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efficient and compact single photon emission platforms operating at room temperature with ultrafast speed and high brightness will be fundamental components of the emerging quantum communications and computing fields. however, so far, it is very challenging to design practical deterministic single photon emitters based on nanoscale solid - state materials that meet the fast emission rate and strong brightness demands. here, a solution is provided to this longstanding problem by using metallic nanocavities integrated with hexagonal boron nitride ( hbn ) flakes with defects acting as nanoscale single photon emitters ( spes ) at room temperature. the presented hybrid nanophotonic structure creates a rapid speedup and large enhancement in single photon emission at room temperature. hence, the nonclassical light emission performance is substantially improved compared to plain hbn flakes and hbn on gold - layered structures without nanocavity. extensive theoretical calculations are also performed to accurately model the new hybrid nanophotonic system and prove that the incorporation of plasmonic nanocavity is key to efficient spe performance. the proposed quantum nanocavity single photon source is expected to be an element of paramount importance to the envisioned room - temperature integrated quantum photonic networks.
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arxiv:2405.09683
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we answer the following question : let l, m, n be arbitrary real numbers. does there exist a 3 - dimensional homogeneous riemannian manifold whose eigenvalues of the ricci tensor are just l, m and n?
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arxiv:gr-qc/0109008
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viewing gravitational energy - momentum $ p _ g ^ \ mu $ as equal by observation, but different in essence from inertial energy - momentum $ p _ i ^ \ mu $ naturally leads to the gauge theory of volume - preserving diffeormorphisms of an inner minkowski space $ { \ bf m } ^ { \ sl 4 } $. to extract its physical content the full gauge group is reduced to its poincar \ ' e subgroup. the respective poincar \ ' e gauge fields, field strengths and poincar \ ' e - covariant field equations are obtained and point - particle source currents are derived. the resulting set of non - linear field equations coupled to point matter is solved in first order resulting in lienard - wiechert - like potentials for the poincar \ ' e fields. after numerical identification of gravitational and inertial energy - momentum newton ' s inverse square law for gravity in the static non - relativistic limit is recovered. the weak equivalence principle in this approximation is proven to be valid and spacetime geometry in the presence of poincar \ ' e fields is shown to be curved. finally, the gravitational radiation of an accelerated point particle is calulated.
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arxiv:1103.0349
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the recent discovery of a higgs - like boson at the lhc with a mass of 126 gev has revived the interest in supersymmetric models, which predicted a higgs boson mass below 130 gev long before its discovery. we compare systematically the allowed parameter space in the constrained minimal supersymmetric standard model ( cmssm ) and the next - to - minimal supersymmetric model ( nmssm ) by minimizing the chi ^ 2 function with respect to all known constraints from accelerators and cosmology using gut scale parameters. for the cmssm the higgs boson mass at tree level is below the z ^ 0 boson mass and large radiative corrections are needed to obtain a higgs boson mass of 126 gev, which requires stop squark masses in the multi - tev range. in contrast, for the nmssm light stop quarks are allowed, since in the nmssm at tree level the higgs boson mass can be above the z ^ 0 boson mass from mixing with the additional singlet higgs boson. predictions for the scalar boson masses are given in both models with emphasis on the unique signatures of the nmssm, where the heaviest scalar higgs boson decays in the two lighter scalar higgs bosons with a significant branching ratio, in which case one should observe double higgs boson production at the lhc. such a signal is strongly suppressed in the cmssm. in addition, since the lsp is higgsino - like, higgs boson decays into lsps can be appreciable, thus leading to invisible higgs decays.
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arxiv:1308.1333
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here, bv ( ri ) c broad band photometry and intermediate resolution spectroscopy in halpha region are presented for two rapidly rotating late - type stars : ey dra and v374 peg. for a third rapid rotator, gsc 02038 - 00293, intermediate resolution halpha spectroscopy and low resolution spectroscopy are used for spectral classification and stellar parameter investigation of this poorly known object. the low resolution spectrum of gsc 02038 - 00293 clearly indicates that it is a k - type star. its intermediate resolution spectrum can be best fitted with a model with teff = 4750k and vsini = 90km / s, indicating a very rapidly rotating mid - k star. the halpha line strength is variable, indicating changing chromospheric emission on gsc 02038 - 00293. in the case of ey dra and v374 peg, the stellar activity in the photosphere is investigated from the photometric observations, and in the chromosphere from the halpha line. the enhanced chromospheric emission in ey dra correlates well with the location of the photospheric active regions, indicating that these features are spatially collocated. hints of this behaviour are also seen in v374 peg, but it cannot be confirmed from the current data. the photospheric activity patterns in ey dra are stable during one observing run lasting several nights, whereas in v374 peg large night - to - night variations are seen. two large flares, one in the halpha observations and one from the broadband photometry, and twelve smaller ones were detected in v374 peg during the observations spanning nine nights. the energy of the photometrically detected largest flare is estimated to be 4. 25x10 ^ 31 - 4. 3x10 ^ 32 ergs, depending on the waveband. comparing the activity patterns in these two stars, which are just below and above the mass limit of full convection, is crucial for understanding dynamo operation in stars with different internal structures.
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arxiv:1007.0242
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in the paper " infinite product representations for kernels and iterations of functions ", the authors associate certain fatou subsets with reproducing kernel hilbert spaces. they also present a method for constructing an orthonormal basis for said hilbert space, but the method depends on the polynomial of the given fatou set. we provide a partial classification of those polynomials the method applies to.
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arxiv:1812.09757
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we study the collective raman cooling of a polarized trapped fermi gas in the festina lente regime, when the heating effects associated with photon reabsorptions are suppressed. we predict that by adjusting the spontaneous raman emission rates and using appropriately designed anharmonic traps, temperatures of the order of 2. 7 % of the fermi temperature can be achieved in 3d.
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arxiv:quant-ph/0010067
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highest standards of honesty and integrity. engineering has a direct and vital impact on the quality of life for all people. accordingly, the services provided by engineers require honesty, impartiality, fairness, and equity, and must be dedicated to the protection of the public health, safety, and welfare. engineers must perform under a standard of professional behavior that requires adherence to the highest principles of ethical conduct. in canada, engineers wear the iron ring as a symbol and reminder of the obligations and ethics associated with their profession. = = relationships with other disciplines = = = = = science = = = scientists study the world as it is ; engineers create the world that has never been. there exists an overlap between the sciences and engineering practice ; in engineering, one applies science. both areas of endeavor rely on accurate observation of materials and phenomena. both use mathematics and classification criteria to analyze and communicate observations. scientists may also have to complete engineering tasks, such as designing experimental apparatus or building prototypes. conversely, in the process of developing technology, engineers sometimes find themselves exploring new phenomena, thus becoming, for the moment, scientists or more precisely " engineering scientists ". in the book what engineers know and how they know it, walter vincenti asserts that engineering research has a character different from that of scientific research. first, it often deals with areas in which the basic physics or chemistry are well understood, but the problems themselves are too complex to solve in an exact manner. there is a " real and important " difference between engineering and physics as similar to any science field has to do with technology. physics is an exploratory science that seeks knowledge of principles while engineering uses knowledge for practical applications of principles. the former equates an understanding into a mathematical principle while the latter measures variables involved and creates technology. for technology, physics is an auxiliary and in a way technology is considered as applied physics. though physics and engineering are interrelated, it does not mean that a physicist is trained to do an engineer ' s job. a physicist would typically require additional and relevant training. physicists and engineers engage in different lines of work. but phd physicists who specialize in sectors of engineering physics and applied physics are titled as technology officer, r & d engineers and system engineers. an example of this is the use of numerical approximations to the navier – stokes equations to describe aerodynamic flow over an aircraft, or the use of the finite element method to calculate the stresses in complex components. second, engineering research employs many semi - empirical methods that are foreign to pure scientific research
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https://en.wikipedia.org/wiki/Engineering
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science journalism reports current scientific discoveries to non - specialists, aiming to enable public comprehension of the state of the art. this task is challenging as the audience often lacks specific knowledge about the presented research. we propose a jre - l framework that integrates three llms mimicking the writing - reading - feedback - revision loop. in jre - l, one llm acts as the journalist, another llm as the general public reader, and the third llm as an editor. the journalist ' s writing is iteratively refined by feedback from the reader and suggestions from the editor. our experiments demonstrate that by leveraging the collaboration of two 7b and one 1. 8b open - source llms, we can generate articles that are more accessible than those generated by existing methods, including prompting single advanced models such as gpt - 4 and other llm - collaboration strategies. our code is publicly available at github. com / zzoay / jre - l.
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arxiv:2501.16865
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expansions then the set of $ q $ - expansions for $ x $ has cardinality equal to that of the continuum, this proves that the continuum hypothesis holds when restricted to this specific case.
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arxiv:1305.3850
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we give a condition for an almost constant - type manifold to be a constant - type manifold, and holomorphic and $ r $ - invariant submanifolds of almost hermitian manifolds are studied. generalizations of some results in [ 5 ] are given.
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arxiv:1311.2515
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phase field crystal methodology is applied, for the first time, to study the effect of alloy composition on the clustering behavior of a quenched / aged supersaturated ternary al alloy system. an analysis of the work of formation is built upon the methodology developed in fallah { \ it et al. } to describe the dislocation - mediated formation mechanisms of early clusters in binary alloys [ phys. rev. b., doi : 10. 1103 / physrevb. 00. 004100 ]. consistent with the experiments, we demonstrate that the addition of mg to an al - 1. 1cu alloy increases the nucleation rate of clusters in the quenched / aged state by increasing the effective driving force for nucleation, enhancing the dislocation stress relaxation and decreasing the surface energy associated with the cu - rich cu - mg co - clusters. furthermore, we show that it is thermodynamically favourable for small sub - critical clusters to have higher affinity for mg than larger overcritical cu - rich clusters, particularly depicting a two - stage clustering phenomenon.
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arxiv:1210.4977
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we predict the polarization of cosmic microwave background ( cmb ) photons that results from a cosmic bubble collision. the polarization is purely e - mode, symmetric around the axis pointing towards the collision bubble, and has several salient features in its radial dependence that can help distinguish it from a more conventional explanation for unusually cold or hot features in the cmb sky. the anomalous " cold spot " detected by the wilkinson microwave anisotropy probe ( wmap ) satellite is a candidate for a feature produced by such a collision, and the planck satellite and other proposed surveys will measure the polarization on it in the near future. the detection of such a collision would provide compelling evidence for the string theory landscape.
