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recent advances in vision transformer ( vit ) have demonstrated its impressive performance in image classification, which makes it a promising alternative to convolutional neural network ( cnn ). unlike cnns, vit represents an input image as a sequence of image patches. the patch - based input image representation makes the following question interesting : how does vit perform when individual input image patches are perturbed with natural corruptions or adversarial perturbations, compared to cnns? in this work, we study the robustness of vit to patch - wise perturbations. surprisingly, we find that vits are more robust to naturally corrupted patches than cnns, whereas they are more vulnerable to adversarial patches. furthermore, we discover that the attention mechanism greatly affects the robustness of vision transformers. specifically, the attention module can help improve the robustness of vit by effectively ignoring natural corrupted patches. however, when vits are attacked by an adversary, the attention mechanism can be easily fooled to focus more on the adversarially perturbed patches and cause a mistake. based on our analysis, we propose a simple temperature - scaling based method to improve the robustness of vit against adversarial patches. extensive qualitative and quantitative experiments are performed to support our findings, understanding, and improvement of vit robustness to patch - wise perturbations across a set of transformer - based architectures.
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arxiv:2111.10659
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in this paper, we introduce a new dataset, \ textbf { kimia path24 }, for image classification and retrieval in digital pathology. we use the whole scan images of 24 different tissue textures to generate 1, 325 test patches of size 1000 $ \ times $ 1000 ( 0. 5mm $ \ times $ 0. 5mm ). training data can be generated according to preferences of algorithm designer and can range from approximately 27, 000 to over 50, 000 patches if the preset parameters are adopted. we propose a compound patch - and - scan accuracy measurement that makes achieving high accuracies quite challenging. in addition, we set the benchmarking line by applying lbp, dictionary approach and convolutional neural nets ( cnns ) and report their results. the highest accuracy was 41. 80 \ % for cnn.
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arxiv:1705.07522
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the purpose of this study is the derivation of the equation of motion for particles and light in the spacetime of reissner - nordstr \ " { o } m - ( anti - ) de sitter black holes in the background of different kinds of regular and exotic matter fields. the complete analytical solutions of the geodesic equations are given in terms of the elliptic weierstra { \ ss } $ \ wp $ - function and the hyperelliptic kleinian $ \ sigma $ - function. finally after analyzing the geodesic motion of test particles and light using parametric diagrams and effective potentials, we present a list of all possible orbits.
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arxiv:1903.11878
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this thesis compiles the results of six works which deal with - inflationary model building and estimation of cosmological parameters from various field theoretic setup, quantification of reheating temperature, studies of leptogenesis in braneworld and estimation of primordial non - gaussianity from $ { \ cal n } = 1 $ supergravity using $ \ delta n $ formalism. we start our discussion with exploring the possibility of mssm inflation in the light of recent observed data from various d - flat directions using the saddle and inflection point techniques. the effective inflaton potential around saddle point and inflection point have been utilized in estimating the observable parameters and confronting them with wmap7 and planck dataset. next we explore the possibility of inflation from the five dimensional $ { \ cal n } = 2 $ supergravity setup by deriving the effective potential in the context of rs like braneworld model and dbi galileon. after deriving an four dimensional effective potential, we obtain the inflationary observables from both the scenarios and confront them with the wmap data. further we fit the cmb angular power spectra from tt anisotropy and other polarization data obtained from wmap. further, we discuss the non - trivial features of reheating from supergravity inspired braneworld model, where the results are to some extent different from that of the usual low energy gr counterpart, because of the modified friedmann equations in this setup. we explicitly derive the analytical expressions for the reheating temperature and further solve the evolution equation of the number density of thermal gravitino which results in the gravitino abundance. finally, we study the primordial local type of non - gaussian features using $ \ delta n $ formalism for a generic class of sub - planckian models dominated by the hubble - induced corrections within $ { \ cal n } = 1 $ supergravity framework.
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arxiv:1603.08306
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we provide description of rapidity spectra of particles produced in p - anti - p collisions using anomalous diffusion approach to account for their non - equilibrium character. in particular, we exhibit connection between multiproduction processes and anomalous diffusion described through the nonlinear focker - planck equation with nonlinearity given by the nonextensivity parameter q describing the underlying tsallis q - statistics and demonstrate how it leads to the feynman scaling violation in these collisions. the q parameter obtained this way turns out to be closely connected to parameter 1 / k converting the original poissonian multiplicity distribution to its observed negative binomial form. the inelasticity of reaction has been also calculated and found to slightly decrease with the increasing energy of reaction. keywords : inelasticity, rapidity spectra, nonextensivity
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arxiv:hep-ph/0206157
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graph in $ \ mathsf { a }. $ we conjecture that the same holds true for distinguishing $ \ mathbb { g } ( n, 1 / 2 ) $ and any graphon if we also add triangles to $ \ mathsf { a }. $
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arxiv:2504.17202
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detection of daemons in low - background conditions in september 2005 and march 2006 has provided evidence for the expected to occur at that times maxima in the flux of daemons with v ~ 10 - 15 km s - 1, which hit the earth from near - earth, almost circular heliocentric orbits. the ability of some feu - 167 - 1 pm tubes with a thicker inner al coating to detect directly daemon passage through them has also been demonstrated, an effect increasing ~ 100 - fold the detector efficiency. as a result, the daemon flux recorded at the maxima was increased from ~ 10 - 9 to ~ 10 - 7 cm - 2 s - 1. the intensity and direction of the flux during maxima depend on the time of day and latitude of observations ( therefore, synchronous measurements in the northern and southern earth ' s hemispheres are desirable ). all the experimental results obtained either support the conclusions following from the daemon paradigm or find a simple interpretation within it.
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arxiv:astro-ph/0607046
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we apply the landau equations, whose solutions parameterize the locus of possible branch points, to the one - and two - loop feynman integrals relevant to mhv amplitudes in planar $ \ mathcal { n } = 4 $ super - yang - mills theory. we then identify which of the landau singularities appear in the symbols of the amplitudes, and which do not. we observe that all of the symbol entries in the two - loop mhv amplitudes are already present as landau singularities of one - loop pentagon integrals.
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arxiv:1512.07909
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in recent years, the interaction between dark matter ( dm ) and dark energy has become a topic of interest in cosmology. interacting dark matter - dark energy ( ide ) models have a substantial impact on the formation of cosmological large - scale structures, which serve as the background for dm halo evolution. this impact can be examined through the shape and spin orientation of halos in numerical simulations incorporating ide effects. in our work, we use the n - body simulation pipeline me - gadget to simulate and study the halo spin and orientation in ide models. we found that in models where dm transfers into de ( ide i ), the alignment of halo shapes with the surrounding tidal field is enhanced, while the alignment of halo spins with the tidal field is decreased compared to { \ lambda } cdm. conversely, in models where de transfers into dm ( ide ii ), the opposite occurs. we have provided fitted functions to describe these alignment signals. our study provides the foundation for more accurate modeling of observations in the future such as china space station telescope.
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arxiv:2501.03750
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purpose : the purpose of this work was to provide a flexible platform for flash research with protons by adapting a former clinical pencil beam scanning gantry to irradiations with ultrahigh dose rates. methods : psi gantry 1 treated patients until december 2018. we optimized the beamline parameters to transport the 250 mev beam extracted from the psi comet accelerator to the treatment room, maximizing the transmission of beam intensity to the sample. we characterized a dose monitor on the gantry to ensure good control of the dose, delivered in spot - scanning mode. we characterized the beam for different dose rates and field sizes for transmission irradiations. we explored scanning possibilities in order to enable conformal irradiations or transmission irradiations of large targets ( with transverse scanning ). results : we achieved a transmission of 86 % from the cyclotron to the treatment room. we reached a peak dose rate of 9000 gy / s at 3 mm water equivalent depth, along the central axis of a single pencil beam. field sizes of up to 5x5 mm $ ^ { 2 } $ were achieved for single spot flash irradiations. fast transverse scanning allowed to cover a field of 16x1. 2 cm $ ^ { 2 } $. with the use of a nozzle - mounted range shifter we are able to span depths in water ranging from 19. 6 to 37. 9 cm. various dose levels were delivered with a precision within less than 1 %. conclusions : we have realized a proton flash irradiation setup able to investigate continuously a wide dose rate spectrum, from 1 to 9000 gy / s in a single spot irradiation as well as in the pencil beam scanning mode. as such, we have developed a versatile test bench for flash research.
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arxiv:2101.01770
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electron drag measurements of electron - electron scattering rates performed close to the fermi temperature are reported. while evidence of an enhancement due to plasmons, as was recently predicted [ k. flensberg and b. y. - k. hu, phys. rev. lett. 73, 3572 ( 1994 ) ], is found, important differences with the random - phase approximation based calculations are observed. although static correlation effects likely account for part of this difference, it is argued that correlation - induced multiparticle excitations must be included to account for the magnitude of the rates and observed density dependences.
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arxiv:cond-mat/9809049
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within the framework of augmented version of the superfield approach to becchi - rouet - stora - tyutin ( brst ) formalism, we derive the superspace unitary operator ( and its hermitian conjugate ) in the context of four ( 3 + 1 ) - dimensional ( 4d ) interacting non - abelian 1 - form gauge theory with dirac fields. the ordinary 4d non - abelian theory, defined on the flat 4d minkowski spacetime manifold, is generalized onto a ( 4, 2 ) - dimensional supermanifold which is parameterized by the spacetime bosonic coordinates x ^ \ mu ( with \ mu = 0, 1, 2, 3 ) and a pair of grassmannian variables ( \ theta, \ bar \ theta ) which satisfy the standard relationships : \ theta ^ 2 = { \ bar \ theta } ^ 2 = 0, \ theta \, \ bar \ theta + \ bar \ theta \, \ theta = 0. various consequences of the application of the above superspace ( susp ) unitary operator ( and its hermitian conjugate ) are discussed. in particular, we obtain the results of the application of horizontality condition ( hc ) and gauge invariant restriction ( gir ) in the language of the above susp operators. one of the novel results of our present investigation is the derivation of explicit expressions for the susp unitary operator ( and its hermitian conjugate ) without imposing any hermitian conjugation condition from outside on the parameters and ( super ) fields of the supersymmetric version of our 4d interacting non - abelian 1 - form theory with dirac fields.
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arxiv:1509.07319
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we employ the very large cosmological hydrodynamical simulation bluetides to investigate the predicted properties of the galaxy population during the epoch of reionisation ( $ z > 8 $ ). bluetides has a resolution and volume ( $ ( 400 / h \ approx 577 ) ^ { 3 } \, { \ rm cmpc ^ 3 } $ ) providing a population of galaxies which is well matched to depth and area of current observational surveys targeting the high - redshift universe. at $ z = 8 $ bluetides includes almost 160, 000 galaxies with stellar masses $ > 10 ^ { 8 } \, { \ rm m _ { \ odot } } $. the population of galaxies predicted by bluetides closely matches observational constraints on both the galaxy stellar mass function and far - uv ( $ 150 \, { \ rm nm } $ ) luminosity function. galaxies in bluetides are characterised by rapidly increasing star formation histories. specific star formation rates decrease with redshift though remain largely insensitive to stellar mass. as a result of the enhanced surface density of metals more massive galaxies are predicted to have higher dust attenuation resulting in a significant steepening of the observed far - uv luminosity function at high luminosities. the contribution of active smbhs to the uv luminosities of galaxies with stellar masses $ 10 ^ { 9 - 10 } \, { \ rm m _ { \ odot } } $ is around $ 3 \ % $ on average. approximately $ 25 \ % $ of galaxies with $ m _ { * } \ approx 10 ^ { 10 } \, { \ rm m _ { \ odot } } $ are predicted to have active smbh which contribute $ > 10 \ % $ of the total uv luminosity.
