text stringlengths 1 3.65k | source stringlengths 15 79 |
|---|---|
we study a disclosure game with a large evidence space. there is an unknown binary state. a sender observes a sequence of binary signals about the state and discloses a left truncation of the sequence to a receiver in order to convince him that the state is good. we focus on truth - leaning equilibria ( cf. hart et al. ( 2017 ) ), where the sender discloses truthfully when doing so is optimal, and the receiver takes off - path disclosure at face value. in equilibrium, seemingly sub - optimal truncations are disclosed, and the disclosure contains the longest truncation that yields the maximal difference between the number of good and bad signals. we also study a general framework of disclosure games which is compatible with large evidence spaces, a wide range of disclosure technologies, and finitely many states. we characterize the unique equilibrium value function of the sender and propose a method to construct equilibria for a broad class of games. | arxiv:1910.13633 |
we present a generalization of the hawking effect for dynamical trapping horizons by calculating the tunneling rate in the hamilton - jacobi formalism. it turns out that all horizons classified by hayward are subjected to thermal quantum effects. while the hawking effect for future outer and past inner trapping horizons is given as a particle emission, we show that the hawking effect for future inner and past outer trapping horizons translates to an absorption. the universality of the treatment allows a natural transfer to the static case. | arxiv:2003.11095 |
we present a new method, called $ x $ - cut cosmic shear, which optimally removes sensitivity to poorly modeled scales from the two - point cosmic shear signal. we show that the $ x $ - cut cosmic shear covariance matrix can be computed from the correlation function covariance matrix in a few minutes, enabling a likelihood analysis at virtually no additional computational cost. further we show how to generalize $ x $ - cut cosmic shear to galaxy - galaxy lensing. performing an $ x $ - cut cosmic shear analysis of the dark energy survey year 1 ( desy1 ) shear data, we reduce the error on $ s _ 8 = \ sigma _ 8 ( \ omega _ m / 0. 3 ) ^ { 0. 5 } $ by $ 32 \ % $ relative to a correlation function analysis with the same priors and angular scale cut criterion, while showing our constraints are robust to different baryonic feedback models. largely driven by information at small angular scales, our result, $ s _ 8 = 0. 734 \ pm 0. 026 $, yields a $ 2. 6 \ sigma $ tension with the planck legacy analysis of the cosmic microwave background. as well as alleviating baryonic modelling uncertainties, our method can be used to optimally constrain a large number of theories of modified gravity where computational limitations make it infeasible to model the power spectrum down to extremely small scales. the key parts of our code are made publicly available. | arxiv:2007.00675 |
coherent interconversion between optical and mechanical excitations in an optomechanical cavity can be used to engineer a quantum heat engine. this heat engine is based on an otto cycle between a cold photonic reservoir and a hot phononic reservoir [ phys. rev. lett. 112, 150602 ( 2014 ) ]. building on our previous work, we ( i ) develop a detailed theoretical analysis of the work and the efficiency of the engine, and ( ii ) perform an investigation of the quantum thermodynamics underlying this scheme. in particular, we analyze the thermodynamic performance in both the dressed polariton picture and the original bare photon and phonon picture. finally, ( iii ) a numerical simulation is performed to derive the full evolution of the quantum optomechanical system during the otto cycle, by taking into account all relevant sources of noise. | arxiv:1406.5160 |
this paper was withdrawn because subsequent measurements produced results not always consistent with the ones presented in the paper. | arxiv:cond-mat/0201006 |
in the framework of teleparallel equivalent of general relativity, we study a gravity theory where a scalar field beyond its minimal coupling, is also coupled with the vector torsion through a non - minimal derivative coupling. after a suitable choice of auxiliary variables that allows us to perform the phase - space analysis of the model we obtain the critical points and their stability. while there is no scaling attractor in non - interacting scenario, by considering an interaction between dark energy and dark matter, we find scaling attractors in which the fractional densities of dark energy and matter are non - vanishing constants over there. the universe can evolve to these scaling attractors regardless of initial conditions and the cosmological coincidence problem could be alleviated without fine - tunings. | arxiv:1604.03080 |
grasping objects requires tight integration between visual and tactile feedback. however, there is an inherent difference in the scale at which both these input modalities operate. it is thus necessary to be able to analyze tactile feedback in isolation in order to gain information about the surface the end - effector is operating on, such that more fine - grained features may be extracted from the surroundings. for tactile perception of the robot, inspired by the concept of the tactile flow in humans, we present the computational tactile flow to improve the analysis of the tactile feedback in robots using a shadow dexterous hand. in the computational tactile flow model, given a sequence of pressure values from the tactile sensors, we define a virtual surface for the pressure values and define the tactile flow as the optical flow of this surface. we provide case studies that demonstrate how the computational tactile flow maps reveal information on the direction of motion and 3d structure of the surface, and feedback regarding the action being performed by the robot. | arxiv:1903.08248 |
early supervised machine learning algorithms have relied on reliable expert labels to build predictive models. however, the gates of data generation have recently been opened to a wider base of users who started participating increasingly with casual labeling, rating, annotating, etc. the increased online presence and participation of humans has led not only to a democratization of unchecked inputs to algorithms, but also to a wide democratization of the " consumption " of machine learning algorithms ' outputs by general users. hence, these algorithms, many of which are becoming essential building blocks of recommender systems and other information filters, started interacting with users at unprecedented rates. the result is machine learning algorithms that consume more and more data that is unchecked, or at the very least, not fitting conventional assumptions made by various machine learning algorithms. these include biased samples, biased labels, diverging training and testing sets, and cyclical interaction between algorithms, humans, information consumed by humans, and data consumed by algorithms. yet, the continuous interaction between humans and algorithms is rarely taken into account in machine learning algorithm design and analysis. in this paper, we present a preliminary theoretical model and analysis of the mutual interaction between humans and algorithms, based on an iterated learning framework that is inspired from the study of human language evolution. we also define the concepts of human and algorithm blind spots and outline machine learning approaches to mend iterated bias through two novel notions : antidotes and reactive learning. | arxiv:1608.07895 |
we employ our new approach to non - relativistic supersymmetric quantum mechanics ( susy - qm ), ( j. phys. chem. a 114, 8202 ( 2010 ) ) for any number of dimensions and distinguishable particles, to treat the hydrogen atom in full three - dimensional detail. in contrast to the standard one - dimensional radial equation susy - qm treatment of the hydrogen atom, where the superpotential is a scalar, in a full three - dimensional treatment, it is a vector which applies regardless of the electron angular momentum. the original scalar schrodinger hamiltonian operator is factored into vector " charge " operators : q and q ^ { dagger }. using these operators, the first sector hamiltonian is written as h1 = q ^ { \ dagger } * q. the second sector hamiltonian is a tensor given by h2 = q q ^ { \ dagger } and is isospectral with h1. the second sector ground state, psi ^ { ( 2 ) } _ 0, can be used to obtain the excited state wave functions of the first sector by application of the adjoint charge operator. alternatively, q applied to analytical, sector one excited states yield analytical results for the sector two vector eigenstates. several of these are plotted for illustration. we then adapt the aufbau principle to show this approach can be applied to treat the helium atom. | arxiv:1106.4603 |
in this paper we explore the use of results on forward particle production at the lhc to constrain nuclear parton density functions ( npdfs ). the case study here is based on a possible future measurement of forward photon production with the forward calorimeter that is currently under discussion as an upgrade of the alice experiment. as a starting point, we use the recent nnnpdf 1. 0 nuclear pdfs, which have been determined using fixed target neutral - current dis data, which constrain the gluon density at x > $ 10 ^ { - 2 } $. the bayesian reweighting technique is used to include the constraints from the future measurement. | arxiv:1909.05338 |
the covid - 19 pandemic has created unprecedented challenges worldwide. strained healthcare providers make difficult decisions on patient triage, treatment and care management on a daily basis. policy makers have imposed social distancing measures to slow the disease, at a steep economic price. we design analytical tools to support these decisions and combat the pandemic. specifically, we propose a comprehensive data - driven approach to understand the clinical characteristics of covid - 19, predict its mortality, forecast its evolution, and ultimately alleviate its impact. by leveraging cohort - level clinical data, patient - level hospital data, and census - level epidemiological data, we develop an integrated four - step approach, combining descriptive, predictive and prescriptive analytics. first, we aggregate hundreds of clinical studies into the most comprehensive database on covid - 19 to paint a new macroscopic picture of the disease. second, we build personalized calculators to predict the risk of infection and mortality as a function of demographics, symptoms, comorbidities, and lab values. third, we develop a novel epidemiological model to project the pandemic ' s spread and inform social distancing policies. fourth, we propose an optimization model to re - allocate ventilators and alleviate shortages. our results have been used at the clinical level by several hospitals to triage patients, guide care management, plan icu capacity, and re - distribute ventilators. at the policy level, they are currently supporting safe back - to - work policies at a major institution and equitable vaccine distribution planning at a major pharmaceutical company, and have been integrated into the us center for disease control ' s pandemic forecast. | arxiv:2006.16509 |
recent theoretical studies ( kou et al., 2023 ; cao et al., 2022 ) have revealed a sharp phase transition from benign to harmful overfitting when the noise - to - feature ratio exceeds a threshold - a situation common in long - tailed data distributions where atypical data is prevalent. however, harmful overfitting rarely happens in overparameterized neural networks. further experimental results suggested that memorization is necessary for achieving near - optimal generalization error in long - tailed data distributions ( feldman & zhang, 2020 ). we argue that this discrepancy between theoretical predictions and empirical observations arises because previous feature - noise data models overlook the heterogeneous nature of noise across different data classes. in this paper, we refine the feature - noise data model by incorporating class - dependent heterogeneous noise and re - examine the overfitting phenomenon in neural networks. through a comprehensive analysis of the training dynamics, we establish test loss bounds for the refined model. our findings reveal that neural networks can leverage " data noise ", previously deemed harmful, to learn implicit features that improve the classification accuracy for long - tailed data. experimental validation on both synthetic and real - world datasets supports our theoretical results. | arxiv:2502.11893 |