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arxiv:1006.0832
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we theoretically expanded the capabilities of optical sensing based on surface plasmon resonance in a prism - coupled configuration by incorporating artificial neural networks ( anns ). we used calculations modeling the situation in which an index - matched substrate with a metal thin film and a porous chiral sculptured thin film ( cstf ) deposited successively on it is affixed to the base of a triangular prism. when a fluid is brought in contact with the exposed face of the cstf, the latter is infiltrated. as a result of infiltration, the traversal of light entering one slanted face of the prism and exiting the other slanted face of the prism is affected. we trained two anns with differing structures using reflectance data generated from simulations to predict the refractive index of the infiltrant fluid. the best predictions were a result of training the ann with simpler structure. with realistic simulated - noise, the performance of this ann is robust.
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arxiv:1908.02128
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we quantify the star formation ( sf ) in the inner cores ( $ \ mathcal { r } $ / $ r _ { 200 } $ $ \ leq $ 0. 3 ) of 24 massive galaxy clusters at 0. 2 $ \ lesssim $ $ z $ $ \ lesssim $ 0. 9 observed by the $ herschel $ lensing survey and the cluster lensing and supernova survey with $ hubble $. these programmes, covering the rest - frame ultraviolet to far - infrared regimes, allow us to accurately characterize stellar mass - limited ( $ \ mathcal { m } _ { * } $ $ > $ $ 10 ^ { 10 } $ $ m _ { \ odot } $ ) samples of star - forming cluster members ( not ) - detected in the mid - and / or far - infrared. we release the catalogues with the photometry, photometric redshifts, and physical properties of these samples. we also quantify the sf displayed by comparable field samples from the cosmic assembly near - infrared deep extragalactic legacy survey. we find that in intermediate - $ z $ cluster cores, the sf activity is suppressed with respect the field in terms of both the fraction ( $ \ mathcal { f } $ ) of star - forming galaxies ( sfg ) and the rate at which they form stars ( $ \ mathcal { sfr } $ and $ s \ mathcal { sfr } = \ mathcal { sfr } / \ mathcal { m } _ { * } $ ). on average, the $ \ mathcal { f } $ of sfgs is a factor $ \ sim $ $ 2 $ smaller in cluster cores than in the field. furthermore, sfgs present average $ \ mathcal { sfr } $ and $ s \ mathcal { sfr } $ typically $ \ sim $ 0. 3 dex smaller in the clusters than in the field along the whole redshift range probed. our results favour long time - scale quenching physical processes as the main driver of sf suppression in the inner cores of clusters since $ z $ $ \ sim $ 0. 9, with shorter time - scale processes being very likely responsible for a fraction of the missing sfg population.
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arxiv:1812.08804
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we consider transient random walks on a strip in a random environment. the model was introduced by bolthausen and goldsheid [ comm. math. phys. 214 ( 2000 ) 429 - - 447 ]. we derive a strong law of large numbers for the random walks in a general ergodic setup and obtain an annealed central limit theorem in the case of uniformly mixing environments. in addition, we prove that the law of the " environment viewed from the position of the walker " converges to a limiting distribution if the environment is an i. i. d. sequence.
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arxiv:math/0603392
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it is conjectured that in the geometric formulation of quantum computing, one can study quantum complexity through classical entropy of statistical ensembles established non - relativistically in the group manifold of unitary operators. the kinetic and positional decompositions of statistical entropy are conjectured to correspond to the kolmogorov complexity and computational complexity, respectively, of corresponding quantum circuits. in this paper, we claim that by applying the virial theorem to the group manifold, one can derive a generic relation between kolmogorov complexity and computational complexity in the thermal equilibrium.
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arxiv:1804.03242
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##itary nature of first - order logical consequence. these results helped establish first - order logic as the dominant logic used by mathematicians. in 1931, godel published on formally undecidable propositions of principia mathematica and related systems, which proved the incompleteness ( in a different meaning of the word ) of all sufficiently strong, effective first - order theories. this result, known as godel ' s incompleteness theorem, establishes severe limitations on axiomatic foundations for mathematics, striking a strong blow to hilbert ' s program. it showed the impossibility of providing a consistency proof of arithmetic within any formal theory of arithmetic. hilbert, however, did not acknowledge the importance of the incompleteness theorem for some time. godel ' s theorem shows that a consistency proof of any sufficiently strong, effective axiom system cannot be obtained in the system itself, if the system is consistent, nor in any weaker system. this leaves open the possibility of consistency proofs that cannot be formalized within the system they consider. gentzen proved the consistency of arithmetic using a finitistic system together with a principle of transfinite induction. gentzen ' s result introduced the ideas of cut elimination and proof - theoretic ordinals, which became key tools in proof theory. godel gave a different consistency proof, which reduces the consistency of classical arithmetic to that of intuitionistic arithmetic in higher types. the first textbook on symbolic logic for the layman was written by lewis carroll, author of alice ' s adventures in wonderland, in 1896. = = = = beginnings of the other branches = = = = alfred tarski developed the basics of model theory. beginning in 1935, a group of prominent mathematicians collaborated under the pseudonym nicolas bourbaki to publish elements de mathematique, a series of encyclopedic mathematics texts. these texts, written in an austere and axiomatic style, emphasized rigorous presentation and set - theoretic foundations. terminology coined by these texts, such as the words bijection, injection, and surjection, and the set - theoretic foundations the texts employed, were widely adopted throughout mathematics. the study of computability came to be known as recursion theory or computability theory, because early formalizations by godel and kleene relied on recursive definitions of functions. when these definitions were shown equivalent to turing ' s formalization involving turing machines, it became clear that a new concept – the computable function – had
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https://en.wikipedia.org/wiki/Mathematical_logic
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strength is maximized with decreasing grain size, ultimately, very small grain sizes make the material brittle. considered in tandem with the fact that the yield strength is the parameter that predicts plastic deformation in the material, one can make informed decisions on how to increase the strength of a material depending on its microstructural properties and the desired end effect. the relation between yield stress and grain size is described mathematically by the hall - petch equation which is σ y = σ 0 + k y d { \ displaystyle \ sigma _ { y } = \ sigma _ { 0 } + { k _ { y } \ over { \ sqrt { d } } } } where ky is the strengthening coefficient ( a constant unique to each material ), σo is a materials constant for the starting stress for dislocation movement ( or the resistance of the lattice to dislocation motion ), d is the grain diameter, and σy is the yield stress. theoretically, a material could be made infinitely strong if the grains are made infinitely small. this is, unfortunately, impossible because the lower limit of grain size is a single unit cell of the material. even then, if the grains of a material are the size of a single unit cell, then the material is in fact amorphous, not crystalline, since there is no long range order, and dislocations can not be defined in an amorphous material. it has been observed experimentally that the microstructure with the highest yield strength is a grain size of about 10 nanometers, because grains smaller than this undergo another yielding mechanism, grain boundary sliding. producing engineering materials with this ideal grain size is difficult because of the limitations of initial particle sizes inherent to nanomaterials and nanotechnology. = = faber - evans model = = the faber - evans model, developed by katherine faber and anthony g. evans, was developed to predict the increase in fracture toughness in ceramics due to crack deflection around second - phase particles that are prone to microcracking in a matrix. the model considers particle morphology, aspect ratio, spacing, and volume fraction of the second phase, as well as the reduction in local stress intensity at the crack tip when the crack is deflected or the crack plane bows. actual crack tortuosity is obtained through imaging techniques, which allows for the direct input of deflection and bowing angles into the model. the model calculates the average strain energy release rate and compares the resulting increase in fracture toughness
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https://en.wikipedia.org/wiki/Ceramic_engineering
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a $ \ { 0, 1 \ } $ - matrix $ \ mathsf { a } $ is balanced if it does not contain a submatrix of odd order having exactly two 1 ' s per row and per column. a graph is balanced if its clique - matrix is balanced. no characterization of minimally unbalanced graphs is known, and even no conjecture on the structure of such graphs has been posed, contrarily to what happened for perfect graphs. in this paper, we provide such a characterization for the class of diamond - free graphs and establish a connection between minimally unbalanced diamond - free graphs and dyck - paths.
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arxiv:1406.6494
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we introduce mask - tof, a method to reduce flying pixels ( fp ) in time - of - flight ( tof ) depth captures. fps are pervasive artifacts which occur around depth edges, where light paths from both an object and its background are integrated over the aperture. this light mixes at a sensor pixel to produce erroneous depth estimates, which can adversely affect downstream 3d vision tasks. mask - tof starts at the source of these fps, learning a microlens - level occlusion mask which effectively creates a custom - shaped sub - aperture for each sensor pixel. this modulates the selection of foreground and background light mixtures on a per - pixel basis and thereby encodes scene geometric information directly into the tof measurements. we develop a differentiable tof simulator to jointly train a convolutional neural network to decode this information and produce high - fidelity, low - fp depth reconstructions. we test the effectiveness of mask - tof on a simulated light field dataset and validate the method with an experimental prototype. to this end, we manufacture the learned amplitude mask and design an optical relay system to virtually place it on a high - resolution tof sensor. we find that mask - tof generalizes well to real data without retraining, cutting fp counts in half.
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arxiv:2103.16693
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i use methods of chai - hida and ordinary $ p $ - hecke correspondences to study the set of irreducible components of special fibers of special cycles of sufficiently low codimension in integral models of gspin shimura varieties, and apply this to prove irreducibility results for the special fibers of the moduli of polarized k3 surfaces. these results are also applied in joint work with howard on the modularity of generating series of higher codimension cycles on gspin shimura varieties.
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arxiv:2505.02084
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social media contains useful information about people and the society that could help advance research in many different areas ( e. g. by applying opinion mining, emotion / sentiment analysis, and statistical analysis ) such as business and finance, health, socio - economic inequality and gender vulnerability. user demographics provide rich information that could help study the subject further. however, user demographics such as gender are considered private and are not freely available. in this study, we propose a model based on transformers to predict the user ' s gender from their images and tweets. we fine - tune a model based on vision transformers ( vit ) to stratify female and male images. next, we fine - tune another model based on bidirectional encoders representations from transformers ( bert ) to recognize the user ' s gender by their tweets. this is highly beneficial, because not all users provide an image that indicates their gender. the gender of such users could be detected form their tweets. the combination model improves the accuracy of image and text classification models by 6. 98 % and 4. 43 %, respectively. this shows that the image and text classification models are capable of complementing each other by providing additional information to one another. we apply our method to the pan - 2018 dataset, and obtain an accuracy of 85. 52 %.
