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many factors influence biomolecules binding, and its assessment constitutes an elusive challenge in computational structural biology. in this respect, the evaluation of shape complementarity at molecular interfaces is one of the main factors to be considered. we focus on the particular case of antibody - antigen complexes to quantify the complementarities occurring at molecular interfaces. we relied on a method we recently developed, which employs the 2d zernike descriptors, to characterize investigated regions with an ordered set of numbers summarizing the local shape properties. collected a structural dataset of antibody - antigen complexes, we applied this method and we statistically distinguished, in terms of shape complementarity, pairs of interacting regions from non - interacting ones. thus, we set up a novel computational strategy based on \ textit { in - silico } mutagenesis of antibody binding site residues. we developed a monte carlo procedure to increase the shape complementarity between the antibody paratope and a given epitope on a target protein surface. we applied our protocol against several molecular targets in sars - cov - 2 spike protein, known to be indispensable for viral cell invasion. we, therefore, optimized the shape of template antibodies for the interaction with such regions. as the last step of our procedure, we performed an independent molecular docking validation of the results of our monte carlo simulations.
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arxiv:2107.07295
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the recently found non - critical open string theories is reviewed. these open strings, noncommutative open string theories ( ncos ), arise as consistent quantum theories describing the low energy theory of d - branes in a background electric b - field in the critical limit. focusing on the d3 - brane case, we construct the most general ( 3 + 1 ) ncos, which is described by four parameters. we study s and t - dualities of these theories and argue the existence of a u - duality group.
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arxiv:hep-th/0101045
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we consider theoretically the transport through the double quantum dot structure of the recent experiment of c. payette { \ it et al. } [ phys. rev. lett. { \ bf 102 }, 026808 ( 2009 ) ] and calculate stationary current and shotnoise. three - level mixing gives rise to a pronounced current suppression effect, the character of which charges markedly with bias direction. we discuss these results in connexion with the dark states of coherent population trapping in quantum dots.
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arxiv:0908.3935
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for continuously orbit equivalent one - sided topological markov shifts $ ( x _ a, \ sigma _ a ) $ and $ ( x _ b, \ sigma _ b ) $, their eventually periodic points and cocycle functions are studied. as a result we directly construct an isomorphism between their ordered cohomology groups $ ( \ bar { h } ^ a, \ bar { h } ^ a _ + ) $ and $ ( \ bar { h } ^ b, \ bar { h } ^ b _ + ) $. we also show that the cocycle functions for the continuous orbit equivalences give rise to positive elements of the ordered cohomology, so that the the zeta functions of continuously orbit equivalent topological markov shifts are related. the set of borel measures is shown to be invariant under continuous orbit equivalence of one - sided topological markov shifts.
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arxiv:1403.0719
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hex - p is a probe - class mission concept that will combine high spatial resolution x - ray imaging ( < 10 " fwhm ) and broad spectral coverage ( 0. 2 - 80 kev ) with an effective area far superior to current facilities ( including xmm - newton and nustar ) to enable revolutionary new insights into a variety of important astrophysical problems. with the recent discoveries of over 40 ultra - high - energy gamma - ray sources ( detected above 100 tev ) and neutrino emission in the galactic plane, we have entered a new era of multi - messenger astrophysics facing the exciting reality of galactic pevatrons. in the next decade, as more galactic pevatrons and tev gamma - ray sources are expected to be discovered, the identification of their acceleration and emission mechanisms will be the most pressing issue in both particle and high - energy astrophysics. in this paper, along with its companion papers ( reynolds et al. 2023, mori et al. 2023 ), we will present that hex - p is uniquely suited to address important problems in various cosmic - ray accelerators, including galactic pevatrons, through investigating synchrotron x - ray emission of tev - pev electrons produced by both leptonic and hadronic processes.
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arxiv:2311.04851
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we report anomalous hall effect ( ahe ) in single crystals of quasi - two - dimensional fe $ _ { 3 - x } $ gete $ _ 2 $ ( $ x \ approx 0. 36 $ ) ferromagnet grown by the flux method which induces defects on fe site and bad metallic resistivity. fe k - edge x - ray absorption spectroscopy was measured to provide information on local atomic environment in such crystals. the dc and ac magnetic susceptibility measurements indicate a second - stage transition below 119 k in addition to the paramagnetic to ferromagnetic transition at 153 k. a linear scaling behavior between the modified anomalous hall resistivity $ \ rho _ { xy } / \ mu _ 0h _ { eff } $ and longitudinal resistivity $ \ rho _ { xx } ^ 2m / \ mu _ 0h _ { eff } $ implies that the ahe in fe $ _ { 3 - x } $ gete $ _ 2 $ should be dominated by the intrinsic karplus - luttinger mechanism rather than the extrinsic skew - scattering and side - jump mechanisms. the observed deviation in the linear - m hall conductivity $ \ sigma _ { xy } ^ a $ below 30 k is in line with its transport characteristic at low temperatures, implying the scattering of conduction electrons due to magnetic disorder and the evolution of the fermi surface induced by possible spin - reorientation transition.
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arxiv:1804.06392
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recent measurements of $ r _ { d ^ * } $ have reduced tension with the standard model prediction. taking all the present data into account, we obtain the values of the wilson coefficients of each new physics four - fermion operator of a given lorentz structure. we find that the combined data rule out most of the solutions based on scalar / pseudoscalar operators. by studying the inter - relations between different solutions, we find that there are only four allowed solutions, which are based on operators with $ ( v - a ) $, linear combination of $ ( v - a ) $ and $ ( v + a ) $, tensor and linear combination of scalar / pseudoscalar and tensor structure. we demonstrate that the need for new physics is driven by those measurement of $ r _ d $ and $ r _ { d ^ * } $ where the $ \ tau $ lepton is not studied. further, we show that new physics only in $ b \ rightarrow c \, \ mu \, \ bar { \ nu } $ is not compatible with the full set of observables in the decays $ b \ rightarrow dl \ bar { \ nu } $ and $ b \ rightarrow d ^ * l \ bar { \ nu } $.
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arxiv:1710.04127
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we study theoretically the lifetimes of attractive and repulsive fermi polarons, as well as the molecule at finite momentum in three dimensions. to this end, we develop a new technique that allows for the computation of green ' s functions in the whole complex frequency plane using exact analytical continuation within the functional renormalization group. the improved numerical stability and reduced computational cost of this method yield access to previously inaccessible momentum - dependent quasiparticle properties of low - lying excited states. while conventional approaches like the non - selfconsistent $ t $ - matrix approximation method cannot determine these lifetimes, we are able to find the momentum - dependent lifetime at different interaction strengths of both the attractive and repulsive polaron as well as the molecule. at weak coupling our results confirm predictions made from effective fermi liquid theory regarding the decay of the attractive polaron, and we demonstrate that fermi liquid - like behavior extends far into the strong - coupling regime where attractive polaron and molecule exhibit a $ p ^ 4 $ momentum scaling in their decay widths. our results offer an intriguing insight into the momentum - dependent quasiparticle properties of the fermi polaron problem, which can be measured using techniques such as raman transfer and ramsey interferometry.
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arxiv:2312.05318
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this paper formulates a conjectural description of of the space of weightless functions ( see \ cite { bk } ) and raises a question about a possibility of extending such a description in a more general context.
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arxiv:2502.01230
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pulsed electron paramagnetic resonance spectroscopy of the photoexcited, metastable triplet state of the oxygen - vacancy center in silicon reveals that the lifetime of the ms = \ pm1 sub - levels differ significantly from that of the ms = 0 state. we exploit this significant difference in decay rates to the ground singlet state to achieve nearly ~ 100 % electron spin polarization within the triplet. we further demonstrate the transfer of a coherent state of the triplet electron spin to, and from, a hyperfine - coupled, nearest - neighbor 29si nuclear spin. we measure the coherence time of the 29 si nuclear spin employed in this operation and find it to be unaffected by the presence of the triplet electron spin and equal to the bulk value measured by nuclear magnetic resonance.
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arxiv:1111.1344
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solved by reverse engineering is the need to support ( maintenance and supply for continuous operation ) existing legacy devices that are no longer supported by their original equipment manufacturer. the problem is particularly critical in military operations. product security analysis. that examines how a product works by determining the specifications of its components and estimate costs and identifies potential patent infringement. also part of product security analysis is acquiring sensitive data by disassembling and analyzing the design of a system component. another intent may be to remove copy protection or to circumvent access restrictions. competitive technical intelligence. that is to understand what one ' s competitor is actually doing, rather than what it says that it is doing. saving money. finding out what a piece of electronics can do may spare a user from purchasing a separate product. repurposing. obsolete objects are then reused in a different - but - useful manner. design. production and design companies applied reverse engineering to practical craft - based manufacturing process. the companies can work on " historical " manufacturing collections through 3d scanning, 3d re - modeling and re - design. in 2013 italian manufactures baldi and savio firmino together with university of florence optimized their innovation, design, and production processes. = = common uses = = = = = machines = = = as computer - aided design ( cad ) has become more popular, reverse engineering has become a viable method to create a 3d virtual model of an existing physical part for use in 3d cad, cam, cae, or other software. the reverse - engineering process involves measuring an object and then reconstructing it as a 3d model. the physical object can be measured using 3d scanning technologies like cmms, laser scanners, structured light digitizers, or industrial ct scanning ( computed tomography ). the measured data alone, usually represented as a point cloud, lacks topological information and design intent. the former may be recovered by converting the point cloud to a triangular - faced mesh. reverse engineering aims to go beyond producing such a mesh and to recover the design intent in terms of simple analytical surfaces where appropriate ( planes, cylinders, etc. ) as well as possibly nurbs surfaces to produce a boundary - representation cad model. recovery of such a model allows a design to be modified to meet new requirements, a manufacturing plan to be generated, etc. hybrid modeling is a commonly used term when nurbs and parametric modeling are implemented together. using a combination of geometric and freeform surfaces can provide a powerful method of 3d modeling. areas of freeform data can be combined with exact geometric
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https://en.wikipedia.org/wiki/Reverse_engineering
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sale. = = applications = = below are some of the most important uses of radio, organized by function. = = = broadcasting = = = broadcasting is the one - way transmission of information from a transmitter to receivers belonging to a public audience. since the radio waves become weaker with distance, a broadcasting station can only be received within a limited distance of its transmitter. systems that broadcast from satellites can generally be received over an entire country or continent. older terrestrial radio and television are paid for by commercial advertising or governments. in subscription systems like satellite television and satellite radio the customer pays a monthly fee. in these systems, the radio signal is encrypted and can only be decrypted by the receiver, which is controlled by the company and can be deactivated if the customer does not pay. broadcasting uses several parts of the radio spectrum, depending on the type of signals transmitted and the desired target audience. longwave and medium wave signals can give reliable coverage of areas several hundred kilometers across, but have a more limited information - carrying capacity and so work best with audio signals ( speech and music ), and the sound quality can be degraded by radio noise from natural and artificial sources. the shortwave bands have a greater potential range but are more subject to interference by distant stations and varying atmospheric conditions that affect reception. in the very high frequency band, greater than 30 megahertz, the earth ' s atmosphere has less of an effect on the range of signals, and line - of - sight propagation becomes the principal mode. these higher frequencies permit the great bandwidth required for television broadcasting. since natural and artificial noise sources are less present at these frequencies, high - quality audio transmission is possible, using frequency modulation. = = = = audio : radio broadcasting = = = = radio broadcasting means transmission of audio ( sound ) to radio receivers belonging to a public audience. analog audio is the earliest form of radio broadcast. am broadcasting began around 1920. fm broadcasting was introduced in the late 1930s with improved fidelity. a broadcast radio receiver is called a radio. most radios can receive both am and fm. am ( amplitude modulation ) – in am, the amplitude ( strength ) of the radio carrier wave is varied by the audio signal. am broadcasting, the oldest broadcasting technology, is allowed in the am broadcast bands, between 148 and 283 khz in the low frequency ( lf ) band for longwave broadcasts and between 526 and 1706 khz in the medium frequency ( mf ) band for medium - wave broadcasts. because waves in these bands travel as ground waves
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https://en.wikipedia.org/wiki/Radio
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exact results for product - form stationary distributions of markov chains are of interest in different fields. in stochastic reaction networks ( crns ), stationary distributions are mostly known in special cases where they are of product - form. however, there is no full characterization of the classes of networks whose stationary distributions have product - form. we develop an algebraic approach to product - form stationary distributions in the framework of crns. under certain hypotheses on linearity and decomposition of the state space for conservative ergodic crns, this gives sufficient and necessary algebraic conditions for product - form stationary distributions. correspondingly we obtain a semialgebraic subset of the parameter space that captures rates where, under the corresponding hypotheses, crns have product - form. we employ the developed theory to crns and some models of statistical mechanics, besides sketching the pertinence in other models from applied probability.
