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covid - 19 spread across the globe at an immense rate has left healthcare systems incapacitated to diagnose and test patients at the needed rate. studies have shown promising results for detection of covid - 19 from viral bacterial pneumonia in chest x - rays. automation of covid - 19 testing using medical images can speed up the testing process of patients where health care systems lack sufficient numbers of the reverse - transcription polymerase chain reaction ( rt - pcr ) tests. supervised deep learning models such as convolutional neural networks ( cnn ) need enough labeled data for all classes to correctly learn the task of detection. gathering labeled data is a cumbersome task and requires time and resources which could further strain health care systems and radiologists at the early stages of a pandemic such as covid - 19. in this study, we propose a randomized generative adversarial network ( randgan ) that detects images of an unknown class ( covid - 19 ) from known and labelled classes ( normal and viral pneumonia ) without the need for labels and training data from the unknown class of images ( covid - 19 ). we used the largest publicly available covid - 19 chest x - ray dataset, covidx, which is comprised of normal, pneumonia, and covid - 19 images from multiple public databases. in this work, we use transfer learning to segment the lungs in the covidx dataset. next, we show why segmentation of the region of interest ( lungs ) is vital to correctly learn the task of classification, specifically in datasets that contain images from different resources as it is the case for the covidx dataset. finally, we show improved results in detection of covid - 19 cases using our generative model ( randgan ) compared to conventional generative adversarial networks ( gans ) for anomaly detection in medical images, improving the area under the roc curve from 0. 71 to 0. 77.
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arxiv:2010.06418
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in this work, we consider achievable secrecy rates for symmetric $ k $ - user ( $ k \ ge 3 $ ) interference channels with confidential messages. we find that nested lattice codes and layered coding are useful in providing secrecy for these channels. achievable secrecy rates are derived for very strong interference. in addition, we derive the secure degrees of freedom for a range of channel parameters. as a by - product of our approach, we also demonstrate that nested lattice codes are useful for k - user symmetric interference channels without secrecy constraints in that they yield higher degrees of freedom than previous results.
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arxiv:0905.2643
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this work aims to develop an integrated control strategy for brushless direct current motors for a wide range of applications in robotics systems. the controller is suited for both high torque - low speed and high - speed control of the motors. hardware validation is done by developing a custom bldc drive system, and the circuit elements are optimised for power efficiency.
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arxiv:2404.17367
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we prove an analytic generalization of koll \ ' ar ' s vanishing theorem, which contains the nadel vanishing theorem as a special case.
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arxiv:1607.04684
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the question has been solved whether bell ' s inequalities cover all possible kinds of hidden - variable theories. it has been shown that the given nequalities can be hardly derived when the changing space position of photon - pair source together with the microscopic space structure of measuring devices are taken into account ; and when corresponding impact parameters ( i. e., exact impact points ) of photons in individual measuring devices ( polarizers ) influence measured values, in addition to usually considered characteristics.
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arxiv:quant-ph/9808005
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in this paper, we systematically investigate both the synfire propagation and firing rate propagation in feedforward neuronal network coupled in an all - to - all fashion. in contrast to most earlier work, where only reliable synaptic connections are considered, we mainly examine the effects of unreliable synapses on both types of neural activity propagation in this work. we first study networks composed of purely excitatory neurons. our results show that both the successful transmission probability and excitatory synaptic strength largely influence the propagation of these two types of neural activities, and better tuning of these synaptic parameters makes the considered network support stable signal propagation. it is also found that noise has significant but different impacts on these two types of propagation. the additive gaussian white noise has the tendency to reduce the precision of the synfire activity, whereas noise with appropriate intensity can enhance the performance of firing rate propagation. further simulations indicate that the propagation dynamics of the considered neuronal network is not simply determined by the average amount of received neurotransmitter for each neuron in a time instant, but also largely influenced by the stochastic effect of neurotransmitter release. second, we compare our results with those obtained in corresponding feedforward neuronal networks connected with reliable synapses but in a random coupling fashion. we confirm that some differences can be observed in these two different feedforward neuronal network models. finally, we study the signal propagation in feedforward neuronal networks consisting of both excitatory and inhibitory neurons, and demonstrate that inhibition also plays an important role in signal propagation in the considered networks.
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arxiv:1111.4526
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as the interferometers detecting gravitational waves are upgraded, improving their sensitivity, the probability of observing strong lensing increases. once a detection is made, it will be critical to gain as much information as possible about the lensing object from these observations. in this work, we present a methodology to rapidly perform model selection between differing mass density profiles for strongly lensed gravitational wave signals, using the results of the fast strong lensing analysis pipeline golum. we demonstrate the validity of this methodology using some illustrative examples adopting the idealised singular isothermal sphere and point mass lens models. we take several simulated lensed signals, analyse them with golum and subject them to our methodology to recover both the model and its parameters. to demonstrate the methodology ' s stability, we show how the result varies with the number of samples used for a subset of these injections. in addition to the analysis of simulations, we also apply our methodology to the gravitational wave event pair gw191230 - - lgw200104, two events with similar frequency evolutions and sky locations, which was analysed in detail as a potential lensing candidate but ultimately discarded when considering the full population and the uncertain nature of the second event. we find a preference for the singular isothermal sphere model over the point mass, though our posteriors are much wider than for the lensed injections, in line with the expectations for a non - lensed event. the methodology developed in this work is made available as part of the gravelamps package of software.
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arxiv:2307.07852
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we present analytic calculations of the electromagnetic torques acting on a magnetic neutron star rotating in vacuum, including near - zone torques associated with the inertia of dipole and quadrupole magnetic fields. we incorporate these torques into the rotational dynamics of a rigid - body neutron star, and show that the effects of the inertial torque can be understood as a modification of the moment of inertia tensor of the star. we apply our rotational dynamics equation to the crab pulsar, including intrinsic distortions of the star and various electromagnetic torques, to investigate the possibility that the counter - alignment of the magnetic inclination angle, as suggested by recent observations, could be explained by pulsar precession. we find that if the effective principal axis of the pulsar is nearly aligned with either the magnetic dipole axis or the rotation axis, then precession may account for the observed counter - alignment over decade timescales. over the spindown timescale of the pulsar, the magnetic inclination angle always decreases.
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arxiv:1503.01486
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we show that the feng - xiong lower bound of $ 1 / 2 $ for the box dimension of $ \ alpha \ beta $ - sets is tight. we also study how much of an $ \ alpha \ beta $ - orbit ` ` carries the dimension ' ' : deleting an arbitararily small positive density set of times can cause the box dimension to drop to zero, but the assouad dimension cannot drop below $ 1 / 4 $.
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arxiv:2410.19640
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weighted shifts on directed trees are a decade old generalisation of classical shift operators in the sequence space $ \ ell ^ 2 $. in this paper we introduce the joint backward extension property ( jbep ) for classes of weighted shifts on directed trees. if a class satisfies jbep, the existence of a common backward extension within the class for a family of weighted shifts on rooted directed trees does not depend on the additional structure of the big tree ( of fixed depth ). we decide whether several classes of operators have jbep. for subnormal or power hyponormal weighted shifts the property is satisfied, while it fails for completely hyperexpansive or quasinormal. nevertheless some positive results on joint backward extensions of completely hyperexpansive weighted shifts are proven.