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arxiv:2205.06801
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we present the full source catalogue from the australia telescope 20 ghz ( at20g ) survey. the at20g is a blind radio survey carried out at 20 ghz with the australia telescope compact array ( atca ) from 2004 to 2008, and covers the whole sky south of declination 0 deg. the at20g source catalogue presented here is an order of magnitude larger than any previous catalogue of high - frequency radio sources, and includes 5890 sources above a 20 ghz flux - density limit of 40 mjy. all at20g sources have total intensity and polarisation measured at 20 ghz, and most sources south of declination - 15 deg also have near - simultaneous flux - density measurements at 5 and 8 ghz. a total of 1559 sources were detected in polarised total intensity at one or more of the three frequencies. we detect a small but significant population of non - thermal sources that are either undetected or have only weak detections in low - frequency catalogues. we introduce the term ultra - inverted spectrum ( uis ) to describe these radio sources, which have a spectral index alpha ( 5, 20 ) > + 0. 7 and which constitute roughly 1. 2 per cent of the at20g sample. the 20 ghz flux densities measured for the strongest at20g sources are in excellent agreement with the wmap 5 - year source catalogue of wright et al. ( 2009 ), and we find that the wmap source catalogue is close to complete for sources stronger than 1. 5 jy at 23 ghz.
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arxiv:0911.0002
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the biharmonic supercritical equation $ \ delta ^ 2u = | u | ^ { p - 1 } u $, where $ n > 4 $ and $ p > ( n + 4 ) / ( n - 4 ) $, is studied in the whole space $ \ mathbb { r } ^ n $ as well as in a modified form with $ \ lambda ( 1 + u ) ^ p $ as right - hand - side with an additional eigenvalue parameter $ \ lambda > 0 $ in the unit ball, in the latter case together with dirichlet boundary conditions. as for entire regular radial solutions we prove oscillatory behaviour around the explicitly known radial { \ it singular } solution, provided $ p \ in ( ( n + 4 ) / ( n - 4 ), p _ c ) $, where $ p _ c \ in ( ( n + 4 ) / ( n - 4 ), \ infty ] $ is a further critical exponent, which was introduced in a recent work by gazzola and the second author. the third author proved already that these oscillations do not occur in the complementing case, where $ p \ ge p _ c $. concerning the dirichlet problem we prove existence of at least one singular solution with corresponding eigenvalue parameter. moreover, for the extremal solution in the bifurcation diagram for this nonlinear biharmonic eigenvalue problem, we prove smoothness as long as $ p \ in ( ( n + 4 ) / ( n - 4 ), p _ c ) $.
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arxiv:0711.2202
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let v, w be real algebraic varieties ( that is, up to isomorphism, real algebraic sets ), and let x be a subset of v. a map f from x into w is said to be regular if it can be extended to a regular map defined on some zariski locally closed subvariety of v that contains x. furthermore, such a map is said to be piecewise - regular if there exists a stratification of v such that the restriction of f to the intersection of x with each stratum is a regular map. by a stratification of v we mean a finite collection of pairwise disjoint zariski locally closed subvarieties whose union is equal to v. assuming that the subset x is compact, we prove that every continuous map from x into a grassmann variety or a unit sphere can be approximated by piecewise - regular maps. as an application, we obtain a variant of the algebraization theorem for topological vector bundles. if the variety v is compact and nonsingular, we prove that each continuous map from v into a unit sphere is homotopic to a piecewise - regular map of class c ^ k, where k is an arbitrary nonnegative integer.
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arxiv:1705.04525
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we present a mechanistic theory for predicting void evolution in the li metal electrode during the charge and discharge of all - solid - state battery cells. a phase field formulation is developed to model vacancy annihilation and nucleation, and to enable the tracking of the void - li metal interface. this is coupled with a viscoplastic description of li deformation, to capture creep effects, and a mass transfer formulation accounting for substitutional ( bulk and surface ) li diffusion and current - driven flux. moreover, we incorporate the interaction between the electrode and the solid electrolyte, resolving the coupled electro - chemical - mechanical problem in both domains. this enables predicting the electrolyte current distribution and thus the emergence of local current ' hot spots ', which act as precursors for dendrite formation and cell death. the theoretical framework is numerically implemented, and single and multiple void case studies are carried out to predict the evolution of voids and current hot spots as a function of the applied pressure, material properties and charge ( magnitude and cycle history ). for both plating and stripping, insight is gained into the interplay between bulk diffusion, li dissolution and deposition, creep, and the nucleation and annihilation of vacancies. the model is shown to capture the main experimental observations, including not only key features of electrolyte current and void morphology but also the sensitivity to the applied current, the role of pressure in increasing the electrode - electrolyte contact area, and the dominance of creep over vacancy diffusion.
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arxiv:2206.14753
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being able to analyze and interpret signal coming from electroencephalogram ( eeg ) recording can be of high interest for many applications including medical diagnosis and brain - computer interfaces. indeed, human experts are today able to extract from this signal many hints related to physiological as well as cognitive states of the recorded subject and it would be very interesting to perform such task automatically but today no completely automatic system exists. in previous studies, we have compared human expertise and automatic processing tools, including artificial neural networks ( ann ), to better understand the competences of each and determine which are the difficult aspects to integrate in a fully automatic system. in this paper, we bring more elements to that study in reporting the main results of a practical experiment which was carried out in an hospital for sleep pathology study. an eeg recording was studied and labeled by a human expert and an ann. we describe here the characteristics of the experiment, both human and neuronal procedure of analysis, compare their performances and point out the main limitations which arise from this study.
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arxiv:cs/0510083
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effective and reliable screening of patients via computer - aided diagnosis can play a crucial part in the battle against covid - 19. most of the existing works focus on developing sophisticated methods yielding high detection performance, yet not addressing the issue of predictive uncertainty. in this work, we introduce uncertainty estimation to detect confusing cases for expert referral to address the unreliability of state - of - the - art ( sota ) dnns on covid - 19 detection. to the best of our knowledge, we are the first to address this issue on the covid - 19 detection problem. in this work, we investigate a number of sota uncertainty estimation methods on publicly available covid dataset and present our experimental findings. in collaboration with medical professionals, we further validate the results to ensure the viability of the best performing method in clinical practice.
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arxiv:2104.14029
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this work presents an empirical approach to quantifying the loss of lexical richness in machine translation ( mt ) systems compared to human translation ( ht ). our experiments show how current mt systems indeed fail to render the lexical diversity of human generated or translated text. the inability of mt systems to generate diverse outputs and its tendency to exacerbate already frequent patterns while ignoring less frequent ones, might be the underlying cause for, among others, the currently heavily debated issues related to gender biased output. can we indeed, aside from biased data, talk about an algorithm that exacerbates seen biases?
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arxiv:1906.12068
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maxar technologies inc. is an american space technology company headquartered in westminster, colorado, united states, specializing in geospatial intelligence, earth observation, and on - orbit servicing satellites, satellite products, and related services. digitalglobe and mda holdings company merged to become maxar technologies on october 5, 2017. maxar technologies is the parent holding company of maxar space systems, headquartered in palo alto, california, us ; and maxar intelligence, headquartered in westminster, colorado, us. from 2017 to 2023, it was dual - listed on the toronto stock exchange and new york stock exchange as maxr. in may 2023, maxar was acquired by private equity firm advent international, in an all - cash transaction worth $ 6. 4 billion. maxar ' s satellite data was used by ukraine as part of its defense against russia ' s invasion of its territory. in march 2025, maxar worked with the donald trump administration to shut down ukraine ' s access to the data. = = history = = maxar technologies was created in 2017 from the purchase of digitalglobe by macdonald, dettwiler and associates ( mda ), who renamed the company maxar. the headquarters of the combined entity was then established in westminster, colorado. the company was dual - listed on the tsx and nyse. in q3 2018 maxar ' s revenue and adjusted profit missed estimates due to a decline in its satellite manufacturing segment oriented towards geosynchronous earth orbit communications, which led to a plunge in the stock price. the situation was compounded in january 2019 with the loss of their relatively new worldview - 4 satellite, and the market capitalization fell from $ 3 to $ 0. 3 billion in half a year, and with an insurance payment only covering a fifth of wv - 4 total launch cost the company had to restructure its debts in april 2019. in may 2019, the company was selected as the provider of the power and propulsion element for the lunar gateway developed by nasa. on december 30, 2019, the company announced that it had entered into a definitive agreement to sell mda ' s assets to a consortium of financial sponsors led by northern private capital for ca $ 1 billion ( us $ 765 million ). the sale includes all of mda ' s canadian businesses, encompassing ground stations, radar satellite products, robotics, defense, and satellite components, representing approximately 1, 900 employees. on april 8, 2020, the sale of mda to npc officially closed. the
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https://en.wikipedia.org/wiki/Maxar_Technologies
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we reply to l. ya. glozman ' s comment " is a consistent holographic description of excited hadrons with fixed $ l $ possible? " in general, the solutions of the bound state hamiltonian equation of motion in qcd have fock state components with different $ l $, and consequently hadronic relativistic wave equations derived in the framework of light - front holography share this property. for example, the proton eigenstate has components with l = 0 and l = 1. the results of ads / qcd are consistent with the requirements of chiral symmetry and do not violate any fundamental physical principle. this is further illustrated with various examples.
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arxiv:0903.4922
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arnold, falk, & winther, in " finite element exterior calculus, homological techniques, and applications " ( 2006 ), show how to geometrically decompose the full and trimmed polynomial spaces on simplicial elements into direct sums of trace - free subspaces and in " geometric decompositions and local bases for finite element differential forms " ( 2009 ) the same authors give direct constructions of extension operators for the same spaces. the two families - - full and trimmed - - are treated separately, using differently defined isomorphisms between each and the other ' s trace - free subspaces and mutually incompatible extension operators. this work describes a single operator $ \ mathring { \ star } _ t $ that unifies the two isomorphisms and also defines a weighted - $ l ^ 2 $ norm appropriate for defining well - conditioned basis functions and dual - basis functionals for geometric decomposition. this work also describes a single extension operator $ \ dot { e } _ { \ sigma, t } $ that implements geometric decompositions of all differential forms as well as for the full and trimmed polynomial spaces separately.
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arxiv:2112.02174
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this paper studies the heat content } for schr \ " odinger operators of the fractional laplacian $ ( - \ delta ) ^ { \ alpha / 2 } $, $ 0 < \ alpha \ leq 2 $ in $ r ^ d $, $ d \ geq 1 $. employing probabilistic and analytic techniques, a small time asymptotic expansion formula is given and the " heat content invariants " are identified. these results are new even in the case of the laplacian, $ \ alpha = 2 $.