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arxiv:2012.03227
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the mushroomed deepfake synthetic materials circulated on the internet have raised a profound social impact on politicians, celebrities, and individuals worldwide. in this survey, we provide a thorough review of the existing deepfake detection studies from the reliability perspective. we identify three reliability - oriented research challenges in the current deepfake detection domain : transferability, interpretability, and robustness. moreover, while solutions have been frequently addressed regarding the three challenges, the general reliability of a detection model has been barely considered, leading to the lack of reliable evidence in real - life usages and even for prosecutions on deepfake - related cases in court. we, therefore, introduce a model reliability study metric using statistical random sampling knowledge and the publicly available benchmark datasets to review the reliability of the existing detection models on arbitrary deepfake candidate suspects. case studies are further executed to justify the real - life deepfake cases including different groups of victims with the help of the reliably qualified detection models as reviewed in this survey. reviews and experiments on the existing approaches provide informative discussions and future research directions for deepfake detection.
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arxiv:2211.10881
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cascading failures in power systems exhibit non - local propagation patterns which make the analysis and mitigation of failures difficult. in this work, we propose a distributed control framework inspired by the recently proposed concepts of unified controller and network tree - partition that offers strong guarantees in both the mitigation and localization of cascading failures in power systems. in this framework, the transmission network is partitioned into several control areas which are connected in a tree structure, and the unified controller is adopted by generators or controllable loads for fast timescale disturbance response. after an initial failure, the proposed strategy always prevents successive failures from happening, and regulates the system to the desired steady state where the impact of initial failures are localized as much as possible. for extreme failures that cannot be localized, the proposed framework has a configurable design, that progressively involves and coordinates more control areas for failure mitigation and, as a last resort, imposes minimal load shedding. we compare the proposed control framework with automatic generation control ( agc ) on the ieee 118 - bus test system. simulation results show that our novel framework greatly improves the system robustness in terms of the n - 1 security standard, and localizes the impact of initial failures in majority of the load profiles that are examined. moreover, the proposed framework incurs significantly less load loss, if any, compared to agc, in all of our case studies.
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arxiv:1904.05461
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we investigate the sensitivity of the heavy ion mode of the lhc to anomalous higgs boson couplings to photons, h - photon - photon, through the analysis of the processes photon photon to b anti - b and photon photon to photon photon in peripheral heavy ion collisions. we suggest cuts to improve the signal over background ratio and determine the capability of lhc to impose bounds on anomalous couplings by searching for a higgs boson signal in these modes.
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arxiv:hep-ph/0009289
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two photons can annihilate into a neutral pion - like resonance via the anomaly coupling, just like $ \ pi ^ 0 \ gamma \ gamma $ in qcd. in some strongly interacting electroweak symmetry breaking models, e. g., technicolor type models, there often exist neutral pion - like resonances. tev photon colliders have a strong capability to discover such particles, because the standard model background in photon scattering goes through box diagrams and is therefore highly suppressed. in this study, we perform a signal - background comparison. we show that $ e ^ + e ^ - $ linear colliders running in $ \ gamma \ gamma $ mode can discover such neutral - pion - like resonances with a decent sensitivity.
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arxiv:hep-ph/0410231
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dictionary definitions are historically the arbitrator of what words mean, but this primacy has come under threat by recent progress in nlp, including word embeddings and generative models like chatgpt. we present an exploratory study of the degree of alignment between word definitions from classical dictionaries and these newer computational artifacts. specifically, we compare definitions from three published dictionaries to those generated from variants of chatgpt. we show that ( i ) definitions from different traditional dictionaries exhibit more surface form similarity than do model - generated definitions, ( ii ) that the chatgpt definitions are highly accurate, comparable to traditional dictionaries, and ( iii ) chatgpt - based embedding definitions retain their accuracy even on low frequency words, much better than glove and fasttext word embeddings.
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arxiv:2311.06362
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a microscopic heterogeneous system under random influence is considered. the randomness enters the system at physical boundary of small scale obstacles as well as at the interior of the physical medium. this system is modeled by a stochastic partial differential equation defined on a domain perforated with small holes ( obstacles or heterogeneities ), together with random dynamical boundary conditions on the boundaries of these small holes. a homogenized macroscopic model for this microscopic heterogeneous stochastic system is derived. this homogenized effective model is a new stochastic partial differential equation defined on a unified domain without small holes, with static boundary condition only. in fact, the random dynamical boundary conditions are homogenized out, but the impact of random forces on the small holes ' boundaries is quantified as an extra stochastic term in the homogenized stochastic partial differential equation. moreover, the validity of the homogenized model is justified by showing that the solutions of the microscopic model converge to those of the effective macroscopic model in probability distribution, as the size of small holes diminishes to zero.
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arxiv:math/0703537
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##s help encode the data of derived noncommutative schemes = = references = = = = = books = = = kirillov, alexander ( 2016 ), quiver representations and quiver varieties, american mathematical society, isbn 978 - 1 - 4704 - 2307 - 0 = = = lecture notes = = = crawley - boevey, william, lectures on representations of quivers ( pdf ), archived from the original on 2017 - 08 - 20 { { citation } } : cs1 maint : bot : original url status unknown ( link ) quiver representations in toric geometry = = = research = = = projective toric varieties as fine moduli spaces of quiver representations = = sources = = derksen, harm ; weyman, jerzy ( february 2005 ), " quiver representations " ( pdf ), notices of the american mathematical society, 52 ( 2 ) dlab, vlastimil ; ringel, claus michael ( 1973 ), on algebras of finite representation type, carleton mathematical lecture notes, vol. 2, department of mathematics, carleton univ., ottawa, ont., mr 0347907 crawley - boevey, william ( 1992 ), notes on quiver representations ( pdf ), oxford university, archived from the original ( pdf ) on 2011 - 07 - 24, retrieved 2007 - 02 - 17 gabriel, peter ( 1972 ), " unzerlegbare darstellungen. i ", manuscripta mathematica, 6 ( 1 ) : 71 – 103, doi : 10. 1007 / bf01298413, issn 0025 - 2611, mr 0332887. victor kac, " root systems, representations of quivers and invariant theory ". invariant theory ( montecatini, 1982 ), pp. 74 – 108, lecture notes in math. 996, springer - verlag, berlin 1983. isbn 3 - 540 - 12319 - 9 king, alastair ( 1994 ), " moduli of representations of finite - dimensional algebras ", quart. j. math., 45 ( 180 ) : 515 – 530, doi : 10. 1093 / qmath / 45. 4. 515 savage, alistair ( 2006 ) [ 2005 ], " finite - dimensional algebras and quivers ", in francoise, j. - p. ; naber, g. l. ; tsou, s. t. ( eds. ), encyclopedia of mathematical physics, vol. 2,
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https://en.wikipedia.org/wiki/Quiver_(mathematics)
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for a large class of $ n = 2 $ scfts, which includes minimal models and many $ \ s $ models on calabi - yau manifolds, the mirror theory can be obtained as an orbifold. we show that in such a situation the construction of the mirror can be extended to the presence of discrete torsions. in the case of the $ \ zz _ 2 \ ex \ zz _ 2 $ torus orbifold, discrete torsion between the two generators directly provides the mirror model. working at the gepner point it is, however, possible to understand this mirror pair as a special case of the berglund - - h " ubsch construction. this seems to indicate that the $ \ zz _ 2 \ ex \ zz _ 2 $ example is a mere coincidence, due to special properties of $ \ zz _ 2 $ twists, rather than a hint at a new mechanism for mirror symmetry.
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arxiv:hep-th/9505120
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human participants play a central role in the development of modern artificial intelligence ( ai ) technology, in psychological science, and in user research. recent advances in generative ai have attracted growing interest to the possibility of replacing human participants in these domains with ai surrogates. we survey several such " substitution proposals " to better understand the arguments for and against substituting human participants with modern generative ai. our scoping review indicates that the recent wave of these proposals is motivated by goals such as reducing the costs of research and development work and increasing the diversity of collected data. however, these proposals ignore and ultimately conflict with foundational values of work with human participants : representation, inclusion, and understanding. this paper critically examines the principles and goals underlying human participation to help chart out paths for future work that truly centers and empowers participants.
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arxiv:2401.08572
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the water gas shift reaction ( wgs ) is important and widely applied in the production of h2. cu modified perovskites are promising catalysts for wgs reactions in hydrogen generation. however, the structure - dependent stability and reaction pathways of such materials remain unclear. herein, we report catalytically active cu modified srtio3 ( nominally srti1 - xcuxo3 ) prepared by a modified polymeric precursor method. microstructural analysis revealed a partially segregated cuo phase in the as - prepared materials. operando x - ray diffraction and absorption spectroscopy showed the reduction of cuo into a stable metallic phase under conditions of wgs reactions for all compositions. among the characterized materials, the x = 0. 20 composition showed the highest turnover frequency, lowest activation energy, and the highest wgs rate at 300c. according to density functional calculations, the formation of cuo is energetically less favorable compared with srtio3, explaining why the segregated cuo phase on the srtio3 surface is reduced to cu during the catalytic reaction, while srtio3 remains. for x = 0. 20, the size of the segregated cuo phase is optimum for facilitating the catalytic reaction. in contrast, a higher cu content ( x = 0. 3 ) results in an aggregation of smaller cuo particles, resulting in fewer surface active sites and a net decrease in catalytic performance.
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arxiv:2104.06739
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this paper describes the application of finite - size scaling concepts to domain growth in systems with a non - conserved order parameter. a finite - size scaling ansatz for the time - dependent order parameter distribution function is proposed, and tested with extensive monte - carlo simulations of domain growth in the 2 - d spin - flip kinetic ising model. the scaling properties of the distribution functions serve to elucidate the configurational self - similarity that underlies the dynamic scaling picture. moreover, it is demonstrated that the application of finite - size - scaling techniques facilitates the accurate determination of the bulk growth exponent even in the presence of strong finite - size effects, the scale and character of which are graphically exposed by the order parameter distribution function. in addition it is found that one commonly used measure of domain size - - the scaled second moment of the magnetisation distribution - - belies the full extent of these finite - size effects.