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arxiv:1704.00954
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5 } _ { - 1. 3 } \ times 10 ^ { - 7 } \, m _ \ odot \, { \ rm mpc } ^ { - 3 } $ ( $ z \ approx 7 $ ). these results are consistent with the expected metal yields from the integrated star formation history at the respective redshifts. this suggests that the majority of metals produced at $ z \ gtrsim 5 $ are confined to the ism of galaxies.
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arxiv:2308.14813
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we consider the $ k $ - dispersion generalized benjamin - ono ( $ k $ - dgbo ) equations. for nonlinearities with power $ k \ geq 4 $, we establish local and global well - posedness results for the associated initial value problem ( ivp ) in both the critical and subcritical regimes, addressing sharp regularity in homogeneous and inhomogeneous sobolev spaces. additionally, our method enables the formulation of a scattering criterion and a scattering theory for small data. we also investigate the case $ k = 3 $ via frequency - restricted estimates, obtaining local well - posedness results for the ivp associated with the $ 3 $ - dgbo equation and generalizing the existing results in the literature for the whole subcritical range. for higher dispersion, these local results can be extended globally even for rough data, particularly for initial data in sobolev spaces with negative indices. as a byproduct, we derive new nonlinear smoothing estimates.
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arxiv:2410.17217
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we study the su ( 2 ) gauge theory with scalar matter in the adjoint representation in 3d at finite temperature. we find evidence for a finite temperature phase transition both in the symmetric and in the broken phase ; such transitions are consistent with the universality class of ising 2d, in agreement with recent analytical arguments.
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arxiv:hep-lat/0409044
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we investigate potential hadronic molecular states in the $ d ^ { ( * ) } \ bar d ^ { ( * ) } $ and $ b ^ { ( * ) } \ bar b ^ { * } $ systems using light meson exchange interactions. our analysis focuses on coupled - channel systems with spin - parity quantum numbers $ j ^ { pc } = 0 ^ { + + } $, $ 1 ^ { + \ pm } $ and $ 2 ^ { + + } $, examining how the $ \ delta ( r ) $ potential affects states near threshold. using coupled - channel analysis, we reproduce the $ x ( 3872 ) $ mass with a given cutoff for the $ ( i ) j ^ { pc } = ( 0 ) 1 ^ { + + } $ state, finding a minimal impact from the $ \ delta ( r ) $ term. at this cutoff, both the $ ( 0 ) 0 ^ { + + } $ state near the $ d \ bar d $ threshold and the $ ( 0 ) 1 ^ { + - } $ state near the $ d \ bar d ^ * $ threshold show less sensitivity to the $ \ delta ( r ) $ term compared to the three states - $ ( 0 ) 0 ^ { + + } $, $ ( 0 ) 1 ^ { + - } $, and $ ( 0 ) 2 ^ { + + } $ - near the $ d ^ * \ bar d ^ * $ threshold. as anticipated, the $ b ^ { ( * ) } \ bar b ^ { * } $ systems exhibit similar behavior but with stronger binding due to their larger reduced mass. these findings suggest promising directions for future experimental searches, particularly in the isoscalar sector, which could substantially advance our understanding of exotic tetraquark states.
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arxiv:2503.01322
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an innovative extension of geometric brownian motion model is developed by incorporating a weighting factor and a stochastic function modelled as a mixture of power and trigonometric functions. simulations based on this modified brownian motion model with optimal weighting factors selected by goodness of fit tests, substantially outperform the basic geometric brownian motion model in terms of fitting the returns distribution of historic data price indices. furthermore we attempt to provide an interpretation of the additional stochastic term in relation to irrational behaviour in financial markets and outline the importance of this novel model.
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arxiv:1507.02203
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we present relations between growth, growth of diameters and the rate of vanishing of the spectral gap in schreier graphs of automaton groups. in particular, we introduce a series of examples, called hanoi towers groups since they model the well known hanoi towers problem, that illustrate some of the possible types of behavior.
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arxiv:math/0601592
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is there an initialization for deep networks that requires no learning? explainfix adopts two design principles : the " fixed filters " principle that all spatial filter weights of convolutional neural networks can be fixed at initialization and never learned, and the " nimbleness " principle that only few network parameters suffice. we contribute ( a ) visual model - based explanations, ( b ) speed and accuracy gains, and ( c ) novel tools for deep convolutional neural networks. explainfix gives key insights that spatially fixed networks should have a steered initialization, that spatial convolution layers tend to prioritize low frequencies, and that most network parameters are not necessary in spatially fixed models. explainfix models have up to 100x fewer spatial filter kernels than fully learned models and matching or improved accuracy. our extensive empirical analysis confirms that explainfix guarantees nimbler models ( train up to 17 \ % faster with channel pruning ), matching or improved predictive performance ( spanning 13 distinct baseline models, four architectures and two medical image datasets ), improved robustness to larger learning rate, and robustness to varying model size. we are first to demonstrate that all spatial filters in state - of - the - art convolutional deep networks can be fixed at initialization, not learned.
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arxiv:2303.10408
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electrodynamics becomes nonlinear and permits the self - interaction of fields when the quantised nature of vacuum states is taken into account. the effect on a plane probe pulse propagating through a stronger constant crossed background is calculated using numerical simulation and by analytically solving the corresponding wave equation. the electromagnetic shock resulting from vacuum high harmonic generation is investigated and a nonlinear shock parameter identified.
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arxiv:1503.05192
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we introduce a new topological property called ( * ) and the corresponding class of topological spaces, which includes spaces with $ g _ \ delta $ - diagonals and gruenhage spaces. using ( * ), we characterise those banach spaces which admit equivalent strictly convex norms, and give an internal topological characterisation of those scattered compact spaces $ k $, for which the dual banach space $ c ( k ) ^ * $ admits an equivalent strictly convex dual norm. we establish some relationships between ( * ) and other topological concepts, and the position of several well - known examples in this context. for instance, we show that $ c ( \ mathcal { k } ) ^ * $ admits an equivalent strictly convex dual norm, where $ \ mathcal { k } $ is kunen ' s compact space. also, under the continuum hypothesis ch, we give an example of a compact scattered non - gruenhage space having ( * ).
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arxiv:1012.5595
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the laser interferometer space antenna ( lisa ) will observe gravitational waves in the millihertz frequency band, detecting signals from a vast number of astrophysical sources embedded in instrumental noise. extracting individual signals from these overlapping contributions is a fundamental challenge in lisa data analysis and is traditionally addressed using computationally expensive stochastic bayesian techniques. in this work, we present a deep learning - based framework for blind source separation in lisa data, employing an encoder - decoder architecture commonly used in digital audio processing to isolate individual signals within complex mixtures. our approach enables signals from massive black - hole binaries, galactic binaries, and instrumental glitches to be disentangled directly in a single step, circumventing the need for sequential source identification and subtraction. by learning clustered latent space representations, the framework provides a scalable alternative to conventional methods, with applications in both low - latency event detection and full - scale global - fit analyses. as a proof of concept, we assess the model ' s performance using simulated lisa data in a controlled setting with a limited number of overlapping sources. the results highlight deep source separation as a promising tool for lisa, paving the way for future extensions to more complex datasets.
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arxiv:2503.10398
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we study phase transition of a nonequilibrium statistical - mechanical model, in which two degrees of freedom with different time scales separated from each other touch to their own heat bath. a general condition for finding anomalous negative latent heat recently discovered is derived a from thermodynamic argument. as a specific example, phase diagram of a spin - lattice gas model is studied based on a mean - field analysis with replica method. while configurational variables are spin and particle in this model, it is found that the negative latent heat appears in a parameter region of the model, irrespective of the order of their time scale. qualitative differences in the phase diagram are also discussed.
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arxiv:0807.4601
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the thermal conductivity of the color - flavor locked phase of dense quark matter is calculated. the dominant contribution to the conductivity comes from photons and nambu - goldstone bosons associated with the breaking of baryon number, both of which are trapped in the quark core. because of their very large mean free path the conductivity is also very large. the cooling of the quark core arises mostly from the heat flux across the surface of direct contact with the nuclear matter. as the thermal conductivity of the neighboring layer is also high, the whole interior of the star should be nearly isothermal. our results imply that the cooling time of compact stars with color - flavor locked quark cores is similar to that of ordinary neutron stars.
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arxiv:astro-ph/0207346
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we present the possibility that the seesaw mechanism with thermal leptogenesis can be tested using the stochastic gravitational background. achieving neutrino masses consistent with atmospheric and solar neutrino data, while avoiding non - perturbative couplings, requires right - neutrinos lighter than the typical scale of grand unification. this scale separation suggests a symmetry protecting the right handed neutrinos from getting a mass. thermal leptogenesis would then require that such a symmetry be broken below the reheating temperature. we enumerate all such possible symmetries consistent with these minimal assumptions and their corresponding defects, finding that in many cases, gravitational waves from the network of cosmic strings should be detectable. estimating the predicted gravitational wave background we find that future space - borne missions could probe the entire range relevant for thermal leptogenesis.
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arxiv:1908.03227
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second harmonic generation and optical parametric amplification in negative - index metamaterials ( nims ) are studied. the opposite directions of the wave vector and the poynting vector in nims results in a " backward " phase - matching condition, causing significant changes in the manley - rowe relations and spatial distributions of the coupled field intensities. it is shown that absorption in nims can be compensated by backward optical parametric amplification. the possibility of distributed - feedback parametric oscillation with no cavity has been demonstrated. the feasibility of the generation of entangled pairs of left - and right - handed counter - propagating photons is discussed.
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arxiv:physics/0601055
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in this paper we characterize the zero sets of functions from $ \ ell ^ { p } _ { a } $ ( the analytic functions on the open unit disk $ d $ whose taylor coefficients form an $ \ ell ^ p $ sequence ) by developing a concept of an " inner function " modeled by beurling ' s discussion of the hilbert space $ \ ell ^ { 2 } _ { a } $ ( the classical hardy space ). the zero set criterion is used to construct families of zero sets which are not covered by classical results. in particular, it is proved that when $ p > 2 $, there are zero sets for $ \ ell ^ { p } _ { a } $ which are not blaschke sequences.
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arxiv:1802.04646
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we consider the non - minimal model of gravity in $ y ( r ) f ^ 2 $ - form. we investigate a particular case of the model, for which the higher order derivatives are eliminated but the scalar curvature $ r $ is kept to be dynamical via the constraint $ y _ rf _ { mn } f ^ { mn } = - \ frac { 2 } { \ kappa ^ 2 } $. the effective fluid obtained can be represented by interacting electromagnetic field and vacuum depending on $ y ( r ) $, namely, the energy density of the vacuum tracks $ r $ while energy density of the conventional electromagnetic field is dynamically scaled with the factor $ \ frac { y ( r ) } { 2 } $. we give exact solutions for anisotropic inflation by assuming the volume scale factor of the universe exhibits a power - law expansion. the directional scale factors do not necessarily exhibit power - law expansion, which would give rise to a constant expansion anisotropy, but expand non - trivially and give rise to a non - monotonically evolving expansion anisotropy that eventually converges to a non - zero constant. relying on this fact, we discuss the anisotropic e - fold during the inflation by considering observed scale invariance in cmb and demanding the universe to undergo the same amount of e - folds in all directions. we calculate the residual expansion anisotropy at the end of inflation, though as a result of non - monotonic behaviour of expansion anisotropy all the axes of the universe undergo the same of amount of e - folds by the end of inflation. we also discuss the generation of the modified electromagnetic field during the first few e - folds of the inflation and its persistence against to the vacuum till end of inflation.