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arxiv:1401.2971
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we present hst / wfpc2 photometry of the central regions of the phoenix dwarf. accurate photometry allows us to : 1 ) confirm the existence of the horizontal branch previously detected by ground - based observations, and use it to determine a distance to phoenix, 2 ) clearly detect the existence of multiple ages in the stellar population of phoenix, 3 ) determine a mean metallicity of the old red giant branch stars in phoenix, and suggest that phoenix has evolved chemically over its lifetime, 4 ) extract a rough star formation history for the central regions which suggests that phoenix has been forming stars roughly continuously over its entire lifetime.
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arxiv:astro-ph/0008468
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in this work, a new numerical method for the transport of delayed neutron precursors ( dnps ) is applied to the aircraft reactor experiment ( are ). the pathline method is based on the method of characteristics ( moc ) and leverages the pathlines of the liquid nuclear fuel to derive an integral form of the dnps balance equation. the method has previously been tested on the cnrs benchmark and in a simplified 2d geometry where turbulent diffusivity was significant compared to advection. here, the pathline method is applied to a real - world molten salt reactor ( msr ), the are. dnps transport is implemented in the framework of the coupling between neutron transport solver apollo3 \ textregistered { } and computational fluid dynamics code triocfd, both developed at the french atomic and energy commission ( cea ). the dnps concentration obtained with the pathline method were compared with those previously computed by triocfd, highlighting the importance of recirculation of fission products. the l - 7 experiment was also replicated to demonstrate the method ' s capability.
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arxiv:2502.17014
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we propose a new way to use optical tools from quantum imaging and quantum communication to search for physics beyond the standard model. spontaneous parametric down conversion ( spdc ) is a commonly used source of entangled photons in which pump photons convert to a signal - idler pair. we propose to search for " dark spdc " ( dspdc ) events in which a new dark sector particle replaces the idler. though it does not interact, the presence of a dark particle can be inferred by the properties of the signal photon. examples of dark states include axion - like - particles and dark photons. we show that the presence of an optical medium opens the phase space of the down - conversion process, or decay, which would be forbidden in vacuum. search schemes are proposed which employ optical imaging and / or spectroscopy of the signal photons. the signal rates in our proposal scales with the second power of the feeble coupling to new physics, as opposed to light - shining - through - wall experiments whose signal scales with coupling to the fourth. we analyze the characteristics of optical media needed to enhance dspdc and estimate the rate. a bench - top demonstration of a high resolution ghost imaging measurement is performed employing a skipper - ccd to demonstrate its utility in a dspdc search.
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arxiv:2012.04707
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here, we show that spacetime modulations provide an exciting route to realize complex nonreciprocal couplings, and in particular the elusive axion response. we develop an analytical formalism to homogenize anisotropic spacetime crystals in the long wavelength limit. it is found that spacetime crystals with suitable glide - rotation symmetry can have a giant axion - type response, several orders of magnitude larger than in natural materials. the nonreciprocal axion response may have interesting applications in optics, for example in electromagnetic isolation, and in addition may enable exciting new forms of light - wave interactions.
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arxiv:2209.03314
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the higher gauge field in 11 - dimensional supergravity - - the c - field - - is constrained by quantum effects to be a cocycle in some twisted version of differential cohomology. we argue that it should indeed be a cocycle in a certain twisted nonabelian differential cohomology. we give a simple and natural characterization of the full smooth moduli 3 - stack of configurations of the c - field, the gravitational field / background, and the ( auxiliary ) e8 - field. we show that the truncation of this moduli 3 - stack to a bare 1 - groupoid of field configurations reproduces the differential integral wu structures that hopkins - singer had shown to formalize witten ' s argument on the nature of the c - field. we give a similarly simple and natural characterization of the moduli 2 - stack of boundary c - field configurations and show that it is equivalent to the moduli 2 - stack of anomaly free heterotic supergravity field configurations. finally we show how to naturally encode the horava - witten boundary condition on the level of moduli 3 - stacks, and refine it from a condition on 3 - forms to a condition on the corresponding full differential cocycles.
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arxiv:1202.2455
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high - resolution submm imaging of the hzrg, 4c60. 07, at z = 3. 8, has revealed two dusty components. spitzer imaging shows that one of these components ( b ) is coincident with an extremely red agn, offset by ~ 4 " ( ~ 30 kpc ) from the hzrg core. the other submm component ( a ) - resolved by our beam and devoid of emission at 3. 6 - 8. 0um - lies between b and the hzrg core. since the hzrg was discovered via its young, steep - spectrum lobes and their creation was likely triggered by the interaction, we argue that we are witnessing an early - stage merger, prior to its eventual equilibrium state. the interaction is between the host galaxy of an actively - fueled bh, and a gas - rich starburst / agn ( b ) marked by the compact submm component and coincident with broad co emission. ` a ' is a plume of cold, dusty gas, associated with a narrow ( ~ 150 km / s ) co feature, and may represent a short - lived tidal structure. it has been claimed that hzrgs and smgs differ only in the activity of their agns, but such complex submm morphologies are seen only rarely amongst smgs. our study has important implications : where a galaxy ' s gas is not aligned with its central bh, co may be an unreliable probe of dynamical mass, affecting work on the co - assembly of bhs and spheroids. our data support the picture wherein close binary agn are induced by mergers. they also raise the possibility that some supposedly jet - induced starbursts may have formed co - evally with ( yet independently of ) the radio jets, both triggered by the same interaction. we note that the hzrg host would have gone unnoticed without its jets / companion, so there may be many other unseen bhs at high redshift, lost in the sea of ~ 5 x 10 ^ 8 similarly bright irac sources - sufficiently massive to drive a > 10 ^ 27 - w radio source, yet practically invisible unless actively fueled ( abridged ).
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arxiv:0808.2188
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we consider the space of germs of fedosov structures at a point, together with the group of origin - preserving diffeomorphisms acting on it. we calculate dimensions of moduli spaces of $ k $ - jets of generic structures and construct poincar \ ' e series. it is shown to be a rational function.
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arxiv:math/0310469
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chirality, a characteristic handedness that distinguishes ' left ' from ' right ', cuts widely across all of nature $ ^ 1 $, from the structure of dna $ ^ 2 $ to opposite chirality of particles and antiparticles $ ^ 3 $. in condensed matter chiral fermions have been identified in weyl semimetals $ ^ 4 $ through their unconventional electrodynamics arising from ' axial ' charge imbalance between chiral weyl nodes of topologically nontrivial electronic bands. up to now it has been challenging or impossible to create transport channels of weyl fermions in a single material that could be easily configured for advancing chiral logic or spintronics $ ^ { 5, 6 } $. here we generate chirality - directed conduction channels in inversion - symmetric weyl ferromagnet ( fm ) $ mnsb _ 2te _ 4 $, emergent from a deep connection between chirality in reciprocal and real space. we alter the bandstructure on - demand with an intake and a subsequent release of ionic hydrogen ( $ h ^ + $ ) $ - $ a process we show to induce the tilt and rotation of weyl bands. the transformed weyl fm states feature a doubled curie temperature $ \ geq50k $ and an enhanced angular transport chirality synchronous with a rare field - antisymmetric longitudinal resistance $ - $ a low - field tunable ' chiral switch ' that roots in the interplay of berry curvature $ ^ 7 $, chiral anomaly $ ^ 8 $ and hydrogen - engendered mutation of weyl nodes.
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arxiv:2312.02315
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the inclusive gluon jet function is evaluated at two - loop accuracy. this function is relevant for resummations of large perturbative logarithms in collider processes involving low - mass gluon jets. the jet function corresponds to the imaginary part of the gluon propagator in light - cone gauge, which is adopted for the calculation. in addition to the leading jet function, the power - suppressed two - gluon jet functions are given and their renormalization is discussed.
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arxiv:1008.1936
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the newly discovered superconductivity in mgcni3, though with tc < 8 k lower than that of the celebrated mgb2, is probably even more interesting in its many puzzling physical properties. mgcni3 has been theoretically speculated to be unstable towards ferromagnetism. however, there are numerous evidences from the specific heat c ( t ), tunneling spectroscopy and nmr experiments indicating conventional s - wave superconductivity in mgcni3. the hall effect and the thermoelectric power experiments suggest that the carriers responsible for the transport properties are electrons, in obvious contrast to holes predicated by the band structure calculations. in this article, we report the results of c ( t ) experiments, upper critical field hc2 measurements, and the pressure effects on mgcni3. these experimental evidences clearly demonstrate that superconductivity in mgcni3 is well explained within the conventional electron - phonon interaction scenario, at most with minor modifications from the magnetic interaction. the thermodynamic data c ( t ) is consistent with the conventional s - wave order parameter. hc2 of all samples follows a universal whh relation. surprisingly, dtc / dp is positive which leaves room for further improvements in band structure calculations. there are other serious discrepancies between experiments and theory like in the transport properties and x - ray photoemission. the possible reconciliation within the two - band model and the consequent difficulties are discussed.
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arxiv:cond-mat/0308198
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mobile edge computing ( mec ) has been envisaged as a promising technique in the next - generation wireless networks. in order to improve the security of computation tasks offloading and enhance user connectivity, physical layer security and non - orthogonal multiple access ( noma ) are studied in mec - aware networks. the secrecy outage probability is adopted to measure the secrecy performance of computation offloading by considering a practically passive eavesdropping scenario. the weighted sum - energy consumption minimization problem is firstly investigated subject to the secrecy offloading rate constraints, the computation latency constraints and the secrecy outage probability constraints. the semi - closed form expression for the optimal solution is derived. we then investigate the secrecy outage probability minimization problem by taking the priority of two users into account, and characterize the optimal secrecy offloading rates and power allocations with closed - form expressions. numerical results demonstrate that the performance of our proposed design are better than those of the alternative benchmark schemes.
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arxiv:1910.09886
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to advance precise inertial navigation, we present a compact quantum sensor which is based on novel quantum phenomenon of the angular bloch oscillations and measures solely the angular acceleration of slow external rotation. we investigate the dynamics of ultra - cold atoms confined in a toroidal trap with a ring - lattice along the azimuth angle, realized with the superposition of two copropagating laguerre - gaussian beams. in the presence of external rotation of small angular acceleration, or prescribed linear chirp between the two beams, the measured angular momentum of trapped atoms displays a specific periodic behaviour in time, which we name as the angular bloch oscillations. this discovered quantum phenomenon is shown to be a key element of fruitful applications for ( i ) an efficient transfer of quantized angular momentum from light field to atoms by controlling the chirp, and ( ii ) the direct determination of the angular acceleration of external rotation by measuring the bloch period.