in the present work, spin orientation and variation of the strength of coupling in [ co / pt ] ml / fe multilayer have been investigated as a function of the thickness of the fe layer. [ co / pt ] ml / fe multilayer has orthogonal anisotropy with the fe layer, and [ co / pt ] ml has in - plane magnetic anisotropy and perpendicular anisotropy, respectively. measurements are performed using in - situ magneto - optical kerr effect ( moke ) and isotope - sensitive depth - resolved nuclear resonance scattering ( nrs ) technique. real - time in - situ moke measurement during fe growth reveals that with an increase in thickness of the fe layer, moments of fe layer reorientation from out of the plane to in - plane direction. this is attributed to the decrease in the coupling between the [ co / pt ] ml and fe layer. for the depth - dependent study, two [ co / pt ] ml / fe multilayers having the same thickness but different positions of the fe57 marker layer ( [ co / pt ] mlfe / fe57 ) and [ co / pt ] mlfe57 / fe ) were studied using the nrs technique. films with varying external magnetic fields were also studied to investigate coupling strength. measurements were performed under the x - ray standing wave conditions to enhance resonance yield. it is observed that for the 75 { \ aa } fe in [ co / pt ] ml / fe multilayer, the coupling varies along the depth of the fe layer. the coupling is strong at [ co / pt ] ml and fe interface with spins of the fe layer aligned in the out - of - plane direction, whereas moments away from the interface are weakly coupled and aligned in - plane along the magnetic easy axis. due to this gradient in strength of coupling along the depth, a large magnetic field is required to reorient spins at the interface along the magnetic hard axis of the fe layer ; however, spins away from the interface can rotate freely even in the low magnetic field. | arxiv:2412.17555 |
we study the covariance property of quadratic time - frequency distributions with respect to the action of the extended symplectic group. we show how covariance is related, and in fact in competition, with the possibility of damping the interferences which arise due to the quadratic nature of the distributions. we also show that the well known fully covariance property of the wigner distribution in fact characterizes it ( up to a constant factor ) among the quadratic distributions $ l ^ { 2 } ( \ mathbb { r } ^ { n } ) \ rightarrow c _ { 0 } ( { \ mathbb { r } ^ { 2n } } ) $. a similar characterization for the closely related weyl transform is given as well. the results are illustrated by several numerical experiments for the wigner and born - jordan distributions of the sum of four gaussian functions in the so - called " diamond configuration ". | arxiv:1611.07442 |
we consider a standard distributed optimisation setting where $ n $ machines, each holding a $ d $ - dimensional function $ f _ i $, aim to jointly minimise the sum of the functions $ \ sum _ { i = 1 } ^ n f _ i ( x ) $. this problem arises naturally in large - scale distributed optimisation, where a standard solution is to apply variants of ( stochastic ) gradient descent. we focus on the communication complexity of this problem : our main result provides the first fully unconditional bounds on total number of bits which need to be sent and received by the $ n $ machines to solve this problem under point - to - point communication, within a given error - tolerance. specifically, we show that $ \ omega ( nd \ log d / n \ varepsilon ) $ total bits need to be communicated between the machines to find an additive $ \ epsilon $ - approximation to the minimum of $ \ sum _ { i = 1 } ^ n f _ i ( x ) $. the result holds for both deterministic and randomised algorithms, and, importantly, requires no assumptions on the algorithm structure. the lower bound is tight under certain restrictions on parameter values, and is matched within constant factors for quadratic objectives by a new variant of quantised gradient descent, which we describe and analyse. our results bring over tools from communication complexity to distributed optimisation, which has potential for further applications. | arxiv:2010.08222 |
we examine the geometry of the post - asymptotic giant branch ( agb ) star binary ac her and its circumbinary disk. we show that the observations describe a binary orbit that is perpendicular to the disk with an angular momentum vector that is within $ 9 ^ \ circ $ of the binary eccentricity vector, meaning that the disk is close to a stable polar alignment. the most likely explanation for the very large inner radius of the dust is a planet within the circumbinary disk. this is therefore both the first reported detection of a polar circumbinary disk around a post - agb binary and the first evidence of a polar circumbinary planet. we consider the dynamical constraints on the circumbinary disk size and mass. the polar circumbinary disk feeds circumstellar disks with gas on orbits that are highly inclined with respect to the binary orbit plane. the resulting circumstellar disk inclination could be anywhere from coplanar to polar depending upon the competition between the mass accretion and binary torques. | arxiv:2310.19600 |
the study of asymptotic properties of solutions to differential equations has a long and arduous history, with the most significant advances having been made in the development of quantum mechanics. a very powerful method of analysis is that of phase integrals, described by heading. key to this analysis are the stokes constants and the rules for analytic continuation of an asymptotic solution through the complex plane. these constants are easily determined for isolated singular points, by analytically continuing around them and, in the case of analytic functions, requiring the asymptotic solution to be single valued. however, most interesting problems of mathematical physics involve several singular points. by examination of analytically tractable problems and more complex bound state problems involving multiple singular points, we show that the method of phase integrals can greatly improve the determination of bound state energies over the simple wkb values. we also find from these examples that in the limit of large separation the stokes constant for a first order singular point approaches the isolated singular point value. | arxiv:1704.01170 |
in this work we investigate dynamical systems designed to approach the solution sets of inclusion problems involving the sum of two maximally monotone operators. our aim is to design methods which guarantee strong convergence of trajectories towards the minimum norm solution of the underlying monotone inclusion problem. to that end, we investigate in detail the asymptotic behavior of dynamical systems perturbed by a tikhonov regularization where either the maximally monotone operators themselves, or the vector field of the dynamical system is regularized. in both cases we prove strong convergence of the trajectories towards minimum norm solutions to an underlying monotone inclusion problem, and we illustrate numerically qualitative differences between these two complementary regularization strategies. the so - constructed dynamical systems are either of krasnoselskii - mann, of forward - backward type or of forward - backward - forward type, and with the help of injected regularization we demonstrate seminal results on the strong convergence of hilbert space valued evolutions designed to solve monotone inclusion and equilibrium problems. | arxiv:1911.04758 |
the zarankiewicz function gives, for a chosen matrix and minor size, the maximum number of ones in a binary matrix not containing an all - one minor. tables of this function for small arguments have been compiled, but errors are known in them. we both correct the errors and extend these tables in the case of square minors by expressing the problem of finding the value at a specific point as a series of boolean satisfiability problems, exploiting permutation symmetries for a significant reduction in the work needed. when the ambient matrix is also square we also give all non - isomorphic examples of matrices attaining the maximum, up to the aforementioned symmetries ; it is found that most maximal matrices have some form of symmetry. | arxiv:2203.02283 |
we solve the dry ten martini problem for the unitary almost mathieu operator with diophantine frequencies in the non - critical regime. | arxiv:2503.06710 |
the present paper introduces a jump - diffusion extension of the classical diffusion default intensity model by means of subordination in the sense of bochner. we start from the bi - variate process $ ( x, d ) $ of a diffusion state variable $ x $ driving default intensity and a default indicator process $ d $ and time change it with a l \ ' { e } vy subordinator $ { \ mathcal { t } } $. we characterize the time - changed process $ ( x ^ { \ phi } _ t, d ^ { \ phi } _ t ) = ( x ( { \ mathcal { t } } _ t ), d ( { \ mathcal { t } } _ t ) ) $ as a markovian - - it \ ^ { o } semimartingale and show from the doob - - meyer decomposition of $ d ^ { \ phi } $ that the default time in the time - changed model has a jump - diffusion or a pure jump intensity. when $ x $ is a cir diffusion with mean - reverting drift, the default intensity of the subordinate model ( subcir ) is a jump - diffusion or a pure jump process with mean - reverting jumps in both directions that stays nonnegative. the subcir default intensity model is analytically tractable by means of explicitly computed eigenfunction expansions of relevant semigroups, yielding closed - form pricing of credit - sensitive securities. | arxiv:1403.5402 |
we report resistivity and calorimetric measurements on two single crystals of cepd2si2 pressurized up to 7. 4 gpa. a weak uniaxial stress induced in the pressure cell demonstrates the sensitivity of the physics to anisotropy. stress applied along the c - axis extends the whole phase diagram to higher pressures and enhances the superconducting phase emerging around the magnetic instability, with a 40 % increase of the maximum superconducting temperature, tc, and a doubled pressure range. calorimetric measurements demonstrate the bulk nature of the superconductivity. | arxiv:cond-mat/0202390 |
the magneto - optical properties of ga $ _ { 1 - x } $ mn $ _ { x } $ as including their most common defects were investigated with precise first - - principles density - functional flapw calculations in order to : { \ em i } ) elucidate the origin of the features in the kerr spectra in terms of the underlying electronic structure ; { \ em ii } ) perform an accurate comparison with experiments ; and { \ em iii } ) understand the role of the mn concentration and occupied sites in shaping the spectra. in the substitutional case, our results show that most of the features have an interband origin and are only slightly affected by drude - - like contributions, even at low photon energies. while not strongly affected by the mn concentration for the intermediately diluted range ( $ x \ sim $ 10 % ), the kerr factor shows a marked minimum ( up to 1. 5 $ ^ o $ ) occurring at a photon energy of $ \ sim $ 0. 5 ev. for interstitial mn, the calculated results bear a striking resemblance to the experimental spectra, pointing to the comparison between simulated and experimental kerr angles as a valid tool to distinguish different defects in the diluted magnetic semiconductors framework. | arxiv:cond-mat/0510697 |
coprethi is a java based web application, which combines the results of methods that predict the location of transmembrane segments in protein sequences into a joint prediction histogram. clearly, the joint prediction algorithm, produces superior quality results than individual prediction schemes. the program is available at http : / / o2. db. uoa. gr / coprethi | arxiv:0902.3132 |
) $. this leads to the question of determining the supremum of such $ s $, for which we provide estimates based on computations for the aforementioned sequences. | arxiv:1208.3267 |
the pip ii linear accelerator includes different types of niobium srf cavities including 650 mhz elliptical low ( 0. 61 ) and high ( 0. 92 ) beta cavities. the elliptical cavity surface is processed with the electropolishing method. the elliptical cavities especially the low - $ \ beta $ 650 mhz cavities showed a rough equator surface after the ep was per - formed with the standard ep conditions. this work was focused to study the effect of different ep parameters, including cathode surface area, temperature and voltage, and optimize them to improve the cavity surface. | arxiv:2208.04424 |
a scanning tunneling microscope ( stm ) supplemented with a force sensor is used to study the mechanical properties of a novel metallic nanostructure : a freely suspended chain of single gold atoms. we find that the bond strength of the nanowire is about twice that of a bulk metallic bond. we perform ab initio calculations of the force at chain fracture and compare quantitatively with experimental measurements. the observed mechanical failure and nanoelastic processes involved during atomic wire fabrication are investigated using molecular dynamics ( md ) simulations, and we find that the total effective stiffness of the nanostructure is strongly affected by the detailed local atomic arrangement at the chain bases. | arxiv:cond-mat/0105277 |