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arxiv:2209.09829
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while non - parametric models, such as neural networks, are sufficient in the load forecasting, separate estimates of fixed and shiftable loads are beneficial to a wide range of applications such as distribution system operational planning, load scheduling, energy trading, and utility demand response programs. a semi - parametric estimation model is usually required, where cost sensitivities of demands must be known. existing research work consistently uses somewhat arbitrary parameters that seem to work best. in this paper, we propose a generic class of data - driven semiparametric models derived from consumption data of residential consumers. a two - stage machine learning approach is developed. in the first stage, disaggregation of the load into fixed and shiftable components is accomplished by means of a hybrid algorithm consisting of non - negative matrix factorization ( nmf ) and gaussian mixture models ( gmm ), with the latter trained by an expectation - maximization ( em ) algorithm. the fixed and shiftable loads are subject to analytic treatment with economic considerations. in the second stage, the model parameters are estimated using an l2 - norm, epsilon - insensitive regression approach. actual energy usage data of two residential customers show the validity of the proposed method.
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arxiv:2011.03519
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different versions of the notion of a state have been formulated for various so - called quantum structures. in this paper, we investigate the interplay among states on synaptic algebras and on its sub - structures. a synaptic algebra is a generalization of the partially ordered jordan algebra of all bounded self - adjoint operators on a hilbert space. the paper culminates with a characterization of extremal states on a commutative generalized hermitian algebra, a special kind of synaptic algebra.
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arxiv:1606.08229
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the local ( v < 1200kms ) and the cosmic expansion field out to 30000kms - 1 are characterized by ho = 58. while the random error is small ( + - 2 ), it may still be affected by systematic errors as large as 10 %. the local expansion is outlined by cepheids and by cepheid - calibrated tf distances of a complete sample of field galaxies and by nearby groups and clusters ; the cosmic expansion is defined by cepheid - calibrated sneia. the main source of systematic errors are therefore the shape and the zero point of the p - l relation of cepheids and its possible dependence on metallicity. gaia will essentially eliminate these error sources. another source of systematic error is due to the homogenization of sneia as to decline rate delta m _ 15 and color ( b - v ). gaia will discover about half of the 2200 sneia which will occur during a four - year lifetime within 10000kms. for many of them ground - based follow - up will provide useful photometric parameters ( and spectra ), which will allow to fix the dependence of the sneia luminosity on delta m _ 15 and ( b - v ) with high accuracy. at the same time they will yield exquisite distances to an corresponding number of field galaxies. - gaia will also revolutionize the very local distance scale by determining fundamental distances of the companion galaxies of the milky way and even of some spirals in - and possibly outside the local group from their rotation curves seen in radial velocities and proper motions. moreover, gaia will obtain trigonometric parallaxes of rr lyrae stars, of red giants defining the trgb, of stars on the zams, of white dwarf defining their cooling sequence, and of globular clusters, and determine the metallicity dependence of these distance indicators. it will thus establish a self - controlling network of distance indicators within the local group and beyond.
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arxiv:astro-ph/0208178
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this paper connects nonpositive sectional curvature of a riemannian manifold with the displacement convexity of the variance functional on the space $ p ( m ) $ of probability measures over $ m $. we show that $ m $ has nonpositive sectional curvature and has trivial topology ( i. e, is homeomorphic to $ \ mathbf { r } ^ n $ ) if and only if the variance functional on $ p ( m ) $ is displacement convex. this is followed by a jensen type inequality for the variance functional with respect to wasserstein barycenters, as well as by a result comparing the variance of the wasserstein and linear barycenters of a probability measure on $ p ( m ) $ ( that is, an element of $ p ( p ( m ) ) $ ). these results are applied to invariant measures under isometry group actions, giving a comparison for the variance functional between the wasserstein projection and the $ l ^ 2 $ projection to the set of invariant measures.
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arxiv:1503.06460
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theory of quasiparticle spectra and the de haas - van alphen ( dhva ) oscillation in type - ii superconductors are developed based on the bogoliubov - de gennes equations for vortex - lattice states. as the pair potential grows through the superconducting transition, each degenerate landau level in the normal state splits into quasiparticle bands in the magnetic brillouin zone. this brings landau - level broadening, which in turn leads to the extra dhva oscillation damping in the vortex state. we perform extensive numerical calculations for three - dimensional systems with various gap structures. it is thereby shown that ( i ) this landau - level broadening is directly connected with the average gap at h = 0 along each fermi - surface orbit perpendicular to the field h ; ( ii ) the extra dhva oscillation attenuation is caused by the broadening around each extremal orbit. these results imply that the dhva experiment can be a unique probe to detect band - and / or angle - dependent gap amplitudes. we derive an analytic expression for the extra damping based on the second - order perturbation with respect to the pair potential for the luttinger - ward thermodynamic potential. this formula reproduces all our numerical results excellently, and is used to estimate band - specific gap amplitudes from available data on nbse _ 2, nb _ 3sn, and yni _ 2b _ 2c. the obtained value for yni _ 2b _ 2c is fairly different from the one through a specific - heat measurement, indicating presence of gap anisotropy in this material. c programs to solve the two - dimensional bogoliubov - de gennes equations are available at http : / / phys. sci. hokudai. ac. jp / ~ kita / index - e. html.
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arxiv:cond-mat/0208012
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current course recommender systems primarily leverage learner - course interactions, course content, learner preferences, and supplementary course details like instructor, institution, ratings, and reviews, to make their recommendation. however, these systems often overlook a critical aspect : the evolving skill demand of the job market. this paper focuses on the perspective of academic researchers, working in collaboration with the industry, aiming to develop a course recommender system that incorporates job market skill demands. in light of the job market ' s rapid changes and the current state of research in course recommender systems, we outline essential properties for course recommender systems to address these demands effectively, including explainable, sequential, unsupervised, and aligned with the job market and user ' s goals. our discussion extends to the challenges and research questions this objective entails, including unsupervised skill extraction from job listings, course descriptions, and resumes, as well as predicting recommendations that align with learner objectives and the job market and designing metrics to evaluate this alignment. furthermore, we introduce an initial system that addresses some existing limitations of course recommender systems using large language models ( llms ) for skill extraction and reinforcement learning ( rl ) for alignment with the job market. we provide empirical results using open - source data to demonstrate its effectiveness.
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arxiv:2404.10876
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we consider a lattice regularization for an ill - posed diffusion equation with trilinear constitutive law and study the dynamics of phase interfaces in the parabolic scaling limit. our main result guarantees for a certain class of single - interface initial data that the lattice solutions satisfy asymptotically a free boundary problem with hysteretic stefan condition. the key challenge in the proof is to control the microscopic fluctuations that are inevitably produced by the backward diffusion when a particle passes the spinodal region.
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arxiv:1610.05447
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this paper is devoted to study the optimal portfolio problem. harry markowitz ' s ph. d. thesis prepared the ground for the mathematical theory of finance. in modern portfolio theory, we typically find asset returns that are modeled by a random variable with an elliptical distribution and the notion of portfolio risk is described by an appropriate risk measure. in this paper, we propose new stochastic models for the asset returns that are based on jumps - diffusion ( j - d ) distributions. this family of distributions are more compatible with stylized features of asset returns. on the other hand, in the past decades, we find attempts in the literature to use well - known risk measures, such as value at risk and expected shortfall, in this context. unfortunately, one drawback with these previous approaches is that no explicit formulas are available and numerical approximations are used to solve the optimization problem. in this paper, we propose to use a new coherent risk measure, so - called, entropic value at risk ( evar ), in the optimization problem. for certain models, including a jump - diffusion distribution, this risk measure yields an explicit formula for the objective function so that the optimization problem can be solved without resorting to numerical approximations.
