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in terms of the exaxt angular momentum projection, properties of the three dimensional cranked hfb ( 3d - chfb ) states are analyzed quantitatively in the context of the relation between the signature of an intrinsic symmetry and the parity of angular momentum, ( - 1 ) ^ i. we found that the tilted states have favorable features to describe states involved with high - k quantum number and / or odd total angular momentum. this implies that 3d - chfb can describe properly the backbending phenomena like a " t - band and g - band " crossing, which is suggested in n = 106 isotopes.
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arxiv:nucl-th/9710028
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sample path large deviations for the laws of the solutions of stochastic nonlinear schrodinger equations when the noise converges to zero are presented. the noise is a complex additive gaussian noise. it is white in time and colored space wise. the solutions may be global or blow - up in finite time, the two cases are distinguished. the results are stated in trajectory spaces endowed with projective limit topologies. in this setting, the support of the law of the solution is also characterized. as a consequence, results on the law of the blow - up time and asymptotics when the noise converges to zero are obtained. an application to the transmission of solitary waves in fiber optics is also given.
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arxiv:math/0406362
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it is well known that two - dimensional ( 2d ) bosons in homogeneous space cannot undergo real bose - einstein condensation, and the superfluid to normal phase transition is berezinskii - kosterlitz - thouless ( bkt ) type, associated with vortex - antivortex pair unbinding. here we point out a 2d bosonic system whose low energy physics goes beyond conventional paradigm of 2d { \ it homogeneous } bosons, i. e., intralayer excitons in monolayer transition metal dichalcogenides. with intrinsic valley - orbit coupling and valley zeeman energy, exciton dispersion becomes linear at small momentum, giving rise to a series of novel features. the critical temperature of bose - einstein condensation of these excitons is nonzero, suggesting true long - range order in 2d homogeneous system. the dispersion of goldstone mode at long wavelength has the form $ \ varepsilon ( \ boldsymbol { q } ) \ sim \ sqrt { q } $, in contrast to conventional linear phonon spectrum. the vortex energy deviates from the usual logarithmic form with respect to system size, but instead has an additional linear term. superfluid to normal phase transition is no longer bkt type for system size beyond a characteristic scale, without discontinuous jump in superfluid density. with the recent experimental progress on exciton fluid at thermal equilibrium in monolayer semiconductors, our work points out an experimentally accessible system to search for unconventional 2d superfluids beyond bkt paradigm.
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arxiv:2302.05585
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glasses possess more low - frequency vibrational modes than predicted by debye theory. these excess modes are crucial for the understanding the low temperature thermal and mechanical properties of glasses, which differ from those of crystalline solids. recent simulational studies suggest that the density of the excess modes scales with their frequency $ \ omega $ as $ \ omega ^ 4 $ in two and higher dimensions. here, we present extensive numerical studies of two - dimensional model glass formers over a large range of glass stabilities. we find that the density of the excess modes follows $ d _ \ text { exc } ( \ omega ) \ sim \ omega ^ 2 $ up to around the boson peak, regardless of the glass stability. the stability dependence of the overall scale of $ d _ \ text { exc } ( \ omega ) $ correlates with the stability dependence of low - frequency sound attenuation. however, we also find that in small systems, where the first sound mode is pushed to higher frequencies, at frequencies below the first sound mode there are excess modes with a system size independent density of states that scales as $ \ omega ^ 3 $.
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arxiv:2107.01505
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for any number field k, upper bounds are established for the number of k - rational points of bounded height on non - singular del pezzo surfaces defined over k, which are equipped with suitable conic bundle structures over k.
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arxiv:1311.1665
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cued speech ( cs ) is a visual communication system for the deaf or hearing impaired people. it combines lip movements with hand cues to obtain a complete phonetic repertoire. current deep learning based methods on automatic cs recognition suffer from a common problem, which is the data scarcity. until now, there are only two public single speaker datasets for french ( 238 sentences ) and british english ( 97 sentences ). in this work, we propose a cross - modal knowledge distillation method with teacher - student structure, which transfers audio speech information to cs to overcome the limited data problem. firstly, we pretrain a teacher model for cs recognition with a large amount of open source audio speech data, and simultaneously pretrain the feature extractors for lips and hands using cs data. then, we distill the knowledge from teacher model to the student model with frame - level and sequence - level distillation strategies. importantly, for frame - level, we exploit multi - task learning to weigh losses automatically, to obtain the balance coefficient. besides, we establish a five - speaker british english cs dataset for the first time. the proposed method is evaluated on french and british english cs datasets, showing superior cs recognition performance to the state - of - the - art ( sota ) by a large margin.
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arxiv:2106.13686
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we study the pairing between fermions of different masses, especially at the unitary limit. at equal populations, the thermodynamic properties are identical with the equal mass case provided an appropriate rescaling is made. at unequal populations, for sufficiently light majority species, the system does not phase separate. for sufficiently heavy majority species, the phase separated normal phase have a density larger than that of the superfluid. for atoms in harmonic traps, the density profiles for unequal mass fermions can be drastically different from their equal - mass counterparts.
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arxiv:cond-mat/0604572
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in the classical pyrochlore lattice heisenberg antiferromagnet, there is a macroscopic continuous ground state degeneracy. we study semiclassical limit of large spin length $ s $, keeping only the lowest order ( in 1 / s ) correction to the classical hamiltonian. we perform a detailed analysis of the spin - wave modes, and using a real - space loop expansion, we produce an effective hamiltonian, in which the degrees of freedom are ising variables representing fluxes through loops in the lattice. we find a family of degenerate collinear ground states, related by gauge - like $ z _ 2 $ transformations and provide bounds for the order of the degeneracy. we further show that the theory can readily be applied to determine the ground states of the heisenberg hamiltonian on related lattices, and to field - induced collinear magnetization plateau states.
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arxiv:cond-mat/0509008
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in this paper, we conducted a multi - perspective comparative narrative analysis ( cna ) on three prominent llms : gpt - 3. 5, palm2, and llama2. we applied identical prompts and evaluated their outputs on specific tasks, ensuring an equitable and unbiased comparison between various llms. our study revealed that the three llms generated divergent responses to the same prompt, indicating notable discrepancies in their ability to comprehend and analyze the given task. human evaluation was used as the gold standard, evaluating four perspectives to analyze differences in llm performance.
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arxiv:2504.08211
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we study the effects of braiding interactions on single anyon dynamics using a quantum walk model on a quasi - 1 - dimensional ladder filled with stationary anyons. the model includes loss of information of the coin and nonlocal fusion degrees of freedom on every second time step, such that the entanglement between the position states and the exponentially growing auxiliary degrees of freedom is lost. the computational complexity of numerical calculations reduces drastically from the fully coherent anyonic quantum walk model, allowing for relatively long simulations for anyons which are spin - 1 / 2 irreps of su ( 2 ) _ k chern - simons theory. we find that for abelian anyons, the walk retains the ballistic spreading velocity just like particles with trivial braiding statistics. for non - abelian anyons, the numerical results indicate that the spreading velocity is linearly dependent on the number of time steps. by approximating the kraus generators of the time evolution map by circulant matrices, it is shown that the spatial probability distribution for the k = 2 walk, corresponding to ising model anyons, is equal to the classical unbiased random walk distribution.
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arxiv:1203.1999
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image inpainting aims to repair a partially damaged image based on the information from known regions of the images. \ revise { achieving semantically plausible inpainting results is particularly challenging because it requires the reconstructed regions to exhibit similar patterns to the semanticly consistent regions }. this requires a model with a strong capacity to capture long - range dependencies. existing models struggle in this regard due to the slow growth of receptive field for convolutional neural networks ( cnns ) based methods and patch - level interactions in transformer - based methods, which are ineffective for capturing long - range dependencies. motivated by this, we propose sem - net, a novel visual state space model ( ssm ) vision network, modelling corrupted images at the pixel level while capturing long - range dependencies ( lrds ) in state space, achieving a linear computational complexity. to address the inherent lack of spatial awareness in ssm, we introduce the snake mamba block ( smb ) and spatially - enhanced feedforward network. these innovations enable sem - net to outperform state - of - the - art inpainting methods on two distinct datasets, showing significant improvements in capturing lrds and enhancement in spatial consistency. additionally, sem - net achieves state - of - the - art performance on motion deblurring, demonstrating its generalizability. our source code will be released in https : / / github. com / chrischen1023 / sem - net.
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arxiv:2411.06318
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in this paper, we define a hopf algebra structure on the vector space spanned by packed words using a selection - quotient coproduct. we show that this algebra is free on its irreducible packed words. finally, we give some brief explanations on the maple codes we have used.
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arxiv:1310.4418
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magnetars have been proposed to be the origin of frbs soon after its initial discovery. the detection of the first galactic frb 20200428 from sgr 1935 + 2154 has made this hypothesis more convincing. in october 2020, this source was supposed to be in an extremely active state again. we then carried out a 1. 6 - hours follow - up observation of sgr 1935 + 2154 using the new ultra - wideband low ( uwl ) receiver of the parkes 64 \, m radio telescope covering a frequency range of 704 $ - $ 4032 mhz. however, no convincing signal was detected in either of our single pulse or periodicity searches. we obtained a limit on the flux density of periodic signal of $ \ rm 3. 6 \, \ mu jy $ using the full 3. 3ghz bandwidth data sets, which is the strictest limit for that of sgr 1935 + 2154. our full bandwidth limit on the single pulses fluence is 35mjy ms, which is well below the brightest single pulses detected by the fast radio telescope just two before our observation. assuming that sgr 1935 + 2154 is active during our observation, our results suggest that its radio bursts are either intrinsically narrowband or show a steep spectrum.
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arxiv:2106.04821
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the study examines whether fama - french equity factors can effectively explain the idiosyncratic risk and return characteristics of bitcoin. by incorporating fama - french factors, the explanatory power of these factors on bitcoin ' s excess returns over various moving average periods is tested through applications of several statistical methods. the analysis aims to determine if equity market factors are significant in explaining and modeling systemic risk in bitcoin.