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arxiv:cond-mat/9401034
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we desire a simple comparison of the absolute effective areas of the current generation of ccd instruments onboard the following observatories : chandra acis - s3, xmm - newton ( epic - mos and epic - pn ), suzaku xis, and swift xrt and a straightforward comparison of the time - dependent response of these instruments across their respective mission lifetimes. we have been using 1e 0102. 2 - 7219, the brightest supernova remnant in the small magellanic cloud, to evaluate and modify the response models of these instruments. 1e 0102. 2 - 7219 has strong lines of o, ne, and mg below 1. 5 kev and little or no fe emission to complicate the spectrum. as part of the activities of the international astronomical consortium for high energy calibration ( iachec ), we have developed a standard spectral model for 1e 0102. 2 - 7219. the model is empirical in that it includes gaussians for the identified lines, an absorption component in the galaxy, another absorption component in the smc, and two thermal continuum components. in our fits, the model is highly constrained in that only the normalizations of the four brightest lines / line complexes ( the o vii he $ \ alpha $ triplet, o viii ly $ \ alpha $ line, the ne ix he $ \ alpha $ triplet, and the ne x ly $ \ alpha $ line ) and an overall normalization are allowed to vary. we have examined these measured line fluxes as a function of time for each instrument after applying the most recent calibrations that account for the time - dependent response of each instrument. we perform our effective area comparison with representative, early mission data when the radiation damage and contamination layers were at a minimum. we find that the measured fluxes of these lines generally agree to within + / - 10 % for all instruments, with 38 of our 48 fitted normalizations within + / - 10 % of the iachec model value.
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arxiv:1607.03069
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the effects of nuclear isospin asymmetry on $ \ alpha $ decay lifetimes of heavy nuclei are investigated within various phenomenological models of nuclear potential for the $ \ alpha $ particle. we consider the widely used simple square well potential and woods - saxon potential, and modify them by including an isospin asymmetry term. we then suggest a model for the potential of the $ \ alpha $ particle motivated by a microscopic phenomenological approach of the skyrme force model, which naturally introduce the isospin dependent form of the nuclear potential for the $ \ alpha $ particle. the empirical $ \ alpha $ decay lifetime formula of viola and seaborg is also modified to include isospin asymmetry effects. the obtained $ \ alpha $ decay half - lives are in good agreement with the experimental data and we find that including the nuclear isospin effects somehow improves the theoretical results for $ \ alpha $ decay half - lives. the implications of these results are discussed and the predictions on the $ \ alpha $ decay lifetimes of superheavy elements are also presented.
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arxiv:1511.02555
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we use the effective lagrangian formalism to describe quark mixing. the new w, z and h couplings generalizing the ckm matrix and the gim mechanism fulfil relations and inequalities which allow to discriminate among different sm extensions. as a by - product we give a useful parametrization of the generalized ckm matrix. we also show that the largest possible departures from the sm predictions result from heavy exotic fermions, which can induce, for example, top fcnc large enough to be observable at future colliders.
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arxiv:hep-ph/0007160
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we present the formulation of the problem of the coherent dynamics of quantum mechanical two - level systems in the adiabatic region in terms of the differential geometry of plane curves. we show that there is a natural plane curve corresponding to the hamiltonian of the system for which the geometrical quantities have a simple physical interpretation. in particular, the curvature of the curve has the role of the nonadiabatic coupling.
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arxiv:1501.03366
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. more recently, the term biological engineering has been applied to environmental modifications such as surface soil protection, slope stabilization, watercourse and shoreline protection, windbreaks, vegetation barriers including noise barriers and visual screens, and the ecological enhancement of an area. because other engineering disciplines also address living organisms, the term biological engineering can be applied more broadly to include agricultural engineering. the first biological engineering program in the united states was started at university of california, san diego in 1966. more recent programs have been launched at mit and utah state university. many old agricultural engineering departments in universities over the world have re - branded themselves as agricultural and biological engineering or agricultural and biosystems engineering. according to professor doug lauffenburger of mit, biological engineering has a broad base which applies engineering principles to an enormous range of size and complexities of systems, ranging from the molecular level ( molecular biology, biochemistry, microbiology, pharmacology, protein chemistry, cytology, immunology, neurobiology and, neuroscience ) to cellular and tissue - based systems ( including devices and sensors ), to whole macroscopic organisms ( plants, animals ), and even to biomes and ecosystems. = = education = = the average length of study is three to five years, and the completed degree is signified as a bachelor of engineering ( b. s. in engineering ). fundamental courses include thermodynamics, biomechanics, biology, genetic engineering, fluid and mechanical dynamics, chemical and enzyme kinetics, electronics, and materials properties. = = sub - disciplines = = depending on the institution and particular definitional boundaries employed, some major branches of bioengineering may be categorized as ( note these may overlap ) : biomedical engineering : application of engineering principles and design concepts to medicine and biology for healthcare purposes. tissue engineering neural engineering pharmaceutical engineering clinical engineering biomechanics biochemical engineering : fermentation engineering, application of engineering principles to microscopic biological systems that are used to create new products by synthesis, including the production of protein from suitable raw materials. biological systems engineering : application of engineering principles and design concepts to agriculture, food sciences, and ecosystems. bioprocess engineering : develop technology to monitor the conditions of where a particular process takes place, ( ex : bioprocess design, biocatalysis, bioseparation, bioenergy ) environmental health engineering : application of engineering principles to control the environment for the health, comfort, and safety of human beings. it includes the field of life - support systems for the
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https://en.wikipedia.org/wiki/Biological_engineering
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multiuser multiple - input multiple - output ( mimo ) systems are a prime candidate for use in massive connection density in machine - type communication ( mtc ) networks. one of the key challenges of mtc networks is to obtain accurate channel state information ( csi ) at the access point ( ap ) so that the spectral efficiency can be improved by enabling enhanced mimo techniques. however, current communication mechanisms relying upon frequency division duplexing ( fdd ) might not fully support an enormous number of devices due to the rate - constrained limited feedback and the time - consuming scheduling architectures. in this paper, we propose a user cooperation - based limited feedback strategy to support high connection density in massive mtc networks. in the proposed algorithm, two close - in users share the quantized version of channel information in order to improve channel feedback accuracy. the cooperation process is performed without any transmitter interventions ( i. e., in a grant - free manner ) to satisfy the low - latency requirement that is vital for mtc services. moreover, based on the sum - rate throughput analysis, we develop an adaptive cooperation algorithm with a view to activating / deactivating the user cooperation mode according to channel and network conditions.
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arxiv:1805.06583
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we derive a complete geometrical characterisation of a large class of $ ads _ 3 $, $ ads _ 4 $ and $ ads _ 5 $ supersymmetric spacetimes in eleven - dimensional supergravity using g - structures. these are obtained as special cases of a class of supersymmetric $ \ mathbb { r } ^ { 1, 1 } $, $ \ mathbb { r } ^ { 1, 2 } $ and $ \ mathbb { r } ^ { 1, 3 } $ geometries, naturally associated to m5 - branes wrapping calibrated cycles in manifolds with $ g _ 2 $, su ( 3 ) or su ( 2 ) holonomy. specifically, the latter class is defined by requiring that the killing spinors satisfy the same set of projection conditions as for wrapped probe branes, and that there is no electric flux. we show how the r - symmetries of the dual field theories appear as isometries of the general ads geometries. we also show how known solutions previously constructed in gauged supergravity satisfy our more general g - structure conditions, demonstrate that our conditions for half - bps $ ads _ 5 $ geometries are precisely those of lin, lunin and maldacena, and construct some new singular solutions.
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arxiv:hep-th/0605146
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the dependence of the moment of inertia $ \ cal j $ on the pairing and axial quadrupole deformation $ \ beta $ in $ ^ { 24 } $ mg and $ ^ { 20 } $ ne was investigated. the study is based on quadrupole - constrained calculations with three cranking approaches for $ \ cal j $ ( inglis - belyaev, thouless - valatin, adiabatic time - dependent hartree - fock ) and a representative set of skyrme forces ( svbas, skm *, sly6 ). at variance with macroscopic collective models, the calculations predict the specific regime $ d { \ cal j } / d \ beta < 0 $ at $ \ beta \ ge 0. 5 $ ( $ ^ { 24 } $ mg ) and $ \ beta \ ge 0. 6 $ ( $ ^ { 20 } $ ne ), where the pairing breaks down. this regime is explained by two effects : full break up of the pairing and specific evolution of a { \ it single } dominant particle - hole ( 1ph ) configuration with $ \ beta $. the analysis of experimental data for the ground - state rotational bands in $ ^ { 24 } $ mg and $ ^ { 20 } $ ne shows that such regime is possible at low spins.
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arxiv:2304.10873
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mu3e is an experiment currently under construction at the paul scherrer institute in switzerland, designed to search for the lepton flavor violating ( lfv ) decay $ \ mu ^ + \ rightarrow e ^ + e ^ - e ^ + $. in extensions of the standard model ( sm ) that account for neutrino masses, this decay is theoretically allowed but occurs only through extremely rare loop processes, with a predicted branching ratio of approximately $ \ mathcal { o } ( 10 ^ { - 54 } ) $. such a small probability implies that any observation of this decay would provide clear evidence for physics beyond the sm. the mu3e experiment aims to probe the $ \ mu ^ + \ rightarrow e ^ + e ^ - e ^ + $ decay with a sensitivity of approximately $ \ mathcal { o } ( 10 ^ { - 15 } ) $ in its phase - 1 and plans to achieve a sensitivity of $ \ mathcal { o } ( 10 ^ { - 16 } ) $ after future upgrades. to reach its phase - 1 ambitious goals, mu3e is going to use the most intense continuous muon beam in the world, generating 10 $ ^ { 8 } $ muon stops per second in the target placed at the center of the mu3e. mu3e will use three main technologies for particle detection. the tracking will done through ultra - thin ( 50 - 70 $ \ mu m $ ) pixel detectors based on mupix11 sensors. these are high - voltage monolithic active pixel sensors ( hv - maps ) with a $ \ sim $ 23 ~ $ \ mu $ m spatial resolution. the timing will be done through scintillating fibres ( $ \ sim $ 250 ps ) and tiles ( $ \ sim $ 40 ps ), coupled to silicon photomultipliers and read out by mutrig3 asics. a triggerless daq system based on fpgas will collect data from the detectors, which will then undergo reconstruction in a gpu filter farm. the assembly of the detectors has started, with a detector commissioning beam time planned for 2025. this document reports on the status of the construction, installation, and data - taking plans for the near future.
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arxiv:2501.14667
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physical meaning and a duality of concepts of wave function, action functional, entropy, the pointing vector, the einstein tensor and so on can be disclosed by investigating the state of material systems such as thermodynamic and gas dynamic systems, systems of charged particles, cosmologic systems and others. these concepts play a same role in mathematical physics. they are quantities that specify a state of material systems and also characteristics of physical fields. the duality of these concepts reveals in the fact that they can at once be both functionals and state functions or potentials. as functionals they are defined on nonintegrable manifold ( for example, on tangent one ), and as a state function they are defined on integrable manifold ( for example, on cotangent one ). the transition from functionals to state functions dicribes the mechanism of physical structure origination. the properties of these concepts can be studied by the example of entropy and action. the role of these concepts in mathematical physics and field theory will be demonstrated. such results have been obtained by using skew - symmetric forms. in addition to exterior forms, the skew - symmetric forms, which are obtained from differential equations and, in distinction to exterior forms, are evolutionary ones and are defined on nonintegrable manifolds, were used.