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arxiv:1406.7040
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electronic hanbury brown twiss correlations are discussed for geometries in which transport is along adiabatically guided edge channels. we briefly discuss partition noise experiments and discuss the effect of inelastic scattering and dephasing on current correlations. we then consider a two - source hanbury brown twiss experiment which demonstrates strikingly that even in geometries without an aharonov - bohm effect in the conductance matrix ( second - order interference ), correlation functions can ( due to fourth - order interference ) be sensitive to a flux. interestingly we find that this fourth - order interference effect is closely related to orbital entanglement. the entanglement can be detected via violation of a bell inequality in this geometry even so particles emanate from uncorrelated sources.
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arxiv:cond-mat/0404123
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we investigate the distinction between color - and flavor - branes, that is usually made in the context of gauge / string duality with backreacting flavors. our remarks are based on a series of examples concerning the role of source terms in relatively simple supergravity backgrounds that allow for a well - controlled approach to the problem. the observations suggest that, in opposite to general practice, one could consider such terms for both kinds of branes, while their presence is only essential for smeared sources - as is commonly the case for flavor - branes. among the examples studied are d3 - d7 systems with eight supercharges, where the d7 - branes are assumed to be smeared. starting from a fairly generic ansatz, we will find new analytic and numeric solutions and briefly compare these to previous work in this field.
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arxiv:1007.1201
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5g technology allows heterogeneous services to share the wireless spectrum within the same radio access network. in this context, spectrum slicing of the shared radio resources is a critical task to guarantee the performance of each service. we analyze a downlink communication serving two types of traffic : enhanced mobile broadband ( embb ) and ultra - reliable low - latency communication ( urllc ). due to the nature of low - latency traffic, the base station knows the channel state information ( csi ) of the embb users while having statistical csi for the urllc users. we study the power minimization problem employing orthogonal multiple access ( oma ) and non - orthogonal multiple access ( noma ) schemes. based on this analysis, we propose a lookup table - based approach and a block coordinated descent ( bcd ) algorithm. we show that the bcd is optimal for the urllc power allocation. the numerical results show that noma leads to lower power consumption than oma, except when the average channel gain of the urllc user is very high. for the latter case, the optimal approach depends on the channel condition of the embb user. even when oma attains the best performance, the gap with noma is negligible, showing the capability of noma to reduce power consumption in practically every condition.
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arxiv:2110.14544
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let f be a totally real number field. using a recent geometric approach developed by andreatta and iovita we construct several variables p - adic families of finite slope quaternionic automorphic forms over f. it is achieved by interpolating the modular sheaves defined over some auxiliary unitary shimura curves. secondly, we attach p - adic l - functions to triples of ordinary p - adic families of quaternionic automorphic eigenforms. this is done by relating trilinear periods to some trilinear products over unitary shimura curves which can be interpolated adapting the work of liu - zhang - zhang to our families.
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arxiv:1908.00091
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stimulated by recent suggestion of cosmic axion spin precession experiment with eu contained compound we develop a new method for accurate calculation of schiff moments of even - odd deformed nuclei. the method is essentially based on experimental data on magnetic moments and e1, e3 - amplitudes in the given even - odd nucleus and in adjacent even - even nuclei. unfortunately such sets of data are not known yet for most of interesting nuclei. fortunately the full set of data is available for $ ^ { 153 } $ eu. hence, we perform the calculation for $ ^ { 153 } $ eu and find value of the schiff moment. the value is about 30 times larger than a typical schiff moment of a spherical heavy nucleus. the enhancement of the schiff moment in $ ^ { 153 } $ eu is related to the low energy octupole mode. on the other hand the value of schiff moment we find is 30 times smaller than that obtained in the assumption of static octupole deformation.
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arxiv:2307.04299
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we study the electrical double layer at the interface between a protein crystal and a salt solution or a dilute solution of protein, and estimate the double layer ' s contribution to the interfacial tension of this interface. this contribution is negative and decreases in magnitude with increasing salt concentration. we also consider briefly the interaction between a pair of protein surfaces.
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arxiv:cond-mat/0206067
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i review the topic of relic neutrino asymmetry generation through active - sterile neutrino and antineutrino oscillations in the early universe. applications to ( i ) the suppression of sterile neutrino production, and ( ii ) the primordial helium abundance are briefly presented.
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arxiv:hep-ph/0006347
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this paper analyzes the convergence and generalization of training a one - hidden - layer neural network when the input features follow the gaussian mixture model consisting of a finite number of gaussian distributions. assuming the labels are generated from a teacher model with an unknown ground truth weight, the learning problem is to estimate the underlying teacher model by minimizing a non - convex risk function over a student neural network. with a finite number of training samples, referred to the sample complexity, the iterations are proved to converge linearly to a critical point with guaranteed generalization error. in addition, for the first time, this paper characterizes the impact of the input distributions on the sample complexity and the learning rate.
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arxiv:2207.03615
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in this paper, we apply the sorting network theory to construct an analog rank order filter. we present a voltage mode cmos two - input sorting element and arrange these to form a rank order filter. the resulting circuit is simpleand is a high - speed, high - precision design. although the transistor count is moderately higher than other designs, the proposed circuit simultaneously outputs signals of all ranks rather than of just one specified rank. we also develop a slightly modified design which calculates the rank of a given signal. we present reports of simulations to verify the performance of the device.
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arxiv:1101.0318
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in this paper, we study a conjecture of gao and wang concerning a proposed formula $ k _ 1 ^ * ( g ) $ for the maximal cross number $ k _ 1 ( g ) $ taken over all unique factorization indexed multisets over a given finite abelian group $ g $. as a corollary of our first main result, we verify the conjecture for abelian groups of the form $ c _ { p ^ m } \ oplus c _ p, c _ { p ^ m } \ oplus c _ q, c _ { p ^ m } \ oplus c _ q ^ 2 $, $ c _ { p ^ m } \ oplus c _ r ^ n $ where $ p, q $ are distinct primes and $ r \ in \ { 2, 3 \ } $. in our second main result we verify that $ k _ 1 ( g ) = k _ 1 ^ * ( g ) $ for groups of the form $ c _ r \ oplus c _ { p ^ m } \ oplus c _ p, c _ { rp ^ mq } $ and $ c _ r \ oplus c _ p \ oplus c _ q ^ 2 $ for $ r \ in \ { 2, 3 \ } $ given some restrictions on $ p $ and $ q $. we also study general techniques for computing and bounding $ k _ 1 ( g ) $, and derive an asymptotic result which shows that $ k _ 1 ( g ) $ becomes arbitrarily close to $ k _ 1 ^ * ( g ) $ as the smallest prime dividing $ | g | $ goes to infinity, given certain conditions on the structure of $ g $. we also derive some necessary properties of the structure of unique factorization indexed multisets which would hypothetically violate $ k ( s ) \ le k _ 1 ^ * ( g ) $.