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arxiv:2406.19401
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we present new calculations of the differential decay rates for $ h \ to \ ell ^ + \ ell ^ - \ gamma $ with $ \ ell = e $ or $ \ mu $ in the standard model. the branching fractions and forward - backward asymmetries, defined in terms of the flight direction of the photon relative to the lepton momenta, depend on the cuts on energies and invariant masses of the final state particles. for typical choices of these cuts we find the branching ratios $ b ( h \ to e \ bar e \ gamma ) = 5. 8 \ cdot 10 ^ { - 5 } $ and $ b ( h \ to \ mu \ bar \ mu \ gamma ) = 6. 4 \ cdot 10 ^ { - 5 } $ and the forward - backward asymmetries $ \ mathcal { a } ^ { ( e ) } _ { \ text { fb } } = 0. 343 $ and $ \ mathcal { a } ^ { ( \ mu ) } _ { \ text { fb } } = 0. 255 $. we provide compact analytic expressions for the differential decay rates for the use in experimental analyses.
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arxiv:2001.06516
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we visualize the kohn - sham kinetic energy density ( ked ), and the ingredients - - the electron density, its gradient and laplacian - - used to construct orbital - free models of it, for the ae6 test set of molecules. these are compared to related quantities used in metagga ' s, to characterize two important limits - - the gradient expansion and the localized - electron limit typified by the covalent bond. we find the second - order gradient expansion of the ked to be a surprisingly successful predictor of the exact ked, particularly at low densities where this approximation fails for exchange. this contradicts the conjointness conjecture that the optimal enhancement factors for orbital - free kinetic and exchange energy functionals are identical. in addition we find significant problems with a recent metagga - level orbital - free ked, especially for regions of strong electron localization. we define an orbital - free description of electron localization and a revised metagga that improves upon atomization energies significantly.
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arxiv:1508.03396
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we study the comoving space density of x - ray - selected luminous active galactic nuclei ( agns ) and the obscured agn fraction at high redshifts ( $ 3 < z < 5 $ ) in the subaru / { \ it xmm - newton } deep survey ( sxds ) field. from an x - ray source catalog with high completeness of optical identification thanks to deep optical images, we select a sample of 30 agns at $ z > 3 $ with intrinsic ( de - absorbed and rest - frame 2 - - 10 kev ) luminosities of $ l _ { \ rm x } = 10 ^ { 44 - 45 } $ erg s $ ^ { - 1 } $ detected in the 0. 5 - - 2 kev band, consisting of 20 and 10 objects with spectroscopic and photometric redshifts, respectively. utilizing the $ 1 / v _ { \ rm max } $ method, we confirm that the comoving space density of luminous agns decreases with redshift above $ z > 3 $. when combined with the { \ it chandra } - cosmos result of civano et al. \ ( 2011 ), the density decline of agns with $ l _ { \ rm x } = 10 ^ { 44 - 45 } $ erg s $ ^ { - 1 } $ is well represented by a power law of $ ( 1 + z ) ^ { - 6. 2 \ pm 0. 9 } $. we also determine the fraction of x - ray obscured agns with $ n _ { \ rm h } > 10 ^ { 22 } $ cm $ ^ { - 2 } $ in the compton - thin population to be 0. 54 $ ^ { + 0. 17 } _ { - 0. 19 } $, by carefully taking into account observational biases including the effects of photon statistics for each source. this result is consistent with an independent determination of the type - 2 agn fraction based on optical properties, for which the fraction is found to be 0. 59 $ \ pm $ 0. 09. comparing our result with that obtained in the local universe, we conclude that the obscured fraction of luminous agns increases significantly from $ z = 0 $ to $ z > 3 $ by a factor of 2. 5 $ \ pm $ 1. 1.
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arxiv:1208.5050
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in this paper, using the techniques of gauge / gravity duality we explore the hydrodynamic regime of $ z = 3 $ lifshitz fixed points in $ 1 + 1 $ dimensions. the speed of sound in the non - relativistic plasma turns out to be $ \ sqrt { 3 } $, which clearly violates the conjectured upper bound. we identify this as a natural consequence of the lorentz symmetry breakdown at $ z = 3 $ lifshitz fixed point. in our analysis, we compute bulk viscosity to entropy ratio for quantum field theory dual to lifshitz gravity in $ 2 + 1 $ dimensions and it turns out that for this particular holographic model this ratio is above the conjectured lower bound.
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arxiv:1503.03254
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single particles moving in a reflection - asymmetric potential are investigated by solving the schr \ " { o } dinger equation of the reflection - asymmetric nilsson hamiltonian with the imaginary time method in 3d lattice space and the harmonic oscillator basis expansion method. in the 3d lattice calculation, the $ \ bm { l } ^ 2 $ divergence problem is avoided by introducing a damping function, and the $ \ langle \ bm { l ^ 2 } \ rangle _ n $ term in the non - spherical case is calculated by introducing an equivalent $ n $ - independent operator. the efficiency of these numerical techniques is demonstrated by solving the spherical nilsson hamiltonian in 3d lattice space. the evolution of the single - particle levels in a reflection - asymmetric potential is obtained and discussed by the above two numerical methods, and their consistency is shown in the obtained single - particle energies with the differences smaller than 10 $ ^ { - 4 } ~ [ \ hbar \ omega _ 0 ] $.
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arxiv:1711.07799
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an entanglement bound based on local measurements is introduced for multipartite pure states. it is the upper bound of the geometric measure and the relative entropy of entanglement. it is the lower bound of minimal measurement entropy. for pure bipartite states, the bound is equal to the entanglement entropy. the bound is applied to pure tripartite qubit states and the exact tripartite relative entropy of entanglement is obtained for a wide class of states.
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arxiv:1104.3280
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in order to unravel the present situation of the pbh overproduction problem, our study emphasizes the critical role played by the equation of state ( eos ) parameter $ w $ within the framework of effective field theory ( eft ) of non - singular bounce. our analysis focuses on a wide range of eos parameter values that are still optimal for explaining the latest data from the pulsar timing array ( pta ). as a result of our study, the most advantageous window, $ 0. 31 \ leq w \ leq 1 / 3 $, is identified as the location of a substantial pbh abundance, $ f _ { \ rm pbh } \ in ( 10 ^ { - 3 }, 1 ) $ with large mass pbhs, $ m _ { \ rm pbh } \ sim { \ cal o } ( 10 ^ { - 7 } - 10 ^ { - 3 } ) m _ { \ odot } $, in the sigw interpretation of the pta signal. when confronted with pta, we find that the overproduction avoiding circumstances are between $ 1 \ sigma - 2 \ sigma $, while the eos parameter lies inside the narrow window, $ 0. 31 < w \ leq 1 / 3 $. we propose a regularized - renormalized - resummed ( rrr ) scalar power spectrum that is large enough to produce eos dependent scalar generated gravitational waves compatible with pta evidence, while satisfying the perturbativity, causality, and unitarity criteria, within the range of $ 0. 88 \ leq c _ { s } \ leq 1 $.
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arxiv:2407.18976
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netizens, michael and ronda hauben ' s foundational treatise on usenet and the internet, was first published in print 25 years ago. in this piece, we trace the history and impact of the book and of usenet itself, contextualising them within the contemporary and modern - day scholarship on virtual communities, online culture, and internet history. we discuss the net as a tool of empowerment, and touch on the social, technical, and economic issues related to the maintenance of shared network infrastructures and to the preservation and commodification of usenet archives. our interview with ronda hauben offers a retrospective look at the development of online communities, their impact, and how they are studied. she recounts her own introduction to the online world, as well as the impetus and writing process for netizens. she presents michael hauben ' s conception of " netizens " as contributory citizens of the net ( rather than mere users of it ) and the " electronic commons " they built up, and argues that this collaborative and collectivist model has been overwhelmed and endangered by the privatisation and commercialisation of the internet and its communities.
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arxiv:2210.02978
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we introduce a hard - core lattice - gas model on generalized bethe lattices and investigate analytically and numerically its compaction behavior. if compactified slowly, the system undergoes a first - order crystallization transition. if compactified much faster, the system stays in a meta - stable liquid state and undergoes a glass transition under further compaction. we show that this behavior is induced by geometrical frustration which appears due to the existence of short loops in the generalized bethe lattices. we also compare our results to numerical simulations of a three - dimensional analog of the model.
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arxiv:cond-mat/0210054
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majorana fermions are particles identical to their own antiparticles. they have been theoretically predicted to exist in topological superconductors. we report electrical measurements on insb nanowires contacted with one normal ( au ) and one superconducting electrode ( nbtin ). gate voltages vary electron density and define a tunnel barrier between normal and superconducting contacts. in the presence of magnetic fields of order 100 mt we observe bound, mid - gap states at zero bias voltage. these bound states remain fixed to zero bias even when magnetic fields and gate voltages are changed over considerable ranges. our observations support the hypothesis of majorana fermions in nanowires coupled to superconductors.
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arxiv:1204.2792
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rydberg atoms are remarkable tools for quantum simulation and computation. they are the focus of an intense experimental activity mainly based on low - angular - momentum rydberg states. unfortunately, atomic motion and levels lifetime limit the experimental time - scale to about 100 $ \ mu $ s. here, we demonstrate laser trapping of long - lived circular rydberg states for up to 10ms. our method is very general and opens many opportunities for quantum simulation. the 10ms trapping time corresponds to thousands of interaction cycles in a circular - state - based quantum simulator. it is also promising for quantum metrology and quantum information with rydberg atoms.
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arxiv:1911.02316
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we present results from fully general relativistic three - dimensional numerical studies of thick - disk accretion onto a rapidly - rotating ( kerr ) black hole with a spin axis that is tilted ( not aligned ) with the angular momentum vector of the disk. we initialize the problem with the solution for an aligned, constant angular momentum, accreting thick disk, which is then allowed to respond to the lense - thirring precession of the tilted black hole. the precession causes the disk to warp, beginning at the inner edge and moving out on roughly the lense - thirring precession timescale. the propagation of the warp stops at a radius in the disk at which other dynamical timescales, primarily the azimuthal sound - crossing time, become shorter than the precession time. at this point, the warp effectively freezes into the disk and the evolution becomes quasi - static, except in cases where the sound - crossing time in the bulk of the disk is shorter than the local precession timescale. we see evidence that such disks undergo near solid - body precession after the initial warping has frozen in. simultaneous to the warping of the disk, there is also a tendency for the midplane to align with the symmetry plane of the black hole due to the preferential accretion of the most tilted disk gas. this alignment is not as pronounced, however, as it would be if more efficient angular momentum transport ( e. g. from viscosity or magneto - rotational instability ) were considered.