a large number of binary neutron star ( bns ) mergers are expected to be detected by gravitational wave ( gw ) detectors and the electromagnetic ( em ) counterparts ( e. g., kilonovae ) of a fraction of these mergers may be detected in multi - bands by large area survey telescopes. for a given number of bns mergers detected by their gw signals, the expected numbers of their em counterparts that can be detected by a survey with given selection criteria depend on the kilonova properties, including the anisotropy. in this paper, we investigate whether the anisotropy of kilonova radiation and the kilonova model can be constrained statistically by the counting method, i. e., using the numbers of bns mergers detected via gw and multi - band em signals. adopting simple models for the bns mergers, afterglows, and a simple two ( blue and red ) - component model for kilonovae, we generate mock samples for gw detected bns mergers, their associated kilonovae and afterglows detected in multi - bands. by assuming some criteria for searching the em counterparts, we simulate the observations of these em counterparts and obtain the em observed samples in different bands. with the numbers of bns mergers detected by gw detectors and em survey telescopes in different bands, we show that the anisotropy of kilonova radiation and the kilonova model can be well constrained by using the bayesian analysis. our results suggest that the anisotropy of kilonova radiation may be demographically and globally constrained by simply using the detection numbers of bns mergers by gw detectors and em survey telescopes in multi - bands. | arxiv:2401.03710 |
we provide a classification of entangled states that uses new discrete entanglement invariants. the invariants are defined by algebraic properties of linear maps associated with the states. we prove a theorem on a correspondence between the invariants and sets of equivalent classes of entangled states. the new method works for an arbitrary finite number of finite - dimensional state subspaces. as an application of the method, we considered a large selection of cases of three subspaces of various dimensions. we also obtain an entanglement classification of four qubits, where we find 27 fundamental sets of classes. | arxiv:1012.2630 |
autonomous graphical user interface ( gui ) agents powered by multimodal large language models have shown great promise. however, a critical yet underexplored issue persists : over - execution, where the agent executes tasks in a fully autonomous way, without adequate assessment of its action confidence to compromise an adaptive human - agent collaboration. this poses substantial risks in complex scenarios, such as those involving ambiguous user instructions, unexpected interruptions, and environmental hijacks. to address the issue, we introduce os - kairos, an adaptive gui agent capable of predicting confidence levels at each interaction step and efficiently deciding whether to act autonomously or seek human intervention. os - kairos is developed through two key mechanisms : ( i ) collaborative probing that annotates confidence scores at each interaction step ; ( ii ) confidence - driven interaction that leverages these confidence scores to elicit the ability of adaptive interaction. experimental results show that os - kairos substantially outperforms existing models on our curated dataset featuring complex scenarios, as well as on established benchmarks such as aitz and meta - gui, with 24. 59 \ % $ \ sim $ 87. 29 \ % improvements in task success rate. os - kairos facilitates an adaptive human - agent collaboration, prioritizing effectiveness, generality, scalability, and efficiency for real - world gui interaction. the dataset and codes are available at https : / / github. com / wuzheng02 / os - kairos. | arxiv:2503.16465 |
we finish the classification of finite - dimensional irreducible representations of rational cherednik algebras $ h _ c ( w ) $ with equal parameters for exceptional coxeter groups by resolving the last open case : when $ w = e _ 8 $ and the denominator of $ c $ is $ 3 $. | arxiv:1612.09430 |
we present pure spectroscopic constraints on the uv luminosity functions and cosmic star formation rate ( sfr ) densities from 25 galaxies at $ z _ \ mathrm { spec } = 8. 61 - 13. 20 $. by reducing the jwst / nirspec spectra taken in multiple programs of ero, ers, go, and ddt with our analysis technique, we independently confirm 16 galaxies at $ z _ \ mathrm { spec } = 8. 61 - 11. 40 $ including new redshift determinations, and a bright interloper at $ z _ \ mathrm { spec } = 4. 91 $ that was claimed as a photometric candidate at z ~ 16. in conjunction with nine galaxies at redshifts up to $ z _ \ mathrm { spec } = 13. 20 $ in the literature, we make a sample of 25 spectroscopically - confirmed galaxies in total and carefully derive the best estimates and lower limits of the uv luminosity functions. these uv luminosity function constraints are consistent with the previous photometric estimates within the uncertainties and indicate mild redshift evolution towards z ~ 12 showing tensions with some theoretical models of rapid evolution. with these spectroscopic constraints, we obtain firm lower limits of the cosmic sfr densities and spectroscopically confirm a high sfr density at z ~ 12 beyond the constant star - formation efficiency models, which supports earlier claims from the photometric studies. while there are no spectroscopically - confirmed galaxies with very large stellar masses violating the $ \ lambda $ cdm model due to the removal of the bright interloper, we confirm star - forming galaxies at $ z _ \ mathrm { spec } = 11 - 13 $ with stellar masses much higher than model predictions. our results indicate possibilities of high star - formation efficiency ( > 5 % ), hidden agn, top - heavy initial mass function ( possibly with pop - iii ), and large scatter / variance. having these successful and unsuccessful spectroscopy results, we suggest observational strategies for efficiently removing low redshift interlopers for future jwst programs. | arxiv:2304.06658 |
gaussian process are a widely - used statistical tool for conducting non - parametric inference in applied sciences, with many computational packages available to fit to data and predict future observations. we study the use of the greta software for bayesian inference to apply gaussian process regression to spatio - temporal data of infectious disease outbreaks and predict future disease spread. greta builds on tensorflow, making it comparatively easy to take advantage of the significant gain in speed offered by gpus. in these complex spatio - temporal models, we show a reduction of up to 70 \ % in computational time relative to fitting the same models on cpus. we show how the choice of covariance kernel impacts the ability to infer spread and extrapolate to unobserved spatial and temporal units. the inference pipeline is applied to weekly incidence data on tuberculosis in the east and west midlands regions of england over a period of two years. | arxiv:2411.05556 |
in lattice field theory, renormalizable simulation algorithms are attractive, because their scaling behaviour as a function of the lattice spacing is predictable. algorithms implementing the langevin equation, for example, are known to be renormalizable if the simulated theory is. in this paper we show that the situation is different in the case of the molecular - dynamics evolution on which the hmc algorithm is based. more precisely, studying the phi ^ 4 theory, we find that the hyperbolic character of the molecular - dynamics equations leads to non - local ( and thus non - removable ) ultraviolet singularities already at one - loop order of perturbation theory. | arxiv:1103.1810 |
we present an analysis of the first kepler k2 mission observations of a rapidly oscillating ap ( roap ) star, hd 24355 ( $ v = 9. 65 $ ). the star was discovered in superwasp broadband photometry with a frequency of 224. 31 d $ ^ { - 1 } $, ( 2596. 18 $ \ mu $ hz ; $ p = 6. 4 $ min ) and an amplitude of 1. 51 mmag, with later spectroscopic analysis of low - resolution spectra showing hd 24355 to be an a5 vp sreu star. the high precision k2 data allow us to identify 13 rotationally split sidelobes to the main pulsation frequency of hd 24355. this number of sidelobes combined with an unusual rotational phase variation show this star to be the most distorted quadrupole roap pulsator yet observed. in modelling this star, we are able to reproduce well the amplitude modulation of the pulsation, and find a close match to the unusual phase variations. we show this star to have a pulsation frequency higher than the critical cut - off frequency. this is currently the only roap star observed with the kepler spacecraft in short cadence mode that has a photometric amplitude detectable from the ground, thus allowing comparison between the mmag amplitude ground - based targets and the $ \ mu $ mag spaced - based discoveries. no further pulsation modes are identified in the k2 data, showing this star to be a single - mode pulsator. | arxiv:1607.03853 |
in this work, we approach the laplacian coflow of a coclosed $ g _ 2 $ - structure $ \ varphi $ using the formulae for the irreducible $ g _ 2 $ - decomposition of the hodge laplacian and the lie derivative of the hodge dual $ 4 $ - form of $ \ varphi $. in terms of this decomposition, we characterise the conditions for a vector field as an infinitesimal symmetry of a coclosed $ g _ 2 $ - structure, as well as the soliton condition for the laplacian coflow. more specifically, we provide an easier proof for the absence of compact shrinking solitons of the laplacian coflow. moreover, we revisit the laplacian coflow of coclosed $ g _ 2 $ - structures on almost abelian lie groups addressed by fino - bagaglini ( 2018 ). however, our approach is based on the bracket flow point of view. notably, by showing that the norm of the lie bracket is strictly decreasing, we prove that we have long - time existence for any coclosed laplacian coflow solution. | arxiv:2304.14930 |
in a recent article, kwon et al. [ nature ( london ) { \ bf 600 }, 64 ( 2021 ) ] revealed nonuniversal dissipative dynamics of quantum vortices in a fermionic superfluid. the enhancement of the dissipative process is pronounced for the bardeen - cooper - schrieffer interaction regime, and it was suggested that the effect is due to the presence of quasiparticles localized inside the vortex core. we test this hypothesis through numerical simulations with time - dependent density - functional theory : a fully microscopic framework with fermionic degrees of freedom. the results of fully microscopic calculations expose the impact of the vortex - bound states on dissipative dynamics in a fermionic superfluid. their contribution is too weak to explain the experimental measurements, and we identify that thermal effects, giving rise to mutual friction between superfluid and the normal component, dominate the observed dynamics. | arxiv:2207.00870 |
a new type of detector for positron - emission tomography ( pet ) has been proposed recently, using a heavy organo - metallic liquid - trimethyl bismuth ( tmbi ) - as target material. tmbi is a transparent liquid with the high z element bismuth contributing 82 % of its mass. 511kev annihilation photons are converted efficiently into photo - electrons within the detector material producing both cherenkov light and free charge carriers in the liquid. while the optical component enables a fast timing, a charge readout using a segmented anode can provide an accurate position reconstruction and energy determination. the charge measurement requires a high level of purification, as any electronegative contaminants cause signal degradation. in addition to the purity requirements, the reactive nature of tmbi poses many challenges that need to be met until a fully functioning detector for pet applications can be realized. the paper presents an experimental setup that aims to remove electronegative impurities by electrostatic filtering and to characterise the properties of tmbi, e. g. the relative permittivity, for its application as a detector medium for charge read out. | arxiv:2209.00996 |
we present the first human - annotated dialogue - based relation extraction ( re ) dataset dialogre, aiming to support the prediction of relation ( s ) between two arguments that appear in a dialogue. we further offer dialogre as a platform for studying cross - sentence re as most facts span multiple sentences. we argue that speaker - related information plays a critical role in the proposed task, based on an analysis of similarities and differences between dialogue - based and traditional re tasks. considering the timeliness of communication in a dialogue, we design a new metric to evaluate the performance of re methods in a conversational setting and investigate the performance of several representative re methods on dialogre. experimental results demonstrate that a speaker - aware extension on the best - performing model leads to gains in both the standard and conversational evaluation settings. dialogre is available at https : / / dataset. org / dialogre /. | arxiv:2004.08056 |