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arxiv:1301.1401
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so far, cosmic ray air showers have been detected using scintillation counter arrays on the ground widely. and also air cherenkov detection method, which is limited its observation period in moonless nights, has been adopted. the detection method of radio emission from cosmic ray air showers is not new, but rather old method. radio emission from cosmic ray air showers has not been detected with the method of self - trigger system. if the detection method of radio emission were available, there is no limit of the observation like cherenkov counter. the developments of high radio frequency ( rf ) technology might make the detection of radio emission from extensive air showers possible. antennas calibrated in laboratory are available. with those antennas, we can directly obtain the absolute intensity of radio frequency from cosmic ray air showers. main issue to detect radio emission is that signal level is quite low. the thermal noise particularly causes background noise source. those issues and detection method are discussed. we also describe an antenna detection method to generate self - trigger signal and a method to identify air shower events from natural and artificial noises.
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arxiv:1907.08617
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quasicrystals represent a category of rarely structured solids that challenge traditional periodicity in crystal materials. recent advancements in the synthesis of two - dimensional ( 2d ) van der waals materials have paved the way for exploring the unique physical properties of these systems. here, we report on the synthesis of 2d quasicrystals featuring 30 { \ deg } alternating twist angles between multiple graphene layers, using chemical vapor deposition ( cvd ). strikingly, we observed periodic moir \ ' e patterns in the quasicrystal, a finding that has not been previously reported in traditional alloy - based quasicrystals. the moir \ ' e periodicity, varying with the parity of the constituent layers, aligns with the theoretical predictions that suggest a stress cancellation mechanism in force. the emergence of moir \ ' e fringes is attributed to the spontaneous mismatched lattice constant in the oriented graphene layers, proving the existence of atomic relaxation. this phenomenon, which has been largely understudied in graphene systems with large twist angles, has now been validated through our use of scanning transmission electron microscopy ( stem ). our cvd - grown moir \ ' e quasicrystal provides an ideal platform for exploring the unusual physical properties that arise from moir \ ' e periodicity within quasicrystals.
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arxiv:2406.07068
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we reanalyze b - > d pi and b - > k j / psi data to extract a set of parameters which give the relevant hadronic matrix elements in terms of factorized amplitudes. various sources of theoretical uncertainties are studied, in particular those depending on the model adopted for the form factors. we find that the fit to the b - > d pi branching ratios substantially depends on the model describing the isgur - wise function and on the value of its slope. this dependence can be reduced by substituting the br ( b - > d pi ) with suitable ratios of non - leptonic to differential semileptonic brs. in this way, we obtain a model - independent determination of these parameters. using these results, the b - > d form factors at q ^ 2 = m _ pi ^ 2 can be extracted from a fit of the br ( b - > d pi ). the comparison between the form factors obtained in this way and the corresponding measurements in semileptonic decays can be used as a test of ( generalized ) factorization free from the uncertainties due to heavy - heavy form factor modeling. finally, we present predictions for yet - unmeasured d pi and d k branching ratios and extract f _ { d _ s } and f _ { d _ s ^ * } from b - > dd _ s decays. we find f _ { d _ s } = 270 + - 45 mev and f _ { d _ s ^ * } = 260 + - 40 mev, in good agreement with recent measurements and lattice calculations.
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arxiv:hep-ph/9810271
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kernel $ k $ - means clustering can correctly identify and extract a far more varied collection of cluster structures than the linear $ k $ - means clustering algorithm. however, kernel $ k $ - means clustering is computationally expensive when the non - linear feature map is high - dimensional and there are many input points. kernel approximation, e. g., the nystr \ " om method, has been applied in previous works to approximately solve kernel learning problems when both of the above conditions are present. this work analyzes the application of this paradigm to kernel $ k $ - means clustering, and shows that applying the linear $ k $ - means clustering algorithm to $ \ frac { k } { \ epsilon } ( 1 + o ( 1 ) ) $ features constructed using a so - called rank - restricted nystr \ " om approximation results in cluster assignments that satisfy a $ 1 + \ epsilon $ approximation ratio in terms of the kernel $ k $ - means cost function, relative to the guarantee provided by the same algorithm without the use of the nystr \ " om method. as part of the analysis, this work establishes a novel $ 1 + \ epsilon $ relative - error trace norm guarantee for low - rank approximation using the rank - restricted nystr \ " om approximation. empirical evaluations on the $ 8. 1 $ million instance mnist8m dataset demonstrate the scalability and usefulness of kernel $ k $ - means clustering with nystr \ " om approximation. this work argues that spectral clustering using nystr \ " om approximation - - - a popular and computationally efficient, but theoretically unsound approach to non - linear clustering - - - should be replaced with the efficient and theoretically sound combination of kernel $ k $ - means clustering with nystr \ " om approximation. the superior performance of the latter approach is empirically verified.
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arxiv:1706.02803
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in this note, we investigate some regularity aspects for solutions of degenerate complex monge - amp \ ` ere equations ( dcmae ) on singular spaces. first, we study the dirichlet problem for dcmae on singular stein spaces, showing a general continuity result. a consequence of our results is that k \ " ahler - einstein potentials are continuous at isolated singularities. next, we establish the global continuity of solutions to dcmae when the reference class belongs to the real n \ ' eron - severi group. this yields in particular the continuity of k \ " ahler - einstein potentials on any irreducible calabi - yau variety.
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arxiv:2012.02018
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radial velocities of 40 intracluster planetary nebulae ( icpne ) in the virgo cluster were obtained with the new multi - fiber flames spectrograph on ut2 at vlt. for the first time, the lambda 4959 aa line of the [ oiii ] doublet is seen in a large fraction ( 50 % ) of icpne spectra, and a large fraction of the photometric candidates with m ( 5007 ) < \ = 27. 2 is spectroscopically confirmed. icpne with the velocity dispersion of the virgo cluster are found in our core field 1 deg from m87. these may have originated from tidal mass loss of smaller galaxies in the m87 subcluster halo. in a field 0. 25 deg from m87, we see an extended stellar halo of m87 in approximate dynamical equilibrium, but with few icpne. finally, in a field near m84 / m86, the icpne velocities are highly correlated with the galaxy velocities, showing that any well - mixed intracluster population is yet to form. overall, the measured velocity distributions confirm the non - uniform dynamical structure and on - going assembly of the virgo cluster. ( based on data collected with the flames spectrograph at the ut2 of the vlt at cerro paranal, chile, operated by eso, during observing run 71. b - 0147 ( a ) )
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arxiv:astro-ph/0502421
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we consider strong relative property $ ( t ) $ for pairs $ ( \ ga, g ) $ where $ \ ga $ acts on $ g $. if $ n $ is a connected lie group and $ \ ga $ is a group of automorphisms of $ n $, we choose a finite index subgroup $ \ ga ^ 0 $ of $ \ ga $ and obtain that $ ( \ ga, [ \ ga ^ 0, n ] ) $ has strong relative property $ ( t ) $ provided zariski - closure of $ \ ga $ has no compact factor of positive dimension. we apply this to obtain the following : $ g $ is a connected lie group with solvable radical $ r $ and a semisimple levi subgroup $ s $. if $ s _ { nc } $ denotes the product of noncompact simple factors of $ s $ and $ s _ t $ denotes the product of simple factors in $ s _ { nc } $ that have property $ ( t ) $, then we show that $ ( \ ga, r ) $ has strong relative property $ ( t ) $ for a zariski - dense closed subgroup of $ s _ { nc } $ if and only if $ r = [ s _ { nc }, r ] $. the case when $ n $ is a vector group is discussed separately and some interesting results are proved. we also considered actions on solenoids $ k $ and proved that if $ \ ga $ acts on a solenoid $ k $, then $ ( \ ga, k ) $ has strong relative property $ ( t ) $ under certain conditions on $ \ ga $. for actions on solenoids we provided some alternatives in terms of amenability and strong relative property $ ( t ) $. we also provide some applications to the spectral gap of $ \ pi ( \ mu ) = \ int \ pi ( g ) d \ mu ( g ) $ where $ \ pi $ is a certain unitary representation and $ \ mu $ is a probability measure.