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arxiv:astro-ph/0403356
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a second peak in extreme ultraviolet sometimes appears during the gradual phase of solar flares, which is known as euv late phase ( elp ). stereotypically elp is associated with two separated sets of flaring loops with distinct sizes, and it has been debated whether elp is caused by additional heating or extended plasma cooling in the longer loop system. here we carry out a survey of 55 m - and - above goes - class flares with elp during 2010 - - 2014. based on the flare - ribbon morphology, these flares are categorized as circular - ribbon ( 19 events ), two - ribbon ( 23 events ), and complex - ribbon ( 13 events ) flares. among them, 22 events ( 40 % ) are associated with coronal mass ejections, while the rest are confined. an extreme elp, with the late - phase peak exceeding the main - phase peak, is found in 48 % of two - ribbon flares, 37 % of circular - ribbon flares, and 31 % of complex - ribbon flares, suggesting that additional heating is more likely present during elp in two - ribbon than in circular - ribbon flares. overall, cooling may be the dominant factor causing the delay of the elp peak relative to the main - phase peak, because the loop system responsible for the elp emission is generally larger than, and well separated from, that responsible for the main - phase emission. all but one of the circular - ribbon flares can be well explained by a composite " dome - plate " quasi - separatrix layer ( qsl ). only half of these show a magnetic null point, with its fan and spine embedded in the dome and plate, respectively. the dome - plate qsl, therefore, is a general and robust structure characterizing circular - ribbon flares.
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arxiv:2001.06929
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we study the dynamics of branes in configurations where 1 ) the brane is the edge of a single anti - de sitter ( ads ) space and 2 ) the brane is the surface of a vacuum bubble expanding into a schwarzschild or ads - schwarzschild bulk. in both cases we find solutions that resemble the standard robertson - walker cosmologies although in the latter, the evolution can be controlled by a mass parameter in the bulk metric. we also include a term in the brane action for the scalar curvature. this term adds a contribution to the low energy theory of gravity which does not need to affect the cosmology but which is necessary for the surface of the vacuum bubble to recover four dimensional gravity.
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arxiv:hep-ph/0003173
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automatic speech recognition ( asr ) for low - resource languages remains a challenging task due to limited training data. this paper introduces a comprehensive study exploring the effectiveness of whisper, a pre - trained asr model, for northern kurdish ( kurmanji ) an under - resourced language spoken in the middle east. we investigate three fine - tuning strategies : vanilla, specific parameters, and additional modules. using a northern kurdish fine - tuning speech corpus containing approximately 68 hours of validated transcribed data, our experiments demonstrate that the additional module fine - tuning strategy significantly improves asr accuracy on a specialized test set, achieving a word error rate ( wer ) of 10. 5 % and character error rate ( cer ) of 5. 7 % with whisper version 3. these results underscore the potential of sophisticated transformer models for low - resource asr and emphasize the importance of tailored fine - tuning techniques for optimal performance.
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arxiv:2410.16330
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we investigated electron phases in the $ f ^ 2 $ - configuration system with the $ \ gamma _ 1 $ crystalline - electric - field ( cef ) ground state in cubic symmetry. an extended three - orbital periodic anderson model, which consists of $ j = 5 / 2 $ states, is evaluated by using the rotationally invariant slave boson formalism. as a result, we found three phases at zero temperature : the $ \ gamma _ 1 $ cef singlet phase, and two kinds of fermi liquid ( fl ). one of the fl arises owing to the presence of the $ \ gamma _ 5 $ cef state, while the other forms a quasi - degenerated cef state. all these phases are separated by first - order transitions : the charge - transfer transition and the cef energy - level crossing. we also found heavy quasiparticle behaviors in the intermediate valence region between the $ f ^ 2 $ and $ f ^ 3 $ configurations. in this region, the mass enhancement factor exhibits a peak structure by increasing the hybridization. physical properties of these phases and transitions are discussed.
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arxiv:1805.03087
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we consider quantum spin hall effect in an anisotropic strip of stripes and address both integer and fractional filling factors. the first model is based on a gradient of spin - orbit interaction in the direction perpendicular to the stripes. the second model is based on two weakly coupled strips with reversed dispersion relations. we demonstrate that these systems host helical modes, modes in which opposite spins propagate in opposite directions. in the integer regime, the modes carry an elementary electron charge whereas in the fractional regime they carry fractional charges, and their excitations possess anyonic braiding statistics. these simple quasi - one - dimensional models can serve as a platform for understanding effects arising due to electron - electron correlations in topological insulators.
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arxiv:1405.4793
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exploring the role of conformal theories of gravity in string theory, we show that the minimal ( n = 2 ) gauged supergravities in five dimensions induce the multiplets and transformations of n = 1 four dimensional conformal supergravity on the spacetime boundary. n = 1 poincare supergravity can be induced by explicitly breaking the conformal invariance via a radial cutoff in the 5d space. the ads / cft correspondence relates the maximal gauged supergravity in five dimensions to n = 4 super yang - mills on the 4d spacetime boundary. in this context we show that the conformal anomaly of the gauge theory induces conformal gravity on the boundary of the space and that this theory, via the renormalization group, encapsulates the gravitational dynamics of the skin of asymptotically ads spacetimes. our results have several applications to the ads / cft correspondence and the randall - sundrum scenario.
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arxiv:hep-th/0007211
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recently, 3d anomaly detection, a crucial problem involving fine - grained geometry discrimination, is getting more attention. however, the lack of abundant real 3d anomaly data limits the scalability of current models. to enable scalable anomaly data collection, we propose a 3d anomaly synthesis pipeline to adapt existing large - scale 3dmodels for 3d anomaly detection. specifically, we construct a synthetic dataset, i. e., anomaly - shapenet, basedon shapenet. anomaly - shapenet consists of 1600 point cloud samples under 40 categories, which provides a rich and varied collection of data, enabling efficient training and enhancing adaptability to industrial scenarios. meanwhile, to enable scalable representation learning for 3d anomaly localization, we propose a self - supervised method, i. e., iterative mask reconstruction network ( imrnet ). during training, we propose a geometry - aware sample module to preserve potentially anomalous local regions during point cloud down - sampling. then, we randomly mask out point patches and sent the visible patches to a transformer for reconstruction - based self - supervision. during testing, the point cloud repeatedly goes through the mask reconstruction network, with each iteration ' s output becoming the next input. by merging and contrasting the final reconstructed point cloud with the initial input, our method successfully locates anomalies. experiments show that imrnet outperforms previous state - of - the - art methods, achieving 66. 1 % in i - auc on anomaly - shapenet dataset and 72. 5 % in i - auc on real3d - ad dataset. our dataset will be released at https : / / github. com / chopper - 233 / anomaly - shapenet
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arxiv:2311.14897
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in this article, we take the point of view that y ( 2175 ) be a tetraquark state which consists of color octet constituents, and calculate its mass and decay constant within the framework of the qcd sum rule approach. we release standard criterion in the qcd sum rules approach and take more phenomenological analysis, the value of the mass of y ( 2175 ) is consistent with experimental data ; there may be some tetraquark components in the state y ( 2175 ). if we retain standard criterion, larger mass than experimental data can be obtained, the current $ j _ \ mu ( x ) $ can interpolate a tetraquark state with larger mass, or y ( 2175 ) has some components with larger mass. the dominating contribution comes from the perturbative term, which is in contrast to the sum rules with interpolating currents constructed from diquark pairs. the tetraquark states may consist of color octet constituents rather than diquark pairs.
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arxiv:hep-ph/0610171
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an approach to analyse the properties of a particle system is to compare it with different processes to understand when one of them is larger than other ones. the main technique for that is coupling, which may not be easy to construct. we give a characterization of stochastic order between different interacting particle systems in a large class of processes with births, deaths and jumps of many particles per time depending on the configuration in a general way : it consists in checking inequalities involving the transition rates. we construct explicitly the coupling that characterizes the stochastic order. as a corollary we get necessary and sufficient conditions for attractiveness. as an application, we first give the conditions on examples including reaction - diffusion processes, multitype contact process and conservative dynamics and then we improve an ergodicity result for an epidemic model.
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arxiv:1003.3548
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we present a discussion of models of nuclear effects used to describe an inclusive electron - nucleus scattering in the quasielastic ( qe ) peak region, aiming to compare them and draw conclusion of their reliability when applied in neutrino - nucleus interactions. a basic motivation is to reduce systematic errors in neutrino oscillation experiments. we concentrate on the neutrino energy profile of the t2k experiment, which provides us a region of the greatest importance in terms of the highest contribution to the charge - current quasielastic ( ccqe ) cross section. we choose only electron - nucleus data that overlaps with this region. in order to clearify the analysis, we split the data sets into three groups and draw conclusion separately from each one of them. we selected six models for this comparison : benhar ' s spectral function with and without final state interaction ( benhar ' s sf + fsi ), valencia spectral function ( valencia sf ), for higher energy transfer only with the hole spectral function ; gibuu and also the local and global fermi gas models. the latter two are included as a benchmark to quantify the effect of various nuclear effects. all the six models are often used in neutrino scattering studies. a short theoretical description of each model is given. although in the selected data sets the qe mechanism dominates, we also briefly discuss a possible impact of $ 2p2h $ and $ \ delta $ contributions.
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arxiv:1706.06739
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firstly, i report on a recent work - - carried out with t. hambye and e. de rafael - - on how to use the large - nc expansion to calculate unfactorized contributions from the strong penguin operators, and their impact on observables such as epsilon ' / epsilon and the delta i = 1 / 2 rule. secondly, based on work done with m. golterman, i explain how this calculation allows one to predict some rather dramatic consequences for quenched qcd. this may help explain the present discrepancy between lattice and experimental results for epsilon ' / epsilon. the emphasis of this article is put on the explanation of the method of calculation used, which is fully analytic. this allows one to build some intuition and understand the role played by the different hadronic scales in determining the size of the different contributions.