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arxiv:1001.1710
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this work presents new sufficient conditions for the absence of a gap corresponding to young measure and occupation measure relaxations for constrained optimal control problems. unlike existing conditions, these sufficient conditions do not rely on convexity of the lagrangian or the set of admissible velocities. we use these conditions to derive new bounds for the size of the relaxation gap.
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arxiv:2503.13780
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pulmonary opacification is the inflammation in the lungs caused by many respiratory ailments, including the novel corona virus disease 2019 ( covid - 19 ). chest x - rays ( cxrs ) with such opacifications render regions of lungs imperceptible, making it difficult to perform automated image analysis on them. in this work, we focus on segmenting lungs from such abnormal cxrs as part of a pipeline aimed at automated risk scoring of covid - 19 from cxrs. we treat the high opacity regions as missing data and present a modified cnn - based image segmentation network that utilizes a deep generative model for data imputation. we train this model on normal cxrs with extensive data augmentation and demonstrate the usefulness of this model to extend to cases with extreme abnormalities.
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arxiv:2005.10052
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the rapid evolution of technology has transformed business operations and customer interactions worldwide, with personalization emerging as a key opportunity for e - commerce companies to engage customers more effectively. the application of machine learning, particularly that of deep learning models, has gained significant traction due to its ability to rapidly recognize patterns in large datasets, thereby offering numerous possibilities for personalization. these models use embeddings to map discrete information, such as product ids, into a latent vector space, a method increasingly popular in recent years. however, e - commerce ' s dynamic nature, characterized by frequent new product introductions, poses challenges for these embeddings, which typically require fixed dimensions and inputs, leading to the need for periodic retraining from scratch. this paper introduces a modular algorithm that extends embedding input size while preserving learned knowledge, addressing the challenges posed by e - commerce ' s dynamism. the proposed algorithm also incorporates strategies to mitigate the cold start problem associated with new products. the results of initial experiments suggest that this method outperforms traditional embeddings.
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arxiv:2408.14118
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w. a. moens proved that a lie algebra is nilpotent if and only if it admits an invertible leibniz - derivation. in this paper we show that with the definition of leibniz - derivation from w. a. moens the similar result for non lie leibniz algebras is not true. namely, we give an example of non nilpotent leibniz algebra which admits an invertible leibniz - derivation. in order to extend the results of paper w. a. moens for leibniz algebras we introduce a definition of leibniz - derivation of leibniz algebras which agrees with leibniz - derivation of lie algebras case. further we prove that a leibniz algebra is nilpotent if and only if it admits an invertible leibniz - derivation. moreover, the result that solvable radical of a lie algebra is invariant with respect to a leibniz - derivation was extended to the case of leibniz algebras.
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arxiv:1204.1721
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we consider non - colliding brownian bridges starting from two points and returning to the same position. these positions are chosen such that, in the limit of large number of bridges, the two families of bridges just touch each other forming a tacnode. we obtain the limiting process at the tacnode, the " asymmetric tacnode process ". it is a determinantal point process with correlation kernel given by two parameters : ( 1 ) the curvature ' s ratio \ lambda > 0 of the limit shapes of the two families of bridges, ( 2 ) a parameter \ sigma controlling the interaction on the fluctuation scale. this generalizes the result for the symmetric tacnode process ( \ lambda = 1 case ).
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arxiv:1112.5002
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we demonstrate a robust frustration - driven charge - order to superconductivity transition in the half - filled negative - u extended hubbard model. superconductivity extends over a broad region of the parameter space. we argue that the model provides the correct insight to understanding unconventional superconductivity in the organic charge - transfer solids and other quarter - filled systems.
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arxiv:0802.1011
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we investigate the critical temperature tc of a thin s - wave superconductor ( nb ) proximity coupled to a helical rare earth ferromagnet ( ho ). as a function of the ho layer thickness, we observe multiple oscillations of tc superimposed on a slow decay, that we attribute to the influence of the ho on the nb proximity effect. because of ho inhomogeneous magnetization, singlet and triplet pair correlations are present in the bilayers. we take both into consideration when solving the self consistent bogoliubov - de gennes equations, and we observe a reasonable agreement. we also observe non - trivial transitions into the superconducting state, the zero resistance state being attained after two successive transitions which appear to be associated with the magnetic structure of ho.
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arxiv:1211.1169
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we prove a general form of the regularity theorem for uniformity norms, and deduce an inverse theorem for these norms which holds for a class of compact nilspaces including all compact abelian groups, and also nilmanifolds ; in particular we thus obtain the first non - abelian versions of such theorems. we derive these results from a general structure theorem for cubic couplings, thereby unifying these results with the host - kra ergodic structure theorem. a unification of this kind had been propounded as a conceptual prospect by host and kra. our work also provides new results on nilspaces. in particular, we obtain a new stability result for nilspace morphisms. we also strengthen a result of gutman, manners and varj \ ' u, by proving that a $ k $ - step compact nilspace of finite rank is a toral nilspace ( in particular, a connected nilmanifold ) if and only if its $ k $ - dimensional cube set is connected. we also prove that if a morphism from a cyclic group of prime order into a compact finite - rank nilspace is sufficiently balanced ( i. e. equidistributed in a certain quantitative and multidimensional sense ), then the nilspace is toral. as an application of this, we obtain a new proof of a refinement of the green - tao - ziegler inverse theorem.
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arxiv:1902.01098
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use - after - free ( uaf ) is a critical and prevalent problem in memory unsafe languages. while many solutions have been proposed, balancing security, run - time cost, and memory overhead ( an impossible trinity ) is hard. in this paper, we show one way to balance the trinity by passing more semantics about the heap object to the allocator for it to make informed allocation decisions. more specifically, we propose a new notion of thread -, context -, and flow - sensitive " type ", sematype, to capture the semantics and prototype a sematype - based allocator that aims for the best trade - off amongst the impossible trinity. in semalloc, only heap objects allocated from the same call site and via the same function call stack can possibly share a virtual memory address, which effectively stops type - confusion attacks and makes uaf vulnerabilities harder to exploit. through extensive empirical evaluation, we show that semalloc is realistic : ( a ) semalloc is effective in thwarting all real - world vulnerabilities we tested ; ( b ) benchmark programs run even slightly faster with semalloc than the default heap allocator, at a memory overhead averaged from 41 % to 84 % ; and ( c ) semalloc balances security and overhead strictly better than other closely related works.
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arxiv:2402.03373
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which god is. " he wrote that religion and science must come together in a new age. = = with lao russell at swannanoa in virginia 1948 – 1963 = = in 1948, at the age of 77, russell divorced his first wife and married daisy stebbing, aged 44, an immigrant from england and former model and businesswoman, amid some controversy. she changed her name to lao ( after lao - tzu, the chinese illuminate ) and they embarked on a cross - country automobile trip from reno looking for a place to establish a workplace and a museum for his work. they discovered swannanoa, the palatial estate of a railroad magnate, long abandoned, on a mountaintop on the border of augusta and nelson counties in virginia, and leased the property for 50 years. there they established the museum and the walter russell foundation, and in 1957 the commonwealth of virginia granted a charter for the university of science and philosophy, a correspondence school with a home study course. ( in 2014, the charter was grandfathered back to 1948. ) the russells collaborated on a number of books. the testing of atomic bombs in the atmosphere prompted them to publish atomic suicide? in 1957, in which they warned of grave consequences for the planet and humankind if radioactivity was exploited as a world fuel. walter russell died in 1963. lao died in 1988. = = books = = the sea children, 1901 the bending of the twig, 1903 the age of innocence, 1904 the universal one, 1926 the russell genero - radiative concept or the cyclic theory of continuous motion, l. middleditch co., 1930 the secret of light, 1st ed., 1947, 3rd ed., univ of science & philosophy, 1994, isbn 1 - 879605 - 44 - 9 the message of the divine iliad, vol. 1, 1948, vol. 2, 1949 the book of early whisperings, 1949 the home study course ( with lao russell ), 1st ed., 1950 – 52 scientific answer to human relations ( with lao russell ), univ of science & philosophy, 1951 a new concept of the universe, univ of science & philosophy, 1953 atomic suicide? ( with lao russell ), univ of science & philosophy, 1957 the world crisis : its explanation and solution, ( with lao russell ), univ of science & philosophy, 1958 the one - world purpose ( with lao russell ), univ of science & philosophy, 1960 = = references = = = = further reading
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https://en.wikipedia.org/wiki/Walter_Russell
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a measurement of time - dependent $ cp $ violation in $ d ^ 0 \ rightarrow \ pi ^ + \ pi ^ - \ pi ^ 0 $ decays using a $ pp $ collision data sample collected by the lhcb experiment in 2012 and from 2015 to 2018, corresponding to an integrated luminosity of 7. 7 $ \, \ mathrm { fb } ^ { - 1 } $, is presented. the initial flavour of each $ d ^ 0 $ candidate is determined from the charge of the pion produced in the $ d ^ * ( 2010 ) ^ + \ rightarrow d ^ 0 \ pi ^ + $ decay. the decay $ d ^ 0 \ rightarrow k ^ - \ pi ^ + \ pi ^ 0 $ is used as a control channel to validate the measurement procedure. the gradient of the time - dependent $ cp $ asymmetry, $ \ delta y $, in $ d ^ 0 \ rightarrow \ pi ^ + \ pi ^ - \ pi ^ 0 $ decays is measured to be \ begin { equation * } \ delta y = ( - 1. 3 \ pm 6. 3 \ pm 2. 4 ) \ times 10 ^ { - 4 }, \ end { equation * } where the first uncertainty is statistical and the second is systematic, which is compatible with $ cp $ conservation.
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arxiv:2405.06556
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we present a novel laser mode - locking scheme and discuss its unusual properties and feasibility using a theoretical model. a large set of single - frequency continuous - wave lasers oscillate by amplification in spatially separated gain media. they are mutually phase - locked by nonlinear feedback from a common saturable absorber. as a result, ultra short pulses are generated. the new scheme offers three significant benefits : the light that is amplified in each medium is continuous wave, thereby avoiding issues related to group velocity dispersion and nonlinear effects that can perturb the pulse shape. the set of frequencies on which the laser oscillates, and therefore the pulse repetition rate, is controlled by the geometry of resonator - internal optical elements, not by the cavity length. finally, the bandwidth of the laser can be controlled by switching gain modules on and off. this scheme offers a route to mode - locked lasers with high average output power, repetition rates that can be scaled into the thz range, and a bandwidth that can be dynamically controlled. the approach is particularly suited for implementation using semiconductor diode laser arrays.
