by a traffic stream which is modeled by a discrete time Gaussian process are presented. Because such a process can capture the full range of second-order statistics and is closed under superposition, it is a good model for correlated asynchronous transfer mode (ATM) statistical multiplexed traffic. The results include simple formulae for cell loss which can be applied to connection admission control for broadband integrated services digital networks (B-ISDNs). > | eng_Latn | 3,896 |
This is page 1 Printer: Opaque this Quantum Monte Carlo Methods for Strongly Correlated Electron Systems | We review some of the recent development in quantum Monte Carlo (QMC) methods for models of strongly correlated electron systems. QMC is a promising general theoretical tool to study many-body systems, and has been widely applied in areas spanning condensed-matter, high-energy, and nuclear physics. Recent progress has included two new methods, the ground-state and finite-temperature constrained path Monte Carlo methods. These methods significantly improve the capability of numerical approaches to lattice models of correlated electron systems. They allow calculations without any decay of the sign, making possible calculations for large system sizes and low temperatures. The methods are approximate. Benchmark calculations show that accurate results on energy and correlation functions can be obtained. This chapter gives a pedagogical introduction to quantum Monte Carlo, with a focus on the constrained path Monte Carlo methods. | A geometric approach in the design of codebooks for OR frequency-hopping multiple-access (FHMA) channels is developed by treating a signal matrix as a finite set of distinct points. The relationship among the parameters of an interference-free j-distinguishable-point codebook, j>or=1, is established by using coordinate-free arguments. Geometry induced by such a codebook is characterized, and the design of a well-structured j-distinguishable-point codebook is related to a block design problem. It is shown that a well-structured 1-distinguishable-point codebook implies the axiom system of a finite affine plane. > | eng_Latn | 3,897 |
the feasibility of a global observation and analysis experiment, | Process for preparing 5-fluoro-2-methyl-1-(p-methylsulfinylbenzylidene)-indenyl-3-acetic acid, by reacting 5-fluoro-2-methylindene-1,3-dione-3,3'-o-ethylene ketal with a p-methylsulfinylbenzyl compound, hydrolysis, and subsequent reaction with a malonic acid ester. | In this paper we consider the classical capacities of quantum-classical channels corresponding to measurement of observables. Special attention is paid to the case of continuous observables. We give the formulas for unassisted and entanglement-assisted classical capacities $C,C_{ea}$ and consider some explicitly solvable cases which give simple examples of entanglement-breaking channels with $C<C_{ea}.$ We also elaborate on the ensemble-observable duality to show that $C_{ea}$ for the measurement channel is related to the $\chi$-quantity for the dual ensemble in the same way as $C$ is related to the accessible information. This provides both accessible information and the $\chi$-quantity for the quantum ensembles dual to our examples. | eng_Latn | 3,898 |
Non-Markovian quantum state diffusion for an open quantum system in fermionic environments | Non-Markovian quantum state diffusion (NMQSD) provides a powerful approach to the dynamics of an open quantum system in bosonic environments. Here we develop an NMQSD method to study the open quantum system in fermionic environments. This problem involves anticommutative noise functions (i.e., Grassmann variables) that are intrinsically different from the noise functions of bosonic baths. We obtain the NMQSD equation for quantum states of the system and the non-Markovian master equation. Moreover, we apply this NMQSD method to single and double quantum-dot systems. | In this paper, a linear-quadratic leader-follower (LQLF) differential game is considered, where the game system is governed by a mean-field stochastic differential equation (MF-SDE). By stochastic maximum principle, the optimal solution to the LF stochastic differential game is expressed as a feedback form of the state and its mean with the aid of two systems of Riccati equations. | eng_Latn | 3,899 |
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