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arxiv:hep-ph/0310063
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a consensus is developing on the nature of various populations of absorbers at different redshift regimes and in particular on their relationships to galaxies at those epochs. as one example we discuss the population of z < 1 mgii absorbers. kinematic models are presented that show this population to be consistent with some combination of halo and disk kinematics and not with a pure disk or halo model. in contrast, the 2 < z < 3 civ absorbers are likely to represent a mix of already formed halos and protogalactic clumps in the process of assembly. clues could be provided by the level at which siiv traces the same kinematic components as civ ( relative to how it traces lower ionization gas ) and this is illustrated by a simple application of principal components analysis. it remains uncertain how much unambiguous information it will be possible to extract about the detailed properties of the gas along the line of sight through an individual absorption profile. however, ratios of various low and high ionization transitions along the line of sight can be combined with insights gained from kinematic models and from observations of galaxy properties. there is reason for optimism that we will progress toward a point when we will someday study the interstellar medium and gaseous halos and environments of absorbing galaxies at close to the same level as we study these components in the milky way.
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arxiv:astro-ph/9707273
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structured population models are a class of general evolution equations which are widely used in the study of biological systems. many theoretical methods are available for establishing existence and stability of steady states of general evolution equations. however, except for very special cases, finding an analytical form of stationary solutions for evolution equations is a challenging task. in the present paper, we develop a numerical framework for computing approximations to stationary solutions of general evolution equations, which can also be used to produce existence and stability regions for steady states. in particular, we use the trotter - kato theorem to approximate the infinitesimal generator of an evolution equation on a finite dimensional space, which in turn reduces the evolution equation into a system of ordinary differential equations. consequently, we approximate and study the asymptotic behavior of stationary solutions. we illustrate the convergence of our numerical framework by applying it to a linear sinko - streifer structured population model for which the exact form of the steady state is known. to further illustrate the utility of our approach, we apply our framework to nonlinear population balance equation, which is an extension of well - known smoluchowksi coagulation - fragmentation model to biological populations. we also demonstrate that our numerical framework can be used to gain insight about the theoretical stability of the stationary solutions of the evolution equations. furthermore, the open source python program that we have developed for our numerical simulations is freely available from our github repository ( github. com / mathbiocu ).
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arxiv:1602.07033
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the performance cost of differential privacy has, for some applications, been shown to be higher for minority groups ; fairness, conversely, has been shown to disproportionally compromise the privacy of members of such groups. most work in this area has been restricted to computer vision and risk assessment. in this paper, we evaluate the impact of differential privacy on fairness across four tasks, focusing on how attempts to mitigate privacy violations and between - group performance differences interact : does privacy inhibit attempts to ensure fairness? to this end, we train $ ( \ varepsilon, \ delta ) $ - differentially private models with empirical risk minimization and group distributionally robust training objectives. consistent with previous findings, we find that differential privacy increases between - group performance differences in the baseline setting ; but more interestingly, differential privacy reduces between - group performance differences in the robust setting. we explain this by reinterpreting differential privacy as regularization.
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arxiv:2203.02745
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starting from a peculiar image observed below a bubble floating at a water - air interface, the article analyzes several optical properties of these special types of refracting objects ( coined \ textit { bubble axicons } ). using mainly geometrical optics, their relation to common axicons, the shadow sausage effect and elementary optical catastrophes ( caustics ) are discussed.
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arxiv:1909.04401
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digital twins ( dts ) help improve real - time monitoring and decision - making in water distribution systems. however, their connectivity makes them easy targets for cyberattacks such as scanning, denial - of - service ( dos ), and unauthorized access. small and medium - sized enterprises ( smes ) that manage these systems often do not have enough budget or staff to build strong cybersecurity teams. to solve this problem, we present a virtual cybersecurity department ( vcd ), an affordable and automated framework designed for smes. the vcd uses open - source tools like zabbix for real - time monitoring, suricata for network intrusion detection, fail2ban to block repeated login attempts, and simple firewall settings. to improve threat detection, we also add a machine - learning - based ids trained on the od - ids2022 dataset using an improved ensemble model. this model detects cyber threats such as brute - force attacks, remote code execution ( rce ), and network flooding, with 92 \ % accuracy and fewer false alarms. our solution gives smes a practical and efficient way to secure water systems using low - cost and easy - to - manage tools.
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arxiv:2504.20266
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1. quantized conductance 2. when 1 mode = 1 atom 3. photons and cooper pairs 4. thermal analogues 5. shot noise 6. solid - state electron optics 7. ultimate confinement 8. landauer formulas
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arxiv:cond-mat/0512609
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in this paper, we first present a classification theorem of infinite - dimensional simple novikov algebras over an algebraically closed field with characteristic 0. then we classify all the irreducible modules of a certain infinite - dimensional simple novikov algebras with an idempotent element whose left action is locally finite.
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arxiv:math/0008072
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in this paper we look at symbolic substitutions and their relationship to bratteli diagrams and their associated operator algebras. in particular, we consider the equivalence relation on substitutions induced by telescope equivalence of bratteli diagrams. such an equivalence preserves pure aperiodicity and primitivity but fails to preserve rank, order, and number of letters. in a similar manner, we consider the equivalence relation on substitutions induced by telescope equivalence of ordered bratteli diagrams. this results in a finer equivalence but fails to provide a complete invariant. an application to fibonacci - like substitutions is developed.
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arxiv:2110.13256
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the quantum approximate optimization algorithm ( qaoa ) is an algorithmic framework for finding approximate solutions to combinatorial optimization problems, derived from an approximation to the quantum adiabatic algorithm ( qaa ). in solving combinatorial optimization problems with constraints in the context of qaoa or qaa, one needs to find a way to encode problem constraints into the scheme. in this paper, we formalize different constraint types to linear equalities, linear inequalities, and arbitrary form. based on this, we propose constraint - encoding schemes well - fitting into the qaoa framework for solving np combinatorial optimization problems. the implemented algorithms demonstrate the effectiveness and efficiency of the proposed scheme by the testing results of varied instances of some well - known np optimization problems. we argue that our work leads to a generalized framework for finding, in the context of qaoa, high - quality approximate solutions to combinatorial problems with various types of constraints.
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arxiv:2002.00943
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we find the conditions for one quantum system to function as a classical controller of another quantum system : the controller must be an open system and rapidly diagonalised in the basis of the controller variable that is coupled to the controlled system. this causes decoherence in the controlled system that can be made small if the rate of diagonalisation is fast. we give a detailed example based on the quantum optomechanical control of a mechanical resonator. the resulting equations are similar in structure to recently proposed models for consistently combining quantum and classical stochastic dynamics.
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arxiv:1201.5111
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researches on the impact of existing baffles on sloshing suppression of two - phase fluids in storage tanks have been widely conducted in literature. however, few studies focus on the effect of the baffles on self - pressurization or thermal stratification of the fluids in containers. this paper uses volume of fluid ( vof ) method to simulate the thermodynamic and fluid dynamic behavior of liquid nitrogen in a tank with different baffle structures under microgravity environment. groups of gravity levels, fill levels and distances, angles and gaps of baffles, are compared and analyzed. up to 54 \ % difference in pressurization can be observed by optimizing the baffle structure and metrics, which is significant to achieve the highest performance of storage fluid control in the tank.
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arxiv:1807.01547
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the local conformal symmetry is spontaneously broken down to the local lorentz invariance symmetry through the approach of nonlinear realization. the resulting effective lagrangian, in the unitary gauge, describes a cosmological vector field non - minimally coupling to the gravitational field. as a result of the higgs mechanism, the vector field absorbs the dilaton and becomes massive, but with an independent energy scale. the proca type vector field can be modelled as dark energy candidate. the possibility that it further triggers lorentz symmetry violation is also pointed out.
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arxiv:0808.3277
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we present a formalism that allows the computation of the baryon asymmetry of the universe from first principles of statistical physics and quantum field theory that is applicable to certain types of beyond the standard model physics ( such as the neutrino minimal standard model - - $ \ nu $ msm ) and does not require the solution of boltzmann or kadanoff - baym equations. the formalism works if a thermal bath of standard model particles is very weakly coupled to a new sector ( sterile neutrinos in the $ \ nu $ msm case ) that is out - of - equilibrium. the key point that allows a computation without kinetic equations is that the number of sterile neutrinos produced during the relevant cosmological period remains small. in such a case, it is possible to expand the formal solution of the von neumann equation perturbatively and obtain a master formula for the lepton asymmetry expressed in terms of non - equilibrium wightman functions. the master formula neatly separates cp - violating contributions from finite temperature correlation functions and satisfies all three sakharov conditions. these correlation functions can then be evaluated perturbatively ; the validity of the perturbative expansion depends on the parameters of the model considered. here we choose a toy model ( containing only two active and two sterile neutrinos ) to illustrate the use of the formalism, but it could be applied to other models.
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arxiv:1012.1126
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we observe the statistical properties of blogs that are expected to reflect social human interaction. firstly, we introduce a basic normalization preprocess that enables us to evaluate the genuine word frequency in blogs that are independent of external factors such as spam blogs, server - breakdowns, increase in the population of bloggers, and periodic weekly behaviors. after this process, we can confirm that small frequency words clearly follow an independent poisson process as theoretically expected. secondly, we focus on each blogger ' s basic behaviors. it is found that there are two kinds of behaviors of bloggers. further, zipf ' s law on word frequency is confirmed to be universally independent of individual activity types.