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arxiv:1611.03393
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we explore the impact of spatial fluctuations in the intergalactic medium temperature on the lyman - alpha forest flux power spectrum near z ~ 3. we develop a semianalytic model to examine temperature fluctuations resulting from inhomogeneous hi and incomplete heii reionizations. detection of these fluctuations might provide insight into the reionization histories of hydrogen and helium. furthermore, these fluctuations, neglected in previous analyses, could bias constraints on cosmological parameters from the lyman - alpha forest. we find that the temperature fluctuations resulting from inhomogeneous hi reionization are likely to be very small, with an rms amplitude of < 5 %, $ \ sigma _ { t _ 0 } / < t _ 0 > < 0. 05 $. more important are the temperature fluctuations that arise from incomplete heii reionization, which might plausibly be as large as 50 %, $ \ sigma _ { t _ 0 } / < t _ 0 > ~ 0. 5 $. in practice, however, these temperature fluctuations have only a small effect on flux power spectrum predictions. the smallness of the effect is possibly due to density fluctuations dominating over temperature fluctuations on the scales probed by current measurements. on the largest scales currently probed, k ~ 0. 001 s / km ( ~ 0. 1 h / mpc ), the effect on the flux power spectrum may be as large as ~ 10 % in extreme models. the effect is larger on small scales, up to ~ 20 % at k = 0. 1 s / km, due to thermal broadening. our results suggest that the omission of temperature fluctuations effects from previous analyses does not significantly bias constraints on cosmological parameters.
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arxiv:astro-ph/0510841
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we present new alma observations of co $ j $ = 2 $ - $ 1 line emission from the dq tau circumbinary disk. these data are used to tomographically reconstruct the keplerian disk velocity field in a forward - modeling inference framework, and thereby provide a dynamical constraint on the mass of the dq tau binary of $ m _ \ ast = 1. 27 _ { - 0. 27 } ^ { + 0. 46 } \, m _ \ odot $. those results are compared with an updated and improved orbital solution for this double - lined system based on long - term monitoring of its stellar radial velocities. both of these independent dynamical constraints on the binary mass are in excellent agreement : taken together, they demonstrate that the dq tau system mass is $ 1. 21 \ pm0. 26 \, m _ \ odot $ and that the disk and binary orbital planes are aligned within $ 3 ^ \ circ $ ( at 3 $ \ sigma $ confidence ). the predictions of various theoretical models for pre - main sequence stellar evolution are also consistent with these masses, although more detailed comparisons are difficult due to lingering uncertainties in the photospheric properties of the individual components. dq tau is the third nearly equal - mass double - lined spectroscopic binary with a circumbinary disk that has been dynamically " weighed " with these two independent techniques : all show consistent results, validating the overall accuracy of the disk - based approach and demonstrating that it can be robustly applied to large samples of young, single stars as alma ramps up to operations at full capacity.
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arxiv:1601.03806
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image quality assessment ( iqa ) focuses on the perceptual visual quality of images, playing a crucial role in downstream tasks such as image reconstruction, compression, and generation. the rapid advancement of multi - modal large language models ( mllms ) has significantly broadened the scope of iqa, moving toward comprehensive image quality understanding that incorporates content analysis, degradation perception, and comparison reasoning beyond mere numerical scoring. previous mllm - based methods typically either generate numerical scores lacking interpretability or heavily rely on supervised fine - tuning ( sft ) using large - scale annotated datasets to provide descriptive assessments, limiting their flexibility and applicability. in this paper, we propose q - insight, a reinforcement learning - based model built upon group relative policy optimization ( grpo ), which demonstrates strong visual reasoning capability for image quality understanding while requiring only a limited amount of rating scores and degradation labels. by jointly optimizing score regression and degradation perception tasks with carefully designed reward functions, our approach effectively exploits their mutual benefits for enhanced performance. extensive experiments demonstrate that q - insight substantially outperforms existing state - of - the - art methods in both score regression and degradation perception tasks, while exhibiting impressive zero - shot generalization to comparison reasoning tasks. code will be available at https : / / github. com / lwq20020127 / q - insight.
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arxiv:2503.22679
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omnipredictors are simple prediction functions that encode loss - minimizing predictions with respect to a hypothesis class $ \ mathcal { h } $, simultaneously for every loss function within a class of losses $ \ mathcal { l } $. in this work, we give near - optimal learning algorithms for omniprediction, in both the online and offline settings. to begin, we give an oracle - efficient online learning algorithm that acheives $ ( \ mathcal { l }, \ mathcal { h } ) $ - omniprediction with $ \ tilde { o } ( \ sqrt { t \ log | \ mathcal { h } | } ) $ regret for any class of lipschitz loss functions $ \ mathcal { l } \ subseteq \ mathcal { l } _ \ mathrm { lip } $. quite surprisingly, this regret bound matches the optimal regret for \ emph { minimization of a single loss function } ( up to a $ \ sqrt { \ log ( t ) } $ factor ). given this online algorithm, we develop an online - to - offline conversion that achieves near - optimal complexity across a number of measures. in particular, for all bounded loss functions within the class of bounded variation losses $ \ mathcal { l } _ \ mathrm { bv } $ ( which include all convex, all lipschitz, and all proper losses ) and any ( possibly - infinite ) $ \ mathcal { h } $, we obtain an offline learning algorithm that, leveraging an ( offline ) erm oracle and $ m $ samples from $ \ mathcal { d } $, returns an efficient $ ( \ mathcal { l } _ { \ mathrm { bv } }, \ mathcal { h }, \ varepsilon ( m ) ) $ - omnipredictor for $ \ varepsilon ( m ) $ scaling near - linearly in the rademacher complexity of $ \ mathrm { th } \ circ \ mathcal { h } $.
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arxiv:2501.17205
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the properties of $ \ pi, \ eta, k ^ + $ and $ k ^ - $ mesons are studied in nuclear reactions from sis to sps energies within the covariant transport approach hsd in comparison to the experimental data. whereas the pion, $ \ eta $ and kaon abundancies and spectra indicate little or vanishing selfe - nergies for these mesons in the medium, antikaons ( as well as antiprotons ) are found to experience strong attractive potentials in nucleus - nucleus collisions at sis energies. however, even when including these potentials the $ k ^ + $ and $ k ^ - $ spectra at ags energies are noticeably underestimated showing an experimental excess of strangeness that points towards a nonhadronic phase in these reactions. on the other hand the $ k ^ +, k ^ - $ production at sps energies is well described by the hadronic approach without incorporating any parton degrees of freedom.
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arxiv:nucl-th/9806051
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unexplainable black - box models create scenarios where anomalies cause deleterious responses, thus creating unacceptable risks. these risks have motivated the field of explainable artificial intelligence ( xai ) to improve trust by evaluating local interpretability in black - box neural networks. unfortunately, the ground truth is unavailable for the model ' s decision, so evaluation is limited to qualitative assessment. further, interpretability may lead to inaccurate conclusions about the model or a false sense of trust. we propose to improve xai from the vantage point of the user ' s trust by exploring a black - box model ' s latent feature space. we present an approach, protoshotxai, that uses a prototypical few - shot network to explore the contrastive manifold between nonlinear features of different classes. a user explores the manifold by perturbing the input features of a query sample and recording the response for a subset of exemplars from any class. our approach is the first locally interpretable xai model that can be extended to, and demonstrated on, few - shot networks. we compare protoshotxai to the state - of - the - art xai approaches on mnist, omniglot, and imagenet to demonstrate, both quantitatively and qualitatively, that protoshotxai provides more flexibility for model exploration. finally, protoshotxai also demonstrates novel explainabilty and detectabilty on adversarial samples.
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arxiv:2110.11597
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we generalize the alvis - curtis duality to the abstract representations of reductive groups with frobenius maps. similar to the case of representations of finite reductive groups, we show that the alvis - curtis duality of infinite type which we define in this paper also interchanges the irreducible representations in the principal representation category.
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arxiv:1907.04515
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nonleptonic weak decays of xi _ c into pi ^ + and a meson ( m ) - baryon ( b ) final state, mb, are analyzed from the viewpoint of probing s = - 2 baryon resonances, i. e. xi ( 1620 ) and xi ( 1690 ), of which spin - parity and other properties are not well known. we argue that the weak decay of xi _ c is dominated by a single quark - line diagram, preferred by the cabibbo - kobayashi - maskawa coefficient, color recombination factor, the diquark correlation, and the kinematical condition. the decay process has an advantage of being free from meson resonances in the pi ^ + m invariant mass distribution. the invariant mass distribution of the meson - baryon final state is calculated with three different chiral unitary approaches, assuming that the xi ( 1620 ) and xi ( 1690 ) resonances have j ^ p = 1 / 2 ^ -. it is found that a clear peak for the xi ( 1690 ) is seen in the pixi and kbarlambda spectra. we also suggest that the ratios of the pixi, kbarlambda and kbarsigma final states are useful to distinguish whether the peak is originated from the xi ( 1690 ) resonance or it is a kbarsigma threshold effect.
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arxiv:1609.00895
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three - dimensional ( 3d ) quantum xyz product can construct a class of non - css codes by using three classical codes. however, their error - correcting performance has not been studied in depth so far and whether this code construction can be generalized to higher dimension is an open question. in this paper, we first study the error - correcting performance of the 3d chamon code, which is an instance of 3d xyz product of three repetition codes. next, we show that 3d xyz product can be generalized to four dimension and propose four - dimensional ( 4d ) xyz product code construction, which constructs a class of non - css codes by using either four classical codes or two css codes. compared with 4d homological product, we show that 4d xyz product can construct non - css codes with higher code dimension or code distance. finally, we consider two instances of 4d xyz product, to which we refer as 4d chamon code and 4d xyz product concatenated code, respectively. our simulation results show that, 4d xyz product can construct non - css codes with better error - correcting performance for $ z $ - biased noise than css codes constructed by 4d homological product.
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arxiv:2408.03123
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iterated conditional expectation ( ice ) g - computation is an estimation approach for addressing time - varying confounding for both longitudinal and time - to - event data. unlike other g - computation implementations, ice avoids the need to specify models for each time - varying covariate. for variance estimation, previous work has suggested the bootstrap. however, bootstrapping can be computationally intense. here, we present ice g - computation as a set of stacked estimating equations. therefore, the variance for the ice g - computation estimator can be consistently estimated using the empirical sandwich variance estimator. performance of the variance estimator was evaluated empirically with a simulation study. the proposed approach is also demonstrated with an illustrative example on the effect of cigarette smoking on the prevalence of hypertension. in the simulation study, the empirical sandwich variance estimator appropriately estimated the variance. when comparing runtimes between the sandwich variance estimator and the bootstrap for the applied example, the sandwich estimator was substantially faster, even when bootstraps were run in parallel. the empirical sandwich variance estimator is a viable option for variance estimation with ice g - computation.