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arxiv:2402.12826
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the conventional model aggregation - based federated learning ( fl ) approach requires all local models to have the same architecture, which fails to support practical scenarios with heterogeneous local models. moreover, frequent model exchange is costly for resource - limited wireless networks since modern deep neural networks usually have over a million parameters. to tackle these challenges, we propose a novel knowledge - aided fl ( kfl ) framework, which aggregates light high - level data features, namely knowledge, in the per - round learning process. this framework allows devices to design their machine - learning models independently and reduces the communication overhead in the training process. we then theoretically analyze the convergence bound of the proposed framework, revealing that scheduling more data volume in each round helps to improve the learning performance. in addition, large data volume should be scheduled in early rounds if the total scheduled data volume during the entire learning course is fixed. inspired by this, we define a new objective function, i. e., the weighted scheduled data sample volume, to transform the inexplicit global loss minimization problem into a tractable one for device scheduling, bandwidth allocation, and power control. to deal with unknown time - varying wireless channels, we transform the considered problem into a deterministic problem for each round with the assistance of the lyapunov optimization framework. then, we derive the optimal bandwidth allocation and power control solution and develop an efficient online device scheduling algorithm to achieve an energy - learning trade - off in the learning process. experimental results on mnist and cifar - 10 show that the proposed kfl is capable of reducing over 99 % communication overhead while achieving better learning performance than the conventional model aggregation - based algorithms.
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arxiv:2209.12277
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this paper describes our experience implementing a hypervisor extension for a 64 - bit risc - v processor. we describe the design process and the main required parts with a brief explanation of each one.
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arxiv:2406.17796
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in this paper we analyze the convergence of the splitting method for shallow water equations. in particular, we give an analytical estimation of the time step which is necessary for the convergence and then we study the behaviour of the motion of the shallow water in the venice lagoon by using the splitting method with a finite element space discretization. the numerical calculations show that the splitting method is convergent if the time step of the first part is sufficiently small and that it gives a good agreement with the experimental data.
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arxiv:funct-an/9707007
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in this contribution we will give a brief overview on the methods used to overcome decoherence in quantum communication protocols. we give an introduction to quantum error correction, entanglement purification and quantum cryptography. it is shown that entanglement purification can be used to create ` ` private entanglement ' ', which makes it a useful tool for cryptographic protocols.
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arxiv:quant-ph/0208014
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in this paper, we investigate the accretion on the reissner - nordstr \ " { o } m anti - de - sitter black hole with global monopole charge. we discuss the general solutions of accretion using the isothermal and polytropic equations of state for steady state, spherically symmetric, non - rotating accretion on the black hole. in the case of isothermal flow, we consider some specific fluids and derive their solutions at the sonic point as well. however, in case of polytropic fluid we calculate the general expressions only, as there exists no global ( bondi ) solutions for polytropic test fluids. in addition to this, the effect of fluid on the mass accretion rate are also studied. moreover, the large monopole parameter $ \ beta $ greatly suppresses the maximum accretion rate.
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arxiv:1610.01129
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maximum likelihood ( ml ) decoding of forward error correction codes is known to be optimally accurate, but is not used in practice as it proves too challenging to efficiently implement. here we introduce a ml decoder called sgrand, which is a development of a previously described hard detection ml decoder called grand, that fully avails of soft detection information and is suitable for use with any arbitrary high - rate, short - length block code. we assess sgrand ' s performance on crc - aided polar ( ca - polar ) codes, which will be used for all control channel communication in 5g nr, comparing its accuracy with crc - aided successive cancellation list decoding ( ca - scl ), a state - of - the - art soft - information decoder specific to ca - polar codes.
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arxiv:2001.03089
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recently the interest of researchers has shifted from the analysis of synchronous relationships of financial instruments to the analysis of more meaningful asynchronous relationships. both of those analyses are concentrated only on pearson ' s correlation coefficient and thus intraday lead - lag relationships associated with such. under efficient market hypothesis such relationships are not possible as all information is embedded in the prices. in this paper we analyse lead - lag relationships of financial instruments and extend known methodology by using mutual information instead of pearson ' s correlation coefficient, which not only is a more general measure, sensitive to non - linear dependencies, but also can lead to a simpler procedure of statistical validation of links between financial instruments. we analyse lagged relationships using nyse 100 data not only on intraday level but also for daily stock returns, which has usually been ignored.
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arxiv:1402.3820
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land \ forall { } x, \, x \ in a \ rightarrow x \ in b }. ⊆ a ⊆ b { \ displaystyle a \ subseteq b } means that a is a subset of b. used for emphasizing that equality is possible, or when a ⊂ b { \ displaystyle a \ subset b } means that a { \ displaystyle a } is a proper subset of b. { \ displaystyle b. } a b { \ displaystyle a \ subsetneq b } means that a is a proper subset of b. used for emphasizing that a = b { \ displaystyle a \ neq b }, or when a ⊂ b { \ displaystyle a \ subset b } does not imply that a { \ displaystyle a } is a proper subset of b. { \ displaystyle b. },, denote the converse relation of ⊂ { \ displaystyle \ subset }, ⊆ { \ displaystyle \ subseteq }, and { \ displaystyle \ subsetneq } respectively. for example, b a { \ displaystyle b \ supset a } is equivalent to a ⊂ b { \ displaystyle a \ subset b }. ∪ denotes set - theoretic union, that is, a ∪ b { \ displaystyle a \ cup b } is the set formed by the elements of a and b together. that is, a ∪ b = { x ( x ∈ a ) ∨ ( x ∈ b ) } { \ displaystyle a \ cup b = \ { x \ mid ( x \ in a ) \ lor ( x \ in b ) \ } }. ∩ denotes set - theoretic intersection, that is, a ∩ b { \ displaystyle a \ cap b } is the set formed by the elements of both a and b. that is, a ∩ b = { x ( x ∈ a ) ∧ ( x ∈ b ) } { \ displaystyle a \ cap b = \ { x \ mid ( x \ in a ) \ land ( x \ in b ) \ } }. ( backslash ) set difference ; that is, a b { \ displaystyle a \ setminus b } is the set formed by the elements of a that are not in b. sometimes, a − b { \ displaystyle a - b } is used instead ; see − in § arithmetic operators. or { \ displaystyle \ triangle } symmetric difference : that
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https://en.wikipedia.org/wiki/Glossary_of_mathematical_symbols
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recent years have seen a considerable surge of research on developing heuristic approaches to realize analog computing using physical waves. among these, neuromorphic computing using light waves is envisioned to feature performance metrics such as computational speed and energy efficiency exceeding those of conventional digital techniques by many orders of magnitude. yet, neuromorphic computing based on photonics remains a challenge due to the difficulty of training and manufacturing sophisticated photonic structures to support neural networks with adequate expressive power. here, we realize a diffractive optical neural network ( onn ) based on metasurfaces that can recognize objects by directly processing light waves scattered from the objects. metasurfaces composed of a two - dimensional array of millions of meta - units can realize precise control of optical wavefront with subwavelength resolution ; thus, when used as constitutive layers of an onn, they can provide exceptionally high expressive power. we experimentally demonstrate onns based on single - layered metasurfaces that modulate the phase and polarization over optical wavefront for recognizing optically coherent binary objects, including hand - written digits and english alphabetic letters. we further demonstrate, in simulation, onns based on metasurface doublets for human facial verification. the advantageous traits of metasurface - based onns, including ultra - compact form factors, zero power consumption, ultra - fast and parallel data processing capabilities, and physics - guaranteed data security, make them suitable as " edge " perception devices that can transform the future of image collection and analysis.
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arxiv:2210.08369
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in this paper we discuss gravity in the light - front formulation ( light - cone gauge ) and show how possible counterterms arise. we find that poincare invariance is not enough to find the three - point counterterms uniquely. higher - spin fields can intrude and mimic three - point higher derivative gravity terms. to select the correct term we have to use the remaining reparametrization invariance that exists after the gauge choice. we finally sketch how the corresponding programme for n = 8 supergravity should work.
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arxiv:1212.2776
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well - designed prompts can guide text - to - image models to generate amazing images. however, the performant prompts are often model - specific and misaligned with user input. instead of laborious human engineering, we propose prompt adaptation, a general framework that automatically adapts original user input to model - preferred prompts. specifically, we first perform supervised fine - tuning with a pretrained language model on a small collection of manually engineered prompts. then we use reinforcement learning to explore better prompts. we define a reward function that encourages the policy to generate more aesthetically pleasing images while preserving the original user intentions. experimental results on stable diffusion show that our method outperforms manual prompt engineering in terms of both automatic metrics and human preference ratings. moreover, reinforcement learning further boosts performance, especially on out - of - domain prompts. the pretrained checkpoints are available at https : / / aka. ms / promptist. the demo can be found at https : / / aka. ms / promptist - demo.
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arxiv:2212.09611
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after some personal recollectioms about rudolf haag and his thoughts which led him to " local quantum physics ", the present work recalls his ideas about scattering theory, the relation between local observables and localized fields and his contributions to the physical aspects of modular operator theory which paved the way for an intrisic understanding of quantum causal localization in which fields " coordinatize " the local algebras. the paper ends with the presentation of string - local fields whose construction and use in a new renormalization theory for higher spin fields is part of an ongoing reformulation of gauge theory in the conceptual setting of haag ' s lqp.
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arxiv:1612.00003
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we show that the category of simplicial sets is a co - reflective subcategory of the category of cubical sets with connections, with the inclusion given by a version of the straightening functor. we show that using the co - reflector, one can transfer any cofibrantly generated model structure in which cofibrations are monomorphisms to cubical sets, thus obtaining cubical analogues of the quillen and joyal model structures.
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arxiv:1906.09203
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we introduce a version of probabilistic kleene algebra with angelic nondeterminism and a corresponding class of automata. our approach implements semantics via distributions over multisets in order to overcome theoretical barriers arising from the lack of a distributive law between the powerset and giry monads. we produce a full kleene theorem and a coalgebraic theory, as well as both operational and denotational semantics and equational reasoning principles.
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arxiv:2412.06754
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we propose a novel biologically - plausible solution to the credit assignment problem motivated by observations in the ventral visual pathway and trained deep neural networks. in both, representations of objects in the same category become progressively more similar, while objects belonging to different categories become less similar. we use this observation to motivate a layer - specific learning goal in a deep network : each layer aims to learn a representational similarity matrix that interpolates between previous and later layers. we formulate this idea using a contrastive similarity matching objective function and derive from it deep neural networks with feedforward, lateral, and feedback connections, and neurons that exhibit biologically - plausible hebbian and anti - hebbian plasticity. contrastive similarity matching can be interpreted as an energy - based learning algorithm, but with significant differences from others in how a contrastive function is constructed.