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arxiv:0906.1744
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spin - orbit interactions in two - dimensional electron liquids are responsible for many interesting transport phenomena in which particle currents are converted to spin polarizations and spin currents and viceversa. prime examples are the spin hall effect, the edelstein effect, and their inverses. by similar mechanisms it is also possible to partially convert an optically induced electron - hole density wave to a spin density wave and viceversa. in this paper we present a unified theoretical treatment of these effects based on quantum kinetic equations that include not only the intrinsic spin - orbit coupling from the band structure of the host material, but also the spin - orbit coupling due to an external electric field and a random impurity potential. the drift - diffusion equations we derive in the diffusive regime are applicable to a broad variety of experimental situations, both homogeneous and non - homogeneous, and include on equal footing " skew scattering " and " side - jump " from electron - impurity collisions. as a demonstration of the strength and usefulness of the theory we apply it to the study of several effects of current experimental interest : the inverse edelstein effect, the spin - current swapping effect, and the partial conversion of an electron - hole density wave to a spin density wave in a two - dimensional electron gas with rashba and dresselhaus spin - orbit couplings, subject to an electric field.
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arxiv:1409.1202
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we present a matrix - free flow solver for high - order finite element discretizations of the incompressible navier - stokes and stokes equations with gpu acceleration. for high polynomial degrees, assembling the matrix for the linear systems resulting from the finite element discretization can be prohibitively expensive, both in terms of computational complexity and memory. for this reason, it is necessary to develop matrix - free operators and preconditioners, which can be used to efficiently solve these linear systems without access to the matrix entries themselves. the matrix - free operator evaluations utilize gpu - accelerated sum - factorization techniques to minimize memory movement and maximize throughput. the preconditioners developed in this work are based on a low - order refined methodology with parallel subspace corrections. the saddle - point stokes system is solved using block - preconditioning techniques, which are robust in mesh size, polynomial degree, time step, and viscosity. for the incompressible navier - stokes equations, we make use of projection ( fractional step ) methods, which require helmholtz and poisson solves at each time step. the performance of our flow solvers is assessed on several benchmark problems in two and three spatial dimensions.
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arxiv:1910.03032
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we show that fixed dimensional klt weak fano pairs with alpha - invariants and volumes bounded away from $ 0 $ and the coefficients of the boundaries belonging to a fixed dcc set $ s $ form a bounded family. moreover, such pairs admit a strong $ \ epsilon $ - lc $ \ mathbb { r } $ - complement for some fixed $ \ epsilon > 0 $.
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arxiv:2002.09899
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an elegant approach on the synthesis of graphene on the strong ferromagnetic ( fm ) material mn $ _ 5 $ ge $ _ 3 $ is proposed via intercalation of mn in the graphene - ge ( 111 ) interface. according to the dft calculations, graphene in this strongly interacting system demonstrates the large exchange splitting of the graphene - derived $ \ pi $ band. in this case only spin - up electrons in graphene preserve the dirac - electron - like character in the vicinity of the fermi level and the k point, whereas such behavior is not detected for the spin - down electrons. this unique feature of the studied gr / fm - mn $ _ 5 $ ge $ _ 3 $ interface which can be prepared on the semiconducting ge can lead to its application in spintronics.
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arxiv:1906.00359
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regular black hole metrics involve a universal, mass - independent regulator that can be up to o ( 700 ) km while remaining consistent with terrestrial tests of newtonian gravity and astrophysical tests of general relativistic orbits. however, for such large values of the regulator scale, the metric describes a compact, astrophysical - mass object with no horizon rather than a black hole. we note that allowing the regulator to have a nontrivial mass dependence preserves the horizon, while allowing large, percent - level effects in black hole observables. by considering the deflection angle of light and the black hole shadow, we demonstrate this possibility explicitly.
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arxiv:2311.16319
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we report a realization of three - dimensional ( 3d ) electromagnetic void space. despite occupying a finite volume of space, such a medium is optically equivalent to an infinitesimal point where electromagnetic waves experience no phase accumulation. the 3d void space is realized by constructing all - dielectric 3d photonic crystals such that the effective permittivity and permeability vanish simultaneously, forming a six - fold dirac - like point with dirac - like linear dispersions at the center of the brillouin zone. we demonstrate, both theoretically and experimentally, that such a 3d void space exhibits unique properties and rich functionalities absent in any other electromagnetic media, such as boundary - control transmission switching and 3d perfect wave - steering mechanisms. especially, contrary to the photonic " doping " effect in its two - dimensional counterpart, the 3d void space exhibits an amazing property of " impurity - immunity ". our work paves a road towards the realization of 3d void space where electromagnetic waves can be manipulated in unprecedented ways.
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arxiv:2012.13547
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. coding theory is the study of the properties of codes ( systems for converting information from one form to another ) and their fitness for a specific application. codes are used for data compression, cryptography, error detection and correction, and more recently also for network coding. codes are studied for the purpose of designing efficient and reliable data transmission methods. = = = = data structures and algorithms = = = = data structures and algorithms are the studies of commonly used computational methods and their computational efficiency. = = = = programming language theory and formal methods = = = = programming language theory is a branch of computer science that deals with the design, implementation, analysis, characterization, and classification of programming languages and their individual features. it falls within the discipline of computer science, both depending on and affecting mathematics, software engineering, and linguistics. it is an active research area, with numerous dedicated academic journals. formal methods are a particular kind of mathematically based technique for the specification, development and verification of software and hardware systems. the use of formal methods for software and hardware design is motivated by the expectation that, as in other engineering disciplines, performing appropriate mathematical analysis can contribute to the reliability and robustness of a design. they form an important theoretical underpinning for software engineering, especially where safety or security is involved. formal methods are a useful adjunct to software testing since they help avoid errors and can also give a framework for testing. for industrial use, tool support is required. however, the high cost of using formal methods means that they are usually only used in the development of high - integrity and life - critical systems, where safety or security is of utmost importance. formal methods are best described as the application of a fairly broad variety of theoretical computer science fundamentals, in particular logic calculi, formal languages, automata theory, and program semantics, but also type systems and algebraic data types to problems in software and hardware specification and verification. = = = applied computer science = = = = = = = computer graphics and visualization = = = = computer graphics is the study of digital visual contents and involves the synthesis and manipulation of image data. the study is connected to many other fields in computer science, including computer vision, image processing, and computational geometry, and is heavily applied in the fields of special effects and video games. = = = = image and sound processing = = = = information can take the form of images, sound, video or other multimedia. bits of information can be streamed via signals. its processing is the central notion of informatics, the european
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https://en.wikipedia.org/wiki/Computer_science
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recent literature has proposed approaches that learn control policies with high performance while maintaining safety guarantees. synthesizing hamilton - jacobi ( hj ) reachable sets has become an effective tool for verifying safety and supervising the training of reinforcement learning - based control policies for complex, high - dimensional systems. previously, hj reachability was restricted to verifying low - dimensional dynamical systems primarily because the computational complexity of the dynamic programming approach it relied on grows exponentially with the number of system states. in recent years, a litany of proposed methods addresses this limitation by computing the reachability value function simultaneously with learning control policies to scale hj reachability analysis while still maintaining a reliable estimate of the true reachable set. these hj reachability approximations are used to improve the safety, and even reward performance, of learned control policies and can solve challenging tasks such as those with dynamic obstacles and / or with lidar - based or vision - based observations. in this survey paper, we review the recent developments in the field of hj reachability estimation in reinforcement learning that would provide a foundational basis for further research into reliability in high - dimensional systems.
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arxiv:2407.09645
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on the former. extraordinary writing by an extraordinary mathematician. mancosu, p. ( ed., 1998 ), from hilbert to brouwer. the debate on the foundations of mathematics in the 1920s, oxford university press, oxford, uk. putnam, hilary ( 1967 ), " mathematics without foundations ", journal of philosophy 64 / 1, 5 – 22. reprinted, pp. 168 – 184 in w. d. hart ( ed., 1996 ). —, " what is mathematical truth? ", in tymoczko ( ed., 1986 ). sudac, olivier ( apr 2001 ). " the prime number theorem is pra - provable ". theoretical computer science. 257 ( 1 – 2 ) : 185 – 239. doi : 10. 1016 / s0304 - 3975 ( 00 ) 00116 - x. troelstra, a. s. ( no date but later than 1990 ), " a history of constructivism in the 20th century ", a detailed survey for specialists : § 1 introduction, § 2 finitism & § 2. 2 actualism, § 3 predicativism and semi - intuitionism, § 4 brouwerian intuitionism, § 5 intuitionistic logic and arithmetic, § 6 intuitionistic analysis and stronger theories, § 7 constructive recursive mathematics, § 8 bishop ' s constructivism, § 9 concluding remarks. approximately 80 references. tymoczko, t. ( 1986 ), " challenging foundations ", in tymoczko ( ed., 1986 ). —, ( ed., 1986 ), new directions in the philosophy of mathematics, 1986. revised edition, 1998. van dalen d. ( 2008 ), " brouwer, luitzen egbertus jan ( 1881 – 1966 ) ", in biografisch woordenboek van nederland. url : http : / / www. inghist. nl / onderzoek / projecten / bwn / lemmata / bwn2 / brouwerle [ 2008 - 03 - 13 ] weyl, h. ( 1921 ), " uber die neue grundlagenkrise der mathematik ", mathematische zeitschrift 10, 39 – 79. translated, " on the new foundational crisis of mathematics ", in ( mancosu 1998 ). wilder, raymond l. ( 1952 ), introduction to the foundations of mathematics, john wiley and sons, new york
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https://en.wikipedia.org/wiki/Foundations_of_mathematics
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in 1969, alan tucker characterized proper circular - arc graphs as those graphs whose augmented adjacency matrices have the circularly compatible ones property. moreover, he also found a polynomial - time algorithm for deciding whether any given augmented adjacency matrix has the circularly compatible ones property. these results allowed him to devise the first polynomial - time recognition algorithm for proper circular - arc graphs. however, as tucker himself remarks, he did not solve the problems of finding a structure theorem and an efficient recognition algorithm for the circularly compatible ones property in arbitrary matrices ( i. e., not restricted to augmented adjacency matrices only ). in this work, we solve these problems. more precisely, we give a minimal forbidden submatrix characterization for the circularly compatible ones property in arbitrary matrices and a linear - time recognition algorithm for the same property. we derive these results from analogous ones for the related $ d $ - circular property. interestingly, these results lead to a minimal forbidden induced subgraph characterization and a linear - time recognition algorithm for proper circular - arc bigraphs, solving a problem first posed by basu, das, ghosh, and sen [ j. graph theory, 73 ( 4 ) : 361 - - 376, 2013 ]. our findings generalize some known results about $ d $ - interval hypergraphs and proper interval bigraphs.