aims. we perform a statistical study of the relations between the properties of solar energetic electron ( see ) events measured by the messenger mission from 2010 to 2015 and the parameters of the respective parent solar activity phenomena to identify the potential correlations between them. during the time of analysis messenger heliocentric distance varied between 0. 31 and 0. 47 au. results. there is an asymmetry to the east in the range of connection angles ( cas ) for which the see events present the highest peak intensities, where the ca is the longitudinal separation between the footpoint of the magnetic field connecting to the spacecraft and the flare location. based on this asymmetry, we define the subsample of well - connected events as when - 65 $ ^ { \ circ } \ leq $ ca $ \ leq + 33 ^ { \ circ } $. conclusions. based on the comparison of the correlation coefficients presented in this study using near 0. 4 au data, ( 1 ) both flare and shock - related processes may contribute to the acceleration of near relativistic electrons in large see events, in agreement with previous studies based on near 1 au data ; and ( 2 ) the maximum speed of the cme - driven shock is a better parameter to investigate particle acceleration related mechanisms than the average cme speed, as suggested by the stronger correlation with the see peak intensities. | arxiv:2212.01592 |
this study examines the capabilities of the vision transformer ( vit ) model in generating visual embeddings for images of auto parts sourced from online marketplaces, such as craigslist and offerup. by focusing exclusively on single - modality data, the analysis evaluates vit ' s potential for detecting patterns indicative of illicit activities. the workflow involves extracting high - dimensional embeddings from images, applying dimensionality reduction techniques like uniform manifold approximation and projection ( umap ) to visualize the embedding space, and using k - means clustering to categorize similar items. representative posts nearest to each cluster centroid provide insights into the composition and characteristics of the clusters. while the results highlight the strengths of vit in isolating visual patterns, challenges such as overlapping clusters and outliers underscore the limitations of single - modal approaches in this domain. this work contributes to understanding the role of vision transformers in analyzing online marketplaces and offers a foundation for future advancements in detecting fraudulent or illegal activities. | arxiv:2502.05756 |
we present a modified nudged elastic band routine that can reduce the number of force calls by more than 50 % for bands with non - uniform convergence. the method, which we call " dyneb ", dynamically and selectively optimizes states based on the perpendicular forces and parallel spring forces acting on that region of the band. the convergence criteria are scaled to focus on the region of interest, i. e., the saddle point, while maintaining continuity of the band and avoiding truncation. we show that this method works well for solid state reaction barriers - - - non - electrochemical in general and electrochemical in particular - - - and that the number of force calls can be significantly reduced without loss of resolution at the saddle point. | arxiv:1906.10257 |
in this paper, we present a data set and methods to compare speech processing models and human behaviour on a phone discrimination task. we provide perceptimatic, an open data set which consists of french and english speech stimuli, as well as the results of 91 english - and 93 french - speaking listeners. the stimuli test a wide range of french and english contrasts, and are extracted directly from corpora of natural running read speech, used for the 2017 zero resource speech challenge. we provide a method to compare humans ' perceptual space with models ' representational space, and we apply it to models previously submitted to the challenge. we show that, unlike unsupervised models and supervised multilingual models, a standard supervised monolingual hmm - gmm phone recognition system, while good at discriminating phones, yields a representational space very different from that of human native listeners. | arxiv:2010.05961 |
protostellar jets are tightly connected to the accretion process and regulate the angular momentum balance of accreting star - disk systems. the dg tau jet is one of the best - studied protostellar jets and contains plasma with temperatures ranging over three orders of magnitude within the innermost 50 au of the jet. we present new hubble space telescope ( hst ) far ultraviolet ( fuv ) long - slit spectra spatially resolving the c iv emission ( t ~ 1e5 k ) from the jet for the first time, and quasi - simultaneous hst observations of optical forbidden emission lines ( [ o i ], [ n ii ], [ s ii ] and [ o iii ] ) and fluorescent h2 lines. the c iv emission peaks at 42 au from the stellar position and has a fwhm of 52 au along the jet. its deprojected velocity of around 200 km / s decreases monotonically away from the driving source. in addition, we compare our hst data with the x - ray emission from the dg tau jet. we investigate the requirements to explain the data by an initially hot jet compared to local heating. both scenarios indicate a mass loss by the t ~ 1e5 k jet of ~ 1e - 9 msun / year, i. e., between the values for the lower temperature jet ( t ~ 1e4 k ) and the hotter x - ray emitting part ( t > 1e6 k ). however, a simple initially hot wind requires a large launching region ( ~ 1 au ), and we therefore favor local heating. | arxiv:1212.6363 |
cybercriminals pose a significant threat to blockchain trading security, causing $ 40. 9 billion in losses in 2024. however, the lack of an effective real - world address dataset hinders the advancement of cybercrime detection research. the anti - cybercrime efforts of researchers from broader fields, such as statistics and artificial intelligence, are blocked by data scarcity. in this paper, we present real - cats, a real - world dataset of cryptocurrency addresses with transaction profiles, serving as a practical training ground for developing and assessing detection methods. real - cats comprises 103, 203 criminal addresses from real - world reports and 106, 196 benign addresses from exchange customers. it satifies the c3r characteristics ( comprehensiveness, classifiability, customizability, and real - world transferability ), which are fundemental for practical detection of cryptocurrency cybercrime. the dataset provides three main functions : 1 ) effective evaluation of detection methods, 2 ) support for feature extensions, and 3 ) a new evaluation scenario for real - world deployment. real - cats also offers opportunities to expand cybercrime measurement studies. it is particularly beneficial for researchers without cryptocurrency - related knowledge to engage in this emerging research field. we hope that studies on cryptocurrency cybercrime detection will be promoted by an increasing number of cross - disciplinary researchers drawn to this versatile data platform. all datasets are available at https : / / github. com / sjdseu / real - cats | arxiv:2501.15553 |
two criteria for a closed connected definite 4 - manifold with infinite cyclic fundamental group to be top - split are given. one criterion extends a sufficient condition made in a previous paper. the result is equivalent to a purely algebraic result on the question asking when a positive definite hermitian form over the ring of integral one - variable laurent polynomials is represented by an integer matrix. as an application, an infinite family of orthogonally indecomposable unimodular odd definite symmetric $ z $ - forms is produced. | arxiv:1804.01380 |
energetic feedback from active galactic nuclei ( agn ) is an important ingredient for regulating the star - formation history of galaxies in models of galaxy formation, which makes it important to study how agn feedback actually occurs in practice. in order to catch agns in the act of quenching star formation we have used the interstellar nad absorption lines to look for cold - gas outflows in a sample of 456 nearby galaxies for which we could unambigously ascertain the presence of radio agn activity, thanks to radio imaging at milli - arcsecond scales. while compact radio emission indicating a radio agn was found in 103 galaxies ( 23 % of the sample ), and 23 objects ( 5 % ) exhibited nad absorption - line kinematics suggestive of cold - gas outflows, not one object showed evidence of a radio agn and of a cold - gas outflow simultaneously. radio agn activity was found predominantly in early - type galaxies, while cold - gas outflows were mainly seen in spiral galaxies with central star - formation or composite star - formation / agn activity. optical agns also do not seem capable of driving galactic winds in our sample. our work adds to a picture of the low - redshift universe where cold - gas outflows in massive galaxies are generally driven by star formation and where radio - agn activity occurs most often in systems in which the gas reservoir has already been significantly depleted. | arxiv:1510.06738 |
in this dissertation we study courant algebroids, objects that first appeared in the work of t. courant on dirac structures ; they were later studied by liu, weinstein and xu who used courant algebroids to generalize the notion of the drinfeld double to lie bialgebroids. as a first step towards understanding the complicated properties of courant algebroids, we interpret them by associating to each courant algebroid a strongly homotopy lie algebra in a natural way. next, we propose an alternative construction of the double of a lie bialgebroid as a homological hamiltonian vector field on an even symplectic supermanifold. the classical brst complex and the weil algebra arise as special cases. we recover the courant algebroid via the derived bracket construction and give a simple proof of the doubling theorem of liu, weinstein and xu. we also introduce a generalization, quasi - lie bialgebroids, analogous to drinfeld ' s quasi - lie bialgebras ; we show that the derived bracket construction in this case also yields a courant algebroid. finally, we compute the poisson cohomology of a one - parameter family of su ( 2 ) - covariant poisson structures on s ^ 2. as an application, we show that these structures are non - trivial deformations of each other, and that they do not admit rescaling. | arxiv:math/9910078 |
we report on the prompt and afterglow emission observations of the dark burst grb010214 with bepposax. the prompt emission shows possible evidence of variable absorption from n _ h = 3. 0 ^ { + 5. 1 } _ { - 2. 0 } x 10 ^ 23 cm - 2 in the first 6 s of the event to a value consistent with the galactic column density ( n _ h ^ ( g ) = 2. 66 x 10 ^ 20 cm - 2 ) in the grb direction. an x - ray afterglow emission in the 2 - 10 kev energy band was detected with bepposax, but an analogue search at lower wavelengths ( optical, ir and radio ) was unsuccessful. the x - ray afterglow spectrum is consistent with a power - law with galactic absorption. the light curve shows a complex decay, if the tail of the prompt emission is assumed as the onset of the afterglow : if the origin of the afterglow is coincident with the grb onset, a bump before ~ 3 x 10 ^ 4 s is inferred, while if the afterglow is assumed to start later, a steepening of the power - law light curve at t ~ 3 x 10 ^ 4 s is deduced. we discuss these results in the light of the current models of afterglows and the possible origin of the grb darkness. finally, we tentatively derive an estimate of the burst redshift. | arxiv:astro-ph/0302007 |
we describe the macaulay2 package tateonproducts and its capabilities, which include computing cohomology tables and beilinson monads of sheaves on products of projective spaces and the derived category pushforward of a sheaf under a morphism from a projective scheme to a projective space. | arxiv:1905.10230 |
on weighted riemannian manifolds we prove the existence of globally lipschitz transport maps between the weight ( probability ) measure and log - lipschitz perturbations of it, via kim and milman ' s diffusion transport map, assuming that the curvature - dimension condition $ \ mathrm { cd } ( \ rho _ { 1 }, \ infty ) $ holds, as well as a second order version of it, namely $ \ gamma _ { 3 } \ geq \ rho _ { 2 } \ gamma _ { 2 } $. we get new results as corollaries to this result, as the preservation of poincar \ ' e ' s inequality for the exponential measure on $ ( 0, + \ infty ) $ when perturbed by a log - lipschitz potential and a new growth estimate for the monge map pushing forward the gamma distribution on $ ( 0, + \ infty ) $ ( then getting as a particular case the exponential one ), via laguerre ' s generator. | arxiv:2310.02478 |