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arxiv:2002.10378
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this paper is based on a talk given to motivated high school ( and younger ) students at a bama ( bay area math adventure ) event. some of the methods used to study primes and twin primes are introduced.
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arxiv:0710.2123
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observations of gravitational waves ( gws ) from merging compact binaries have become a regular occurrence. the continued advancement of the ligo - virgo - kagra ( lvk ) collaboration detectors have now produced a catalog of over 90 such mergers, from which we can begin to uncover the formation history of merging compact binaries. in this work, we search for subpopulations in the lvk ' s third gravitational wave transient catalog ( gwtc - 3 ) by incorporating discrete latent variables in the hierarchical bayesian inference framework to probabilistically assign each bbh observation into separate categories associated with distinctly different population distributions. by incorporating formation channel knowledge within the mass and spin correlations found in each category, we find an over density of mergers with a primary mass of $ \ sim10 m _ \ odot $, consistent with isolated binary formation. this low - mass subpopulation has a spin magnitude distribution peaking at $ a _ \ mathrm { peak } = 0. 16 ^ { 0. 19 } _ { - 0. 16 } $, exhibits spins preferentially aligned with the binary ' s orbital angular momentum, is constrained by $ 15 ^ { + 0. 0 } _ { - 1. 0 } $ of our observations, and contributes $ 82 \ % ^ { + 8. 0 \ % } _ { - 16 \ % } $ to the overall population of bbhs. additionally, we find that the component of the mass distribution containing the previously identified $ 35m _ \ odot $ peak has spins consistent with the $ 10m _ \ odot $ events, with $ 99 \ % $ of primary masses less than $ m _ { 1, 99 \ % } = 49 ^ { + 25 } _ { - 8. 1 } m _ \ odot $, providing an estimate of the lower edge of the theorized pair instability mass gap. this work is a first step in gaining a deeper understanding of compact binary formation and evolution, and will provide more robust conclusions as the catalog of observations becomes larger.
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arxiv:2304.01288
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we study a family of polynomials whose values express degrees of schubert varieties in the generalized complex flag manifold g / b. the polynomials are given by weighted sums over saturated chains in the bruhat order. we derive several explicit formulas for these polynomials, and investigate their relations with schubert polynomials, harmonic polynomials, demazure characters, and generalized littlewood - richardson coefficients. in the second half of the paper, we concern with the case of to the classical flag manifold of lie type a and discuss related combinatorial objects : flagged schur polynomials, 312 - avoiding permutations, generalized gelfand - tsetlin polytopes, the inverse schubert - kostka matrix, parking functions, and binary trees.
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arxiv:math/0502363
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a novel approach for the state - specific enantiomeric enrichment and the spatial separation of enantiomers is presented. our scheme utilizes techniques from strong - field laser physics, specifically an optical centrifuge in conjunction with a static electric field, to create a chiral field with defined handedness. molecular enantiomers experience unique rotational excitation dynamics and this can be exploited to spatially separate the enantiomers using electrostatic deflection. notably, the rotational - state - specific enantiomeric enhancement and its handedness is fully controllable. to explain these effects, we introduce the conceptual framework of $ field \ text { - } induced ~ diastereomers $ of a chiral molecule and perform robust quantum mechanical simulations on the prototypical chiral molecule propylene oxide ( c $ _ 3 $ h $ _ 6 $ o ), for which ensembles with an enantiomeric excess of up to $ 30 ~ \ % $ were obtained.
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arxiv:1905.07166
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we show that gravitational interactions between massless thermal modes and a nucleating coleman - de luccia bubble may lead to efficient decoherence and strongly suppress metastable vacuum decay for bubbles that are small compared to the hubble radius. the vacuum decay rate including gravity and thermal photon interactions has the exponential scaling $ \ gamma \ sim \ gamma _ { cdl } ^ { 2 } $, where $ \ gamma _ { cdl } $ is the coleman - de luccia decay rate neglecting photon interactions. for the lowest metastable initial state an efficient quantum zeno effect occurs due to thermal radiation of temperatures as low as the de sitter temperature. this strong decoherence effect is a consequence of gravitational interactions with light external mode. we argue that efficient decoherence does not occur for the case of hawking - moss decay. this observation is consistent with requirements set by poincare recurrence in de sitter space.
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arxiv:1203.1619
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we present a pion photoproduction model on the free nucleon based on an effective lagrangian approach ( ela ) which includes the nucleon resonances ( $ \ delta ( 1232 ) $, n ( 1440 ), n ( 1520 ), n ( 1535 ), $ \ delta ( 1620 ) $, n ( 1650 ), and $ \ delta ( 1700 ) $ ), in addition to born and vector meson exchange terms. the model incorporates a new theoretical treatment of spin - 3 / 2 resonances, first introduced by pascalutsa, avoiding pathologies present in previous models. other main features of the model are chiral symmetry, gauge invariance, and crossing symmetry. we use the model combined with modern optimization techniques to assess the parameters of the nucleon resonances on the basis of world data on electromagnetic multipoles. we present results for electromagnetic multipoles, differential cross sections, asymmetries, and total cross sections for all one pion photoproduction processes on free nucleons. we find overall agreement with data from threshold up to 1 gev in laboratory frame.
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arxiv:nucl-th/0509020
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we construct stable configurations of n overlapping discs of radius r in a unit square, with r = o ( 1 / n ). by a result of diaconis, lebeau, and michel, this result is best possible, up to a constant factor. a consequence is that the metropolis algorithm, a well - studied markov chain on the hardcore model, is not irreducible in this range of parameters.
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arxiv:0908.1830
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we reconsider the study of optimal dividend strategies in the cram \ ' er - lundberg risk model. it is well - known that the solution of the classical dividend problem is in general a band strategy. however, the numerical techniques for the identification of the optimal bands available in the literature are very hard to implement and explicit numerical results are known for very few cases only. in this paper we put a gradient - based method into place which allows to determine optimal bands in more general situations. in addition, we adapt an evolutionary algorithm to this dividend problem, which is not as fast, but applicable in considerable generality, and can serve for providing a competitive benchmark. we illustrate the proposed methods in concrete examples, reproducing earlier results in the literature as well as establishing new ones for claim size distributions that could not be studied before.
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arxiv:2207.01329
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recently non - linear control methods like model predictive control ( mpc ) and reinforcement learning ( rl ) have attracted increased interest in the quadrotor control community. in contrast to classic control methods like cascaded pid controllers, mpc and rl heavily rely on an accurate model of the system dynamics. the process of quadrotor system identification is notoriously tedious and is often pursued with additional equipment like a thrust stand. furthermore, low - level details like motor delays which are crucial for accurate end - to - end control are often neglected. in this work, we introduce a data - driven method to identify a quadrotor ' s inertia parameters, thrust curves, torque coefficients, and first - order motor delay purely based on proprioceptive data. the estimation of the motor delay is particularly challenging as usually, the rpms can not be measured. we derive a maximum a posteriori ( map ) - based method to estimate the latent time constant. our approach only requires about a minute of flying data that can be collected without any additional equipment and usually consists of three simple maneuvers. experimental results demonstrate the ability of our method to accurately recover the parameters of multiple quadrotors. it also facilitates the deployment of rl - based, end - to - end quadrotor control of a large quadrotor under harsh, outdoor conditions.
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arxiv:2404.07837
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we propose a unified framework to speed up the existing stochastic matrix factorization ( smf ) algorithms via variance reduction. our framework is general and it subsumes several well - known smf formulations in the literature. we perform a non - asymptotic convergence analysis of our framework and derive computational and sample complexities for our algorithm to converge to an $ \ epsilon $ - stationary point in expectation. in addition, extensive experiments for a wide class of smf formulations demonstrate that our framework consistently yields faster convergence and a more accurate output dictionary vis - \ ` a - vis state - of - the - art frameworks.
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arxiv:1705.06884
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this expository paper introduces a simplified approach to image - based quality inspection in manufacturing using openai ' s clip ( contrastive language - image pretraining ) model adapted for few - shot learning. while clip has demonstrated impressive capabilities in general computer vision tasks, its direct application to manufacturing inspection presents challenges due to the domain gap between its training data and industrial applications. we evaluate clip ' s effectiveness through five case studies : metallic pan surface inspection, 3d printing extrusion profile analysis, stochastic textured surface evaluation, automotive assembly inspection, and microstructure image classification. our results show that clip can achieve high classification accuracy with relatively small learning sets ( 50 - 100 examples per class ) for single - component and texture - based applications. however, the performance degrades with complex multi - component scenes. we provide a practical implementation framework that enables quality engineers to quickly assess clip ' s suitability for their specific applications before pursuing more complex solutions. this work establishes clip - based few - shot learning as an effective baseline approach that balances implementation simplicity with robust performance, demonstrated in several manufacturing quality control applications.
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arxiv:2501.12596
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we investigate the problem of learning to generate 3d parametric surface representations for novel object instances, as seen from one or more views. previous work on learning shape reconstruction from multiple views uses discrete representations such as point clouds or voxels, while continuous surface generation approaches lack multi - view consistency. we address these issues by designing neural networks capable of generating high - quality parametric 3d surfaces which are also consistent between views. furthermore, the generated 3d surfaces preserve accurate image pixel to 3d surface point correspondences, allowing us to lift texture information to reconstruct shapes with rich geometry and appearance. our method is supervised and trained on a public dataset of shapes from common object categories. quantitative results indicate that our method significantly outperforms previous work, while qualitative results demonstrate the high quality of our reconstructions.
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arxiv:2008.07760
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it has been known since the pioneering work of bernal, fowler and pauling that common, hexagonal ( ih ) water ice is the archetype of a frustrated material : a proton - bonded network in which protons satisfy strong local constraints - the " ice rules " - but do not order. while this proton disorder is well established, there is now a growing body of evidence that quantum effects may also have a role to play in the physics of ice at low temperatures. in this article we use a combination of numerical and analytic techniques to explore the nature of proton correlations in both classical and quantum models of ice ih. in the case of classical ice ih, we find that the ice rules have two, distinct, consequences for scattering experiments - singular " pinch points ", reflecting a zero - divergence condition on the uniform polarization of the crystal, and broad, asymmetric features, coming from its staggered polarisation. in the case of the quantum model, we find that the collective quantum tunnelling of groups of protons can convert states obeying the ice rules into a quantum liquid, whose excitations are birefringent, emergent photons. we make explicit predictions for scattering experiments on both classical and quantum ice ih, and show how the quantum theory can explain the " wings " of incoherent inelastic scattering observed in recent neutron scattering experiments [ bove et al., phys. rev. lett. 103, 165901 ( 2009 ) ]. these results raise the intriguing possibility that the protons in ice ih could form a quantum liquid at low temperatures, in which protons are not merely disordered, but continually fluctuate between different configurations obeying the ice rules.