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arxiv:2306.10976
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the abstract of a scientific paper distills the contents of the paper into a short paragraph. in the biomedical literature, it is customary to structure an abstract into discourse categories like background, objective, method, result, and conclusion, but this segmentation is uncommon in other fields like computer science. explicit categories could be helpful for more granular, that is, discourse - level search and recommendation. the sparsity of labeled data makes it challenging to construct supervised machine learning solutions for automatic discourse - level segmentation of abstracts in non - bio domains. in this paper, we address this problem using transfer learning. in particular, we define three discourse categories background, technique, observation - for an abstract because these three categories are the most common. we train a deep neural network on structured abstracts from pubmed, then fine - tune it on a small hand - labeled corpus of computer science papers. we observe an accuracy of 75 % on the test corpus. we perform an ablation study to highlight the roles of the different parts of the model. our method appears to be a promising solution to the automatic segmentation of abstracts, where the labeled data is sparse.
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arxiv:2005.05414
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for a quantum lie algebra $ \ gamma $, let $ \ gamma ^ \ wedge $ be its exterior extension ( the algebra $ \ gamma ^ \ wedge $ is canonically defined ). we introduce a differential on the exterior extension algebra $ \ gamma ^ \ wedge $ which provides the structure of a complex on $ \ gamma ^ { \ wedge } $. in the situation when $ \ gamma $ is a usual lie algebra this complex coincides with the " standard complex ". the differential is realized as a commutator with a ( brst ) operator $ q $ in a larger algebra $ \ gamma ^ \ wedge [ \ omega ] $, with extra generators canonically conjugated to the exterior generators of $ \ gamma ^ { \ wedge } $. a recurrent relation which defines uniquely the operator $ q $ is given.
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arxiv:math/0010060
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we propose an explanation for the far - infrared / radio correlation of galaxies in terms of the energy balance of the interstellar medium and determine the flux from high - energy photons and neutrinos from starburst galaxies. we present a catalog of the 127 brightest starburst galaxies with redshifts of z < 0. 03. in order to investigate the correlation between radio - and far - infrared emission, we apply the leaky box approximation. further, we derive photon - and neutrino spectra from proton - proton interactions in supernova remnants ( snrs ). here, we assume that a fraction of the snr ' s energy is transferred to the acceleration of cosmic rays. we also investigate the possibility of detecting gamma ray bursts from nearby starburst galaxies, using the catalog defined here. we show that the radio emission is only weakly dependent on the magnetic field. it turns out that the intensity of the radio signal is directly proportional to the number of supernova explosions, which scales with the far - infrared luminosity. in addition, we find that high - energy photons from proton - proton interactions in snrs in starbursts can make up several percent of the diffuse gamma - ray background. the neutrino flux from the same sources has a maximum energy of ~ 1e5 gev. neutrinos can, on the other hand, can be observed if a gamma ray burst happens in a nearby starburst. about 0. 03 grbs per year are expected to occur in the entire catalog. the true number is expected to be even higher, since we only include the brightest sources. the number of events per burst in icecube varies between about one event and more than 1000 events. this provides good prospects for icecube to detect a significant event, since the background for a grb search is close to zero.
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arxiv:0901.1775
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for statistical decision problems with finite parameter space, it is well - known that the upper value ( minimax value ) agrees with the lower value ( maximin value ). only under a generalized notion of prior does such an equivalence carry over to the case infinite parameter spaces, provided nature can play a prior distribution and the statistician can play a randomized strategy. various such extensions of this classical result have been established, but they are subject to technical conditions such as compactness of the parameter space or continuity of the risk functions. using nonstandard analysis, we prove a minimax theorem for arbitrary statistical decision problems. informally, we show that for every statistical decision problem, the standard upper value equals the lower value when the $ \ sup $ is taken over the collection of all internal priors, which may assign infinitesimal probability to ( internal ) events. applying our nonstandard minimax theorem, we derive several standard minimax theorems : a minimax theorem on compact parameter space with continuous risk functions, a finitely additive minimax theorem with bounded risk functions and a minimax theorem on totally bounded metric parameter spaces with lipschitz risk functions.
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arxiv:2212.13250
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universal continuous calculi are defined and it is shown that for every finite tuple of pairwise commuting hermitian elements of a su * - algebra ( an ordered * - algebra that is symmetric, i. e. " strictly " positive elements are invertible, and uniformly complete ), such a universal continuous calculus exists. this generalizes the continuous calculus for c * - algebras to a class of generally unbounded ordered * - algebras. on the way, some results about * - algebras of continuous functions on locally compact spaces are obtained. the approach used throughout is rather elementary and especially avoids any representation theory.
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arxiv:1901.04076
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we compare the asymptotic behavior of carmichael ' s lambda function composed with euler ' s totient function to the asymptotic behavior of carmichael ' s lambda function composed with itself. we establish the normal order of the logarithm of the ratio.
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arxiv:1206.0286
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for contracting / expanding bouncing cosmologies, the formulation of junction conditions at a bouncing was recently revisited by the author in collaboration with b. le floch and g. veneziano. the regime of interest here is the so - called quiescent regime, in which a monotone behavior of the metric is observed and asymptotic expansions can be derived. here, we overview our new methodology based on the notion of { \ sl singularity scattering maps } and { \ sl cyclic spacetimes }, and we present our main conclusions. in particular, we provide a classification of all allowed bouncing junction conditions, including three universal laws.
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arxiv:2106.07958
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the broad - line region ( blr ) of flat - spectrum radio quasars ( fsrqs ) could have a " flat " geometrical structure to allow gev gamma - ray photons escape, to produce the observed gamma - ray flares with short timescales. in this paper, we collect the quasi - simultaneous spectral energy distributions ( seds ) of the fsrq 3c 454. 3 obtained by the multi - wavelength campaigns spanning from 2007 july to 2011 january, and use a model with the " flat " structure blr, the accretion disc and the dust torus to explain the seds of gamma - ray outbursts. we obtain the following results : ( i ) the jet is almost in equipartition between magnetic and particle energy densities during the outbursts ; ( ii ) when the emitting region locates inside the cavity of the blr, the covering factor $ f _ { \ rm blr } $ of the blr is very small ; as the emitting region goes into the blr structure, $ f _ { \ rm blr } $ increases. ( iii ) the aperture angle $ \ alpha $ describing the blr structure is about $ 45 ^ { \ circ } $ ; ( iv ) the central black hole ( bh ) mass is about $ 5 \ times 10 ^ { 8 } $ \, $ m _ { \ odot } $ rather than $ 4. 4 \ times 10 ^ { 9 } $ \, $ m _ { \ odot } $.
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arxiv:1407.2500
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the $ \ delta $ - isobar degrees of freedom are included in the covariant density functional ( cdf ) theory to study the equation of state ( eos ) and composition of dense matter in compact stars. in addition to $ \ delta $ ' s we include the full octet of baryons, which allows us to study the interplay between the onset of delta isobars and hyperonic degrees of freedom. using both the hartree and hartree - fock approximation we find that $ \ delta $ ' s appear already at densities slightly above the saturation density of nuclear matter for a wide range of the meson - $ \ delta $ coupling constants. this delays the appearance of hyperons and significantly affects the gross properties of compact stars. specifically, $ \ delta $ ' s soften the eos at low densities but stiffen it at high densities. this softening reduces the radius of a canonical $ 1. 4 m _ \ odot $ star by up to 2 ~ km for a reasonably attractive $ \ delta $ potential in matter, while the stiffening results in larger maximum masses of compact stars. we conclude that the hypernuclear cdf parametrizations that satisfy the 2 $ m _ \ odot $ maximum mass constraint remain valid when $ \ delta $ isobars are included, with the important consequence that the resulting stellar radii are shifted toward lower values, which is in agreement with the analysis of neutron star radii.
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arxiv:1803.03661
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this is the first part of a small - scale explorative study in an effort to start assessing reproducibility issues specific to scientometrics research. this effort is motivated by the desire to generate empirical data to inform debates about reproducibility in scientometrics. rather than attempt to reproduce studies, we explore how we might assess " in principle " reproducibility based on a critical review of the content of published papers. the first part of the study focuses on direct reproducibility - that is the ability to reproduce the specific evidence produced by an original study using the same data, methods, and procedures. the second part ( velden et al. 2018 ) is dedicated to conceptual reproducibility - that is the robustness of knowledge claims towards verification by an alternative approach using different data, methods and procedures. the study is exploratory : it investigates only a very limited number of publications and serves us to develop instruments for identifying potential reproducibility issues of published studies : these are a categorization of study types and a taxonomy of threats to reproducibility. we work with a select sample of five publications in scientometrics covering a variation of study types of theoretical, methodological, and empirical nature. based on observations made during our exploratory review, we conclude this paper with open questions on how to approach and assess the status of direct reproducibility in scientometrics, intended for discussion at the special track on " reproducibility in scientometrics " at sti2018 in leiden.
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arxiv:1804.05024
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we aim to identify and quantify the effects of the satellite distribution around a sample of galaxies in the catalogue of isolated galaxies ( cig ), as well as the effects of the large scale structure ( lss ) using the sdss - dr9. to recover the physically bound galaxies we focus on the satellites which are within the escape speed of each cig galaxy. we also propose a more conservative method using the stacked gaussian distribution of the velocity difference of the neighbours. the tidal strengths affecting the primary galaxy are estimated to quantify the effects of the local and lss environments. we also define the projected number density parameter at the 5 $ ^ { \ rm th } $ nearest neighbour to characterise the lss around the cig galaxies. out of the 386 cig galaxies considered in this study, at least 340 ( 88 \ % of the sample ) have no physically linked satellite. out of the 386 cig galaxies, 327 ( 85 \ % of the sample ) have no physical companion within a projected distance of 0. 3 mpc. the cig galaxies are distributed following the lss of the local universe, although presenting a large heterogeneity in their degree of connection with it. a clear segregation appears between early - type cig galaxies with companions and isolated late - type cig galaxies. isolated galaxies are in general bluer, with likely younger stellar populations and rather high star formation with respect to older, redder cig galaxies with companions. reciprocally, the satellites are redder and with an older stellar populations around massive early - type cig galaxies, while they have a younger stellar content around massive late - type cig galaxies. this suggests that the cig is composed of a heterogeneous population of galaxies, sampling from old to more recent, dynamical systems of galaxies.
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arxiv:1402.5526
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we present a novel method for computing correspondences across 3d shapes using unsupervised learning. our method computes a non - linear transformation of given descriptor functions, while optimizing for global structural properties of the resulting maps, such as their bijectivity or approximate isometry. to this end, we use the functional maps framework, and build upon the recent fmnet architecture for descriptor learning. unlike that approach, however, we show that learning can be done in a purely \ emph { unsupervised setting }, without having access to any ground truth correspondences. this results in a very general shape matching method that we call surfmnet for spectral unsupervised fmnet, and which can be used to establish correspondences within 3d shape collections without any prior information. we demonstrate on a wide range of challenging benchmarks, that our approach leads to state - of - the - art results compared to the existing unsupervised methods and achieves results that are comparable even to the supervised learning techniques. moreover, our framework is an order of magnitude faster, and does not rely on geodesic distance computation or expensive post - processing.
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arxiv:1812.03794
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advancements in the fabrication of superconducting quantum devices have highlighted tantalum as a promising material, owing to its low surface oxidation microwave loss at low temperatures. however, tantalum films exhibit significantly larger kinetic inductances compared to materials such as aluminum or niobium. given the inevitable variations in film thickness, this increased kinetic inductance leads to considerable, uncontrolled frequency variances and shifts in components like superconducting coplanar waveguide ( scpw ) resonators. achieving high precision in resonator frequencies is crucial, particularly when multiple resonators share a common purcell filter with limited bandwidth in superconducting quantum information processors. here, we tackle this challenge from both fabrication and design perspectives, achieving a reduction in resonator frequency fluctuation by a factor of more than 100. concurrently, the internal quality factor of the scpw resonator remains at high level. our findings open up new avenues for the enhanced utilization of tantalum in large - scale superconducting chips.