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arxiv:1008.4700
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constraints on the possible shape and clustering, as well as optical properties, of grains responsible for the 2175 angstrom interstellar extinction feature ( interstellar uv bump ) are discussed. these constraints are based on the observation that the peak position of the interstellar uv feature is very stable ( variations < ~ 1 % ), that the large variations in width ( < ~ 25 % ) are uncorrelated with the peak position except for the widest bumps, and that the shape of the feature is described extremely well by a drude profile. the uv extinction of small graphite grains is computed for various clustering models involving rayleigh spheres. it is shown that compact clusters qualitatively satisfy the above observational constraints, except that the peak position falls at the wrong wavelength. as an alternative to graphite to model the optical properties of the interstellar uv feature carrier, a single - lorentz oscillator model is considered, in conjunction with a clustering model based on clusters of spheres. intrinsic changes in the peak position and width are attributed to variations in chemical composition of the grains, impacting upon the parameters of the lorentz oscillator. further broadening is attributed to clustering. these models are shown to satisfy the above observational constraints. furthermore, the correlated shift of peak position with increased width, observed for the widest interstellar uv features, is reproduced. models involving a second lorentz oscillator to reproduce the fuv rise are also considered. the impact of this extra lorentz oscillator on the peak position, width, and shape of the bump is investigated. synthetic extinction curves are generated to model actual ones exhibiting a wide range of fuv curvatures. physical mechanisms which might be of relevance to explain the variations of these optical properties are discussed.
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arxiv:astro-ph/9611203
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generalized matrix approximation plays a fundamental role in many machine learning problems, such as cur decomposition, kernel approximation, and matrix low rank approximation. especially with today ' s applications involved in larger and larger dataset, more and more efficient generalized matrix approximation algorithems become a crucially important research issue. in this paper, we find new sketching techniques to reduce the size of the original data matrix to develop new matrix approximation algorithms. our results derive a much tighter bound for the approximation than previous works : we obtain a $ ( 1 + \ epsilon ) $ approximation ratio with small sketched dimensions which implies a more efficient generalized matrix approximation.
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arxiv:1609.02258
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we pose the estimation and predictability of stock market performance. three cases are taken : us, japan, germany, the monthly index of the value of realized investment in stocks, prices plus the value of dividend payments ( oecd data ). once deflated and trend removed, harmonic analysis is applied. the series are taken with and without the periods with evidence of exogenous shocks. the series are erratic and the random walk hypothesis is reasonably falsified. the estimation reveals relevant hidden periodicities, which approximate stock value movements. from july 2008 onwards, it is successfully analyzed whether the subsequent fall in share value would have been predictable. again, the data are irregular and scattered, but the sum of the first five harmonics in relevance anticipates the fall in stock market values that followed.
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arxiv:2305.05762
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a review of the soft supersymmetry - breaking parameters and the $ \ mu $ term arising in superstring models is performed paying special attention to their phenomenological implications. in particular, the violation of the scalar mass universality which may lead to dangerous flavor changing neutral current phenomena and the existence of charge and color breaking minima are discussed. finally, quadratically - divergent loop effects by pure supergravity interactions on soft parameters and the $ \ mu $ term are also reviewed and applied to superstring models. they provide several new sources of the $ \ mu $ term, naturally of order the weak scale, but also may lead to non - - universal soft terms.
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arxiv:hep-ph/9710388
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a boundary integral equation method for the 3 - d helmholtz equation in multilayered media with many quasi - periodic layers is presented. compared with conventional quasi - periodic green ' s function method, the new method is robust at all scattering parameters. a periodizing scheme is used to decompose the solution into near - and far - field contributions. the near - field contribution uses the free - space green ' s function in an integral equation on the interface in the unit cell and its immediate eight neighbors ; the far - field contribution uses proxy point sources that enclose the unit cell. a specialized high - order quadrature is developed to discretize the underlying surface integral operators to keep the number of unknowns per layer small. we achieve overall linear computational complexity in the number of layers by reducing the linear system into block tridiagonal form and then solving the system directly via block lu decomposition. the new solver is capable of handling a 100 - interface structure with 961. 3k unknowns to $ 10 ^ { - 5 } $ accuracy in less than 2 hours on a desktop workstation.
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arxiv:2211.14656
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we find new bounds on the conformal dimension of small cancellation groups. these are used to show that a random few relator group has conformal dimension 2 + o ( 1 ) asymptotically almost surely ( a. a. s. ). in fact, if the number of relators grows like l ^ k in the length l of the relators, then a. a. s. such a random group has conformal dimension 2 + k + o ( 1 ). in gromov ' s density model, a random group at density d < 1 / 8 a. a. s. has conformal dimension $ \ asymp dl / | \ log d | $. the upper bound for c ' ( 1 / 8 ) groups has two main ingredients : $ \ ell _ p $ - cohomology ( following bourdon - kleiner ), and walls in the cayley complex ( building on wise and ollivier - wise ). to find lower bounds we refine the methods of [ mackay, 2012 ] to create larger ` round trees ' in the cayley complex of such groups. as a corollary, in the density model at d < 1 / 8, the density d is determined, up to a power, by the conformal dimension of the boundary and the euler characteristic of the group.
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arxiv:1409.0802
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this technical report provides detailed theoretical analysis of the algorithm used in \ textit { alternating minimization based trajectory generation for quadrotor aggressive flight }. an assumption is provided to ensure that settings for the objective function are meaningful. what ' s more, we explore the structure of the optimization problem and analyze the global / local convergence rate of the employed algorithm.
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arxiv:2002.09254
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we propose a scheme for enhancing bipartite quantum entanglement in a double - cavity molecular optomechanical ( mcom ) system incorporating an intracavity optical parametric amplifier ( opa ). utilizing a set of linearized quantum langevin equations and numerical simulations, we investigate the impact of the opa on both optical - vibration and vibration - vibration entanglement. our key findings reveal a counterintuitive trade - off : while the opa significantly enhances vibration - vibration entanglement, a critical resource for quantum memories and transducers, it simultaneously suppresses optical - vibration entanglement. we demonstrate that maximal vibration - vibration entanglement is achieved when the molecular collective vibrational modes are symmetrically populated, providing a clear experimental guideline for optimizing entanglement sources. in particular, the vibration - vibration entanglement generated in our opa - enhanced mcom system exhibits remarkable robustness to thermal noise, persisting at temperatures approaching \ si { e3 } { \ kelvin }, significantly exceeding conventional optomechanical systems, and highlighting the potential for room temperature quantum information processing. these results establish a promising theoretical foundation for opa - enhanced mcom systems as a robust and scalable platform for quantum technologies, paving the way for future experimental implementations and advanced quantum information processing applications.
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arxiv:2503.23201
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using the wei - norman theory we obtain a time - dependent complex riccati equation ( tdcre ) as the solution of the time evolution operator ( teo ) of quantum systems described by time - dependent ( td ) hamiltonians that are linear combinations of the generators of the $ \ mathfrak { su } ( 1, 1 ) $, $ \ mathfrak { su } ( 2 ) $ and $ \ mathfrak { so } ( 2, 1 ) $ lie algebras. using a recently developed solution for the time evolution of these quantum systems we solve the tdcre recursively as generalized continued fractions, which are optimal for numerical implementations, and establish the necessary and sufficient conditions for the unitarity of the teo in the factorized representation. the inherited symmetries of quantum systems can be recognized by a simple inspection of the tdcre, allowing effective quantum hamiltonians to be associated with it, as we show for the bloch - riccati equation whose hamiltonian corresponds to that of a generic td system of the lie algebra $ \ mathfrak { su } ( 2 ) $. as an application, but also as a consistency test, we compare our solution with the analytic one for the bloch - riccati equation considering the rabi frequency driven by a complex hyperbolic secant pulse generating spin inversion, showing an excellent agreement.
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arxiv:2209.03504
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monitoring performance and availability are critical to operating successful content provider networks. internet measurements provide data needed for traffic engineering, alerting, and network diagnostics. while there are significant benefits to combining server - side passive measurements with end - user active measurements, these capabilities are limited to a small number of content providers with both network and application control. in this work, we present a solution to a long - standing problem for a method to issue active measurements from clients without application control. our approach uses features of the w3c network error logging specification that allow a cdn to induce a browser connection to an https server of the cdn ' s choosing.
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arxiv:2007.12798
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an interferometer with effectively infinite maximum optical path difference removes the dominant resolution limitation for interferometric spectroscopy. we present mass - correlated rotational raman spectra that represent the world ' s highest resolution scanned interferometric data and discuss the current and expected future limitations in achievable spectroscopic performance.
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arxiv:2209.10885
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for an image with multiple scene texts, different people may be interested in different text information. current text - aware image captioning models are not able to generate distinctive captions according to various information needs. to explore how to generate personalized text - aware captions, we define a new challenging task, namely question - controlled text - aware image captioning ( qc - textcap ). with questions as control signals, this task requires models to understand questions, find related scene texts and describe them together with objects fluently in human language. based on two existing text - aware captioning datasets, we automatically construct two datasets, controltextcaps and controlvizwiz to support the task. we propose a novel geometry and question aware model ( gqam ). gqam first applies a geometry - informed visual encoder to fuse region - level object features and region - level scene text features with considering spatial relationships. then, we design a question - guided encoder to select the most relevant visual features for each question. finally, gqam generates a personalized text - aware caption with a multimodal decoder. our model achieves better captioning performance and question answering ability than carefully designed baselines on both two datasets. with questions as control signals, our model generates more informative and diverse captions than the state - of - the - art text - aware captioning model. our code and datasets are publicly available at https : / / github. com / hawlyq / qc - textcap.
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arxiv:2108.02059
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we have analyzed the complete visual and infrared mapping spectrometer ( vims ) data archive of titan. our objective is to build global surface cartographic products, by combining all the data gathered during the 127 targeted flybys of titan into synthetic global maps interpolated on a grid at 32 pixels per degree ( ~ 1. 4 km / pixel at the equator ), in seven infrared spectral atmospheric windows. multispectral summary images have been computed for each single vims cube in order to rapidly identify their scientific content and assess their quality. these summary images are made available to the community on a public website ( vims. univ - nantes. fr ). the global mapping work faced several challenges due to the strong absorbing and scattering effects of the atmosphere coupled to the changing observing conditions linked to the orbital tour of the cassini mission. we determined a surface photometric function which accounts for variations in incidence, emergence and phase angles, and which is able to mitigate brightness variations linked to the viewing geometry of the flybys. the atmospheric contribution has been reduced using the subtraction of the methane absorption band wings, considered as proxies for atmospheric haze scattering. we present a new global three color composite map of band ratios ( red : 1. 59 / 1. 27 { \ mu } m ; green : 2. 03 / 1. 27 { \ mu } m ; blue : 1. 27 / 1. 08 { \ mu } m ), which has also been empirically corrected from an airmass ( the solar photon path length through the atmosphere ) dependence. this map provides a detailed global color view of titan ' s surface partially corrected from the atmosphere and gives a global insight of the spectral variability, with the equatorial dunes fields appearing in brownish tones, and several occurrences of bluish tones localized in areas such as sinlap, menvra and selk craters. (... )
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arxiv:1809.06545
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community structures in collaboration networks reflect the natural tendency of individuals to organize their work in groups in order to better achieve common goals. in most of the cases, individuals exploit their connections to introduce themselves to new areas of interests, giving rise to multifaceted collaborations which span different fields. in this paper, we analyse collaborations in science and among movie actors as multiplex networks, where the layers represent respectively research topics and movie genres, and we show that communities indeed coexist and overlap at the different layers of such systems. we then propose a model to grow multiplex networks based on two mechanisms of intra and inter - layer triadic closure which mimic the real processes by which collaborations evolve. we show that our model is able to explain the multiplex community structure observed empirically, and we infer the strength of the two underlying social mechanisms from real - world systems. being also able to correctly reproduce the values of intra - layer and inter - layer assortativity correlations, the model contributes to a better understanding of the principles driving the evolution of social networks.