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arxiv:1504.04158
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a mental health disorder is a clinically significant impairment in a persons intellect, emotional control, or behavior. mental disorders and outpatient morbidity are a challenge to public health in kenya. the spatial distribution and study of factors associated with these conditions remain limited. the study aimed to conduct spatial modeling of mental health on outpatient mobility in kenya. this project used spatial modeling to explore the relationship between infectious diseases and mental disorders. the results showed that mental health issues were not distributed uniformly, with higher frequency found in western and nairobi regions. possible connections between hiv, tb, and stis with mental health have been suggested by the substantial correlation found between infectious diseases and mental health issues. the spatial model demonstrated excellent validity and accuracy, providing policymakers with a useful tool to better allocate resources and enhance mental health treatments, especially in high - risk locations. in conclusion, the research improved knowledge of the spatial patterns of mental health disorders and guides intervention tactics and healthcare policies in kenya and other comparable settings. geographically tailored mental health intervention programs should be developed and implemented in accordance with the high - prevalence areas.
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arxiv:2502.10402
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in this paper we give the functional characteristics of the rothberger and menger properties.
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arxiv:1805.11019
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accurate, reliable sampling from fully - connected graphs with arbitrary correlations is a difficult problem. such sampling requires knowledge of the probabilities of observing every possible state of a graph. as graph size grows, the number of model states becomes intractably large and efficient computation requires full sampling be replaced with heuristics and algorithms that are only approximations of full sampling. this work investigates the potential impact of adiabatic quantum computation for sampling purposes, building on recent successes training boltzmann machines using a quantum device. we investigate the use case of quantum computation to train boltzmann machines for predicting the 2016 presidential election.
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arxiv:1802.00069
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emotion recognition is a core research area at the intersection of artificial intelligence and human communication analysis. it is a significant technical challenge since humans display their emotions through complex idiosyncratic combinations of the language, visual and acoustic modalities. in contrast to traditional multimodal fusion techniques, we approach emotion recognition from both direct person - independent and relative person - dependent perspectives. the direct person - independent perspective follows the conventional emotion recognition approach which directly infers absolute emotion labels from observed multimodal features. the relative person - dependent perspective approaches emotion recognition in a relative manner by comparing partial video segments to determine if there was an increase or decrease in emotional intensity. our proposed model integrates these direct and relative prediction perspectives by dividing the emotion recognition task into three easier subtasks. the first subtask involves a multimodal local ranking of relative emotion intensities between two short segments of a video. the second subtask uses local rankings to infer global relative emotion ranks with a bayesian ranking algorithm. the third subtask incorporates both direct predictions from observed multimodal behaviors and relative emotion ranks from local - global rankings for final emotion prediction. our approach displays excellent performance on an audio - visual emotion recognition benchmark and improves over other algorithms for multimodal fusion.
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arxiv:1809.04931
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domain walls are functionally different from the domains they separate, but little is known about their mechanical properties. using scanning probe microscopy, we have measured the mechanical response of ferroelectric 180o domain walls and observed that, despite separating domains that are mechanically identical ( non - ferroelastic ), the walls are mechanically distinct - - softer - - compared to the domains. this effect has been observed in different ferroelectric materials ( linbo3, batio3, pbtio3 ) and with different morphologies ( from single crystals to thin films ) so it appears to be universal. we propose a theoretical framework that explains the domain wall softening and justifies that the effect should be common to all ferroelectrics.
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arxiv:2005.04249
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rotation is thought to drive cyclic magnetic activity in the sun and sun - like stars. stellar dynamos, however, are poorly understood owing to the scarcity of observations of rotation and magnetic fields in stars. here, inferences are drawn on the internal rotation of a distant sun - like star by studying its global modes of oscillation. we report asteroseismic constraints imposed on the rotation rate and the inclination of the spin axis of the sun - like star hd 52265, a principal target observed by the corot satellite that is known to host a planetary companion. these seismic inferences are remarkably consistent with an independent spectroscopic observation ( rotational line broadening ) and with the observed rotation period of star spots. furthermore, asteroseismology constrains the mass of exoplanet hd 52265b. under the standard assumption that the stellar spin axis and the axis of the planetary orbit coincide, the minimum spectroscopic mass of the planet can be converted into a true mass of 1. 85 ( + 0. 52, - 0. 42 ) m _ jupiter, which implies that it is a planet, not a brown dwarf.
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arxiv:1308.4352
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if the electroweak symmetry - breaking sector becomes strongly interacting at high energies, it can be probed through longitudinal $ w $ scattering. we present a model with many inelastic channels in the $ w _ l w _ l $ scattering process, corresponding to the production of heavy fermion pairs. these heavy fermions affect the elastic scattering of $ w _ l $ ' s by propagating in loops, greatly reducing the amplitudes in some charge channels. we conclude that the symmetry - breaking sector cannot be fully explored by using, for example, the $ w _ l ^ \ pm w _ l ^ \ pm $ mode alone, even when no resonance is present ; all $ w _ l w _ l \ to w _ l w _ l $ scattering modes must be measured.
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arxiv:hep-ph/9302226
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generalizing the polynomial web category, we introduce a diagrammatic $ \ bbbk $ - linear monoidal category, the affine web category, for any commutative ring $ \ bbbk $. integral bases consisting of elementary diagrams are obtained for the affine web category and its cyclotomic quotient categories. connections between cyclotomic web categories and finite $ w $ - algebras are established, leading to a diagrammatic presentation of idempotent subalgebras of $ w $ - schur algebras introduced by brundan - kleshchev. the affine web category will be used as a basic building block of another $ \ bbbk $ - linear monoidal category, the affine schur category, formulated in a sequel.
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arxiv:2406.13172
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we review constructions of three - dimensional ` quantum ' black holes. such spacetimes arise via holographic braneworlds and are exact solutions to an induced higher - derivative theory of gravity consistently coupled to a large $ - c $ quantum field theory with an ultraviolet cutoff, accounting for all orders of semi - classical backreaction. notably, such quantum - corrected black holes are much larger than the planck length. we describe the geometry and horizon thermodynamics of a host of asymptotically ( anti - ) de sitter and flat quantum black holes. a summary of higher - dimensional extensions is given. we survey multiple applications of quantum black holes and braneworld holography.
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arxiv:2407.03410
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the largest uncertainty on measurements of dark energy using type ia supernovae is presently due to systematics from photometry ; specifically to the relative uncertainty on photometry as a function of wavelength in the optical spectrum. we show that a precise constraint on relative photometry between the visible and near - infrared can be achieved in upcoming surveys ( such as in lsst at the vera c. rubin observatory ) via a mountaintop - located laser source tuned to the 342. 78 nm vacuum excitation wavelength of neutral sodium atoms. using a high - power ( 500 w ) laser modified from laser guide star studies, this excitation will produce an artificial star ( which we term a " laser photometric ratio star, " or lprs ) of de - excitation light in the mesosphere that is observable from the ground at approximately 20 magnitude ( i. e., well within the expected single - image magnitude limit of lsst ) at wavelengths in vacuum of 589. 16 nm, 589. 76 nm, 818. 55 nm, and 819. 70 nm, with the sum of the numbers of 589. 16 nm and 589. 76 nm photons produced by this process equal to the sum of the numbers of 818. 55 nm and 819. 70 nm photons, establishing a precise calibration ratio between, for example, the lsst r and z filters. this technique can thus provide a novel mechanism for establishing a spectrophotometric calibration ratio of unprecedented precision, from above most of the earth ' s atmosphere, for upcoming telescopic observations across astronomy and atmospheric physics. this article is the first in a pair of articles on this topic. the second article of the pair describes an alternative technique to achieve a similar, but brighter, lprs than the technique described in this paper, by using two mountaintop - located lasers, at optical frequencies approximately 4 ghz away from resonances at wavelengths in vacuum of 589. 16 nm and 819. 71 nm respectively.
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arxiv:2001.10958
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achieving optimal transmission throughput in data networks in a multi - hop wireless networks is fundamental but hard problem. the situation is aggravated when nodes are mobile. further, multi - rate system make the analysis of throughput more complicated. in mobile scenario, link may break or be created as nodes are moving within communication range. ` route discovery ' which is to find the optimal route and transmission schedule is an important issue. route discovery entails some cost ; so one would not like to initiate discovery too often. on the other hand, not discovering reasonably often entails the risk of being stuck with a suboptimal route and / or schedule, which hurts end - to - end throughput. the implementation of the routing decision problem in one dimensional mobile ad hoc network as markov decision process problem is already is discussed in the paper [ 1 ]. a heuristic based on threshold policy is discussed in the same paper without giving a way to find the threshold. in this paper, we suggested a rule for setting the threshold, given the parameters of the system. we also point out that our results remain valid in a slightly different mobility model ; this model is a first step towards an ` open ' network in which existing relay nodes can leave and / or new relay nodes can join the network.
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arxiv:1009.4672
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the effectiveness of deep neural networks ( dnns ) heavily relies on the abundance and accuracy of available training data. however, collecting and annotating data on a large scale is often both costly and time - intensive, particularly in medical cases where practitioners are already occupied with their duties. moreover, ensuring that the model remains robust across various scenarios of image capture is crucial in medical domains, especially when dealing with ultrasound images that vary based on the settings of different devices and the manual operation of the transducer. to address this challenge, we introduce a novel pipeline called meddap, which leverages stable diffusion ( sd ) models to augment existing small datasets by automatically generating new informative labeled samples. pretrained checkpoints for sd are typically based on natural images, and training them for medical images requires significant gpu resources due to their heavy parameters. to overcome this challenge, we introduce uslora ( ultrasound low - rank adaptation ), a novel fine - tuning method tailored specifically for ultrasound applications. uslora allows for selective fine - tuning of weights within sd, requiring fewer than 0. 1 \ % of parameters compared to fully fine - tuning only the unet portion of sd. to enhance dataset diversity, we incorporate different adjectives into the generation process prompts, thereby desensitizing the classifiers to intensity changes across different images. this approach is inspired by clinicians ' decision - making processes regarding breast tumors, where tumor shape often plays a more crucial role than intensity. in conclusion, our pipeline not only outperforms classifiers trained on the original dataset but also demonstrates superior performance when encountering unseen datasets. the source code is available at https : / / github. com / yasamin - med / meddap.