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arxiv:2405.02955
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we study one of the simplest covariant modified - gravity models based on the dvali - gabadadze - porrati ( dgp ) brane cosmology, a self - accelerating universe. in this model gravitational leakage into extra dimensions is responsible of late - time acceleration. we mainly focus on the effects of the model parameters on the geometry and the age of universe. also we investigate the evolution of matter density perturbations in the modified gravity model, and obtain an analytical expression for the growth index, $ f $. we show that increasing $ \ omega _ { r _ c } $ leads to less growth of the density contrast $ \ delta $, and also decreases the growth index. we give a fitting formula for the growth index at the present time and indicate that dominant term in this expression verifies the well - known approximation relation $ f \ simeq \ omega _ m ^ { \ gamma } $. as the observational test, the new supernova type ia ( snia ) gold sample and supernova legacy survey ( snls ) data, size of baryonic acoustic peak from sloan digital sky survey ( sdss ), the position of the acoustic peak from the cmb observations and the cluster baryon gas mass fraction ( gas ) are used to constrain the parameters of the dgp model. we also combine previous results with large scale structure formation ( lss ) from the 2dfgrs survey. finally to check the consistency of the dgp model, we compare the age of old cosmological objects with age of universe in this model.
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arxiv:astro-ph/0701339
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this paper presents a new approach for the challenging problem of geo - locating an image using image matching in a structured database of city - wide reference images with known gps coordinates. we cast the geo - localization as a clustering problem on local image features. akin to existing approaches on the problem, our framework builds on low - level features which allow partial matching between images. for each local feature in the query image, we find its approximate nearest neighbors in the reference set. next, we cluster the features from reference images using dominant set clustering, which affords several advantages over existing approaches. first, it permits variable number of nodes in the cluster which we use to dynamically select the number of nearest neighbors ( typically coming from multiple reference images ) for each query feature based on its discrimination value. second, as we also quantify in our experiments, this approach is several orders of magnitude faster than existing approaches. thus, we obtain multiple clusters ( different local maximizers ) and obtain a robust final solution to the problem using multiple weak solutions through constrained dominant set clustering on global image features, where we enforce the constraint that the query image must be included in the cluster. this second level of clustering also bypasses heuristic approaches to voting and selecting the reference image that matches to the query. we evaluated the proposed framework on an existing dataset of 102k street view images as well as a new dataset of 300k images, and show that it outperforms the state - of - the - art by 20 % and 7 %, respectively, on the two datasets.
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arxiv:1702.01238
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novel designs of josephson weak links based on semiconducting nanowires combined with circuit qed techniques have enabled the resolution of their fine structure due to spin - orbit interactions, opening a path towards andreev spin qubits. nevertheless, direct manipulation of the spin within a given andreev state is in general suppressed compared to inter - doublet manipulation in the absence of zeeman effects. in addition, noisy spin - flip mechanisms limit any coherent manipulation protocol to spin post - selection. we propose a combination of a spin polarization protocol analogous to sideband cooling with stimulated raman adiabatic passage specifically tailored for these systems. we show this approach is robust for a large range of design parameters, including the currently rather stringent coherence times.
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arxiv:2012.07132
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we discuss technical aspects and first results of a lattice qcd study of the $ a _ 0 ( 980 ) $ state. we employ various interpolating operators of quark - antiquark, mesonic molecule, diquark - antidiquark and two - meson type. both connected and disconnected contributions including diagrams with closed fermion loops are computed. to keep statistical errors small, it is essential to optimize the computation of these diagrams by choosing that combination of techniques most appropriate for each type of diagram from the correlation matrix of interpolating operators. we illustrate, how this can be done, by discussing certain diagrams in detail. we also present preliminary results corresponding to a $ 4 \ times 4 $ submatrix computed with 2 + 1 flavors of clover fermions.
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arxiv:1410.8757
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the absence of efficient light modulators for extreme ultraviolet ( euv ) and x - ray photons significantly limits their real - life application, particularly when even slight complexity of the beam patterns is required. here we report on a novel approach to reversible imprinting of a holographic mask in an electronic wigner crystal material with a sub - 90 nm feature size. the structure is imprinted on a sub - picosecond time - scale using euv laser pulses and acts as a high - efficiency diffraction grating that deflects euv or soft x - ray light. the imprinted nanostructure is stable after the removal of the exciting beams at low temperatures but can be easily erased by a single heating beam. modeling shows that the efficiency of the device can exceed 1 %, approaching state - of - the - art etched gratings, but with the benefit of being programmable and tunable over a large range of wavelengths. the observed effect is based on the rapid change of lattice constant upon transition between metastable electronically - ordered phases in a layered transition metal dichalcogenide. the proposed approach is potentially useful for creating tunable light modulators in the euv and soft x - ray spectral ranges.
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arxiv:2311.08809
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we review and update the effects of physics beyond the standard model on cp asymmetries in b decays. these asymmetries can be significantly altered if there are important new - physics contributions to \ bqbqbar mixing. this same new physics will therefore also contribute to rare, flavor - changing b decays. through a study of such decays, we show that it is possible to partially distinguish the different models of new physics.
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arxiv:hep-ph/9608430
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we study conformal metrics on r ^ { 2m } with constant q - curvature and finite volume. when m = 3 we show that there exists v * such that for any v \ in [ v *, \ infty ) there is a conformal metric g on r ^ { 6 } with q _ g = q - curvature of s ^ 6, and vol ( g ) = v. this is in sharp contrast with the four - dimensional case, treated by c - s. lin. we also prove that when $ m $ is odd and greater than 1, there is a constant v _ m > \ vol ( s ^ { 2m } ) such that for every v \ in ( 0, v _ m ] there is a conformal metric g on r ^ { 2m } with q _ g = q - curvature of s ^ { 2m }, vol ( g ) = v. this extends a result of a. chang and w - x. chen. when m is even we prove a similar result for conformal metrics of negative q - curvature.
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arxiv:1202.1222
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the fda drafted a guidance for low risk devices advises that personal health wearables are general wellness products if they only collect data on weight management, physical fitness, relaxation or stress management, mental acuity, self - esteem, sleep management, or sexual function. this was due to the privacy risks that were surrounding the devices. as more and more of the devices were being used as well as improved soon enough these devices would be able to tell if a person is showing certain health issues and give a course of action. with the rise of these devices being consumed so to the fda drafted this guidance in order to decrease risk of a patient in case the app does not function properly. it is argued the ethics of it as well because although they help track health and promote independence there is still an invasion of privacy that ensues to gain information. this is due to the huge amounts of data that has to be transferred which could raise issues for both the user and the companies if a third partied gets access to this data. there was an issue with google glass that was used by surgeons in order to track vital signs of a patient where it had privacy issues relating to third party use of non - consented information. the issue is consent as well when it comes to wearable technology because it gives the ability to record and that is an issue when permission is not asked when a person is being recorded. compared to smartphones, wearable devices pose several new reliability challenges to device manufacturers and software developers. limited display area, limited computing power, limited volatile and non - volatile memory, non - conventional shape of the devices, abundance of sensor data, complex communication patterns of the apps, and limited battery size — all these factors can contribute to salient software bugs and failure modes, such as, resource starvation or device hangs. moreover, since many of the wearable devices are used for health purposes ( either monitoring or treatment ), their accuracy and robustness issues can give rise to safety concerns. some tools have been developed to evaluate the reliability and the security properties of these wearable devices. the early results point to a weak spot of wearable software whereby overloading of the devices, such as through high ui activity, can cause failures. privacy and security risks still remain significant concerns in the use of health monitoring wearables. as these devices collect and transmit sensitive health data, they become vulnerable to cyberattacks and unauthorized data access. several case studies highlight these risks, exposing how user data can be exploited or misused. for example, period - tracking apps
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https://en.wikipedia.org/wiki/Wearable_technology
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the quantum fisher information is a riemannian metric, defined on the state space of a quantum system, which is symmetric and decreasing under stochastic mappings. contrary to the classical case such a metric is not unique. we complete the characterization, initiated by morozova, chentsov and petz, of these metrics by providing a closed and tractable formula for the set of morozova - chentsov functions. in addition, we provide a continuously increasing bridge between the smallest and largest symmetric monotone metrics.
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arxiv:math-ph/0601056
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simplex - valued data appear throughout statistics and machine learning, for example in the context of transfer learning and compression of deep networks. existing models for this class of data rely on the dirichlet distribution or other related loss functions ; here we show these standard choices suffer systematically from a number of limitations, including bias and numerical issues that frustrate the use of flexible network models upstream of these distributions. we resolve these limitations by introducing a novel exponential family of distributions for modeling simplex - valued data - the continuous categorical, which arises as a nontrivial multivariate generalization of the recently discovered continuous bernoulli. unlike the dirichlet and other typical choices, the continuous categorical results in a well - behaved probabilistic loss function that produces unbiased estimators, while preserving the mathematical simplicity of the dirichlet. as well as exploring its theoretical properties, we introduce sampling methods for this distribution that are amenable to the reparameterization trick, and evaluate their performance. lastly, we demonstrate that the continuous categorical outperforms standard choices empirically, across a simulation study, an applied example on multi - party elections, and a neural network compression task.
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arxiv:2002.08563
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accurate branch prediction is a critical part of high performance instruction stream processing. in this paper, i present a hardware implementation of branch prediction for a rv32im cpu, starting with static decode stage predictions and culminating in the use of batage. in addition, i detail my experience writing the rtl in hardcaml, a hardware description library for the functional programming language ocaml.
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arxiv:2312.10426
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we develop the theory of algebraic groups over real closed fields and apply the results to construct a geometric object $ \ mathcal { b } $ and to prove that $ \ mathcal { b } $ is an affine $ \ lambda $ - building. we use a model theoretic transfer principle to prove generalizations of statements about semisimple lie groups. in this direction we give proofs for the iwasawa - decomposition $ kau $, the cartan - decomposition $ kak $ and the bruhat - decomposition $ bwb $. for unipotent subgroups we prove the baker - campbell - hausdorff formula and use it to analyse root groups. we give a proof of the jacobson - morozov lemma about subgroups whose lie algebra is isomorphic to $ \ mathfrak { sl } _ 2 $ and we describe other rank 1 subgroups which are the semisimple parts of levi - subgroups. we prove a semialgebraic version of kostant ' s convexity. over the reals, semisimple lie groups are closely related to the symmetry groups of symmetric spaces of non - compact type. these symmetric spaces can be described semialgebraically, which allows us to consider their semialgebraic extension over any real closed field. starting from these non - standard symmetric spaces we use a valuation ( with image some non - discrete ordered abelian group $ \ lambda $ ) on the fields to define a $ \ lambda $ - pseudometric. identifying points of distance zero results in a $ \ lambda $ - metric space $ \ mathcal { b } $. assuming that the root system of the associated lie group is reduced, we prove that $ \ mathcal { b } $ is an affine $ \ lambda $ - building. the proof relies on a thorough analysis of stabilizers.