propagating two - dimensional plasmon modes guided along silver nanoridge waveguides with triangular and inverted triangular cross sections are investigated in this paper. mode field profiles, dispersion curves, propagation distances, and figure - of - merits of the plasmon ridge modes are calculated for silver nanoridge waveguides with various triangular and inverted triangular waveguide cross sections. it is found that the triangular cross section nanoridge waveguide, if designed properly, can have longer propagation distance and higher figure - of - merit than the flat - top nanoridge waveguide of the same width. when the triangle height of the nanoridge is high, the mode approaches to the small angle wedge mode. an inverted triangular cross section nanoridge mode can be considered as a hybrid mode of two metal wedge plasmon modes. when inverted triangle depth increases, the propagation distance and the figure - of - merit decrease dramatically, suggesting the poorer performance when compared to the flat - top nanoridge plasmon waveguide. | arxiv:1202.2477 |
moir \ ' e systems provide a highly tunable platform for engineering band structures and exotic correlated phases. here, we theoretically study a model for a single layer of graphene subject to a smooth moir \ ' e electrostatic potential, induced by an insulating substrate layer. for sufficiently large moir \ ' e unit cells, we find that ultra - flat bands coexist with a triangular network of chiral one - dimensional ( 1d ) channels. these channels mediate an effective interaction between localized modes with spin -, orbital - and valley degrees of freedom emerging from the flat bands. the form of the interaction reflects the chiralilty and 1d nature of the network. we study this interacting model within an $ su ( 4 ) $ mean - field theory, semi - classical monte - carlo simulations, and an $ su ( 4 ) $ spin - wave theory, focusing on commensurate order stabilized by local two - site and chiral three - site interactions. by tuning a gate voltage, one can trigger a non - coplanar phase characterized by a peculiar coexistence of three different types of order : ferromagnetic spin order in one valley, non - coplanar chiral spin order in the other valley, and 120 $ ^ \ circ $ order in the remaining spin and valley - mixed degrees of freedom. quantum and classical fluctuations have qualitatively different effects on the observed phases and can, for example, create a finite spin - chirality purely via fluctuation effects. | arxiv:2212.08180 |
= bodyweight - supported treadmill training ( bwstt ) is used to enhance walking ability of people with neurological injury. these machines are therapist - assisted devices that are used in the clinical setting, but is limited by the personnel and labor requirements placed on physical therapists. the bwstt device, and many others like it, assist physical therapists by providing task - specific practice of walking in people following neurological injury. = = = prosthesis = = = a prosthesis, prosthetic, or prosthetic limb is a device that replaces a missing body part. it is part of the field of biomechatronics, the science of using mechanical devices with human muscular, musculoskeletal, and nervous systems to assist or enhance motor control lost by trauma, disease, or defect. prostheses are typically used to replace parts lost by injury ( traumatic ) or missing from birth ( congenital ) or to supplement defective body parts. inside the body, artificial heart valves are in common use with artificial hearts and lungs seeing less common use but under active technology development. other medical devices and aids that can be considered prosthetics include hearing aids, artificial eyes, palatal obturator, gastric bands, and dentures. prostheses are specifically not orthoses, although given certain circumstances a prosthesis might end up performing some or all of the same functionary benefits as an orthosis. prostheses are technically the complete finished item. for instance, a c - leg knee alone is not a prosthesis, but only a prosthetic component. the complete prosthesis would consist of the attachment system to the residual limb – usually a " socket ", and all the attachment hardware components all the way down to and including the terminal device. despite the technical difference, the terms are often used interchangeably. the terms " prosthetic " and " orthotic " are adjectives used to describe devices such as a prosthetic knee. the terms " prosthetics " and " orthotics " are used to describe the respective allied health fields. an occupational therapist ' s role in prosthetics include therapy, training and evaluations. prosthetic training includes orientation to prosthetics components and terminology, donning and doffing, wearing schedule, and how to care for residual limb and the prosthesis. = = = exoskeletons = = = a powered exoskeleton is a wear | https://en.wikipedia.org/wiki/Assistive_technology |
in this paper, we address the problem of achieving efficient code - based digital signatures with small public keys. the solution we propose exploits sparse syndromes and randomly designed low - density generator matrix codes. based on our evaluations, the proposed scheme is able to outperform existing solutions, permitting to achieve considerable security levels with very small public keys. | arxiv:1305.5436 |
##al study, experimental study, repeated measures design, and mixed - methods procedures. = = = self - report data = = = relationship science relies predominantly on individuals ' self - reported evaluations and descriptions of their own relationship processes. this method of data collection often comes in the form of answering a questionnaire that requires either selection from a set of fixed responses or providing open - ended responses. it is often the simplest way to study relationships, but researchers have cautioned against solely relying on this form of measurement. some issues that arise with the use of self - report data is the difficulty of accurately answering retrospective questions or questions that require introspection. recently, particularly in light of the anti - false positive movement in psychology, relationship scientists are encouraging the use of multiple methods ( e. g., self - report data, observational data ) to study the same or similar constructs in different ways. however, an identified benefit of using specifically self - report questionnaires is that many of the measures used to study relationships are standardized and are therefore used in multiple different studies, where findings across studies can provide insight into replicability. = = = experimental data = = = some of the earliest studies conducted in relationship science were done using laboratory experiments. the field has since used experimental methods in order to infer causality about a relationship phenomenon of interest. this requires identification of a dependent variable that will be the measured effect ( e. g., performance on a stressful task ) and an independent variable that will be what is manipulated ( e. g., social support vs. no social support ). however, a common concern with experimental study of relationship phenomena is the potential lack of generalizability of laboratory setting findings to real - world contexts. = = = observational data = = = observational ( or, behavioral ) data in relationship science is a method of making inferences about relationship processes that relies on an observer ' s reports, rather than a participant ' s own reports of their relationship. this is often done through videotaping or audio recording participants ' interactions with one another and having outside observers systematically identify ( i. e., code ) aspects of interest dependent upon the type of relationship being studied ( e. g., patience exhibited during a parent - child activity ; affection exhibited during a romantic couple ' s discussion ). this method enables researchers to study aspects of a relationship that may be sub - conscious to participants or would otherwise not be detectable through self - report measures. however, a hurdle of observational research is establishing strong | https://en.wikipedia.org/wiki/Relationship_science |
we investigate the deconvolved color profiles of 223 disk galaxies at redshifts of $ z = 1 $ - 3 observed by the james webb space telescope ( jwst ) as part of the cosmic evolution early release science survey ( ceers ). the filters were selected to approximate the rest - frame $ b - y $ color, which is used to identify u - shaped color profiles - - those becoming progressively bluer with increasing radius, then turning redder beyond a specific point. we find that 36 % of type ii ( down - bending ) disks exhibit u - shaped color profiles with a minimum at or near the disk break. in contrast, no type i ( single - exponential ) disks and only 9 % of type iii ( up - bending ) disks show such a profile. the presence of u - shaped color profiles in type ii disks likely arises from the interplay between a star - formation threshold and spiral - or bar - driven secular radial migration of older stars outward. the fraction of type ii disks exhibiting a u - shaped color profile remains almost consistent across two redshift bins, $ z = 1 $ - $ 2 $ and $ z = 2 $ - $ 3 $, but is significantly lower than that observed in the local universe, likely because the secular process of radial migration at high redshift may not have had sufficient time to significantly influence the disk structure. the absence of u - shaped color profiles in type ii disks could point to rapid rather than secular radial star migration potentially caused by violent clump instabilities, transporting both younger and older stars to the outer disk. our results provide useful constraints on the formation and evolution models of disk galaxies in the early universe. | arxiv:2412.13064 |
we study the absorption spectrum for a strongly degenerate fermi gas confined in a harmonic trap. the spectrum is calculated using both the exact summation and also the thomas - fermi ( tf ) approximation. in the latter case, relatively simple analytical expressions are obtained for the absorption lineshape at large number of trapped atoms. at zero temperature, the approximated lineshape is characterized by a $ ( 1 - z ^ 2 ) ^ { 5 / 2 } $ dependence which agrees well with the exact numerical calculations. at non - zero temperature, the spectrum becomes broader, although remains non - gaussian as long as the fermion gas is degenerate. the changes in the trap frequency for an electronically excited atom can introduce an additional line broadening. | arxiv:quant-ph/0011041 |
closed time - like curves ( ctc ) in cosmic strings in teleparallel $ t _ { 4 } $ gravity are forbidden. this result shown here in $ t _ { 4 } $ was shown by soleng ( phys. rev. d49 ( 1994 ) 1124 ) also to be valid in einstein - cartan ( ec ) gravity. here we show that in $ t _ { 4 } $ to allow for ctc we are also led to a lower bound on the angular momentum of the cosmic string. this result is obtained by matching the interior $ t _ { 4 } $ solution to a general relativity ( gr ) vacuum solution. one of the main differences of the present report and the one by soleng is that here the interior symmetric solution does not have necessary polarized spins but only cartan torsion in the spirit of teleparallelism. torsion flux is computed and it is show that the center of cylinder singularity corresponds to a 2 + 1 spacetime rotating point particle in $ t _ { 4 } $. therefore the possibility of building time machines seems to be strongly constraint than in the case of ec gravity. | arxiv:gr-qc/0102094 |
modulation instability is a phenomenon of spontaneous pattern formation in nonlinear media, oftentimes leading to an unpredictable behaviour and a degradation of a signal of interest. we propose an approach based on reinforcement learning to suppress the unstable modes by optimizing the parameters for the time modulation of the potential in the nonlinear system. we test our approach in 1d and 2d cases and propose a new class of physically - meaningful reward functions to guarantee tamed instability. | arxiv:2404.04310 |
the indian institutes of technology ( iit ) are a network of engineering and technology institutions in india. established in 1950, they are under the purview of the ministry of education of the indian government and are governed by the institutes of technology act, 1961. the act refers to them as institutes of national importance and lays down their powers, duties, and framework for governance as the country ' s premier institutions in the field of technology. 23 iits currently fall under the tenor of this act. each iit operates autonomously and is linked to others through a common council called the iit council, which oversees their administration. the minister of education of india is the ex officio chairperson of the iit council. according to data obtained through right to information ( rti ) applications, approximately 38 % of indian institute of technology ( iit ) graduates from the class of 2024 have not secured job placements. this is the highest percentage in the past three years, with a steady increase from 19 % in 2021 and 21 % in 2022. = = list of all indian institutes of technology = = = = history = = in the late 1940s, a 22 - member committee, headed by nalini ranjan sarkar, recommended the establishment of these institutions in various parts of india, along the lines of the massachusetts institute of technology ( mit ), with affiliated secondary institutions. the first indian institute of technology was founded in may 1950 at the site of the hijli detention camp in kharagpur, west bengal. the name " indian institute of technology " was adopted before the formal inauguration of the institute on 18 august 1951 by maulana abul kalam azad. on 15 september 1956, the parliament of india passed the indian institute of technology ( kharagpur ) act, declaring it as an institute of national importance. jawaharlal nehru, first prime minister of india, in the first convocation address of iit kharagpur in 1956, said : here in the place of that hijli detention camp stands the fine monument of india, representing india ' s urges, india ' s future in the making. this picture seems to me symbolically of the changes coming to india. on the recommendations of the sarkar committee, four campuses were established at bombay ( 1958 ), madras ( 1959 ), kanpur ( 1959 ), and delhi ( 1961 ). the location of these campuses was chosen to be scattered throughout india to prevent regional imbalance. the indian institutes of technology act was amended to reflect the addition of new ii | https://en.wikipedia.org/wiki/Indian_Institutes_of_Technology |