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arxiv:1111.5148
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the recent embrace of machine learning ( ml ) in the development of autonomous weapons systems ( aws ) creates serious risks to geopolitical stability and the free exchange of ideas in ai research. this topic has received comparatively little attention of late compared to risks stemming from superintelligent artificial general intelligence ( agi ), but requires fewer assumptions about the course of technological development and is thus a nearer - future issue. ml is already enabling the substitution of aws for human soldiers in many battlefield roles, reducing the upfront human cost, and thus political cost, of waging offensive war. in the case of peer adversaries, this increases the likelihood of " low intensity " conflicts which risk escalation to broader warfare. in the case of non - peer adversaries, it reduces the domestic blowback to wars of aggression. this effect can occur regardless of other ethical issues around the use of military ai such as the risk of civilian casualties, and does not require any superhuman ai capabilities. further, the military value of aws raises the specter of an ai - powered arms race and the misguided imposition of national security restrictions on ai research. our goal in this paper is to raise awareness among the public and ml researchers on the near - future risks posed by full or near - full autonomy in military technology, and we provide regulatory suggestions to mitigate these risks. we call upon ai policy experts and the defense ai community in particular to embrace transparency and caution in their development and deployment of aws to avoid the negative effects on global stability and ai research that we highlight here.
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arxiv:2405.01859
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we re - examine the zero temperature phase diagram of the two - leg hubbard ladder in the small $ u $ limit, both analytically and using density - matrix renormalization group ( dmrg ). we find a ubiquitous luther - emery phase, but with a crossover in behavior at a characteristic interaction strength, $ u ^ \ star $ ; for $ u \ gtrsim u ^ \ star $, there is a single emergent correlation length $ \ log [ \ xi ] \ sim 1 / u $, characterizing the gapped modes of the system, but for $ u \ lesssim u ^ \ star $ there is a hierarchy of length scales, differing parametrically in powers of $ u $, reflecting a two - step renormalization group flow to the ultimate fixed point. finally, to illustrate the versatility of the approach developed here, we sketch its implications for a half - filled triangular lattice hubbard model on a cylinder, and find results in conflict with inferences concerning the small $ u $ phase from recent dmrg studies of the same problem.
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arxiv:2007.00661
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we present the results of both global cylindrical disc simulations and local shearing box simulations of protoplanets interacting with a disc undergoing mhd turbulence with zero net flux magnetic fields. we investigate the nature of the disc response and conditions for gap formation. this issue is an important one for determining the type and nature of the migration of the protoplanet, with the presence of a deep gap being believed to enable slower migration. for both types of simulation we find a common pattern of behaviour for which the main parameter determining the nature of the response is $ m _ p r ^ 3 / ( m _ * h ^ 3 ) $, with $ m _ p $, $ m _ * $, $ r $, and $ h $ being the protoplanet mass, the central mass, the orbital radius and the disc semi - thickness respectively. we find that as this parameter is increased towards 0. 1, the presence of the protoplanet is first indicated by the appearance of the well known trailing wake which, although it may appear erratic on account of the turbulence, appears to be well defined. once the above parameter exceeds a number around unity a gap starts to develop inside which the magnetic energy density tends to be concentrated in the high density wakes. this gap formation condition can be understood from simple dimensional considerations of the conditions for nonlinearity, and the balance of angular momentum transport due to maxwell and reynolds ' stresses with that due to tidal torques. an important result is that the basic flow morphology in the vicinity of the protoplanet is very similar in both the local and global simulations. this indicates that local shearing box simulations, which are computationally less demanding, capture much of the physics of disc - planet interaction. thus they may provide a useful tool for studying the local interaction between forming protoplanets and turbulent, protostellar discs.
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arxiv:astro-ph/0308351
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the eclipsing binary cm dra contains nearly identical red dwarfs of spectral class dm4. 5. their masses and radii have been reported with unprecedentedly small statistical errors. when compared with standard stellar models of appropriate age ( \ approx4 gyr ), the empirical results indicate that both components are larger in r, and lower in luminosity l, by several standard deviations. here, we attempt at first to model the components in the context of standard stellar models using differ
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arxiv:1106.1452
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summary. a simple derivation of finite schmidt decomposition of pure states describing finite dimensional systems interacting with the infinite dimensional ones is presented. in particular, maximally entangled pure states in such systems are being characterized. the concept of mixed - pure states has been introduced and some criterions for checking separability and entanglement of them are presented. the notion of locc equivalence and locc semi - order on the space of pure states of systems analyzed has been adopted suitably. in particular a nielsen - like theorem has been extended to the pure ( d, infinity ) - states case. the notion of spin - orbit entanglement in the context of atomic physics is being discussed from a mathematical perspective. keywords : quantum entanglement, schmidt decomposition, mixed - pure states, locc semi - order, spin - orbit entanglement
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arxiv:1803.09541
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in the context of ghost - free infinite derivative gravity, we consider the single graviton exchange between two spinless particles, a spinless particle and a photon, or between a spinless particle and a spin - 1 / 2 particle. to this end, we compute the gravitational potential for the three aforementioned cases and derive the $ \ mathcal { o } ( g \ hbar ^ 2 ) $ correction that arises at the linearised level. in the local theory, it is well - known that such a correction appears in the form of a dirac delta function. here, we show that this correction is smeared out for the nonlocal theory and, in contrast to the local theory, takes on non - zero values for a non - zero separation between the two particles. in the case of the single graviton exchange between a spinless particle and a spin - 1 / 2 particle, we also compute the $ \ mathcal { o } ( g \ hbar ) $ correction that arises in the non - static case within the non - relativistic approximation and show that it is finite in the nonlocal theory.
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arxiv:2402.18694
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in this paper, a new descriptor selection method for selecting an optimal combination of important descriptors of sulfonamide derivatives data, named self tuned reweighted sampling ( strs ), is developed. descriptors are defined as the descriptors with large absolute coefficients in a multivariate linear regression model such as partial least squares ( pls ). in this study, the absolute values of regression coefficients of pls model are used as an index for evaluating the importance of each descriptor then, based on the importance level of each descriptor, strs sequentially selects n subsets of descriptors from n monte carlo ( mc ) sampling runs in an iterative and competitive manner. in each sampling run, a fixed ratio ( e. g. 80 % ) of samples is first randomly selected to establish a regresson model. next, based on the regression coefficients, a two - step procedure including rapidly decreasing function ( rdf ) based enforced descriptor selection and self tuned sampling ( sts ) based competitive descriptor selection is adopted to select the important descriptorss. after running the loops, a number of subsets of descriptors are obtained and root mean squared error of cross validation ( rmsecv ) of pls models established with subsets of descriptors is computed. the subset of descriptors with the lowest rmsecv is considered as the optimal descriptor subset. the performance of the proposed algorithm is evaluated by sulfanomide derivative dataset. the results reveal an good characteristic of strs that it can usually locate an optimal combination of some important descriptors which are interpretable to the biologically of interest. additionally, our study shows that better prediction is obtained by strs when compared to full descriptor set pls modeling, monte carlo uninformative variable elimination ( mc - uve ).