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arxiv:2407.20406
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the basic equations, concepts, and modes of linear, ideal, mhd waves - - slow, alfv \ ' en and fast - - are set out and generalised to gravitationally - stratified atmospheres. particular attention is devoted to mode conversion, wherein the local behavior of a global wave changes from one mode to another in passing through particular atmospheric layers. exact solutions are explored where available. eikonal methods - - wkbj and ray theory - - are described. although our emphasis is on the theoretical underpinning of the subject, the solar atmospheric heating implications of fast / slow and fast / alfv \ ' en conversions are discussed in detail.
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arxiv:2408.01591
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effective integration of terrestrial and non - terrestrial segments is one of the key research avenues in the design of current and future wireless communication networks. to this aim, modern communication - satellite constellations intend to attain sufficiently high throughput in terms of bit rate per unit area on the ground by rather aggressive patterns of spatial frequency reuse. this goal calls for on - board narrow - beam antennas, whose size turns out to be in many cases incompatible with the size / mass and accommodation constraints of the hosting satellite. this paper investigates the attainable performance of large distributed arrays of antennas implemented as the ensemble of a few to many simpler sub - antennas of smaller sizes, carried by one ( small ) satellite each. the sub - antennas can in their turn be implemented like ( regular ) 2d arrays of simple radiating elements, realizing an overall ( distributed ) antenna architecture that we call " formation of arrays " ( foa ). the satellites that implement this radiating architecture need to be relatively close to each other and constitute a formation of flying objects, to be coordinated and controlled as a whole. in this paper, we develop a theoretical analysis of an foa antenna, and we show how to take advantage of this new technology to improve network throughput in a multi - beam s - band mobile communication network with low - earth or geostationary orbiting satellites directly providing 5g - like communication services to hand - held user terminals.
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arxiv:2302.13674
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we investigate the rigidity problem for the sharp spectral gap on finsler manifolds of weighted ricci curvature bound $ \ text { ric } _ { \ infty } \ geq k > 0 $. our main results show that if the equality holds, the manifold necessarily admits a diffeomorphic splitting ( or isometric splitting in the particular class of berwald spaces ). this splitting phenomenon is comparable to the cheeger - gromoll type splitting theorem by ohta. we also obtain the rigidity results of logarithmic sobolev and bakry - ledoux isoperimetric inequalities via needle decomposition as corollaries.
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arxiv:2204.02298
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pesticide application has been heavily used in the cultivation of major crops, contributing to the increase of crop production over the past decades. however, their appropriate use and calibration of machines rely upon evaluation methodologies that can precisely estimate how well the pesticides ' spraying covered the crops. a few strategies have been proposed in former works, yet their elevated costs and low portability do not permit their wide adoption. this work introduces and experimentally assesses a novel tool that functions over a smartphone - based mobile application, named dropleaf - spraying meter. tests performed using dropleaf demonstrated that, notwithstanding its versatility, it can estimate the pesticide spraying with high precision. our methodology is based on image analysis, and the assessment of spraying deposition measures is performed successfully over real and synthetic water - sensitive papers. the proposed tool can be extensively used by farmers and agronomists furnished with regular smartphones, improving the utilization of pesticides with well - being, ecological, and monetary advantages. dropleaf can be easily used for spray drift assessment of different methods, including emerging uav ( unmanned aerial vehicle ) sprayers.
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arxiv:2009.00453
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conditional density estimation ( cde ) models can be useful for many statistical applications, especially because the full conditional density is estimated instead of traditional regression point estimates, revealing more information about the uncertainty of the random variable of interest. in this paper, we propose a new methodology called odds conditional density estimator ( ocde ) to estimate conditional densities in a supervised learning scheme. the main idea is that it is very difficult to estimate $ p _ { x, y } $ and $ p _ { x } $ in order to estimate the conditional density $ p _ { y | x } $, but by introducing an instrumental distribution, we transform the cde problem into a problem of odds estimation, or similarly, training a binary probabilistic classifier. we demonstrate how ocde works using simulated data and then test its performance against other known state - of - the - art cde methods in real data. overall, ocde is competitive compared with these methods in real datasets.
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arxiv:2107.04118
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the icecube collaboration has instrumented a cubic kilometer of ice with $ 5160 $ photo - multipliers. while mainly developed to detect cherenkov light, any visible light can be used to detect particles within the ice. magnetic monopoles are hypothetical particles predicted by many theories that extend the standard model of particle physics. they are carriers of a single elementary magnetic charge. for this particle, different light production mechanisms dominate from direct cherenkov light at highly relativistic velocities $ \ left ( > 0. 76 \, c \ right ) $, indirect cherenkov light at mildly relativistic velocities $ \ left ( \ approx 0. 5 \, c \ textrm { to } 0. 76 \, c \ right ) $, luminescence light at low relativistic velocities $ \ left ( \ gtrsim 0. 1 \, c \ textrm { to } 0. 5 \, c \ right ) $, as well as catalysis of proton decay at non relativistic velocities $ \ left ( \ lesssim 0. 1 \, c \ right ) $. for each of this speed ranges, searches for magnetic monopoles at the icecube experiment are either in progress or they have already set the world ' s best limits on the flux of magnetic monopoles. a summary of these searches will be presented, outlining already existing results as well as methods used by the currently conducted searches.
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arxiv:1807.10001
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this paper presents a state estimation - based robust optimal control strategy for influenza epidemics in an interactive human society in the presence of modeling uncertainties. interactive society is influenced by the random entrance of individuals from other human societies whose effects can be modeled as a non - gaussian noise. since only the number of exposed and infected humans can be measured, states of the influenza epidemics are first estimated by an extended maximum correntropy kalman filter ( emckf ) to provide a robust state estimation in the presence of the non - gaussian noise. an online quadratic program ( qp ) optimization is then synthesized subject to a robust control lyapunov function ( rclf ) to minimize susceptible and infected humans, while minimizing and bounding the rates of vaccination and antiviral treatment. the joint qp - rclf - emckf meets multiple design specifications such as state estimation, tracking, pointwise control optimality, and robustness to parameter uncertainty and state estimation errors that have not been achieved simultaneously in previous studies. the uniform ultimate boundedness ( uub ) / convergence of error trajectories is guaranteed using a lyapunov stability argument. the soundness of the proposed approach is validated on the influenza epidemics of an interactive human society with a population of 16000. simulation results show that the qp - rclf - emckf achieves appropriate tracking and state estimation performance. the robustness of the proposed controller is finally illustrated in the presence of modeling error and non - gaussian noise.
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arxiv:2005.13101
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we provide a detailed treatment of ruijsenaars - toda ( rt ) hierarchy with special emphasis on its the theta function representation of all algebro - geometric solutions. the basic tools involve hyperelliptic curve $ \ mathcal { k } _ p $ associated with the burchnall - chaundy polynomial, dubrovin - type equations for auxiliary divisors and associated trace formulas. with the help of a foundamental meromorphic function $ \ phi $, baker - akhiezer vector $ \ psi $ on $ \ mathcal { k } _ p $, the complex - valued algebro - geometric solutions of rt hierarchy are derived.
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arxiv:1204.4240
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the recent discovery of unconventional surface state pairs, which give rise to fermi arcs and spin textures, in antiferromagnetically ordered ndbi raised the interest in rare - earth monopnictides. several scenarios of antiferromagnetic order have been suggested to explain the origin of these states with some of them being consistent with the presence of non - trivial topologies. in this study, we use angle - resolved photoemission spectroscopy ( arpes ) and density - functional - theory ( dft ) calculations to investigate the electronic structure of ndsb. we found the presence of distinct domains that have different electronic structure at the surface. these domains correspond to different orientations of magnetic moments in the afm state with respect to the surface. we demonstrated remarkable agreement between dft calculations and arpes that capture all essential changes in the band structure caused by transition to a magnetically ordered state.
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arxiv:2305.17085
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we study the momentum distribution of the electrons in an extended periodic anderson model, where the interaction, $ u _ { cf } $, between itinerant and localized electrons is taken into account. in the symmetric half - filled model, due to the increase of the interorbital interaction, the $ f $ electrons become more and more delocalized, while the itinerancy of conduction electrons decreases. above a certain value of $ u _ { cf } $ the $ f $ electrons become again localized together with the conduction electrons. in the less than half - filled case, we observe that $ u _ { cf } $ causes strong correlations between the $ f $ electrons in the mixed valence regime.
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arxiv:1505.02115
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symmetric nonnegative matrix factorization ( nmf ), a special but important class of the general nmf, is demonstrated to be useful for data analysis and in particular for various clustering tasks. unfortunately, designing fast algorithms for symmetric nmf is not as easy as for the nonsymmetric counterpart, the latter admitting the splitting property that allows efficient alternating - type algorithms. to overcome this issue, we transfer the symmetric nmf to a nonsymmetric one, then we can adopt the idea from the state - of - the - art algorithms for nonsymmetric nmf to design fast algorithms solving symmetric nmf. we rigorously establish that solving nonsymmetric reformulation returns a solution for symmetric nmf and then apply fast alternating based algorithms for the corresponding reformulated problem. furthermore, we show these fast algorithms admit strong convergence guarantee in the sense that the generated sequence is convergent at least at a sublinear rate and it converges globally to a critical point of the symmetric nmf. we conduct experiments on both synthetic data and image clustering to support our result.
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arxiv:1811.05642
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an efficient matrix formalism for finding power series solutions to boundary value problems typical for technological plasticity is developed. hyperbolic system of two first order quasilinear pdes that models two - dimensional plastic flow of von mises material is converted to the telegraph equation by the hodograph transformation. solutions to the boundary value problems are found in terms of hypergeometric functions. convergence issue is also addressed. the method is illustrated by two test problems of metal forming.
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arxiv:math/0701047
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the normalized incomplete beta function can be defined either as cumulative distribution function of beta density or as the gauss hypergeometric function with one of the upper parameters equal to unity. logarithmic concavity / convexity of this function in parameters was established by finner and roters in 1997. their proof is indirect and rather difficult ; it is based on generalized reproductive property of certain more general distributions. these authors remark that these results " seems to be very hard to obtain by usual analytic methods ". in the first part of this paper we provide such proof based on standard tools of analysis. in the second part we go one step further and investigate the sign of generalized tur \ ' { a } n determinants formed by shifts of the normalized incomplete beta function. under some additional restrictions we demonstrate that these coefficients are of the same sign. we further conjecture that such restrictions can be removed without altering the results. our method of proof also leads to various companion results which may be of independent interest. in particular, we establish linearization formulas and two - sided bounds for the above mentioned tur \ ' { a } n determinants. further, we find two combinatorial style identities for finite sums which we believe to be new.
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arxiv:1509.05120
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we present a planar spectro - polarimeter based on fabry - p { \ ' e } rot cavities with embedded polarization - sensitive high - index nanostructures. a $ 7 ~ \ mu $ m - thick spectro - polarimetric system for 3 spectral bands and 2 linear polarization states is experimentally demonstrated. furthermore, an optimal design is theoretically proposed, estimating that a system with a bandwidth of 127 ~ nm and a spectral resolution of 1 ~ nm is able to reconstruct the first three stokes parameters \ textcolor { black } { with a signal - to - noise ratio of - 13. 14 ~ db with respect to the the shot noise limited snr }. the pixelated spectro - polarimetric system can be directly integrated on a sensor, thus enabling applicability in a variety of miniaturized optical devices, including but not limited to satellites for earth observation.