with the boom of edge intelligence, its vulnerability to adversarial attacks becomes an urgent problem. the so - called adversarial example can fool a deep learning model on the edge node to misclassify. due to the property of transferability, the adversary can easily make a black - box attack using a local substitute model. nevertheless, the limitation of resource of edge nodes cannot afford a complicated defense mechanism as doing on the cloud data center. to overcome the challenge, we propose a dynamic defense mechanism, namely ei - mtd. it first obtains robust member models with small size through differential knowledge distillation from a complicated teacher model on the cloud data center. then, a dynamic scheduling policy based on a bayesian stackelberg game is applied to the choice of a target model for service. this dynamic defense can prohibit the adversary from selecting an optimal substitute model for black - box attacks. our experimental result shows that this dynamic scheduling can effectively protect edge intelligence against adversarial attacks under the black - box setting. | arxiv:2009.10537 |
assuming that the cosmological principle holds, maartens, ellis and stoeger ( mes ) recently constructed a detailed scheme linking anisotropies in the cosmic background radiation ( cmb ) with anisotropies and inhomogeneities in the large scale structure of the universe and showed how to place limits on those anisotropies and inhomogeneities simply by using cmb quadrupole and octupole limits. first we indicate and discuss the connection between the covariant multipole moments of the temperature anisotropy used in the mes scheme and the quadrupole and octupole results from cobe. then we introduce those results into the mes limit equations to obtain definite quantitative limits on the complete set of cosmological measures of anisotropy and inhomogeneity. we find that all the anisotropy measures are less than 10 ^ { - 4 } in the case of those not affected by the expansion rate h, and less than 10 ^ { - 6 } mpc ^ { - 1 } in the case of those which are. these results quantitatively demonstrate that the observable universe is indeed close to friedmann - lemaitre - robertson - walker ( flrw ) on the largest scales, and can be adequately modelled by an almost - flrw model - - that is, the anisotropies and inhomogeneities characterizing the observable universe on the largest scales are not too large to be considered perturbations to flrw. | arxiv:astro-ph/9904346 |
we present numerical simulations of electron magnetohydrodynamic ( emhd ) and electron reduced mhd ( ermhd ) turbulence. comparing scaling relations, we find that both emhd and ermhd turbulence show similar spectra and anisotropy. we develop new techniques to study anisotropy of emhd turbulence. our detailed study of anisotropy of emhd turbulence supports our earlier result of k _ par ~ k _ perp ^ ( 1 / 3 ) scaling. we find that the high - order statistics show a scaling that is similar to the she - leveque scaling. we observe that the bispectra, which characterize the interaction of different scales within the turbulence cascade, are very different for emhd and mhd turbulence. we show that both decaying and driven emhd turbulence have the same statistical properties. we calculate the probability distribution functions ( pdfs ) of mhd and emhd turbulence and compare them with those of interplanetary turbulence. we find that, as in the case of the solar wind, the pdfs of the increments of magnetic field strength in mhd and emhd turbulence are well described by the tsallis distribution. we discuss implications of our results for astrophysical situations, including the adafs and magnetic reconnection. | arxiv:0904.0661 |
consanguinity of entropy and complexity is pointed out through the example of coherent states of the $ sl ( 2, \ c ) $ group. both are obtained from the k \ " ahler potential of the underlying geometry of the sphere corresponding to the fubini - study metric. entropy is shown to be equal to the k \ " ahler potential written in terms of dual symplectic variables as the guillemin potential for toric manifolds. the logarithm of complexity relating two states is shown to be equal to calabi ' s diastasis function. optimality of the fubini - study metric is indicated by considering its deformation. | arxiv:2407.13327 |
a left - invariant sub - riemannian metric $ d $ on the shortened lorentz group $ so _ 0 ( 2, 1 ) $ under the condition that $ d $ is right - invariant relative to the orthogonal lie subgroup $ 1 \ otimes so ( 2 ) $ is studied. the distance between arbitrary two elements, the cut locus ( as the union of the subgroup $ 1 \ otimes so ( 2 ) $ with the antipodal set to the submanifold of symmetric matrices in the open solid torus $ so _ 0 ( 2, 1 ) $ ), and the conjugate set for the unit are found for $ ( so _ 0 ( 2, 1 ), d ) $. | arxiv:1507.05554 |
we consider generalizations of the classical inverse problem to bayesien type estimators, where the result is not one optimal parameter but an optimal probability distribution in parameter space. the practical computational tool to compute these distributions is the metropolis monte carlo algorithm. we derive kinetic theories for the metropolis monte carlo method in different scaling regimes. the derived equations yield a different point of view on the classical algorithm. it further inspired modifications to exploit the difference scalings shown on an simulation example of the lorenz system. | arxiv:2405.01232 |
large language models ( llms ) often struggle with tasks requiring external knowledge, such as knowledge - intensive multiple choice question answering ( mcqa ). integrating knowledge graphs ( kgs ) can enhance reasoning ; however, existing methods typically demand costly fine - tuning or retrieve noisy kg information. recent approaches leverage graph neural networks ( gnns ) to generate kg - based input embedding prefixes as soft prompts for llms but fail to account for question relevance, resulting in noisy prompts. moreover, in mcqa tasks, the absence of relevant kg knowledge for certain answer options remains a significant challenge. to address these issues, we propose question - aware knowledge graph prompting ( qap ), which incorporates question embeddings into gnn aggregation to dynamically assess kg relevance. qap employs global attention to capture inter - option relationships, enriching soft prompts with inferred knowledge. experimental results demonstrate that qap outperforms state - of - the - art methods across multiple datasets, highlighting its effectiveness. | arxiv:2503.23523 |
the gottesman - kitaev - preskill ( gkp ) error correcting code encodes a finite dimensional logical space in one or more bosonic modes, and has recently been demonstrated in trapped ions and superconducting microwave cavities. in this work we introduce a new subsystem decomposition for gkp codes that we call the stabilizer subsystem decomposition, analogous to the usual approach to quantum stabilizer codes. the decomposition has the defining property that a partial trace over the non - logical stabilizer subsystem is equivalent to an ideal decoding of the logical state. we describe how to decompose arbitrary states across the subsystem decomposition using a set of transformations that move between the decompositions of different gkp codes. besides providing a convenient theoretical view on gkp codes, such a decomposition is also of practical use. we use the stabilizer subsystem decomposition to efficiently simulate noise acting on single - mode gkp codes, and in contrast to more conventional fock basis simulations, we are able to to consider essentially arbitrarily large photon numbers for realistic noise channels such as loss and dephasing. | arxiv:2210.14919 |
the pseudoscalar and pseudovector $ \ eta n $ coupling constants are calculated from an effective vertex associated with the $ a _ 0 ( 980 ) \ pi n $ triangle diagram. the predicted values are in agreement with the ones concluded from fitting $ \ eta $ photoproduction amplitudes. in this context we stress the importance of the properties of the scalar meson octet for $ \ eta $ meson physics. | arxiv:nucl-th/9601002 |
cross - correlations between biased tracers and the dark matter field encode information about the physical variables which characterize these tracers. however, if the physical variables of interest are correlated with one another, then extracting this information is not as straightforward as one might naively have thought. we show how to exploit these correlations so as to estimate scale - independent bias factors of all orders in a model - independent way. we also show that failure to account for this will lead to incorrect conclusions about which variables matter and which do not. morever, accounting for this allows one to use the scale dependence of bias to constrain the physics of halo formation ; to date the argument has been phrased the other way around. we illustrate by showing that the scale dependence of linear and nonlinear bias, measured on nonlinear scales, can be used to provide consistent estimates of how the critical density for halo formation depends on halo mass. our methods work even when the bias is nonlocal and stochastic, such as when, in addition to the spherically averaged density field and its derivatives, the quadrupolar shear field also matters for halo formation. in such models, the nonlocal bias factors are closely related to the more familiar local nonlinear bias factors, which are much easier to measure. our analysis emphasizes the fact that biased tracers are biased because they do not sample fields ( density, velocity, shear, etc. ) at all positions in space in the same way that the dark matter does. | arxiv:1611.03613 |
we analyze low resolution spitzer infrared ( ir ) 5 - 14 micron spectra of the diffuse emission toward a carefully selected sample of stars. the sample is composed of sight lines toward stars that have well determined ultraviolet ( uv ) extinction curves and which are shown to lie beyond effectively all of the extinguishing and emitting dust along their lines of sight. our sample includes sight lines whose uv curve extinction curves exhibit a wide range of curve morphology and which sample a variety of interstellar environments. as a result, this unique sample enabled us to study the connection between the extinction and emission properties of the same grains, and to examine their response to different physical environments. we quantify the emission features in terms of the pah model given by draine & li ( 2007 ) and a set of additional features, not known to be related to pah emission. we compare the intensities of the different features in the spitzer mid - ir spectra with the fitzpatrick & massa ( 2007 ) parameters which describe the shapes of uv to near - ir extinction curves. our primary result is that there is a strong correlation between the area of the 2175 a uv bump in the extinction curves of the program stars and the strengths of the major pah emission features in the mid - ir spectra for the same lines of sight. | arxiv:2112.02631 |
we study pattern selection of cracks in directionally drying fractures by analyzing the experimental systems recently devised by c. allain and l. limat. [ phys. rev. lett. { \ bf 74 }, 2981 ( 1995 ). ] proposing a simple picture of crack formation, we clarify the mechanism of how cracks array regularly and find that the interval between neighboring cracks is proportional to the $ 2 / 3 $ power of the cell thickness. this result explains well the experimental data of allain and limat. | arxiv:patt-sol/9510002 |