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arxiv:1906.00321
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time series forecasting is often fundamental to scientific and engineering problems and enables decision making. with ever increasing data set sizes, a trivial solution to scale up predictions is to assume independence between interacting time series. however, modeling statistical dependencies can improve accuracy and enable analysis of interaction effects. deep learning methods are well suited for this problem, but multivariate models often assume a simple parametric distribution and do not scale to high dimensions. in this work we model the multivariate temporal dynamics of time series via an autoregressive deep learning model, where the data distribution is represented by a conditioned normalizing flow. this combination retains the power of autoregressive models, such as good performance in extrapolation into the future, with the flexibility of flows as a general purpose high - dimensional distribution model, while remaining computationally tractable. we show that it improves over the state - of - the - art for standard metrics on many real - world data sets with several thousand interacting time - series.
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arxiv:2002.06103
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one of the goals of computer - aided surgery is to match intraoperative data to preoperative images of the anatomy and add complementary information that can facilitate the task of surgical navigation. in this context, mechanical palpation can reveal critical anatomical features such as arteries and cancerous lumps which are stiffer that the surrounding tissue. this work uses position and force measurements obtained during mechanical palpation for registration and stiffness mapping. prior approaches, including our own, exhaustively palpated the entire organ to achieve this goal. to overcome the costly palpation of the entire organ, a bayesian optimization framework is introduced to guide the end effector to palpate stiff regions while simultaneously updating the registration of the end effector to an a priori geometric model of the organ, hence enabling the fusion of ntraoperative data into the a priori model obtained through imaging. this new framework uses gaussian processes to model the stiffness distribution and bayesian optimization to direct where to sample next for maximum information gain. the proposed method was evaluated with experimental data obtained using a cartesian robot interacting with a silicone organ model and an ex vivo porcine liver.
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arxiv:1509.05830
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time - series photometry of the corot field sra01 was carried out with the berlin exoplanet search telescope ii ( best ii ) in 2008 / 2009. a total of 1, 161 variable stars were detected, of which 241 were previously known and 920 are newly found. several new, variable young stellar objects have been discovered. the study of the spatial distribution of eclipsing binaries revealed the higher relative frequency of algols toward the center of the young open cluster ngc 2264. in general algol frequency obeys an isotropic distribution of their angular momentum vectors, except inside the cluster, where a specific orientation of the inclinations is the case. we suggest that we see the orbital plane of the binaries almost edge - on.
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arxiv:1306.5908
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creating fully annotated labels for medical image segmentation is prohibitively time - intensive and costly, emphasizing the necessity for innovative approaches that minimize reliance on detailed annotations. scribble annotations offer a more cost - effective alternative, significantly reducing the expenses associated with full annotations. however, scribble annotations offer limited and imprecise information, failing to capture the detailed structural and boundary characteristics necessary for accurate organ delineation. to address these challenges, we propose helpnet, a novel scribble - based weakly supervised segmentation framework, designed to bridge the gap between annotation efficiency and segmentation performance. helpnet integrates three modules. the hierarchical perturbations consistency ( hpc ) module enhances feature learning by employing density - controlled jigsaw perturbations across global, local, and focal views, enabling robust modeling of multi - scale structural representations. building on this, the entropy - guided pseudo - label ( egpl ) module evaluates the confidence of segmentation predictions using entropy, generating high - quality pseudo - labels. finally, the structural prior refinement ( spr ) module incorporates connectivity and bounded priors to enhance the precision and reliability and pseudo - labels. experimental results on three public datasets acdc, mscmrseg, and chaos show that helpnet significantly outperforms state - of - the - art methods for scribble - based weakly supervised segmentation and achieves performance comparable to fully supervised methods. the code is available at https : / / github. com / ipmi - nwu / helpnet.
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arxiv:2412.18738
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the class of $ n $ - koszul graded algebras of finite global dimension has gained lots of attention in recent years, especially in the study of artin - schelter regular algebras. while structurally rich and concrete, the only known examples of such algebras are either when $ n = 2 $, i. e. the algebra is koszul, or when $ n = 3 $. under a mild hilbert series assumption, we rule out the existence of $ n $ - koszul graded algebras of finite global dimension for $ n $ not prime. furthermore, we establish strong restrictions on the global dimension of such algebras. this suggests that perhaps the existence of 3 - koszul algebras with finite global dimension and ` nice ' hilbert series is an anomaly.
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arxiv:2404.10125
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recent temporal action segmentation approaches need frame annotations during training to be effective. these annotations are very expensive and time - consuming to obtain. this limits their performances when only limited annotated data is available. in contrast, we can easily collect a large corpus of in - domain unannotated videos by scavenging through the internet. thus, this paper proposes an approach for the temporal action segmentation task that can simultaneously leverage knowledge from annotated and unannotated video sequences. our approach uses multi - stream distillation that repeatedly refines and finally combines their frame predictions. our model also predicts the action order, which is later used as a temporal constraint while estimating frames labels to counter the lack of supervision for unannotated videos. in the end, our evaluation of the proposed approach on two different datasets demonstrates its capability to achieve comparable performance to the full supervision despite limited annotation.
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arxiv:2211.01311
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this paper presents the design, construction and commissioning of a pneumatic system for pressure probe measurements in flows of organic vapors in non - ideal conditions, close to the liquid - vapor saturation curve and the critical point where the ideal gas law is not applicable. experiments were performed with fluid siloxane mm, employed in medium / high temperature organic rankine cycles, in the trova blow - down wind tunnel at politecnico milano. challenges linked to condensation in pneumatic lines ( vapor - liquid menisci, hydrostatic head, mass - sink ), were evaluated with theoretical calculation and experiments, and were avoided with a nitrogen flushing procedure. commissioning tests were performed with a pitot tube in non - ideal subsonic flows at mach numbers of 0. 2 and 0. 5. measurement delay issues were identified and solved through a dynamic testing procedure. the correct performance of the complete system was verified for probe measurements of total, static and dynamic pressure in non - ideal flows of organic vapors.
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arxiv:2205.07766
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it is predicted that orbital decay by gravitational - wave radiation and tidal interaction will cause some close - binary stars to merge within a hubble time. the merger of a helium - core white dwarf with a main - sequence star can produce a red giant branch star that has a low - mass hydrogen envelope when helium is ignited and thus become a hot subdwarf. because detailed calculations have not been made, we compute post - merger models with a stellar evolution code. we find the evolutionary paths available to merger remnants and find the pre - merger conditions that lead to the formation of hot subdwarfs. we find that some such mergers result in the formation of stars with intermediate helium - rich surfaces. these stars later develop helium - poor surfaces owing to diffusion. combining our results with a model population and comparing to observed stars, we find that some observed intermediate helium - rich hot subdwarfs can be explained as the remnants of the mergers of helium - core white dwarfs with low - mass main - sequence stars.
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arxiv:1701.02437
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we present a symbolic - numeric method to refine an approximate isolated singular solution $ \ hat { \ mathbf { x } } = ( \ hat { x } _ { 1 },..., \ hat { x } _ { n } ) $ of a polynomial system $ f = \ { f _ 1,..., f _ n \ } $ when the jacobian matrix of $ f $ evaluated at $ \ hat { \ mathbf { x } } $ has corank one approximately. our new approach is based on the regularized newton iteration and the computation of approximate max noether conditions satisfied at the approximate singular solution. the size of matrices involved in our algorithm is bounded by $ n \ times n $. the algorithm converges quadratically if $ \ hat { \ xx } $ is close to the isolated exact singular solution.
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arxiv:1008.0061
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zhang introduced semipositive metrics on a line bundle of a proper variety. in this paper, we generalize such metrics for a line bundle $ l $ of a paracompact strictly $ k $ - analytic space $ x $ over any non - archimedean field $ k $. we prove various properties in this setting such as density of piecewise $ \ mathbb { q } $ - linear metrics in the space of continuous metrics on $ l $. if $ x $ is proper scheme, then we show that algebraic, formal and piecewise linear metrics are the same. our main result is that on a proper scheme $ x $ over an arbitrary non - archimedean field $ k $, the set of semipositive model metrics is closed with respect to pointwise convergence generalizing a result from boucksom, favre and jonsson where $ k $ was assumed to be discretely valued with residue characteristic $ 0 $.
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arxiv:1608.08030
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retrial phenomenon naturally arises in various systems such as call centers, cellular networks and random access protocols in local area networks. this paper gives a comprehensive survey on theory and applications of retrial queues in these systems. we investigate the state of the art of the theoretical researches including exact solutions, stability, asymptotic analyses and multidimensional models. we present an overview on retrial models arising from real world applications. some open problems and promising research directions are also discussed.
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arxiv:1906.09560
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we probed the bending of actin subject to external forcing and viscous drag. single actin filaments were moved perpendicular to their long axis in an oscillatory way by means of an optically tweezed latex bead attached to one end of the filaments. shapes of these polymers were observed by epifluorescence microscopy. they were found to be in agreement with predictions of semiflexible polymer theory and slender - body hydrodynamics. a persistence length of $ 7. 4 \ pm 0. 2 \ mu $ m could be extracted.
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arxiv:cond-mat/9704225
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mobile ad hoc networks ( manet ), distinct from traditional distributed systems, are dynamic and self - organizing networks. manet requires a leader to coordinate and organize tasks. the challenge is to have the right election algorithm that chooses the right leader based on various factors in manet. in this paper, we analyze four leader election algorithms used in mobile ad hoc networks. factors considered in our analysis are time complexity, message complexity, assumptions considered, fault tolerance and timing model. our proposed enhancements include recovered nodes inquiring about the current leader and the use of candidates during election to reduce the overhead of starting a new election session. in addition, better election criteria specific to manet, such as battery life and signal strength, are proposed. our evaluation and discussion shows that the proposed enhancements are effective. the analysis can be used as a reference for system designers in choosing the right election algorithm for manet.