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arxiv:1402.5360
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we suggest the possibility to disentangle anisotropic flow, flow fluctuation, and nonflow using two -, four -, and six - particle azimuthal moments assuming gaussian fluctuations. we show that such disentanglement is possible when the flow fluctuations are large, comparable to the average flow magnitude. when fluctuations are small, the disentanglement becomes difficult. we verify our results with a toy - model monte carlo simulation.
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arxiv:1101.4646
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center. another part of tech square, the privately owned centergy one complex, contains the technology square research building ( tsrb ), holding faculty and graduate student offices for the college of computing and the school of electrical and computer engineering, as well as the gvu center, a multidisciplinary technology research center. the advanced technology development center ( atdc ) is a science and business incubator, run by the georgia institute of technology, and is also headquartered in technology square ' s centergy one complex. other georgia tech - affiliated buildings in the area host the center for quality growth and regional development, the georgia tech enterprise innovation institute, the advanced technology development center, venturelab, the georgia electronics design center and the new coda ( mixed - use development ). technology square also hosts a variety of restaurants and businesses, including the headquarters of notable consulting companies like accenture and also including the official institute bookstore, a barnes & noble bookstore, and a georgia tech - themed waffle house. = = = science square = = = science square is a georgia tech mixed ‐ use development dedicated to life sciences and biomedical research. it is located southwest to georgia tech ’ s main campus, serving as a link between the institute and atlanta ’ s rapidly evolving westside community. opened in april 2024, the district spans 18 acres and features over 1. 8 million square feet of laboratory and office space, 500 residential units, and 25, 000 square feet of retail area. due to eventually be connected to the main campus by a pedestrian bridge, science square is the starting point for a multi - phase project designed to lure industry research partners closer to the campus. one of its central components is science square labs, a 13 - story tower designed to accommodate wet and dry laboratories for academia, industry, and startups. = = = satellite campuses = = = in 1999, georgia tech began offering local degree programs to engineering students in southeast georgia, and in 2003 established a physical campus in savannah, georgia. until 2013, georgia tech savannah offered undergraduate and graduate programs in engineering in conjunction with georgia southern university, south georgia college, armstrong atlantic state university, and savannah state university. the university further collaborated with the national university of singapore to set up the logistics institute – asia pacific in singapore. the campus now serves the institute ' s hub for professional and continuing education and is home to the regional offices of the georgia tech enterprise innovation institute, the savannah advanced technology development center, and the georgia logistics innovation center. georgia tech also operates a campus in metz, in northeastern
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https://en.wikipedia.org/wiki/Georgia_Tech
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state of the art models in intent induction require annotated datasets. however, annotating dialogues is time - consuming, laborious and expensive. in this work, we propose a completely unsupervised framework for intent induction within a dialogue. in addition, we show how pre - processing the dialogue corpora can improve results. finally, we show how to extract the dialogue flows of intentions by investigating the most common sequences. although we test our work in the multiwoz dataset, the fact that this framework requires no prior knowledge make it applicable to any possible use case, making it very relevant to real world customer support applications across industry.
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arxiv:2307.15410
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we explore a fermionic dark matter model with a possible extension of standard model ( sm ) of particle physics into two higgs doublet model. higgs doublets couple to the singlet fermionic dark matter ( fdm ) through a non renormalisable coupling providing a new physics scale. we explore the viability of such dark matter candidate and constrain the model parameter space by collider serach, relic density of dm, direct detection measurements of dm - nucleon scattreing cross - section and with the experimentally obtained results from indirect search of dark matter.
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arxiv:1311.0126
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despite recent advances in audio content - based music emotion recognition, a question that remains to be explored is whether an algorithm can reliably discern emotional or expressive qualities between different performances of the same piece. in the present work, we analyze several sets of features on their effectiveness in predicting arousal and valence of six different performances ( by six famous pianists ) of bach ' s well - tempered clavier book 1. these features include low - level acoustic features, score - based features, features extracted using a pre - trained emotion model, and mid - level perceptual features. we compare their predictive power by evaluating them on several experiments designed to test performance - wise or piece - wise variations of emotion. we find that mid - level features show significant contribution in performance - wise variation of both arousal and valence - - even better than the pre - trained emotion model. our findings add to the evidence of mid - level perceptual features being an important representation of musical attributes for several tasks - - specifically, in this case, for capturing the expressive aspects of music that manifest as perceived emotion of a musical performance.
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arxiv:2107.13231
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the ever - growing power consumption of wireless communication systems necessitates more energy - efficient algorithms. this paper introduces spikacom ( { spik } ing { a } daptive { com } munication ), a neuromorphic computing - based framework for power - intensive wireless communication tasks. spikacom leverages brain - inspired spiking neural networks ( snns ) for efficient signal processing. it is designed for dynamic wireless environments, helping to mitigate catastrophic forgetting and facilitate adaptation to new circumstances. moreover, spikacom is customizable, allowing flexibly integration of domain knowledge to enhance it interpretability and efficacy. we validate its performance on fundamental wireless communication tasks, including task - oriented semantic communication, multiple - input multiple - output ( mimo ) beamforming, and orthogonal frequency - division multiplexing ( ofdm ) channel estimation. the simulation results show that spikacom significantly reduces power consumption while matching or exceeding the performance of conventional algorithms. this study highlights the potential of snns for enabling greener and smarter wireless communication systems.
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arxiv:2502.17168
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spin - orbit coupled bose - einstein condensates ( becs ) provide a powerful tool to investigate interesting gauge - field related phenomena. we study the ground state properties of such a system and show that it can be mapped to the well - known dicke model in quantum optics, which describes the interactions between an ensemble of atoms and an optical field. a central prediction of the dicke model is a quantum phase transition between a superradiant phase and a normal phase. here we detect this transition in a spin - orbit coupled bec by measuring various physical quantities across the phase transition. these quantities include the spin polarization, the relative occupation of the nearly degenerate single particle states, the quantity analogous to the photon field occupation, and the period of a collective oscillation ( quadrupole mode ). the applicability of the dicke model to spin - orbit coupled becs may lead to interesting applications in quantum optics and quantum information science.
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arxiv:1405.2132
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moscab equipment, a geyser - concept bubble - chamber originally thought for the search of dark matter in the form of wimps, is employed for the detection of fast neutrons. once the background - free operating conditions are determined such that the detector is sensitive only to neutrons, which occurs when the neutron energy threshold required for nucleation is higher than approximately 2. 5 mev, the detector response to fast neutrons is investigated using an ambe neutron source. sets of detection efficiency functions are then produced via monte carlo simulations and post - processing, their validation being performed experimentally and discussed. finally, the use of the detector to measure the fast neutron activity of very weak n - sources in clean environments, as well as to monitor the cosmic ray variations through the neutron component of the extensive air showers, is considered.