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arxiv:2403.16335
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package - x, a mathematica package for the analytic computation of one - loop integrals dimensionally regulated near 4 spacetime dimensions is described. package - x computes arbitrarily high rank tensor integrals with up to three propagators, and gives compact expressions of uv divergent, ir divergent, and finite parts for any kinematic configuration involving real - valued external invariants and internal masses. output expressions can be readily evaluated numerically and manipulated symbolically with built - in mathematica functions. emphasis is on evaluation speed, on readability of results, and especially on user - friendliness. also included is a routine to compute traces of products of dirac matrices, and a collection of projectors to facilitate the computation of fermion form factors at one - loop. the package is intended to be used both as a research tool and as an educational tool.
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arxiv:1503.01469
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we advocate the possibility that the observed diphoton excess at 750 gev at the lhc can be addressed by the scalar field that is a part of the su ( 5 ) symmetry breaking sector. the field in question is the standard model singlet that resides in the adjoint representation that breaks su ( 5 ) down to su ( 3 ) x su ( 2 ) x u ( 1 ). we also show that the required production and subsequent decay to two photons of this singlet can be induced by individual or combined contribution of two scalar multiplets $ s _ 3 $ and $ r _ 2 $ that transform as ( 3, 3, - 1 / 3 ) and ( 3, 2, 7 / 6 ) under su ( 3 ) x su ( 2 ) x u ( 1 ), respectively. the individual dominance of these multiplets is directly related to the issue of the charged fermion mass generation within the su ( 5 ) framework and can be unambiguously tested through the diboson decay signatures of the standard model singlet field.
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arxiv:1601.03267
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for the planetary nebula ngc 7009, we present a comparison of two unpublished very large array archive data sets taken with a time separation of 8. 09 years to confirm the proper motions of its ansae observed in the optical. we determine values of 23 $ \ pm $ 6 and 34 $ \ pm $ 10 mas yr $ ^ { - 1 } $ for the eastern and western ansae, respectively. there is marginal evidence suggesting that the flux densities of the jets that connect the ansae with the main body of the nebula diminished in about 30 % over the period between the two observations. we also set an upper limit to the expansion of the main body of the planetary nebula, setting a lower limit of $ \ sim $ 700 pc for its distance.
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arxiv:astro-ph/0611753
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designing cable harnesses can be time - consuming and complex due to many design and manufacturing aspects and rules. automating the design process can help to fulfil these rules, speed up the process, and optimize the design. to accommodate this, we formulate a harness routing optimization problem to minimize cable lengths, maximize bundling by rewarding shared paths, and optimize the cables ' spatial location with respect to case - specific information of the routing environment, e. g., zones to avoid. a deterministic and computationally effective cable harness routing algorithm has been developed to solve the routing problem and is used to generate a set of cable harness topology candidates and approximate the pareto front. our approach was tested against a stochastic and an exact solver and our routing algorithm generated objective function values better than the stochastic approach and close to the exact solver. our algorithm was able to find solutions, some of them being proven to be near - optimal, for three industrial - sized 3d cases within reasonable time ( in magnitude of seconds to minutes ) and the computation times were comparable to those of the stochastic approach.
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arxiv:2311.09061
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we present a new class of topological conformal field theories ( tcft ) characterized by a rational $ w $ potential, which includes the minimal models of a and d types as its subclasses. an explicit form of the $ w $ potential is found by solving the underlying dispersionless kp hierarchy in a particular small phase space. we discuss also the dispersionless kp hierarchy in large phase spaces by reformulating the hierarchy, and show that the $ w $ potential takes a universal form, which does not depend on a specific form of the solution in a large space.
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arxiv:hep-th/9404011
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for the eddington mission, the intrinsic stellar variability can be a major source of noise in the detection of extrasolar planets by the transit method. we derive that most detections of terrestrial planets ( 1 - 2 r _ earth ) will occur around g or k stars with 15 - 16th magnitude. when these stars are 7 - 12 times more variable than the sun on a 10 hour timescale, we demonstrate that the detection can be performed with a higher s / n provided composite lightcurves obtained with the combination of two colors are used instead of white ones. the level of 10 hour variability for k stars is quite uncertain. we make two " guess - estimates " of it and find that it could be several times larger than the solar value. if these estimates were relevant, the color information would not provide a significant advantage. although we do not demonstrate a need for colors, we point out the risk of an unpleasant surprise regarding the 10 hour stellar variability. indeed, there is presently no qualified proxy for this variability. besides, if eddington were designed to provide this information at the cost of added complexity but not sensitivity, white photometry by channel summation would still be as efficient. considering the risk that 10 hour variability is higher than estimated, the precaution imperative points to a study of practical implementations of photometry in different colors before taking irreversible decisions about the eddington instrument.
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arxiv:astro-ph/0301430
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in this paper, the quaternion matrix utv ( qutv ) decomposition and quaternion tensor utv ( qtutv ) decomposition are proposed. to begin, the terms qutv and qtutv are defined, followed by the algorithms. subsequently, by employing random sampling from the quaternion normal distribution, randomized qutv and randomized qtutv are generated to provide enhanced algorithmic efficiency. these techniques produce decompositions that are straightforward 9 to understand and require minimal cost. furthermore, theoretical analysis is discussed. specifically, the upper bounds for approximating qutv on the rank - k and qtutv on the tqt - rank k errors are provided, followed by deterministic error bounds and average - case error bounds for the randomized situations, which demonstrate the correlation between the accuracy of the low - rank approximation and the singular values. finally, numerous numerical experiments are presented to verify that the proposed algorithms work more efficiently and with similar relative errors compared to other comparable decomposition methods. for the novel decompositions, the theory analysis offers a solid theoretical basis and the experiments show significant potential for the associated processing tasks of color images and color videos.
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arxiv:2406.05734
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most astrophysical accretion disks are likely to be warped. in x - ray binaries the spin evolution of an accreting neutron star is critically dependent on the interaction between the neutron star magnetic field and the accretion disk. there have been extensive investigations on the accretion torque exerted by a coplanar disk that is magnetically threaded by the magnetic field lines from the neutron stars, but relevant works on warped / tilted accretion disks are still lacking. in this paper we develop a simplified two - component model, in which the disk is comprised of an inner coplanar part and an outer, tilted part. based on standard assumption on the formation and evolution of the toroidal magnetic field component, we derive the dimensionless torque and show that a warped / titled disk is more likely to spin up the neutron star compared with a coplanar disk. we also discuss the possible influence of various initial parameters on the torque.
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arxiv:2009.07019
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we survey recent results about asymptotic functions of groups, obtained by the authors in collaboration with j. - c. birget, v. guba and e. rips. we also discuss methods used in the proofs of these results.
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arxiv:math/9811107
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text - based person search ( tps ), is targeted on retrieving pedestrians to match text descriptions instead of query images. recent vision - language pre - training ( vlp ) models can bring transferable knowledge to downstream tps tasks, resulting in more efficient performance gains. however, existing tps methods improved by vlp only utilize pre - trained visual encoders, neglecting the corresponding textual representation and breaking the significant modality alignment learned from large - scale pre - training. in this paper, we explore the full utilization of textual potential from vlp in tps tasks. we build on the proposed vlp - tps baseline model, which is the first tps model with both pre - trained modalities. we propose the multi - integrity description constraints ( midc ) to enhance the robustness of the textual modality by incorporating different components of fine - grained corpus during training. inspired by the prompt approach for zero - shot classification with vlp models, we propose the dynamic attribute prompt ( dap ) to provide a unified corpus of fine - grained attributes as language hints for the image modality. extensive experiments show that our proposed tps framework achieves state - of - the - art performance, exceeding the previous best method by a margin.
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arxiv:2303.04497
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many natural combinatorial problems can be expressed as constraint satisfaction problems. this class of problems is known to be np - complete in general, but certain restrictions on the form of the constraints can ensure tractability. the standard way to parameterize interesting subclasses of the constraint satisfaction problem is via finite constraint languages. the main problem is to classify those subclasses that are solvable in polynomial time and those that are np - complete. it was conjectured that if a constraint language has a weak near unanimity polymorphism then the corresponding constraint satisfaction problem is tractable, otherwise it is np - complete. in the paper we present an algorithm that solves constraint satisfaction problem in polynomial time for constraint languages having a weak near unanimity polymorphism, which proves the remaining part of the conjecture.
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arxiv:1704.01914
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among all bi - perron numbers, we characterise those all of whose galois conjugates are real or unimodular as the ones that admit a power which is the stretch factor of a pseudo - anosov homeomorphism arising from thurston ' s construction. this is in turn equivalent to admitting a power which is the spectral radius of a bipartite coxeter transformation.
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arxiv:2009.03647
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bistable valency in individual atoms presents a new approach toward single - atom memory, as well as a building block to create tunable and stochastic multi - well energy landscapes. yet, this concept of orbital memory has thus far only been observed for cobalt atoms on the surface of black phosphorus, which are switched using tip - induced ionization. here, we show that individual iron atoms on the surface of black phosphorus exhibit orbital memory using a combination of scanning tunneling microscopy and spectroscopy with ab initio calculations based on density functional theory. unlike cobalt, the iron orbital memory can be switched in its non - ionized ground state. based on calculations, we confirm that each iron valency has a distinct magnetic moment that is characterized by a distinguishable charge distribution due to the different orbital population. by studying the stochastic switching of the valency with varying tunneling conditions, we propose that the switching mechanism is based on a two - electron tunneling process.
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arxiv:2204.06915
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we report the discovery of a cyclotron resonance scattering feature ( crsf ) in the x - ray spectrum of gx 304 - 1, obtained by rxte and suzaku during major outbursts detected by maxi in 2010. the peak intensity in august reached 600 mcrab in the 2 - 20 kev band, which is the highest ever observed from this source. the rxte observations on more than twenty occasions and one suzaku observation revealed a spectral absorption feature at around 54 kev, which is the first crsf detection from this source. the estimated strength of surface magnetic field, $ 4. 7 \ times 10 ^ { 12 } $ g, is one of the highest among binary x - ray pulsars from which crsfs have ever been detected. the rxte spectra taken during the august outburst also suggest that the crsf energy changed over 50 - 54 kev, possibly in a positive correlation with the x - ray flux. the behavior is qualitatively similar to that observed from her x - 1 on long time scales, or from a 0535 + 26, but different from the negative correlation observed from 4u 0115 + 63 and x 0331 + 53.
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arxiv:1102.4232
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