we propose that dirac cones can be engineered in phosphorene with fourfold - coordinated phosphorus atom. the key is to separate in energy the in - plane ( $ s $, $ p _ x $ and $ p _ y $ ) and out - of - plane ( $ p _ z $ ) oribtals through the $ sp ^ 2 $ configuration, yielding respective $ \ sigma $ - and $ \ pi $ - character dirac cones, and then quench the latter. as a proof - of - principle study, we realize $ \ sigma $ - character dirac cone in hydrogenated / fluorinated phosphorene with the honeycomb lattice. the obtained dirac cones are at $ k $ - points, slightly anisotropic, with fermi velocities of 0. 91 / 1. 23 times that of graphene along $ \ gamma $ k / km direction, and maintain a good linearity up to $ \ sim $ 2 ev for holes. one substantive advantage of $ \ sigma $ - character dirac cone is its convenience to tune the dirac gap via in - plane strain. our findings pave a new way for development of high performance electronic devices based on dirac materials. | arxiv:1408.6310 |
in this paper the next attempt is made to clarify the nature of the euclidean behavior of the boundary in the angular size - redshift cosmological test. it is shown experimentally that this can be explained by the selection determined by anisotropic morphology and anisotropic radiation of extended radio sources. a catalogue of extended radio sources with minimal flux densities of about 0. 01 jy at 1. 4 ghz was compiled for conducting the test. without the assumption of their size evolution, the agreement between the experiment and calculation was obtained both in the lambda cdm model ( omega _ m = 0. 27, omega _ v = 0. 73. ) and the friedman model ( omega = 0. 1 ). | arxiv:1501.02690 |
a quantitative evaluation method for a reduced - order model of the flow field around an naca0015 airfoil based on particle image velocimetry ( piv ) data is proposed in the present paper. the velocity field data obtained by the time - resolved piv measurement were decomposed into significant modes by a proper orthogonal decomposition ( pod ) technique, and a linear reduced - order model was then constructed by the linear regression of the time advancement of the pod modes or the sparsity promoting dynamic mode decomposition ( dmd ). the present evaluation method can be used for the evaluation of the estimation error and the model predictability. the model was constructed using different numbers of pod or dmd modes for order reduction of the fluid data and different methods of estimating the linear coefficients, and the effects of these conditions on the model performance were quantitatively evaluated. the results illustrates that forward ( standard ) model works the best with two to ten significant dmd modes selected by sparsity promoting dmd. | arxiv:1907.12239 |
quantum stabilizer states over gf ( m ) can be represented as self - dual additive codes over gf ( m ^ 2 ). these codes can be represented as weighted graphs, and orbits of graphs under the generalized local complementation operation correspond to equivalence classes of codes. we have previously used this fact to classify self - dual additive codes over gf ( 4 ). in this paper we classify self - dual additive codes over gf ( 9 ), gf ( 16 ), and gf ( 25 ). assuming that the classical mds conjecture holds, we are able to classify all self - dual additive mds codes over gf ( 9 ) by using an extension technique. we prove that the minimum distance of a self - dual additive code is related to the minimum vertex degree in the associated graph orbit. circulant graph codes are introduced, and a computer search reveals that this set contains many strong codes. we show that some of these codes have highly regular graph representations. | arxiv:0801.3773 |
we have observed the flare star yy gem simultaneously with xmm - newton and chandra as part of a multi - wavelength campaign aiming at a study of variability related to magnetic activity in this short - period eclipsing binary. here we report on the first results from the analysis of the x - ray spectrum. the vicinity of the star provides high enough s / n in the ccd cameras onboard xmm - newton to allow for time - resolved spectroscopy. since the data are acquired simultaneously they allow for a cross - calibration check of the performance of the xmm - newton rgs and the letgs on chandra. | arxiv:astro-ph/0109413 |
the results of the quantitative investigations of the renormalization of the absorption edge of different compounds by the isotope effect are described. | arxiv:0807.2152 |
we have performed density functional calculations of the formation energies of substitutional transition metal ( tm ) defects, c vacancies, and c interstitial defects in tic. in addition we have evaluated the migration energy barriers for c atoms in the presence of tm impurities. we find that the solubility of tm impurities taken from the 3d tm series is low and only sc and v impurities can be dissolved into tic at equilibrium. in addition, we find that the migration energy barriers of c in tic are greatly affected by the presence of tm impurities : the migration barriers are generally lower in the presence of impurities compared to pure tic and show a clear dependence on the atomic size of the tm impurities. we propose that the mobility of c in tic will be the highest in the presence of tm impurities from the middle of the 3d tm series. | arxiv:1303.2848 |
social media platforms have emerged as prominent information sharing ecosystems in the context of a variety of recent crises, ranging from mass emergencies, to wars and political conflicts. we study affective responses in social media and how they might indicate desensitization to violence experienced in communities embroiled in an armed conflict. specifically, we examine three established affect measures : negative affect, activation, and dominance as observed on twitter in relation to a number of statistics on protracted violence in four major cities afflicted by the mexican drug war. during a two year period ( aug 2010 - dec 2012 ), while violence was on the rise in these regions, our findings show a decline in negative emotional expression as well as a rise in emotional arousal and dominance in twitter posts : aspects known to be psychological markers of desensitization. we discuss the implications of our work for behavioral health, facilitating rehabilitation efforts in communities enmeshed in an acute and persistent urban warfare, and the impact on civic engagement. | arxiv:1507.01287 |
competition among cooperators, defectors, and loners is studied in an evolutionary prisoner ' s dilemma game with optional participation. loners are risk averse i. e. unwilling to participate and rather rely on small but fixed earnings. this results in a rock - scissors - paper type cyclic dominance of the three strategies. the players are located either on square lattices or random regular graphs with the same connectivity. occasionally, every player reassesses its strategy by sampling the payoffs in its neighborhood. the loner strategy efficiently prevents successful spreading of selfish, defective behavior and avoids deadlocks in states of mutual defection. on square lattices, monte carlo simulations reveal self - organizing patterns driven by the cyclic dominance, whereas on random regular graphs different types of oscillatory behavior are observed : the temptation to defect determines whether damped, periodic or increasing oscillations occur. these results are compared to predictions by pair approximation. although pair approximation is incapable of distinguishing the two scenarios because of the equal connectivity, the average frequencies as well as the oscillations on random regular graphs are well reproduced. | arxiv:cond-mat/0208478 |
whilst risc - v has grown phenomenally quickly in embedded computing, it is yet to gain significant traction in high performance computing ( hpc ). however, as we move further into the exascale era, the flexibility offered by risc - v has the potential to be very beneficial in future supercomputers especially as the community places an increased emphasis on decarbonising its workloads. sophon ' s sg2042 is the first mass produced, commodity available, high - core count risc - v cpu designed for high performance workloads. first released in summer 2023, and at the time of writing now becoming widely available, a key question is whether this is a realistic proposition for hpc applications. in this paper we use nasa ' s nas parallel benchmark ( npb ) suite to characterise performance of the sg2042 against other cpus implementing the risc - v, x86 - 64, and aarch64 isas. we find that the sg2042 consistently outperforms all other risc - v solutions, delivering between a 2. 6 and 16. 7 performance improvement at the single core level. when compared against the x86 - 64 and aarch64 cpus, which are commonplace for high performance workloads, we find that the sg2042 performs comparatively well with computationally bound algorithms but decreases in relative performance when the algorithms are memory bandwidth or latency bound. based on this work, we identify that performance of the sg2042 ' s memory subsystem is the greatest bottleneck. | arxiv:2406.12394 |
we show that the solution ( in the sense of distribution ) to the cauchy problem with the periodic boundary condition associated with the modified benjamin - ono equation is unique in $ l ^ \ infty _ t ( h ^ s ( \ mathbb { t } ) ) $ for $ s > 1 / 2 $. the proof is based on the analysis of a normal form equation obtained by infinitely many reduction steps using integration by parts in time after a suitable gauge transform. | arxiv:1912.01363 |
both multi - streaming ( random motion ) and bulk motion cause the finger - of - god ( fog ) effect in redshift space distortion ( rsd ). we apply a direct measurement of the multi - streaming effect in rsd from simulations, proving that it induces an additional, non - negligible fog damping to the redshift space density power spectrum. we show that, including the multi - streaming effect, the rsd modelling is significantly improved. we also provide a theoretical explanation based on halo model for the measured effect, including a fitting formula with one to two free parameters. the improved understanding of fog helps break the $ f \ sigma _ 8 - \ sigma _ v $ degeneracy in rsd cosmology, and has the potential of significantly improving cosmological constraints. | arxiv:1611.09075 |
we study a generalized frenkel - kontorova model. using minimal and birkhoff solutions as building blocks, we construct a lot of homoclinic solutions and heteroclinic solutions for this generalized frenkel - kontorova model under gap conditions. these new solutions are not minimal and birkhoff any more. we use constrained minimization method to prove our results. | arxiv:2004.04868 |
we consider a keller - segel model with non - linear porous medium type diffusion and non - local attractive power law interaction, focusing on potentials that are less singular than newtonian interaction. here, the nonlinear diffusion is chosen to be $ m = 2 - \ frac { 2s } { d } $, in which case the steady states are compactly supported. we analyse under what conditions on the initial data the regime that attractive forces are stronger than diffusion occurs and classify the conditions for global existence and finite time blow - up of solutions. it is shown that there exists a threshold value which is characterized by the optimal constant of a variant of the hardy - littlewood - sobolev inequality. specifically, the solution will exist globally if the initial data is below the threshold, while the solution blows up in finite time when the initial data is above the threshold. | arxiv:2412.12586 |
motivated by the belle collaboration ' s new observation of $ y ( 4626 ) $, we investigate the possibility of its configuration as a $ p $ - wave $ [ cs ] [ \ bar { c } \ bar { s } ] $ tetraquark state from qcd sum rules. eventually, the extracted mass $ 4. 60 ^ { + 0. 13 } _ { - 0. 19 } ~ \ mbox { gev } $ for the $ p $ - wave $ cs $ - scalar - diquark $ \ bar { c } \ bar { s } $ - scalar - antidiquark state agrees well with the experimental data of $ y ( 4626 ) $, which could support its interpretation as a $ p $ - wave scalar - scalar $ [ cs ] [ \ bar { c } \ bar { s } ] $ tetraquark state. | arxiv:2004.10985 |
the apparent contradiction between the recently observed weak charge disproportion and the traditional mn $ ^ { 3 + } $ / mn $ ^ { 4 + } $ picture of the charge - orbital orders in half - doped manganites is resolved by a novel wannier states analysis of the lda $ + u $ electronic structure. strong electron itinerancy in this charge - transfer system significantly delocalizes the occupied low - energy " mn $ ^ { 3 + } $ " wannier states such that charge leaks into the " mn $ ^ { 4 + } $ " - sites. furthermore, the leading mechanisms of the charge order are quantified via our first - principles derivation of the low - energy effective hamiltonian. the electron - electron interaction is found to play a role as important as the electron - lattice interaction. \ ignore { a general picture of doped holes in strongly correlated charge - transfer systems is presented and applied to the study of charge order in half - doped manganites, using a novel wannier states analysis of the lda $ + u $ electronic structure. while residing primarily in the oxygen atoms, the doped holes form additional effective $ e _ g $ orbitals at the low - energy scale, leading to an effective mn $ ^ { 3 + } $ / mn $ ^ { 4 + } $ valence picture that enables weak charge disproportion, resolving the current serious contradictions between the recent experimental observations of charge distribution and traditional models. furthermore, the leading mechanisms of the observed charge order are quantified via our first - principles derivation of the low - energy effective hamiltonian | arxiv:0704.1834 |