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arxiv:2003.04403
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in recent years, automatic text summarization has witnessed significant advancement, particularly with the development of transformer - based models. however, the challenge of controlling the readability level of generated summaries remains an under - explored area, especially for languages with complex linguistic features like turkish. this gap has the effect of impeding effective communication and also limits the accessibility of information. controlling readability of textual data is an important element for creating summaries for different audiences with varying literacy and education levels, such as students ranging from primary school to graduate level, as well as individuals with diverse educational backgrounds. summaries that align with the needs of specific reader groups can improve comprehension and engagement, ensuring that the intended message is effectively communicated. furthermore, readability adjustment is essential to expand the usability of summarization models in educational and professional domains. current summarization models often don ' t have the mechanisms to adjust the complexity of their outputs, resulting in summaries that may be too simplistic or overly complex for certain types of reader groups. developing adaptive models that can tailor content to specific readability levels is therefore crucial. to address this problem, we create our own custom dataset and train a model with our custom architecture. our method ensures that readability levels are effectively controlled while maintaining accuracy and coherence. we rigorously compare our model to a supervised fine - tuned baseline, demonstrating its superiority in generating readability - aware summaries.
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arxiv:2503.10675
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in this letter we show that although the application of standard lyapunov analysis predicts that completely integrable kepler motion is unstable, the geometrical analysis of horwitz et al [ 1 ] predicts the observed stability. this seems to us to provide evidence for both the incompleteness of the standard lyapunov analysis and the strength of the geometrical analysis. moreover, we apply this approach to the three body problem in which the third body is restricted to move on a circle of large radius which induces an adiabatic time dependent potential on the second body. this causes the second body to move in a very interesting and intricate but periodic trajectory ; however, the standard lyapunov analysis, as well as methods based on the parametric variation of curvature associated with the jacobi metric, incorrectly predict chaotic behavior. the geometric approach predicts the correct stable motion in this case as well.
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arxiv:0908.1124
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both the design and control of a robot play equally important roles in its task performance. however, while optimal control is well studied in the machine learning and robotics community, less attention is placed on finding the optimal robot design. this is mainly because co - optimizing design and control in robotics is characterized as a challenging problem, and more importantly, a comprehensive evaluation benchmark for co - optimization does not exist. in this paper, we propose evolution gym, the first large - scale benchmark for co - optimizing the design and control of soft robots. in our benchmark, each robot is composed of different types of voxels ( e. g., soft, rigid, actuators ), resulting in a modular and expressive robot design space. our benchmark environments span a wide range of tasks, including locomotion on various types of terrains and manipulation. furthermore, we develop several robot co - evolution algorithms by combining state - of - the - art design optimization methods and deep reinforcement learning techniques. evaluating the algorithms on our benchmark platform, we observe robots exhibiting increasingly complex behaviors as evolution progresses, with the best evolved designs solving many of our proposed tasks. additionally, even though robot designs are evolved autonomously from scratch without prior knowledge, they often grow to resemble existing natural creatures while outperforming hand - designed robots. nevertheless, all tested algorithms fail to find robots that succeed in our hardest environments. this suggests that more advanced algorithms are required to explore the high - dimensional design space and evolve increasingly intelligent robots - - an area of research in which we hope evolution gym will accelerate progress. our website with code, environments, documentation, and tutorials is available at http : / / evogym. csail. mit. edu.
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arxiv:2201.09863
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this paper studies projections of uniform random elements of ( co ) adjoint orbits of compact lie groups. such projections generalize several widely studied ensembles in random matrix theory, including the randomized horn ' s problem, the randomized schur ' s problem, and the orbital corners process. in this general setting, we prove integral formulae for the probability densities, establish some properties of the densities, and discuss connections to multiplicity problems in representation theory as well as to known results in the symplectic geometry literature. as applications, we show a number of results on marginal problems in quantum information theory and also prove an integral formula for restriction multiplicities.
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arxiv:2112.13908
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principal stratification provides a robust causal inference framework for the adjustment of post - treatment variables when comparing the effects of a treatment in health and social sciences. in this paper, we introduce a novel bayesian nonparametric model for principal stratification, leveraging the dependent dirichlet process to flexibly model the distribution of potential outcomes. by incorporating confounders and potential outcomes for the post - treatment variable in the bayesian mixture model for the final outcome, our approach improves the accuracy of missing data imputation and allows for the characterization of treatment effects across strata defined based on the values of the post - treatment variable. we assess the performance of our method through a monte carlo simulation study where we compare the proposed method with state - of - the - art bayesian method in principal stratification. finally, we leverage the proposed method to evaluate the principal causal effects of exposure to air pollution on social mobility in the us on strata defined by educational attainment.
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arxiv:2412.00311
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consider a completely bounded fourier multiplier phi of a locally compact group g, and take 1 < = p < = infinity. one can associate to phi a schur multiplier on the schatten classes s _ p ( l ^ 2 g ), as well as a fourier multiplier on lp ( lg ), the non - commutative lp - space of the group von neumann algebra of g. we prove that the completely bounded norm of the schur multiplier is not greater than the completely bounded norm of the lp - fourier multiplier. when g is amenable we show that equality holds, extending a result by neuwirth and ricard to non - discrete groups. for a discrete group g and in the special case when p > 2 is an even integer, we show the following. if there exists a map between lp ( lg ) and an ultraproduct of lp ( m ) \ otimes s _ p ( l ^ 2 g ) that intertwines the fourier multiplier with the schur multiplier, then g must be amenable. this is an obstruction to extend the neuwirth - ricard result to non - amenable groups.
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arxiv:1303.0135
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the intricate interplay between charge motion and magnetic order in geometrically frustrated lattices is central for the properties of many two - dimensional quantum materials. the triangular lattice antiferromagnet is a canonical example of a frustrated system, and here we analyse the dynamics of a hole in such a lattice focusing on observables that have become accessible in a new generation of experiments. using the $ t $ - $ j $ model, we solve the problem exactly within linear spin wave theory in the limit of strong magnetic interactions, showing that the ground state is described by a coherent state of spin waves. the derivation highlights the crucial role played by the interaction between a static hole and the neighboring spins, which originates in the geometric frustration and has often been omitted in earlier works. furthermore, we show that the non - equilibrium dynamics after a hole has abruptly been inserted at a lattice site is given exactly by a coherent state with time - dependent oscillatory coefficients. physically, this describes a burst of magnetic frustration propagating through only two - thirds of the lattice sites, since a destructive interference of spin waves leaves spins parallel to that removed by the hole unperturbed. after the wave has propagated through the lattice, the magnetization relaxes to that of the ground state. we then use our analytical solution to benchmark the widely used self - consistent born approximation ( scba ), showing that it is very accurate also for a triangular lattice. the magnetic polaron spectrum is analysed for general magnetic interactions using the scba, and we compare our results with those for a square lattice.
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arxiv:2209.05131
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by encoding logical qubits into specific types of photonic graph states, one can realize quantum repeaters that enable fast entanglement distribution rates approaching classical communication. however, the generation of these photonic graph states requires a formidable resource overhead using traditional approaches based on linear optics. overcoming this challenge, a number of new schemes have been proposed that employ quantum emitters to deterministically generate photonic graph states. although these schemes have the potential to significantly reduce the resource cost, a systematic comparison of the repeater performance among different encodings and different generation schemes is lacking. here, we quantitatively analyze the performance of quantum repeaters based on two different graph states, i. e. the tree graph states and the repeater graph states. for both states, we compare the performance between two generation schemes, one based on a single quantum emitter coupled to ancillary matter qubits, and one based on a single quantum emitter coupled to a delayed feedback. we identify the numerically optimal scheme at different system parameters. our analysis provides a clear guideline on the selection of the generation scheme for graph - state - based quantum repeaters, and lays out the parameter requirements for future experimental realizations of different schemes.
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arxiv:2209.11430
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a broad survey of viscoelastic data demonstrates that van der waals, hydrogen - bonded, and ionic liquids, as well as polymeric, inorganic, and metallic melts share a structural relaxation pattern virtually insensitive to their morphological details. this mechanical simplicity is connected with that characterizing the fast reorientation dynamics prevailing in liquids devoid of a distinguishable secondary loss peak. by these means one is able to uncover a generic spectral pattern which rationalizes the recently reported " universality " of relaxation strength vs. stretching of the dielectric response of viscous liquids, significantly broadening the framework in which their relaxation behavior is assessed.
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arxiv:1904.08853
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higher - order predictions through the combined accuracy including next - to - leading order ( nlo ) electroweak ( ew ) and next - to - nlo ( nnlo ) quantum chromodynamics ( qcd ) corrections in underlying perturbation theories are presented thoroughly for the invisible decay of the $ z $ boson into neutrino pair relative to its decay into charged - lepton pair ( leptonic decay ). the combined nnlo qcd + nlo ew predictions are achieved based on the fully - differential calculations of cross sections of both the invisible and leptonic processes in proton - proton ( $ pp $ ) collisions at 13 tev center - of - mass energy. differential distributions of cross - section ratios of the invisible process to the leptonic process are presented as a function of the transverse momentum of the $ z $ boson $ p ^ { z } _ { \ rm { t } } $. for the first time, the predictions for differential distributions of cross - section asymmetries between the invisible process and the leptonic process are presented in bins of the $ p ^ { z } _ { \ rm { t } } $. the cross - section ratio and asymmetry distributions, which are referred to as the invisible probes, are considered to be important for controlling the invisible process by the leptonic process of the $ z $ boson and probing deviation from the standard model ( sm ) for new - physics searches. the predictions are extensively presented beyond the $ z $ - boson mass resonance region to assess the potential of the invisible ratio and asymmetry probes for new - phenomena searches in high - invariant mass region of the lepton - pair final states. various tests with threshold requirements of transverse momenta of neutrino pair and leptons are performed to assess the impact on the combined predictions. the invisible ratio and asymmetry probes are proposed to be important probes for indirect searches of new - physics scenarios.
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arxiv:2307.09875
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galactic cosmic - ray ( gcr ) flux short - term variations ( $ < $ 1 month ) in the inner heliosphere are mainly associated with the passage of high - speed solar wind streams ( hss ) and interplanetary ( ip ) counterparts of coronal mass ejections ( icmes ). data gathered with a particle detector flown on board the esa lisa pathfinder ( lpf ) spacecraft, during the declining part of the solar cycle 24 ( february 2016 - july 2017 ) around the lagrange point l1, have allowed to study the characteristics of recurrent cosmic - ray flux modulations above 70 mev n $ ^ { - 1 } $. % these modulations are observed when the solar wind speed is $ > $ 400 km s $ ^ { - 1 } $ and / or the ip magnetic field intensity $ > $ 10 nt. it is shown that the amplitude and evolution of individual modulations depend in a unique way on both ip plasma parameters and particle flux intensity before hss and icmes transit. by comparing the lpf data with those gathered contemporaneously with the magnetic spectrometer experiment ams - 02 on board the international space station and with those of earth polar neutron monitors, the gcr flux modulation was studied at different energies during recurrent short - term variations. it is also aimed to set the near real - time particle observation requirements to disentangle the role of long and short - term variations of the gcr flux to evaluate the performance of high - sensitivity instruments in space such as the future interferometers for gravitational wave detection. finally, the association between recurrent gcr flux variation observations in l1 and weak to moderate geomagnetic activity in 2016 - 2017 is discussed. short - term recurrent gcr flux variations are good proxies of recurrent geomagnetic activity when the b $ _ z $ component of the ip magnetic field is directed northern.
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arxiv:2012.01152
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in this paper for any dimension n we give a complete list of lattice convex polytopes in r ^ n that are regular with respect to the group of affine transformations preserving the lattice.