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arxiv:2106.13654
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to go beyond quantum optics in free - space setups, atom - light interfaces with structured photonic environments are often employed to realize unconventional quantum electrodynamics ( qed ) phenomena. however, when employed as quantum buses, those long - distance nanostructures are limited by fabrication disorders. in this work, we alternatively propose to realize structured lightmatter interactions by engineering multiple coupling points of hybrid giant atom - conventionalenvironments without any periodic structure. we present a generic optimization method to obtain the real - space coupling sequence for multiple coupling points. we report a broadband chiral emission in a very wide frequency regime, with no analog in other quantum setups. moreover, we show that the qed phenomena in the band gap environment, such as fractional atomic decay and dipole - dipole interactions mediated by a bound state, can be observed in our setup. numerical results indicate that our proposal is robust against fabrication disorders of the coupling sequence. our work opens up a new route for realizing unconventional light - matter interactions.
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arxiv:2304.10710
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a model of correlated random networks is examined, i. e. networks with correlations between the degrees of neighboring nodes. these nodes do not necessarily have to be direct neighbors, the maximum range of the correlations can be arbitrarily chosen. two different methods for the creation of such networks are presented : one of them is a generalization of a well - known algorithm by maslov and sneppen. the percolation threshold for the model is calculated and the result is tested using analytically solvable examples and simulations. in the end the principal importance of correlations and clustering for the topology of networks is discussed. using a straight - forward extension of the network model by barabasi and albert, it is shown how a clustering - coefficient independent of the network size can originate in growing networks.
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arxiv:cond-mat/0509389
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in new higgs inflation the higgs kinetic terms are non - minimally coupled to the einstein tensor, allowing the higgs field to play the role of the inflaton. the new interaction is non - renormalizable, and the model only describes physics below some cutoff scale. even if the unknown uv physics does not affect the tree level inflaton potential significantly, it may still enter at loop level and modify the running of the standard model ( sm ) parameters. this is analogous to what happens in the original model for higgs inflation. a key difference, though, is that in new higgs inflation the inflationary predictions are sensitive to this running. thus the boundary conditions at the ew scale as well as the unknown uv completion may leave a signature on the inflationary parameters. however, this dependence can be evaded if the kinetic terms of the sm fermions and gauge fields are non - minimally coupled to gravity as well. our approach to determine the model ' s uv dependence and the connection between low and high scale physics can be used in any particle physics model of inflation.
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arxiv:1711.08761
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in automated pronunciation assessment, recent emphasis progressively lies on evaluating multiple aspects to provide enriched feedback. however, acquiring multi - aspect - score labeled data for non - native language learners ' speech poses challenges ; moreover, it often leads to score - imbalanced distributions. in this paper, we propose two acoustic feature mixup strategies, linearly and non - linearly interpolating with the in - batch averaged feature, to address data scarcity and score - label imbalances. primarily using goodness - of - pronunciation as an acoustic feature, we tailor mixup designs to suit pronunciation assessment. further, we integrate fine - grained error - rate features by comparing speech recognition results with the original answer phonemes, giving direct hints for mispronunciation. effective mixing of the acoustic features notably enhances overall scoring performances on the speechocean762 dataset, and detailed analysis highlights our potential to predict unseen distortions.
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arxiv:2406.15723
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larger space densities $ \ sim3 \ times 10 ^ { - 5 } $ mpc $ ^ { - 3 } $, higher duty cycles $ 50 - 100 \ % $, contributing more to the csfrd, and potentially dominating the high - mass galaxy stellar mass function.
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arxiv:1905.11996
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we consider determinantal point processes on the $ d $ - dimensional unit sphere $ \ mathbb s ^ d $. these are finite point processes exhibiting repulsiveness and with moment properties determined by a certain determinant whose entries are specified by a so - called kernel which we assume is a complex covariance function defined on $ \ mathbb s ^ d \ times \ mathbb s ^ d $. we review the appealing properties of such processes, including their specific moment properties, density expressions and simulation procedures. particularly, we characterize and construct isotropic dpps models on $ \ mathbb { s } ^ d $, where it becomes essential to specify the eigenvalues and eigenfunctions in a spectral representation for the kernel, and we figure out how repulsive isotropic dpps can be. moreover, we discuss the shortcomings of adapting existing models for isotropic covariance functions and consider strategies for developing new models, including a useful spectral approach.
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arxiv:1607.03675
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recently lhcb experimental group find an exotic state $ t ^ + _ { cc } $ from the process $ p \ bar { p } \ to d ^ 0d ^ 0 \ pi ^ + + x $. a key question is if it is just a molecule or may have confined tetraquark ingredient. to investigate this, different methods are taken, including two channel ( $ d ^ { * + } d ^ 0 $ and $ d ^ { * 0 } d ^ + $ ) k - matrix unitarization and single channel flatt \ ' e - like parametrization method analysed by pole counting rule and spectral density function sum rule. it demonstrates that $ t ^ + _ { cc } $ is a molecular state, though the possibility that there may exist elementary ingredient can not be excluded, by rough analysis on its production rate.
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arxiv:2307.12069
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the inclusive production of doubly heavy baryons $ \ xi _ { cc } $ and $ \ xi _ { bb } $ at $ \ gamma \ gamma $ collider is investigated. it is found that the contribution from the heavy quark pair $ qq $ in color triplet and color sextet are important.
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arxiv:hep-ph/0701212
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the strong coupling between elementary excitations of the electromagnetic field ( photons ) and quantized mechanical vibrations ( phonons ) produces hybrid quasi - particle states, known as phonon - polaritons. their typical signature is the avoided crossing between the eigenfrequencies of the coupled system, as paradigmatically illustrated by the jaynes - cummings hamiltonian, and observed in quantum electrodynamics experiments where cavity photons are coupled to atoms, ions, excitons, spin ensambles and superconducting qubits. in this work, we demonstrate the generation of phonon - polaritons in the quantum motion of an optically - levitated nanosphere. the particle is trapped in high vacuum by an optical tweezer and strongly coupled to a single cavity mode by coherent scattering of the tweezer photons. the two - dimensional motion splits into two nearly - degenerate components that, together with the optical cavity mode, define an optomechanical system with three degrees - of - freedom. as such, when entering the strong coupling regime, we observe hybrid light - mechanical states with a dispersion law typical of tripartite quantum systems. remarkably, the independent components of motion here identify a physical vibration direction on a plane that, similarly to the polarization of light, confers a vectorial nature to the polariton field. our results pave the way to novel protocols for quantum information transfer between photonic and phononic components and represent a key - step towards the demonstration of optomechanical entangled states at room temperature.
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arxiv:2012.15265
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previous work on voter control, which refers to situations where a chair seeks to change the outcome of an election by deleting, adding, or partitioning voters, takes for granted that the chair knows all the voters ' preferences and that all votes are cast simultaneously. however, elections are often held sequentially and the chair thus knows only the previously cast votes and not the future ones, yet needs to decide instantaneously which control action to take. we introduce a framework that models online voter control in sequential elections. we show that the related problems can be much harder than in the standard ( non - online ) case : for certain election systems, even with efficient winner problems, online control by deleting, adding, or partitioning voters is pspace - complete, even if there are only two candidates. in addition, we obtain ( by a new characterization of conp in terms of weight - bounded alternating turing machines ) completeness for conp in the deleting / adding cases with a bounded deletion / addition limit, and we obtain completeness for np in the partition cases with an additional restriction. we also show that for plurality, online control by deleting or adding voters is in p, and for partitioning voters is conp - hard.