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arxiv:1506.01280
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we show how an electrical measurement can detect the pairing of electrons on the same side of the fermi surface ( amperian pairing ), recently proposed by patrick lee for the pseudogap phase of high - $ t _ c $ cuprate superconductors. bragg scattering from the pair - density wave introduces odd multiples of $ 2k _ { \ rm f } $ momentum shifts when an electron incident from a normal metal is andreev - reflected as a hole. these andreev - bragg reflections can be detected in a three - terminal device, containing a ballistic y - junction between normal leads $ ( 1, 2 ) $ and the superconductor. the cross - conductance $ di _ 1 / dv _ 2 $ has the opposite sign for amperian pairing than it has either in the normal state or for the usual bcs pairing.
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arxiv:1409.2834
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rough terrain locomotion has remained one of the most challenging mobility questions. in 2022, nasa ' s innovative advanced concepts ( niac ) program invited us academic institutions to participate nasa ' s breakthrough, innovative \ & game - changing ( big ) idea competition by proposing novel mobility systems that can negotiate extremely rough terrain, lunar bumpy craters. in this competition, northeastern university won nasa ' s top artemis award award by proposing an articulated robot tumbler called cobra ( crater observing bio - inspired rolling articulator ). this report briefly explains the underlying principles that made cobra successful in competing with other concepts ranging from cable - driven to multi - legged designs from six other participating us institutions.
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arxiv:2311.14878
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we introduce the notion of a chopped and sliced cone in combinatorial geometry and prove two structure theorems for the number of integral points in the individual slices of such a cone. we observe that this notion applies to weight multiplicities of kac - moody algebras and littlewood - richardson coefficients of semisimple lie algebras, where we obtain the corresponding results.
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arxiv:0902.1810
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we introduce a new model to study the effect of surface roughness on the jamming transition. by performing numerical simulations, we show that for a smooth surface, the jamming transition density and the contact number at the transition point both increase upon increasing asphericity, as for ellipsoids and spherocylinders. conversely, for a rough surface, both quantities decrease, in quantitative agreement with the behavior of frictional particles. furthermore, in the limit corresponding to the coulomb friction law, the model satisfies a generalized isostaticity criterion proposed in previous studies. we introduce a counting argument that justifies this criterion and interprets it geometrically. finally, we propose a simple theory to predict the contact number at finite friction from the knowledge of the force distribution in the infinite friction limit.
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arxiv:2001.09665
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we show that a continuous local semiflow of $ c ^ k $ - maps on a finite - dimensional $ c ^ k $ - manifold m can be embedded into a local $ c ^ k $ - flow on m under some weak ( necessary ) assumptions. this result is applied to an open problem in [ fil / tei : 01 ]. we prove that finite - dimensional realizations for interest rate models are highly regular objects, namely given by submanifolds m of $ d ( a ^ { \ infty } ) $, where a is the generator of a strongly continuous semigroup.
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arxiv:math/0112244
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we solve a long standing open problem concerning the structure of finite cycles in the category mod a of finitely generated modules over an arbitrary artin algebra a, that is, the chains of homomorphisms $ m _ 0 \ stackrel { f _ 1 } { \ rightarrow } m _ 1 \ to \ cdots \ to m _ { r - 1 } \ stackrel { f _ r } { \ rightarrow } m _ r = m _ 0 $ between indecomposable modules in mod a which do not belong to the infinite radical of mod a. in particular, we describe completely the structure of an arbitrary module category mod a whose all cycles are finite. the main structural results of the paper allow to derive several interesting combinatorial and homological properties of indecomposable modules lying on finite cycles. for example, we prove that for all but finitely many isomorphism classes of indecomposable modules m lying on finite cycles of a module category mod a the euler characteristic of m is well defined and nonnegative. as an another application of these results we obtain a characterization of all cycle - finite module categories mod a having only a finite number of functorially finite torsion classes. moreover, new types of examples illustrating the main results of the paper are presented.
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arxiv:1306.0929
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who proposed that a coupled oscillating electric field and magnetic field could travel through space as a wave, and proposed that light consisted of electromagnetic waves of short wavelength. on 11 november 1886, german physicist heinrich hertz, attempting to confirm maxwell ' s theory, first observed radio waves he generated using a primitive spark - gap transmitter. experiments by hertz and physicists jagadish chandra bose, oliver lodge, lord rayleigh, and augusto righi, among others, showed that radio waves like light demonstrated reflection, refraction, diffraction, polarization, standing waves, and traveled at the same speed as light, confirming that both light and radio waves were electromagnetic waves, differing only in frequency. in 1895, guglielmo marconi developed the first radio communication system, using a spark - gap transmitter to send morse code over long distances. by december 1901, he had transmitted across the atlantic ocean. marconi and karl ferdinand braun shared the 1909 nobel prize in physics " for their contributions to the development of wireless telegraphy ". during radio ' s first two decades, called the radiotelegraphy era, the primitive radio transmitters could only transmit pulses of radio waves, not the continuous waves which were needed for audio modulation, so radio was used for person - to - person commercial, diplomatic and military text messaging. starting around 1908 industrial countries built worldwide networks of powerful transoceanic transmitters to exchange telegram traffic between continents and communicate with their colonies and naval fleets. during world war i the development of continuous wave radio transmitters, rectifying electrolytic, and crystal radio receiver detectors enabled amplitude modulation ( am ) radiotelephony to be achieved by reginald fessenden and others, allowing audio to be transmitted. on 2 november 1920, the first commercial radio broadcast was transmitted by westinghouse electric and manufacturing company in pittsburgh, under the call sign kdka featuring live coverage of the harding - cox presidential election. = = technology = = radio waves are radiated by electric charges undergoing acceleration. they are generated artificially by time - varying electric currents, consisting of electrons flowing back and forth in a metal conductor called an antenna. as they travel farther from the transmitting antenna, radio waves spread out so their signal strength ( intensity in watts per square meter ) decreases ( see inverse - square law ), so radio transmissions can only be received within a limited range of the transmitter, the distance depending on the transmitter power, the antenna radiation pattern, receiver sensitivity, background noise level, and presence of obstructions between transmitter and receiver. an
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https://en.wikipedia.org/wiki/Radio
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slow dynamics in glassy systems is often interpreted as due to thermally activated events between " metastable " states. this emphasizes the role of nonperturbative fluctuations, which is especially dramatic when these fluctuations destroy a putative phase transition predicted at the mean - field level. to gain insight into such hard problems, we consider the implementation of a generic back - and - forth process, between microscopic theory and observable behavior via effective theories, in a toy model that is simple enough to allow for a thorough investigation : the one - dimensional $ \ varphi ^ 4 $ theory at low temperature. we consider two ways of restricting the extent of the fluctuations, which both lead to a nonconvex effective potential ( or free energy ) : either through a finite - size system or by means of a running infrared cutoff within the nonperturbative renormalization group formalism. we discuss the physical insight one can get and the ways to treat strongly nonperturbative fluctuations in this context.
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arxiv:1507.02498
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histo - genomic multi - modal methods have recently emerged as a powerful paradigm, demonstrating significant potential for improving cancer prognosis. however, genome sequencing, unlike histopathology imaging, is still not widely accessible in underdeveloped regions, limiting the application of these multi - modal approaches in clinical settings. to address this, we propose a novel genome - informed hyper - attention network, termed g - hanet, which is capable of effectively distilling the histo - genomic knowledge during training to elevate uni - modal whole slide image ( wsi ) - based inference for the first time. compared with traditional knowledge distillation methods ( i. e., teacher - student architecture ) in other tasks, our end - to - end model is superior in terms of training efficiency and learning cross - modal interactions. specifically, the network comprises the cross - modal associating branch ( cab ) and hyper - attention survival branch ( hsb ). through the genomic data reconstruction from wsis, cab effectively distills the associations between functional genotypes and morphological phenotypes and offers insights into the gene expression profiles in the feature space. subsequently, hsb leverages the distilled histo - genomic associations as well as the generated morphology - based weights to achieve the hyper - attention modeling of the patients from both histopathology and genomic perspectives to improve cancer prognosis. extensive experiments are conducted on five tcga benchmarking datasets and the results demonstrate that g - hanet significantly outperforms the state - of - the - art wsi - based methods and achieves competitive performance with genome - based and multi - modal methods. g - hanet is expected to be explored as a useful tool by the research community to address the current bottleneck of insufficient histo - genomic data pairing in the context of cancer prognosis and precision oncology.
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arxiv:2403.10040
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many physical adversarial patch generation methods are widely proposed to protect personal privacy from malicious monitoring using object detectors. however, they usually fail to generate satisfactory patch images in terms of both stealthiness and attack performance without making huge efforts on careful hyperparameter tuning. to address this issue, we propose a novel naturalistic adversarial patch generation method based on the diffusion models ( dm ). through sampling the optimal image from the dm model pretrained upon natural images, it allows us to stably craft high - quality and naturalistic physical adversarial patches to humans without suffering from serious mode collapse problems as other deep generative models. to the best of our knowledge, we are the first to propose dm - based naturalistic adversarial patch generation for object detectors. with extensive quantitative, qualitative, and subjective experiments, the results demonstrate the effectiveness of the proposed approach to generate better - quality and more naturalistic adversarial patches while achieving acceptable attack performance than other state - of - the - art patch generation methods. we also show various generation trade - offs under different conditions.
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arxiv:2307.08076
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this paper delves into the distressing prevalence of gender - based violence ( gbv ) and its deep - seated psychological ramifications, particularly among muslim south asian women living in diasporic communities. despite the gravity of gbv, these women often face formidable barriers in voicing their experiences and accessing support. " augmented voices " emerges as a technological beacon, harnessing the potential of augmented reality ( ar ) to bridge the digital and physical realms through mobile devices, enhancing the visibility of these often - silenced voices. with its technological motivation firmly anchored in the convergence of ar and real - world interactions, " augmented voices " offers a digital platform where storytelling acts as a catalyst, bringing to the fore the experiences shared by these women. by superimposing their narratives onto physical locations via geographic information system ( gis ) mapping, the application " augments their voices " in the diaspora, providing a conduit for expression and solidarity. this project, currently at its developmental stage, aspires to elevate the stories of gbv victims to a level where their struggles are not just heard but felt, forging a powerful connection between the user and the narrative. it is designed to transcend the limitations of conventional storytelling, creating an " augmented " reality where voices that are often muted by societal constraints can resonate powerfully. the project underscores the urgent imperative to confront gbv, catalyzing societal transformation and fostering robust support networks for those in the margins. it is a pioneering example of how technology can become a formidable ally in the fight for social justice and the empowerment of the oppressed. additionally, this paper delves into the ar workflow illustrating its relevance and contribution to the broader theme of site - specific ar for social justice.
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arxiv:2404.15239
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functional near - infrared spectroscopy ( fnirs ) is a non - invasive optical technique that measures brain activity by estimating blood oxygenation using near - infrared light. traditionally, psychopy is used in many studies to send task - specific markers, requiring a separate device to interface with the fnirs data collection system. in this work, we present a python - based implementation to send markers directly, eliminating the need for an additional device. this approach allows researchers to run both marker transmission and fnirs data collection on the same computer, simplifying the setup and enhancing accessibility. this streamlined solution reduces hardware requirements and makes fnirs studies more efficient.