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arxiv:1210.1686
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to reduce the implementation complexity of a belief propagation ( bp ) based low - density parity - check ( ldpc ) decoder, shuffled bp decoding schedules, which serialize the decoding process by dividing a complete parallel message - passing iteration into a sequence of sub - iterations, have been proposed. the so - called group horizontal shuffled bp algorithm partitions the check nodes of the code graph into groups to perform group - by - group message - passing decoding. this paper proposes a new grouping technique to accelerate the message - passing rate. performance of the proposed algorithm is analyzed by a gaussian approximation approach. both analysis and numerical experiments verify that the new algorithm does yield a convergence rate faster than that of existing conventional or group shuffled bp decoder with the same computing complexity constraint.
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arxiv:1202.1060
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the recent experimental realization of spin - orbit coupling ( soc ) for ultra - cold atoms opens a completely new avenue for exploring new quantum matter. in experiments, the soc is implemented simultaneously with a zeeman field. such spin - orbit coupled fermi gases are predicted to support majorana fermions with non - abelian exchange statistics in one dimension ( 1d ). however, as shown in recent theory and experiments for 1d spin - imbalanced fermi gases, the zeeman field can lead to the long - sought fulde - ferrell - larkin - ovchinnikov ( fflo ) superfluids with non - zero momentum cooper pairings, in contrast to the zero momentum pairing in majorana superfluids. therefore a natural question to ask is which phase, fflo or majorana superfluids, will survive in spin - orbit coupled fermi gases in the presence of a large zeeman field. in this paper, we address this question by studying the mean field quantum phases of 1d ( quasi - 1d ) spin - orbit coupled fermionic cold atom optical lattices.
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arxiv:1304.3926
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the classical hennessy - milner theorem says that two states of an image - finite transition system are bisimilar if and only if they satisfy the same formulas in a certain modal logic. in this paper we study this type of result in a general context, moving from transition systems to coalgebras and from bisimilarity to coinductive predicates. we formulate when a logic fully characterises a coinductive predicate on coalgebras, by providing suitable notions of adequacy and expressivity, and give sufficient conditions on the semantics. the approach is illustrated with logics characterising similarity, divergence and a behavioural metric on automata.
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arxiv:2006.12465
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the high energy stereoscopic system ( h. e. s. s. ) experiment, a ground - based gamma - ray cherenkov telescope array located in namibia, has now detected many extragalactic objects, which redshifts range from z = 0. 00183 up to z = 0. 2, possibly more. with the increasing performances of cherenkov telescopes, it now becomes possible to probe these objects at small timescales in gamma - ray, allowing the study of regions thought to be very close to the central supermassive black holes. furthermore, h. e. s. s. has confirmed a gamma - ray emission from m87, which is thus the first extragalactic source seen at the tev range that is not a blazar. among blazars, tev bl lacs are the most challenging objects to test the jet emission models and to shed light on particle acceleration mechanisms. the study of blazars with h. e. s. s. also revealed various temporal behaviors among them. some objects presents a highly variable x - ray flux with small variation of the gamma - ray, while others show the inverse behavior. the interpretation of such differences is puzzling. observations at very high energies also bring indirect measurements of the infrared extragalactic background light ( ebl ). the interpretation of gamma - ray emission of radiogalaxies such as m87 in terms of misaligned blazars and the understanding of the properties of the ebl represent new challenges brought by h. e. s. s. observations of extragalactic sources.
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arxiv:0709.1366
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high - dimensional tensor - valued data have recently gained attention from researchers in economics and finance. we consider the estimation and inference of high - dimensional tensor factor models, where each dimension of the tensor diverges. our focus is on a factor model that admits cp - type tensor decomposition, which allows for non - orthogonal loading vectors. based on the contemporary covariance matrix, we propose an iterative simultaneous projection estimation method. our estimator is robust to weak dependence among factors and weak correlation across different dimensions in the idiosyncratic shocks. we establish an inferential theory, demonstrating both consistency and asymptotic normality under relaxed assumptions. within a unified framework, we consider two eigenvalue ratio - based estimators for the number of factors in a tensor factor model and justify their consistency. through a simulation study and two empirical applications featuring sorted portfolios and international trade flows, we illustrate the advantages of our proposed estimator over existing methodologies in the literature.
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arxiv:2406.17278
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graph embedding methods represent nodes in a continuous vector space, preserving information from the graph ( e. g. by sampling random walks ). there are many hyper - parameters to these methods ( such as random walk length ) which have to be manually tuned for every graph. in this paper, we replace random walk hyper - parameters with trainable parameters that we automatically learn via backpropagation. in particular, we learn a novel attention model on the power series of the transition matrix, which guides the random walk to optimize an upstream objective. unlike previous approaches to attention models, the method that we propose utilizes attention parameters exclusively on the data ( e. g. on the random walk ), and not used by the model for inference. we experiment on link prediction tasks, as we aim to produce embeddings that best - preserve the graph structure, generalizing to unseen information. we improve state - of - the - art on a comprehensive suite of real world datasets including social, collaboration, and biological networks. adding attention to random walks can reduce the error by 20 % to 45 % on datasets we attempted. further, our learned attention parameters are different for every graph, and our automatically - found values agree with the optimal choice of hyper - parameter if we manually tune existing methods.
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arxiv:1710.09599
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the approximate solution of the klein - gordon equation for a real scalar field of mass $ \ mu $ in the geometry of a kerr black hole obtained by detweiler \ cite { detweiler : 1980uk } is widely used in the analysis of the stability of black holes as well as the search of axion - like particles. in this work, we confirm a missing factor $ 1 / 2 $ in this solution, which was first identified in ref. ~ \ cite { pani : 2012bp }. the corrected result has strange features that put questions on the power - counting strategy. we solve this problem by adding the next - to - leading order ( nlo ) contribution. compared to the numerical results, the nlo solution reduces the percentage error of the lo solution by a factor of 2 for all important values of $ r _ g \ mu $. especially the percentage error is $ \ lesssim 10 \ % $ in the region of $ r _ g \ mu \ lesssim 0. 35 $. the nlo solution also has a compact form and could be used straightforwardly.
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arxiv:2201.10941
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recent fermi results have focused attention on gamma - ray burst ' s ( grb ) prompt emission phase, which is rich in phenomenology and poorly understood. the broad band spectra observed by fermi does not fit into any of the frameworks of existing theoretical models. thus, fermi results force new thinking of questions that were thought to be solved. i highlight here the basic open questions prior to the launch of fermi, key fermi results, and new theoretical ideas that emerged following these results. these include : ( i ) renewed interest in magnetized outflows as a way to understand the dynamics and composition ; ( ii ) interest in photospheric emission, in particular ways to broaden " planck " spectrum to resemble the observed " band " spectrum ; ( iii ) the puzzling origin of the high energy ( lat ) photons, first observed in short grbs ; and ( iv ) new methods to estimate the lorentz factor of the outflow.
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arxiv:1111.3378
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multi - wavelength images from the faruv ( ~ 0. 15 micron ) to the sub - millimeter of the central region of the galaxy ngc 3351 are analyzed to constrain its stellar populations and dust attenuation. despite hosting a ~ 1 kpc circumnuclear starburst ring, ngc 3351 deviates from the irx - beta relation, the relation between the infrared - to - uv luminosity ratio and the uv continuum slope ( beta ) that other starburst galaxies follow. to understand the reason for the deviation, we leverage the high angular resolution of archival nearuv - to - nearir hst images to divide the ring into ~ 60 - 180 pc size regions and model each individually. we find that the uv slope of the combined intrinsic ( dust - free ) stellar populations in the central region is redder than what is expected for a young model population. this is due to the region ' s complex star formation history, which boosts the nearuv emission relative to the faruv. the resulting net attenuation curve has a uv slope that lies between those of the starburst attenuation curve ( calzetti et al. 2000 ) and the small magellanic cloud extinction curve ; the total - to - selective attenuation value, r ' ( v ) = 4. 93, is larger than both. as found for other star - forming galaxies, the stellar continuum of ngc 3351 is less attenuated than the ionized gas, with e ( b - v ) _ { star } = 0. 40 e ( b - v ) _ { gas }. the combination of the ` red ' intrinsic stellar population and the new attenuation curve fully accounts for the location of the central region of ngc 3351 on the irx - beta diagram. thus, the observed characteristics result from the complex mixture of stellar populations and dust column densities in the circumnuclear region. despite being a sample of one, these findings highlight the difficulty of defining attenuation curves of general applicability outside the regime of centrally - concentrated starbursts.
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arxiv:2103.12117
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in this paper, we show that the quotient space of the domain by the reflection group for an elliptic root system has a structure of frobenius manifold for the case of codimension 1. we also give a characterization of this frobenius manifold structure under some suitable condition.
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arxiv:math/0611553
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we set up a general framework for systematically building and classifying, in the linear regime, causal and stable dissipative hydrodynamic theories that, alongside with the usual hydrodynamic modes, also allow for an arbitrary number of non - hydrodynamic modes with complex dispersion relation ( such theories are often referred to as " quasi - hydrodynamic " ). to increase the number of non - hydrodynamic modes one needs to add more effective fields to the model. the system of equations governing this class of quasi - hydrodynamic theories is symmetric hyperbolic, thermodynamically consistent ( i. e. the entropy is a lyapunov function ) and can be derived from an action principle. as a first application of the formalism, we prove that, in the linear regime, the israel - stewart theory in the eckart frame and the israel - stewart theory in the landau frame are exactly the same theory. in addition, with an onsager - casimir analysis, we show that in strongly coupled plasmas the non - equilibrium degrees of freedom typically appear in pairs, whose members acquire opposite phase under time reversal. we use this insight to modify cattaneo ' s model for diffusion, in a way to make its initial transient consistent with the transient dynamics of holographic plasmas.
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arxiv:2207.14778
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we report the first measurement of the double - spin asymmetry $ a _ { lt } $ for charged pion electroproduction in semi \ nobreakdash - inclusive deep \ nobreakdash - inelastic electron scattering on a transversely polarized $ ^ { 3 } $ he target. the kinematics focused on the valence quark region, $ 0. 16 < x < 0. 35 $ with $ 1. 4 < q ^ { 2 } < 2. 7 \, \ textrm { gev } ^ { 2 } $. the corresponding neutron $ a _ { lt } $ asymmetries were extracted from the measured $ ^ { 3 } $ he asymmetries and proton over $ ^ { 3 } $ he cross section ratios using the effective polarization approximation. these new data probe the transverse momentum dependent parton distribution function $ g _ { 1t } ^ { q } $ and therefore provide access to quark spin - orbit correlations. our results indicate a positive azimuthal asymmetry for $ \ pi ^ { - } $ production on $ ^ { 3 } $ he and the neutron, while our $ \ pi ^ { + } $ asymmetries are consistent with zero.