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arxiv:math/0602193
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jwst / nircam obtained high angular - resolution ( 0. 05 - 0. 1 ' ' ), deep near - infrared 1 - - 5 micron imaging of supernova ( sn ) 1987a taken 35 years after the explosion. in the nircam images, we identify : 1 ) faint h2 crescents, which are emissions located between the ejecta and the equatorial ring, 2 ) a bar, which is a substructure of the ejecta, and 3 ) the bright 3 - 5 micron continuum emission exterior to the equatorial ring. the emission of the remnant in the nircam 1 - 2. 3 micron images is mostly due to line emission, which is mostly emitted in the ejecta and in the hot spots within the equatorial ring. in contrast, the nircam 3 - 5 micron images are dominated by continuum emission. in the ejecta, the continuum is due to dust, obscuring the centre of the ejecta. in contrast, in the ring and exterior to the ring, synchrotron emission contributes a substantial fraction to the continuum. dust emission contributes to the continuum at outer spots and diffuse emission exterior to the ring, but little within the ring. this shows that dust cooling and destruction time scales are shorter than the synchrotron cooling time scale, and the time scale of hydrogen recombination in the ring is even longer than the synchrotron cooling time scale. with the advent of high sensitivity and high angular resolution images provided by jwst / nircam, our observations of sn 1987a demonstrate that nircam opens up a window to study particle - acceleration and shock physics in unprecedented details, probed by near - infrared synchrotron emission, building a precise picture of how a sn evolves.
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arxiv:2404.10042
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a possible generalization of plane fronted waves with parallel rays ( gpp - wave ) fall into a more general class of metrics admitting parallel null 1 - planes. for gpp - wave metric, the zero - curvature condition is given, the killing - yano tensors of order two and three are found and the corresponding killing tensors are constructed. henceforth, the compatibility between geometric duality and non - generic symmetries is presented.
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arxiv:gr-qc/0206045
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terzan 5 is a rich globular cluster within the galactic bulge that contains 39 known millisecond pulsars, the largest known population of any globular cluster. the terzan 5 pulsars are faint, so that individual observations of most of the pulsars have too little signal - to - noise ( s / n ) to measure reliable flux density or polarization information. we combined over 5. 2 \, days of archival data, at each of 1. 5 \, ghz and 2. 0 \, ghz, taken with the green bank telescope over the past 11 \, years. we created high s / n profiles for 32 of the pulsars and determined precise rotation measures ( rms ) for 28 of them. we used the rms, and the known pulsar positions and dispersion measures ( dms ), to map the projected parallel component of the galactic magnetic field toward the cluster. the $ \ langle b _ { | | } \ rangle $ shows a rough gradient of $ \ sim $ 6 \, ng / arcsec ( $ \ sim $ 160 \, ng / parsec ), or fractionally, a change of $ \ sim $ 20 $ \ % $ in the right ascension direction across the cluster, implying galactic magnetic field variability at sub - parsec scales. we also measured average flux densities $ s _ \ nu $ for the pulsars, ranging from $ \ sim $ 10 \, $ \ mu $ jy to $ \ sim $ 2 \, mjy, and an average spectral index $ \ alpha = - 1. 35 $, where $ s _ \ nu \ propto \ nu ^ { \ alpha } ) $. this spectral index is flatter than most known pulsars, likely a selection effect due to the high frequencies used in pulsar searches to mitigate dispersion and scattering. the inferred pulsar luminosity function is roughly power - law, with slope $ ( d \ log n ) / ( d \ log l ) = - 1 $ at the high - luminosity end. at the low - luminosity end, there are incompleteness effects implying that terzan 5 contains many more pulsars to be found.
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arxiv:2204.06158
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we report the characteristic magnetic properties of several members of the rare - earth garnet family, gd $ _ 3 $ ga $ _ 5 $ o $ _ { 12 } $ ( ggg ), dy $ _ 3 $ ga $ _ 5 $ o $ _ { 12 } $ ( dgg ), tb $ _ 3 $ ga $ _ 5 $ o $ _ { 12 } $ ( tgg ), and nd $ _ 3 $ ga $ _ 5 $ o $ _ { 12 } $ ( ngg ), and compare their relative potential utility for magnetocaloric cooling, including their minimal adiabatic demagnetization refrigeration ( adr ) temperatures and relative cooling parameters. a main objective of this work concerns the identification of potential improvements over the magnetocaloric properties of ggg for use in low temperature adr cryostats. using tb $ ^ { + 3 } $ and dy $ ^ { + 3 } $ in the rare - earth site offers, in principle, a higher saturation magnetization and nd $ ^ { + 3 } $ gives a lower de gennes factor and therefore potentially reduced magnetic transition temperatures, limiting the useful temperature range. our results show that dy $ _ 3 $ ga $ _ 5 $ o $ _ { 12 } $ yields an optimal relative cooling parameter ( $ rcp $ ) at low applied fields and low limiting temperatures, which would allow for the design of more efficient adr cryostats.
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arxiv:2204.01752
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measuring the physical parameters of coronal mass ejections ( cmes ), particularly their entrained magnetic field, is crucial for understanding their physics and for assessing their geo - effectiveness. at the moment, only remote sensing techniques can probe these quantities in the corona, the region where cmes form and acquire their defining characteristics. radio observations offer the most direct means for estimating the magnetic field when gyrosynchontron emission is detected. in this work we measure various cme plasma parameters, including its magnetic field, by modelling the gyrosynchrotron emission from a cme. the dense spectral coverage over a wide frequency range provided by the murchison widefield array ( mwa ) affords a much better spectral sampling than possible before. the mwa images also provide much higher imaging dynamic range, enabling us to image these weak emissions. hence we are able to detect radio emission from a cme at larger distances ( $ 4. 73 r _ \ odot $ ) than have been reported before. the flux densities reported here are amongst the lowest measured in similar works. our ability to make extensive measurements on a slow and otherwise unremarkable cme suggest that with the availability of data from the new generation instruments like the mwa, it should now be possible to make routine direct detections of radio counterparts of cmes.
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arxiv:1909.12041
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in this short note, we answer a question raised by m. papikian on a universal upper bound for the degree of the extension of $ k _ \ infty $ given by adjoining the periods of a drinfeld module of rank 2. we show that contrary to the rank 1 case such a universal upper bound does not exist, and the proof generalises to higher rank. moreover, we give an upper and lower bound for the extension degree depending on the valuations of the defining coefficients of the drinfeld module. in particular, the lower bound shows the non - existence of a universal upper bound.
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arxiv:1902.10380
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this paper presents a new deformable convolution - based video frame interpolation ( vfi ) method, using a coarse to fine 3d cnn to enhance the multi - flow prediction. this model first extracts spatio - temporal features at multiple scales using a 3d cnn, and estimates multi - flows using these features in a coarse - to - fine manner. the estimated multi - flows are then used to warp the original input frames as well as context maps, and the warped results are fused by a synthesis network to produce the final output. this vfi approach has been fully evaluated against 12 state - of - the - art vfi methods on three commonly used test databases. the results evidently show the effectiveness of the proposed method, which offers superior interpolation performance over other state of the art algorithms, with psnr gains up to 0. 19db.
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arxiv:2202.07731
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we present a general methodology in order to build mathematical models of genetic regulatory networks. this approach is based on the mass action law and on the jacob and monod operon model. the mathematical models are built symbolically by the \ emph { mathematica } software package \ emph { geneticnetworks }. this package accepts as input the interaction graphs of the transcriptional activators and repressors and, as output, gives the mathematical model in the form of a system of ordinary differential equations. all the relevant biological parameters are chosen automatically by the software. within this framework, we show that threshold effects in biology emerge from the catalytic properties of genes and its associated conservation laws. we apply this methodology to the segment patterning in \ emph { drosophila } early development and we calibrate and validate the genetic transcriptional network responsible for the patterning of the gap proteins hunchback and knirps, along the antero - posterior axis of the \ emph { drosophila } embryo. this shows that patterning at the gap genes stage is a consequence of the relations between the transcriptional regulators and their initial conditions along the embryo.
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arxiv:0909.4248
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the application of psychophysiology in human - computer interaction is a growing field with significant potential for future smart personalised systems. working in this emerging field requires comprehension of an array of physiological signals and analysis techniques. methods to study central nervous system ( cns ) are usually expensive and laborious. however, electroencephalography ( eeg ) is one of the most affordable and ambulatory methodologies for cns research. it is in use in various clinical studies and have been broadly studied over decades. despite that the recorded eeg signals are quite prone to noise and environmental factors it is the most widely used method in study of brain - computer interaction ( bci ). here we discuss briefly on various aspects of the recorded signals, their interpretation, and usage in the field of interaction studies. this paper aims to serve as a primer for the novice, enabling rapid familiarisation with the latest core concepts. we put special emphasis on everyday human - computer interface applications to distinguish from the more common clinical or sports uses of psychophysiology. this paper is an extract from a comprehensive review of the entire field of ambulatory psychophysiology, including 12 similar chapters, plus application guidelines and systematic review. thus any citation should be made using the following reference : b. cowley, m. filetti, k. lukander, j. torniainen, a. henelius, l. ahonen, o. barral, i. kosunen, t. valtonen, m. huotilainen, n. ravaja, g. jacucci. the psychophysiology primer : a guide to methods and a broad review with a focus on human - computer interaction. foundations and trends in human - computer interaction, vol. 9, no. 3 - 4, pp. 150 - - 307, 2016.
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arxiv:1609.00183
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, and the developments in geometry that were involved, were studied intensely. = = mathematics during the scientific revolution = = = = = 17th century = = = the 17th century saw an unprecedented increase of mathematical and scientific ideas across europe. tycho brahe had gathered a large quantity of mathematical data describing the positions of the planets in the sky. by his position as brahe ' s assistant, johannes kepler was first exposed to and seriously interacted with the topic of planetary motion. kepler ' s calculations were made simpler by the contemporaneous invention of logarithms by john napier and jost burgi. kepler succeeded in formulating mathematical laws of planetary motion. the analytic geometry developed by rene descartes ( 1596 – 1650 ) allowed those orbits to be plotted on a graph, in cartesian coordinates. building on earlier work by many predecessors, isaac newton discovered the laws of physics that explain kepler ' s laws, and brought together the concepts now known as calculus. independently, gottfried wilhelm leibniz, developed calculus and much of the calculus notation still in use today. he also refined the binary number system, which is the foundation of nearly all digital ( electronic, solid - state, discrete logic ) computers. science and mathematics had become an international endeavor, which would soon spread over the entire world. in addition to the application of mathematics to the studies of the heavens, applied mathematics began to expand into new areas, with the correspondence of pierre de fermat and blaise pascal. pascal and fermat set the groundwork for the investigations of probability theory and the corresponding rules of combinatorics in their discussions over a game of gambling. pascal, with his wager, attempted to use the newly developing probability theory to argue for a life devoted to religion, on the grounds that even if the probability of success was small, the rewards were infinite. in some sense, this foreshadowed the development of utility theory in the 18th and 19th centuries. = = = 18th century = = = the most influential mathematician of the 18th century was arguably leonhard euler ( 1707 – 1783 ). his contributions range from founding the study of graph theory with the seven bridges of konigsberg problem to standardizing many modern mathematical terms and notations. for example, he named the square root of minus 1 with the symbol i, and he popularized the use of the greek letter π { \ displaystyle \ pi } to stand for the ratio of a circle ' s circumference to its diameter. he made numerous contributions to the study
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https://en.wikipedia.org/wiki/History_of_mathematics
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