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arxiv:2411.06523
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we study the general dynamics of the spherically symmetric gravitational collapse of a massless scalar field. we apply the galerkin projection method to transform a system of partial differential equations into a set of ordinary differential equations for modal coefficients, after a convenient truncation procedure, largely applied to problems of turbulence. in the present case, we have generated a finite dynamical system that reproduces the essential features of the dynamics of the gravitational collapse, even for a lower order of truncation. each initial condition in the space of modal coefficients corresponds to a well definite spatial distribution of scalar field. numerical experiments with the dynamical system show that depending on the strength of the scalar field packet, the formation of black - holes or the dispersion of the scalar field leaving behind flat spacetime are the two main outcomes. we also found numerical evidence that between both asymptotic states, there is a critical solution represented by a limit cycle in the modal space with period $ \ delta u \ approx 3. 55 $.
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arxiv:gr-qc/0202046
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we compare the domain of the assembly map in algebraic k - theory with respect to the family of finite subgroups with the domain of the assembly map with respect to the family of virtually cyclic subgroups and prove that the former is a direct summand of the later.
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arxiv:math/0311216
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} _ { k } [ p ^ { - 1 } ] $ with $ k $ a number field only depending on $ f _ 1, f _ 2 $. our approach relies on a reinterpretation of the local rankin - selberg integral, and works of assing and saha on values of $ p $ - adic whittaker new - vectors.
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arxiv:2501.16972
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min - max formulations have attracted great attention in the ml community due to the rise of deep generative models and adversarial methods, while understanding the dynamics of gradient algorithms for solving such formulations has remained a grand challenge. as a first step, we restrict to bilinear zero - sum games and give a systematic analysis of popular gradient updates, for both simultaneous and alternating versions. we provide exact conditions for their convergence and find the optimal parameter setup and convergence rates. in particular, our results offer formal evidence that alternating updates converge " better " than simultaneous ones.
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arxiv:1908.05699
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in optimal quantum - mechanical evolutions, motion can occur along non - predetermined paths of shortest length in an optimal time. alternatively, optimal evolutions can happen along predefined paths with no waste of energy resources and 100 % speed efficiency. unfortunately, realistic physical scenarios typically result in less - than - ideal evolutions. in this paper, we study different families of sub - optimal qubit hamiltonians, both stationary and time - varying, for which the so - called geodesic efficiency and the speed efficiency of the corresponding quantum evolutions are less than one. furthermore, after proposing an alternative hybrid efficiency measure constructed out of the two previously mentioned efficiency quantifiers, we provide illustrative examples where the average departures from time - optimality and 100 % speed efficiency are globally captured over a limited time period. in particular, thanks to this hybrid measure, quantum evolutions are partitioned in four categories : geodesic unwasteful, nongeodesic unwasteful, geodesic wasteful and, lastly, nongeodesic wasteful. finally, we discuss hamiltonians specified by magnetic field configurations, both stationary and nonstationary, yielding optimal hybrid efficiency ( that it, both time - optimality and 100 % speed efficiency ) over a finite time interval.
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arxiv:2408.14230
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quantum computing is an emerging technology that offers exponential speedups for certain problems. at the core of quantum - centric supercomputing is advanced middleware that manages the interaction between quantum hardware and classical computing infrastructure. circuit knitting is a technique that leverages classical computation to offload some of the computational burden from quantum circuits, enabling them to exceed the capacity of current noisy intermediate - scale quantum ( nisq ) devices. this is done by partitioning large circuits into smaller subcircuits, though at the cost of classical reconstruction and increased sampling overhead. despite significant advancements in reducing the theoretical costs of circuit knitting, efficiently deploying these techniques across a broad range of quantum algorithms remains a challenge. in this work, we propose cifold, a novel graph - based system that, at the individual qubit ' s level, identifies and leverages repeated structures within quantum circuits. by folding these repeated modules in parallel, cifold constructs a meta - graph that guides the partitioning process, optimizing the cutting strategy through the integration of advanced circuit knitting techniques. our system has been extensively evaluated across various quantum algorithms, achieving up to 799. 2 \ % reduction in quantum resource usage, demonstrating its scalability and substantial performance improvements over state - of - the - art approaches.
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arxiv:2412.18705
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self - assembly of particles with short - range attraction and long - range repulsion ( salr ) interactions on a flat and on a spherical surface is compared. molecular dynamics ( md ) simulations are performed for the two systems having the same area and the density optimal for formation of stripes of particles. structural characteristics, e. g. a cluster size distribution, a number of defects and an orientational order parameter ( op ), as well as the specific heat, are obtained for a range of temperature. in both cases, the cluster size distribution becomes bimodal and elongated clusters appear at the temperature corresponding to the maximum of the specific heat. when the temperature decreases, orientational ordering of the stripes takes place, and the number of particles per cluster or stripe increases in both cases. however, only on the flat surface the specific heat has another maximum at the temperature corresponding to a rapid change of the op. on the sphere, the crossover between the isotropic and anisotropic structures occurs in a much broader temperature interval, the orientational order is weaker, and occurs at significantly lower temperature. at low temperature the stripes on the sphere form spirals, and the defects resemble defects in the nematic phase of rods adsorbed at a sphere.
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arxiv:1804.04180
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we study some of the local properties of the fiber - full scheme, which is a fine moduli space that generalizes the hilbert scheme by parametrizing closed subschemes with prescribed cohomological data. as a consequence, we provide sufficient conditions for cohomology to remain constant under gr \ " obner degenerations. we also describe a tangent - obstruction theory for the fiber - full scheme in analogy with the one for the hilbert scheme.
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arxiv:2202.06652
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we present an improved determination of the cp and cpt violation parameters re ( epsilon ) and im ( delta ) based on the unitarity condition ( bell - steinberger relation ) and on recent results from the kloe experiment. we find re ( epsilon ) = ( 159. 6 \ pm 1. 3 ) 10 ^ - 5 and im ( delta ) = ( 0. 4 \ pm 2. 1 ) 10 ^ - 5, consistent with no cpt violation.
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arxiv:hep-ex/0610034
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, the researcher ( s ) may collect primary or secondary data. primary data is data collected specifically for the research, such as through interviews or questionnaires. secondary data is data that already exists, such as census data, which can be re - used for the research. it is good ethical research practice to use secondary data wherever possible. mixed - method research, i. e. research that includes qualitative and quantitative elements, using both primary and secondary data, is becoming more common. this method has benefits that using one method alone cannot offer. for example, a researcher may choose to conduct a qualitative study and follow it up with a quantitative study to gain additional insights. big data has brought big impacts on research methods so that now many researchers do not put much effort into data collection ; furthermore, methods to analyze easily available huge amounts of data have also been developed. non - empirical research non - empirical ( theoretical ) research is an approach that involves the development of theory as opposed to using observation and experimentation. as such, non - empirical research seeks solutions to problems using existing knowledge as its source. this, however, does not mean that new ideas and innovations cannot be found within the pool of existing and established knowledge. non - empirical research is not an absolute alternative to empirical research because they may be used together to strengthen a research approach. neither one is less effective than the other since they have their particular purpose in science. typically empirical research produces observations that need to be explained ; then theoretical research tries to explain them, and in so doing generates empirically testable hypotheses ; these hypotheses are then tested empirically, giving more observations that may need further explanation ; and so on. see scientific method. a simple example of a non - empirical task is the prototyping of a new drug using a differentiated application of existing knowledge ; another is the development of a business process in the form of a flow chart and texts where all the ingredients are from established knowledge. much of cosmological research is theoretical in nature. mathematics research does not rely on externally available data ; rather, it seeks to prove theorems about mathematical objects. = = research ethics = = = = problems in research = = = = = metascience = = = metascience is the study of research through the use of research methods. also known as " research on research ", it aims to reduce waste and increase the quality of research in all fields. meta - research concerns itself with the detection of bias, methodological flaws, and other
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https://en.wikipedia.org/wiki/Research
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sub - harmonics of electric dipole spin resonance ( edsr ) mediated by landau - zener - st { \ " u } ckelberg - majorana ( lzsm ) tunneling transitions are studied numerically and analytically in a zeeman - split four level system with strong spin - orbit coupling that can be realized, for example, in a gaas - based double quantum dot in a single - hole regime. the spin qubit is formed in one of the dots and the second dot is used as an auxiliary element to enhance functionality of the spin qubit. in particular, it is found that the spin rotation rate can be essentially enhanced due to the tunnel coupling with the auxiliary dot on both the main edsr frequency and at its high sub - harmonics allowing the coherent spin $ \ pi $ - rotations on a 10 - ns time scale. spin manipulation on high sub - harmonics is promising for new time - efficient schemes of the spin control and readout in qubit devices operating at high magnetic fields where the main harmonic is inaccessible due to hardware limitations.
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arxiv:2311.01607
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we identify analytically a multiple - peak structure in the energy - density spectrum of induced gravitational waves ( gws ) generated at second - order from a primordial scalar perturbations also with multiple ( $ n $ ) peaks at small scales $ k _ { * i } $. the energy - density spectrum of induced gws exhibits at most $ c _ { n + 1 } ^ 2 $ and at least $ n $ peaks at wave - vectors $ k _ { ij } \ equiv ( k _ { * i } + k _ { * j } ) / \ sqrt { 3 } $ due to resonant amplification, and, under the narrow - width approximation, it contains an universal factor that can be interpreted as a result of momentum conservation. we also extend these discussions to the case of non - gaussian perturbations.
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arxiv:1901.10152
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this paper has been withdrawn as the statements in proposition 4. 4 and theorem 1. 4 ( i ) are not correct.
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arxiv:math/0612859
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a divisible binary classical code is one in which every code word has weight divisible by a fixed integer. if the divisor is $ 2 ^ \ nu $ for a positive integer $ \ nu $, then one can construct a calderbank - shor - steane ( css ) code, where $ x $ - stabilizer space is the divisible classical code, that admits a transversal gate in the $ \ nu $ - th level of clifford hierarchy. we consider a generalization of the divisibility by allowing a coefficient vector of odd integers with which every code word has zero dot product modulo the divisor. in this generalized sense, we construct a css code with divisor $ 2 ^ { \ nu + 1 } $ and code distance $ d $ from any css code of code distance $ d $ and divisor $ 2 ^ \ nu $ where the transversal $ x $ is a nontrivial logical operator. the encoding rate of the new code is approximately $ d $ times smaller than that of the old code. in particular, for large $ d $ and $ \ nu \ ge 2 $, our construction yields a css code of parameters $ [ [ o ( d ^ { \ nu - 1 } ), \ omega ( d ), d ] ] $ admitting a transversal gate at the $ \ nu $ - th level of clifford hierarchy. for our construction we introduce a conversion from magic state distillation protocols based on clifford measurements to those based on codes with transversal $ t $ - gates. our tower contains, as a subclass, generalized triply even css codes that have appeared in so - called gauge fixing or code switching methods.