the image retrieval ( ir ) approach to image localization has distinct advantages to the 3d and the deep learning ( dnn ) approaches : it is seen - agnostic, simpler to implement and use, has no privacy issues, and is computationally efficient. the main drawback of this approach is relatively poor localization in both position and orientation of the query camera when compared to the competing approaches. this paper represents a hybrid approach that stores only image features in the database like some ir methods, but relies on a latent 3d reconstruction, like 3d methods but without retaining a 3d scene reconstruction. the approach is based on two ideas : { \ em ( i ) } a novel proposal where query camera center estimation relies only on relative translation estimates but not relative rotation estimates through a decoupling of the two, and { \ em ( ii ) } a shift from computing optimal pose from estimated relative pose to computing optimal pose from multiview correspondences, thus cutting out the ` ` middle - man ' '. our approach shows improved performance on the 7 - scenes and cambridge landmarks datasets while also improving on timing and memory footprint as compared to state - of - the - art. | arxiv:2503.23577 |
we present a sample of 17 objects from the califa survey where we find initial evidence of galactic winds based on their off - axis ionization properties. we identify the presence of outflows using various optical diagnostic diagrams ( e. g., ew ( h $ \ alpha $ ), [ nii ] / h $ \ alpha $, [ sii ] / h $ \ alpha $, [ oi ] / h $ \ alpha $ line - ratio maps ). we find that all 17 candidate outflow galaxies lie along the sequence of active star formation in the m $ _ \ star $ vs. star - formation rate diagram, without a clear excess in the integrated sfr. the location of galaxies along the star - formation main sequence ( sfms ) does not influence strongly the presence or not of outflows. the analysis of the star - formation rate density ( $ \ sigma _ { \ rm sfr } $ ) reveals that the califa sources present higher values when compared with normal star - forming galaxies. the strength of this relation depends on the calibrator used to estimate the sfr. this excess in $ \ sigma _ { \ rm sfr } $ is significant within the first effective radius supporting the idea that most outflows are driven by processes in the inner regions of a galaxy. we find that the molecular gas mass density ( $ \ sigma _ \ mathrm { gas } $ ) is a key parameter that plays an important role in the generation of outflows through its association with the local sfr. the canonical threshold reported for the generation of outflows - - $ \ sigma _ { \ rm sfr } > 0. 1 $ $ \ mathrm { m } _ \ odot \ mathrm { yr } ^ { - 1 } \ mathrm { kpc } ^ { - 2 } $ - - is only marginally exceeded in our sample. within the kennicutt - schmidt diagram we propose a domain for galaxies hosting starburst - driven outflows defined by $ \ sigma _ { \ rm sfr } > 10 ^ { - 2 } \, \ mathrm { m } _ \ odot \ mathrm { yr } ^ { - 1 } \ mathrm { kpc } ^ { - 2 } $ and $ \ sigma _ \ mathrm { gas } > 10 ^ { 1. 2 } \, \ mathrm { m } _ \ odot \ mathrm { pc } ^ { - 2 } | arxiv:1811.01253 |
we prove a duality theorem for graded algebras over a field that implies several known duality results : graded local duality, versions of serre duality for local cohomology and of suzuki duality for generalized local cohomology, and herzog - rahimi bigraded duality. | arxiv:0705.2662 |
we detect electroluminescence in single layer molybdenum disulphide ( mos2 ) field - effect transistors built on transparent glass substrates. by comparing absorption, photoluminescence, and electroluminescence of the same mos2 layer, we find that they all involve the same excited state at 1. 8ev. the electroluminescence has pronounced threshold behavior and is localized at the contacts. the results show that single layer mos2, a direct band gap semiconductor, is promising for novel optoelectronic devices, such as 2 - dimensional light detectors and emitters. | arxiv:1211.4311 |
we derive formulas for the mean curvature of special lagrangian 3 - folds in the general case where the ambient 6 - manifold has intrinsic torsion. consequently, we are able to characterize those su ( 3 ) - structures for which every special lagrangian 3 - fold is a minimal submanifold. in the process, we obtain an obstruction to the local existence of special lagrangian 3 - folds. | arxiv:1905.03713 |
##ated blood in a particular region is assumed to correlate with an increase in neural activity in that part of the brain. this allows us to localize particular functions within different brain regions. fmri has moderate spatial and temporal resolution. optical imaging. this technique uses infrared transmitters and receivers to measure the amount of light reflectance by blood near different areas of the brain. since oxygenated and deoxygenated blood reflects light by different amounts, we can study which areas are more active ( i. e., those that have more oxygenated blood ). optical imaging has moderate temporal resolution, but poor spatial resolution. it also has the advantage that it is extremely safe and can be used to study infants ' brains. magnetoencephalography. meg measures magnetic fields resulting from cortical activity. it is similar to eeg, except that it has improved spatial resolution since the magnetic fields it measures are not as blurred or attenuated by the scalp, meninges and so forth as the electrical activity measured in eeg is. meg uses squid sensors to detect tiny magnetic fields. = = = computational modeling = = = computational models require a mathematically and logically formal representation of a problem. computer models are used in the simulation and experimental verification of different specific and general properties of intelligence. computational modeling can help us understand the functional organization of a particular cognitive phenomenon. approaches to cognitive modeling can be categorized as : ( 1 ) symbolic, on abstract mental functions of an intelligent mind by means of symbols ; ( 2 ) subsymbolic, on the neural and associative properties of the human brain ; and ( 3 ) across the symbolic – subsymbolic border, including hybrid. symbolic modeling evolved from the computer science paradigms using the technologies of knowledge - based systems, as well as a philosophical perspective ( e. g. " good old - fashioned artificial intelligence " ( gofai ) ). they were developed by the first cognitive researchers and later used in information engineering for expert systems. since the early 1990s it was generalized in systemics for the investigation of functional human - like intelligence models, such as personoids, and, in parallel, developed as the soar environment. recently, especially in the context of cognitive decision - making, symbolic cognitive modeling has been extended to the socio - cognitive approach, including social and organizational cognition, interrelated with a sub - symbolic non - conscious layer. subsymbolic modeling includes connectionist / neural network models. connectionism relies on the idea that the mind / brain | https://en.wikipedia.org/wiki/Cognitive_science |
we prove that mild solutions to the stochastic heat equation with superlinear accretive forcing and polynomially growing multiplicative noise cannot explode under two sets of assumptions. the first set of assumptions allows both the deterministic forcing and multiplicative noise terms to grow polynomially, as long as the multiplicative noise is sufficiently larger. the second set of assumptions imposes an osgood condition on the deterministic forcing and allows the multiplicative noise to grow polynomially. in both cases, the multiplicative noise cannot grow faster than $ u ^ { \ frac { 3 } { 2 } } $, as this would cause explosion. | arxiv:2409.15527 |
let $ \ mathfrak { f } _ n $ be the set of all cuspidal automorphic representations $ \ pi $ of $ \ mathrm { gl } _ n $ with unitary central character over a number field $ f $. we prove the first unconditional zero density estimate for the set $ \ mathcal { s } = \ { l ( s, \ pi \ times \ pi ' ) \ colon \ pi \ in \ mathfrak { f } _ n \ } $ of rankin - selberg $ l $ - functions, where $ \ pi ' \ in \ mathfrak { f } _ { n ' } $ is fixed. we use this density estimate to establish ( i ) a hybrid - aspect subconvexity bound at $ s = \ frac { 1 } { 2 } $ for almost all $ l ( s, \ pi \ times \ pi ' ) \ in \ mathcal { s } $, ( ii ) a strong on - average form of effective multiplicity one for almost all $ \ pi \ in \ mathfrak { f } _ n $, and ( iii ) a positive level of distribution for $ l ( s, \ pi \ times \ tilde { \ pi } ) $, in the sense of bombieri - vinogradov, for each $ \ pi \ in \ mathfrak { f } _ n $. | arxiv:2103.05634 |
the measurement of circular dichroism ( cd ) has widely been exploited to distinguish the different enantiomers of chiral structures. it has been applied to natural materials ( e. g. molecules ) as well as to artificial materials ( e. g. nanophotonic structures ). however, especially for chiral molecules the signal level is very low and increasing the signal - to - noise ratio is of paramount importance to either shorten the necessary measurement time or to lower the minimum detectable molecule concentration. as one solution to this problem, we propose here to use quantum states of light in cd sensing to reduce the noise below the shot noise limit that is encountered when using coherent states of light. through a multi - parameter estimation approach, we identify the ultimate quantum limit to precision of cd sensing, allowing for general schemes including additional ancillary modes. we show that the ultimate quantum limit can be achieved by various optimal schemes. it includes not only fock state input in direct sensing configuration but also twin - beam input in ancilla - assisted sensing configuration, for both of which photon number resolving detection needs to be performed as the optimal measurement setting. these optimal schemes offer a significant quantum enhancement even in the presence of additional system loss. the optimality of a practical scheme using a twin - beam state in direct sensing configuration is also investigated in details as a nearly optimal scheme for cd sensing when the actual cd signal is very small. alternative schemes involving single - photon sources and detectors are also proposed. this work paves the way for further investigations of quantum metrological techniques in chirality sensing. | arxiv:2008.03888 |
we scatter a meson off of a scalar kink in quantum field theory, at leading order in perturbation theory. we calculate the full quantum state, at leading order, at all times and also check that the reflection and transmission coefficients agree with those which would be obtained in relativistic quantum mechanics. | arxiv:2210.12725 |
machine learning is traditionally studied at the model level : researchers measure and improve the accuracy, robustness, bias, efficiency, and other dimensions of specific models. in practice, the societal impact of machine learning is determined by the surrounding context of machine learning deployments. to capture this, we introduce ecosystem - level analysis : rather than analyzing a single model, we consider the collection of models that are deployed in a given context. for example, ecosystem - level analysis in hiring recognizes that a job candidate ' s outcomes are not only determined by a single hiring algorithm or firm but instead by the collective decisions of all the firms they applied to. across three modalities ( text, images, speech ) and 11 datasets, we establish a clear trend : deployed machine learning is prone to systemic failure, meaning some users are exclusively misclassified by all models available. even when individual models improve at the population level over time, we find these improvements rarely reduce the prevalence of systemic failure. instead, the benefits of these improvements predominantly accrue to individuals who are already correctly classified by other models. in light of these trends, we consider medical imaging for dermatology where the costs of systemic failure are especially high. while traditional analyses reveal racial performance disparities for both models and humans, ecosystem - level analysis reveals new forms of racial disparity in model predictions that do not present in human predictions. these examples demonstrate ecosystem - level analysis has unique strengths for characterizing the societal impact of machine learning. | arxiv:2307.05862 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.