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arxiv:1108.0489
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we study moduli stabilization via fluxes in the $ 2 ^ 6 $ landau - ginzburg model. fluxes not only give masses to scalar fields but can also induce higher order couplings that stabilize massless fields. we investigate this for several different flux choices in the $ 2 ^ 6 $ model and find two examples that are inconsistent with the refined tadpole conjecture. we also present, to our knowledge, the first 4d $ \ mathcal { n } = 1 $ minkowski solution in string theory without any flat direction.
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arxiv:2407.16756
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it is a classical result from universal algebra that the notions of polymorphisms and invariants provide a galois connection between suitably closed classes ( clones ) of finitary operations $ f \ colon b ^ n \ to b $, and classes ( coclones ) of relations $ r \ subseteq b ^ k $. we will present a generalization of this duality to classes of ( multi - valued, partial ) functions $ f \ colon b ^ n \ to b ^ m $, employing invariants valued in partially ordered monoids instead of relations. in particular, our set - up encompasses the case of permutations $ f \ colon b ^ n \ to b ^ n $, motivated by problems in reversible computing.
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arxiv:1612.04353
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identity is one of the most commonly studied constructs in social science. however, despite extensive theoretical work on identity, there remains a need for additional empirical data to validate and refine existing theories. this paper introduces a novel approach to studying identity by enhancing word embeddings with socio - demographic information. as a proof of concept, we demonstrate that our approach successfully reproduces and extends established findings regarding gendered self - views. our methodology can be applied in a wide variety of settings, allowing researchers to tap into a vast pool of naturally occurring data, such as social media posts. unlike similar methods already introduced in computer science, our approach allows for the study of differences between social groups. this could be particularly appealing to social scientists and may encourage the faster adoption of computational methods in the field.
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arxiv:2407.00340
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photonic nanostructures provide means of tailoring the interaction between light and matter and the past decade has witnessed a tremendous experimental and theoretical progress in this subject. in particular, the combination with semiconductor quantum dots has proven successful. this manuscript reviews quantum optics with excitons in single quantum dots embedded in photonic nanostructures. the ability to engineer the light - matter interaction strength in integrated photonic nanostructures enables a range of fundamental quantum - electrodynamics experiments on, e. g., spontaneous - emission control, modified lamb shifts, and enhanced dipole - dipole interaction. furthermore, highly efficient single - photon sources and giant photon nonlinearities may be implemented with immediate applications for photonic quantum - information processing. the review summarizes the general theoretical framework of photon emission including the role of dephasing processes, and applies it to photonic nanostructures of current interest, such as photonic - crystal cavities and waveguides, dielectric nanowires, and plasmonic waveguides. the introduced concepts are generally applicable in quantum nanophotonics and apply to a large extent also to other quantum emitters, such as molecules, nitrogen vacancy ceters, or atoms. finally, the progress and future prospects of applications in quantum - information processing are considered.
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arxiv:1312.1079
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based on a large fermi blazar sample, the blazar sequence ( synchrotron peak frequency $ \ nu _ { \ rm peak } $ versus synchrotron peak luminosity $ l _ { \ rm peak } $ ) is revisited. it is found that there is significant anti - correlation between $ \ nu _ { \ rm peak } $ and $ l _ { \ rm peak } $ for blazars. however, after being doppler corrected, the anti - correlation disappears. the jet cavity power ( $ p _ { \ rm jet } $ ) is estimated from extended radio luminosity. so it is free of beaming effect. we find that there are significant anti - correlations between $ p _ { \ rm jet } $ and beam - corrected $ \ nu _ { \ rm peak } ^ { ' } $ for both blazars and radio galaxies, which supports the blazar sequence and unification of blazars and radio galaxies ( an alternative relationship is the correlation between jet power and $ \ gamma $ - ray photon index ).
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arxiv:1505.01408
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optimized schwarz methods ( osms ) are based on optimized transmission conditions along the interfaces between the subdomains. optimized transmission conditions are derived at the theoretical level, using techniques developed in the last decades. the hypothesis behind these analyses are quite strong, so that the applicability of osms is still limited. in this manuscript, we present a numerical algorithm to obtain optimized transmission conditions for any given problem at hand. this algorithm requires few subdomain solves to be performed in an offline phase. this additional cost is usually negligible due to the resulting faster convergence, even in a single - query context.
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arxiv:2103.09562
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we introduce a natural but seemingly yet unstudied generalization of the problem of scheduling jobs on a single machine so as to minimize the number of tardy jobs. our generalization lies in simultaneously considering several instances of the problem at once. in particular, we have $ n $ clients over a period of $ m $ days, where each client has a single job with its own processing time and deadline per day. our goal is to provide a schedule for each of the $ m $ days, so that each client is guaranteed to have their job meet its deadline in at least $ k \ le m $ days. this corresponds to an equitable schedule where each client is guaranteed a minimal level of service throughout the period of $ m $ days. we provide a thorough analysis of the computational complexity of three main variants of this problem, identifying both efficient algorithms and worst - case intractability results.
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arxiv:2010.04643
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we study the moduli space of 4d n = 1 supersymmetric qcd in the veneziano limit using hilbert series. in this limit, the numbers of colours and flavours are taken to be large with their ratio fixed. it is shown that the hilbert series, which is a partition function of an ensemble of gauge invariant quantities parametrising the moduli space, can also be realised as a partition function of a system of interacting coulomb gas in two dimensions. in the electrostatic equilibrium, exact and asymptotic analyses reveal that such a system exhibits two possible phases. physical quantities, such as charge densities, free energies, and hilbert series, associated with each phase, are computed explicitly and discussed in detail. we then demonstrate the existence of the third order phase transition in this system.
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arxiv:1303.6289
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despite the high biometric performance, finger - vein recognition systems are vulnerable to presentation attacks ( aka., spoofing attacks ). in this paper, we present a new and robust approach for detecting presentation attacks on finger - vein biometric systems exploiting the 3d shape ( normal - map ) and material properties ( diffuse - map ) of the finger. observing the normal - map and diffuse - map exhibiting enhanced textural differences in comparison with the original finger - vein image, especially in the presence of varying illumination intensity, we propose to employ textural feature - descriptors on both of them independently. the features are subsequently used to compute a separating hyper - plane using support vector machine ( svm ) classifiers for the features computed from normal - maps and diffuse - maps independently. given the scores from each classifier for normal - map and diffuse - map, we propose sum - rule based score level fusion to make detection of such presentation attack more robust. to this end, we construct a new database of finger - vein images acquired using a custom capture device with three inbuilt illuminations and validate the applicability of the proposed approach. the newly collected database consists of 936 images, which corresponds to 468 bona fide images and 468 artefact images. we establish the superiority of the proposed approach by benchmarking it with classical textural feature - descriptor applied directly on finger - vein images. the proposed approach outperforms the classical approaches by providing the attack presentation classification error rate ( apcer ) & bona fide presentation classification error rate ( bpcer ) of 0 % compared to comparable traditional methods.
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arxiv:1912.01408
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harnessing power - law interactions ( $ 1 / r ^ \ alpha $ ) in a large variety of physical systems are increasing. we study the dynamics of chiral spin chains as a possible multi - directional quantum channel. this arises from the nonlinear character of the dispersion with complex quantum interference effects. using complementary numerical and analytical techniques, we propose a model to guide quantum states to a desired direction. we illustrate our approach using the long - range xxz model modulated by dzyaloshinskii - moriya ( dm ) interaction. by exploring non - equilibrium dynamics after a local quantum quench, we identify the interplay of interaction range $ \ alpha $ and dzyaloshinskii - moriya coupling giving rise to an appreciable asymmetric spin excitations transport. this could be interesting for quantum information protocols to transfer quantum states, and it may be testable with current trapped - ion experiments. we further explore the growth of block entanglement entropy in these systems, and an order of magnitude reduction is distinguished.
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arxiv:2108.07738
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it is assumed that under suitable economic and information - theoretic conditions, market exchange rates are free from arbitrage. commodity markets in which trades occur over a complete graph are shown to be trivial. we therefore examine the vector space of no - arbitrage exchange rate ensembles over an arbitrary connected undirected graph. consideration is given for the minimal information for determination of an exchange rate ensemble. we conclude with a topical discussion of exchanges in which our analyses may be relevant, including the emergent but highly - regulated ( and therefore not a complete graph ) market for digital currencies.
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arxiv:1406.1547
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we generalize the tutte polynomial of a matroid to a morphism of matroids via the k - theory of flag varieties. we introduce two different generalizations, and demonstrate that each has its own merits, where the trade - off is between the ease of combinatorics and geometry. one generalization recovers the las vergnas tutte polynomial of a morphism of matroids, which admits a corank - nullity formula and a deletion - contraction recursion. the other generalization does not, but better reflects the geometry of flag varieties.
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arxiv:2004.00112
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let $ l / k $ be a finite galois extension of local fields. the hasse - arf theorem says that if gal $ ( l / k ) $ is abelian then the upper ramification breaks of $ l / k $ must be integers. we prove the following converse to the hasse - arf theorem : let $ g $ be a nonabelian group which is isomorphic to the galois group of some totally ramified extension $ e / f $ of local fields with residue characteristic $ p > 2 $. then there is a totally ramified extension of local fields $ l / k $ with residue characteristic $ p $ such that gal $ ( l / k ) \ cong g $ and $ l / k $ has at least one nonintegral upper ramification break.
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arxiv:2302.00222
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we study limit shapes for dimer models on domains of the hexagonal lattice with free boundary conditions. this is equivalent to the large deviation phenomenon for a random stepped surface over domains fixed only at part of the boundary.
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arxiv:0908.1630
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