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arxiv:1709.08658
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electronic health records ( ehrs ) are a pivotal data source that enables numerous applications in computational medicine, e. g., disease progression prediction, clinical trial design, and health economics and outcomes research. despite wide usability, their sensitive nature raises privacy and confidentially concerns, which limit potential use cases. to tackle these challenges, we explore the use of generative models to synthesize artificial, yet realistic ehrs. while diffusion - based methods have recently demonstrated state - of - the - art performance in generating other data modalities and overcome the training instability and mode collapse issues that plague previous gan - based approaches, their applications in ehr generation remain underexplored. the discrete nature of tabular medical code data in ehrs poses challenges for high - quality data generation, especially for continuous diffusion models. to this end, we introduce a novel tabular ehr generation method, ehr - d3pm, which enables both unconditional and conditional generation using the discrete diffusion model. our experiments demonstrate that ehr - d3pm significantly outperforms existing generative baselines on comprehensive fidelity and utility metrics while maintaining less attribute and membership vulnerability risks. furthermore, we show ehr - d3pm is effective as a data augmentation method and enhances performance on downstream tasks when combined with real data.
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arxiv:2404.12314
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the pandemic of covid - 19 has caused severe public health consequences around the world. many interventions of covid - 19 have been implemented. it is of great public health and societal importance to evaluate the effects of interventions in the pandemic of covid - 19. in this paper, with help of synthetic control method, regression discontinuity and a susceptible - infected and infectious without isolation - hospitalized in isolation - removed ( sihr ) model, we evaluate the horizontal and longitudinal effects of stringent interventions implemented in wenzhou, a representative urban city of china, where stringent interventions were enforced to curb its own epidemic situation with rapidly increasing newly confirmed cases. we found that there were statistically significant treatment effects of those stringent interventions which reduced the cumulative confirmed cases of covid - 19. those reduction effects would increase over time. also, if the stringent interventions were delayed by 2 days or mild interventions were implemented instead, the expected number of cumulative confirmed cases would have been nearly 2 times or 5 times of the actual number. the effects of stringent interventions are significant in mitigating the epidemic situation of covid - 19. the slower the interventions were implemented, the more severe the epidemic would have been, and the stronger the interventions would have been required.
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arxiv:2006.00523
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we study the power density spectrum ( pds ) of light curves of the observed gamma - ray bursts ( grbs ) to search for a direct signature for cosmological time dilation in the pds statistics with the grbs whose redshifts $ z $ ' s are known. the anticorrelation of a timescale measure and a brightness measure is indirect evidence of its effect. on the other hand, we directly demonstrate that a time dilation effect can be seen in grb light curves. we find that timescales tend to be shorter in bursts with small redshift, as expected from cosmological time - dilation effects, and we also find that there may be non - cosmological effects constituting to this correlation. we discuss its implication on interpretations of the pds analysis results. we put forward another caution to this kind of analysis when we statistically exercise with grbs whose $ z $ is unknown.
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arxiv:astro-ph/0106220
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neural network has attracted great attention for a long time and many researchers are devoted to improve the effectiveness of neural network training algorithms. though stochastic gradient descent ( sgd ) and other explicit gradient - based methods are widely adopted, there are still many challenges such as gradient vanishing and small step sizes, which leads to slow convergence and instability of sgd algorithms. motivated by error back propagation ( bp ) and proximal methods, we propose a semi - implicit back propagation method for neural network training. similar to bp, the difference on the neurons are propagated in a backward fashion and the parameters are updated with proximal mapping. the implicit update for both hidden neurons and parameters allows to choose large step size in the training algorithm. finally, we also show that any fixed point of convergent sequences produced by this algorithm is a stationary point of the objective loss function. the experiments on both mnist and cifar - 10 demonstrate that the proposed semi - implicit bp algorithm leads to better performance in terms of both loss decreasing and training / validation accuracy, compared to sgd and a similar algorithm proxbp.
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arxiv:2002.03516
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we consider the stochastic quantization of a quartic double - well energy functional in the semiclassical regime and derive optimal asymptotics for the exponentially small splitting of the ground state energy. our result provides an infinite - dimensional version of some sharp tunneling estimates known in finite dimensions for semiclassical witten laplacians in degree zero. from a stochastic point of view it proves that the $ l ^ 2 $ spectral gap of the stochastic one - dimensional allen - cahn equation in finite volume satisifies a kramers - type formula in the limit of vanishing noise. we work with finite - dimensional lattice approximations and establish semiclassical estimates which are uniform in the dimension. our key estimate shows that the constant separating the two exponentially small eigenvalues from the rest of the spectrum can be taken independently of the dimension.
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arxiv:1911.03187
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we study the relation of the notion of weak admissibility in families of filtered phi - modules, as considered in a companion paper, with the adjoint quotient. we show that the weakly admissible subset is an open subvariety in the fibers over the adjoint quotient. further we determine the image of the weakly admissible set in the adjoint quotient generalizing earlier work of breuil and schneider.
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arxiv:1102.0119
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the problem of measurement in quantum mechanics is reanalyzed within a general, strictly probabilistic framework ( without reduction postulate ). based on a novel comprehensive definition of measurement the natural emergence of objective events is demonstrated and their formal representation within quantum mechanics is obtained. in order to be objective an event is required to be observable or readable in at least two independent, mutually non - interfering ways with necessarily agreeing results. consistency in spite of unrestricted validity of reversibility of the evolution or the superposition principle is demonstrated and the role played by state reduction, in a properly defined restricted sense, is discussed. some general consequences are pointed out.
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arxiv:quant-ph/9811074
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multimodal entity linking ( mel ) is a crucial task that aims at linking ambiguous mentions within multimodal contexts to the referent entities in a multimodal knowledge base, such as wikipedia. existing methods focus heavily on using complex mechanisms and extensive model tuning methods to model the multimodal interaction on specific datasets. however, these methods overcomplicate the mel task and overlook the visual semantic information, which makes them costly and hard to scale. moreover, these methods can not solve the issues like textual ambiguity, redundancy, and noisy images, which severely degrade their performance. fortunately, the advent of large language models ( llms ) with robust capabilities in text understanding and reasoning, particularly multimodal large language models ( mllms ) that can process multimodal inputs, provides new insights into addressing this challenge. however, how to design a universally applicable llms - based mel approach remains a pressing challenge. to this end, we propose unimel, a unified framework which establishes a new paradigm to process multimodal entity linking tasks using llms. in this framework, we employ llms to augment the representation of mentions and entities individually by integrating textual and visual information and refining textual information. subsequently, we employ the embedding - based method for retrieving and re - ranking candidate entities. then, with only ~ 0. 26 % of the model parameters fine - tuned, llms can make the final selection from the candidate entities. extensive experiments on three public benchmark datasets demonstrate that our solution achieves state - of - the - art performance, and ablation studies verify the effectiveness of all modules. our code is available at https : / / github. com / javkonline / unimel.
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arxiv:2407.16160
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steady - state advective accretion flows in the presence of thermal conduction are studied. all three components of velocity in a spherical coordinates are considered and the flow displays both inflowing and outflowing regions according to our similarity solutions. thermal conductivity provides latitudinal energy transport and so, the flow rotates more slowly and becomes hotter with increasing thermal conductivity coefficient. we also show that opening angle of the outflow region decreases as thermal conduction becomes stronger.
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arxiv:1309.5710
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this letter investigates the prescribed - instant stabilization problem for high - order integrator systems. in anothor word, the settling time under the presented controller is independent of the initial conditions and equals the prescribed time instant. the controller is designed with the concept of backstepping. a strict proof based on the lyapunov method is presented to clamp the settling time to the prescribed time instant from both the left and right sides. this proof serves as an example to present a general framework to verify the designed stabilization property. it should be emphasized that the prescribed - time stability ( psts ) [ 1 ] can only prescribe the upper bound of the settling time and is different from this work. the detailed argumentation will be presented after a brief review of the existing important research.
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arxiv:2302.11334
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recent years have seen a significant progress in the development of general relativistic codes for the numerical solution of the equations of magnetohydrodynamics in spacetimes with high and dynamical curvature. these codes are valuable tools to explore the large - scale plasma dynamics such as that takes place when two neutron stars collide or when matter accretes onto a supermassive black hole. this chapter is meant to provide a very brief but complete overview of the set of equations that are normally solved in modern numerical codes after they are cast into a conservative formulation within a 3 + 1 split of spacetime.
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arxiv:2404.13824
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lattice matched n - type alinp ( 100 ) charge selective contacts are commonly grown on n - p gainp ( 100 ) top absorbers in high - efficiency iii - v multijunction solar or photoelectrochemical cells. the cell performance can be greatly limited by the electron selectivity and valance band offset at this heterointerface. understanding of the atomic and electronic properties of the gainp / alinp heterointerface is crucial for the reduction of photocurrent losses in iii - v multijunction devices. in our paper, we investigated chemical composition and electronic properties of n - gainp / n - alinp heterostructures by x - ray photoelectron spectroscopy ( xps ). to mimic an in - situ interface experiment with in - situ stepwise deposition of the contact material, 1 nm - 50 nm thick n - alinp ( 100 ) epitaxial layers were grown on n - gainp ( 100 ) buffer layer on n - gaas ( 100 ) substrates by metal organic vapor phase epitaxy. we observed ( 2x2 ) / c ( 4x2 ) low - energy electron diffraction patterns with characteristic diffuse streaks along the [ 01 - 1 ] direction due to p - p dimers on both alinp ( 100 ) and gainp ( 100 ) as - prepared surfaces. atomic composition analysis confirmed p - rich termination on both surfaces. angle - resolved xps measurements revealed a surface core level shift of 0. 9 ev in p 2p peaks and the absence of interface core level shifts. we assigned the surface chemical shift in the p2p spectrum to p - p bonds on a surface. we found an upward surface band bending on the ( 2x2 ) / c ( 4x2 ) surfaces most probably caused by localized mid - gap electronic states. pinning of the fermi level by localized electronic states remained in n - gainp / n - alinp heterostructures. a valence band offset of 0. 2 ev was derived by xps and band alignment diagram models for the n - n junctions were suggested.
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arxiv:2207.08606
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we establish the ultimate quantum limits to the amplification of an unknown coherent state, both in the deterministic and probabilistic case, investigating the realistic scenario where the expected photon number is finite. in addition, we provide the benchmark that experimental realizations have to surpass in order to beat all classical amplification strategies and to demonstrate genuine quantum amplification. our result guarantees that a successful demonstration is in principle possible for every finite value of the expected photon number.
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arxiv:1301.1170
|
wannier functions have become a powerful tool in the electronic structure calculations of extended systems. the generalized pipek - mezey wannier functions exhibit appealing characteristics ( e. g., reaching an optimal localization and the separation of the $ \ sigma $ - $ \ pi $ orbitals ) when compared with other schemes. however, when applied to giant nanoscale systems, the orbital localization suffers from a large computational cost overhead when one is interested in localized states in a small fragment of the system. herein we present a swift, efficient, and robust approach for obtaining regionally localized orbitals of a subsystem within the generalized pipek - mezey scheme. the proposed algorithm introduces a reduced workspace and sequentially exhausts the entire orbital space until the convergence of the localization functional. it tackles systems with $ \ sim $ 10000 electrons within 0. 5 hours with no loss in localization quality compared to the traditional approach. regionally localized orbitals with a higher extent of localization are obtained via judiciously extending the subsystem ' s size. exemplifying on large bulk and a 4 - nm wide slab of diamond with nv $ ^ - $ center, we demonstrate the methodology and discuss how the choice of the localization region affects the excitation energy of the defect. furthermore, we show how the sequential algorithm is easily extended to stochastic methodologies that do not provide individual single - particle eigenstates. it is thus a promising tool to obtain regionally localized states for solving the electronic structure problems of a subsystem embedded in giant condensed systems.
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arxiv:2204.00252
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