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arxiv:1203.0411
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we consider a vector bundle $ e $ over a compact riemannian manifold $ m $ = $ m ^ { n } $, $ n \ geq 4 $, and $ a $ is a yang - mills connection with $ l ^ { \ frac { n } { 2 } } $ curvature $ f _ { a } $ on $ e $. then we prove a mean value inequality for the density $ | f _ { a } | ^ { \ frac { n } { 2 } } $. this inequality give rise to an energy concentrate principle for sequences of solutions that have bounded energy. we also proof that the energy must be bounded from below by some positive constant unless $ e $ is a flat bundle.
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arxiv:1502.03198
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we consider a network of randomly coupled rate - based neurons influenced by external and internal noise. we derive a second - order stochastic mean - field model for the network dynamics and use it to analyze the stability and bifurcations in the thermodynamic limit, as well as to study the fluctuations due to the finite - size effect. it is demonstrated that the two types of noise have substantially different impact on the network dynamics. while both sources of noise give rise to stochastic fluctuations in the case of the finite - size network, only the external noise affects the stationary activity levels of the network in the thermodynamic limit. we compare the theoretical predictions with the direct simulation results and show that they agree for large enough network sizes and for parameter domains sufficiently away from bifurcations.
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arxiv:1512.03561
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erd \ " os proved in 1946 that if a set $ e \ subset \ mathbb { r } ^ n $ is closed and non - empty, then the set, called ambiguous locus or medial axis, of points in $ \ mathbb { r } ^ n $ with the property that the nearest point in $ e $ is not unique, can be covered by countably many surfaces, each of finite $ ( n - 1 ) $ - dimensional measure. we improve the result by obtaining a new regularity result for these surfaces in terms of convexity and $ c ^ 2 $ regularity.
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arxiv:2011.14508
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we study ultra - violet completions for d = 6 four - fermion operators in the standard model effective field theory ( smeft ), focusing on models that contain cold dark matter candidates. via a diagrammatic method, we generate systematically lists of possible uv completions, with the aim of providing sets of models, which are complete under certain, well specified assumptions. within these lists of models we rediscover many known dm models, as diverse as r - parity conserving supersymmetry or the scotogenic neutrino mass model. our lists, however, also contain many new constructions, which have not been studied in the literature so far. we also briefly discuss how our dm models could be constrained by reinterpretations of lhc searches and the prospects for hl - lhc and future lepton colliders.
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arxiv:2302.03485
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learning with noisy labels ( lnl ) has become an appealing topic, as imperfectly annotated data are relatively cheaper to obtain. recent state - of - the - art approaches employ specific selection mechanisms to separate clean and noisy samples and then apply semi - supervised learning ( ssl ) techniques for improved performance. however, the selection step mostly provides a medium - sized and decent - enough clean subset, which overlooks a rich set of clean samples. to fulfill this, we propose a novel lnl framework promix that attempts to maximize the utility of clean samples for boosted performance. key to our method, we propose a matched high confidence selection technique that selects those examples with high confidence scores and matched predictions with given labels to dynamically expand a base clean sample set. to overcome the potential side effect of excessive clean set selection procedure, we further devise a novel ssl framework that is able to train balanced and unbiased classifiers on the separated clean and noisy samples. extensive experiments demonstrate that promix significantly advances the current state - of - the - art results on multiple benchmarks with different types and levels of noise. it achieves an average improvement of 2. 48 \ % on the cifar - n dataset. the code is available at https : / / github. com / justherozen / promix
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arxiv:2207.10276
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altermagnetism is an emerging series of unconventional magnetic materials characterized by time - reversal symmetry breaking and spin - split bands in the momentum space with zero net magnetization. metallic altermagnets offer unique advantages for exploring applications in spintronics as conductive metals allows for serving as electrode in magnetic tunneling junction ( mtj ) and / or manipulation of spincurrent through external field. through density functional theory calculations, the 2d altermagnet cr4b3n was predicted to be stable, resulting from a n atom substitution in the fese - like crb bilayer. both intra - and inter - layered magnetic exchanges between cr atoms are in antiferromagnetic with the first three neighbours. leveraging the anisotropic spin - splittings with momentum dependency revealed in band structure, we designed three edge dependent cr4b3n / square / cr4b3n in - plane mtjs with the 7 \ aa vaccume the barrie. we found that the cr - b vertical edge - assembled electrodes based mtjs exhibited giant tunneling magnetoresistance ( tmr ) ratios of 91001 %, by aligning the conduction channels of the electrodes in parallel and anti - parallel states in the momentum space. our work deepens and generalizes understanding toward altermagnetic 2d metallic electrode with a newly established metal boride ( mbene ), and broadens applications of the nanoscale spintronics.
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arxiv:2502.03165
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determination of the neutrino mass hierarchy using a reactor neutrino experiment at $ \ sim $ 60 km is analyzed. such a measurement is challenging due to the finite detector resolution, the absolute energy scale calibration, as well as the degeneracies caused by current experimental uncertainty of $ | \ delta m ^ 2 _ { 32 } | $. the standard $ \ chi ^ 2 $ method is compared with a proposed fourier transformation method. in addition, we show that for such a measurement to succeed, one must understand the non - linearity of the detector energy scale at the level of a few tenths of percent.
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arxiv:1208.1551
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in - bulk processing of materials by laser radiation has largely evolved over the last decades and still opensup new scientific and industrial potentials. the development of any in - bulk processing application relieson the knowledge of laser propagation and especially the volumetric field distribution near the focus. many commercial programs can simulate this, but, in order to adapt them, or to develop new methods, one usually needs to create a specific software. besides, most of the time people also need to measurethe actual field distribution near the focus to evaluate their assumptions in the simulation. to easily get access to this knowledge, we present our high - precision field distribution measuring method and release our in - house software infocus, under the creative commons 4. 0 license. our measurementsprovide 300 - nm longitudinal resolution and diffraction limited lateral resolution. the in - house softwareallows fast vectorial analysis of the focused volumetric field distribution in the bulk. the simulationsof light propagation under different conditions ( focusing optics, wavelength, spatial shape, propagationmedium ) are in excellent agreement with propagation imaging experiments. the aberrations provoked by the refractive index mismatch as well as those induced by the focusing optics are both taken into account. the results indicate that our proposed model is suitable for the precise evaluation of energy deposition
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arxiv:2102.13414
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an explicit relativistic light - front quark model is presented which gives the momentum transfer dependent form factors of weak hadronic currents among heavy pseudoscalar and vector mesons in the whole accessible kinematic region $ 0 \ leq q ^ 2 \ leq q ^ 2 _ { max } $. for the numerical investigations of the $ b \ to d ^ * l \ nu _ l $, $ b \ to \ rho l \ nu _ l $, $ d \ to k ^ * l \ nu _ l $ and $ d \ to \ rho l \ nu _ l $ semileptonic decays the equal time wave functions corresponding to the updated version of the isgw model are adopted. using the available experimental information on branching fractions $ br ( b \ to d ^ * l \ nu _ l ) $ and $ br ( b \ to \ rho l \ nu _ l ) $ the ckm parameters $ v _ { cb } $ and $ v _ { ub } $ were estimated : $ | v _ { cb } | = 0. 036 \ pm 0. 004 $, $ | v _ { ub } | = 0. 0033 \ pm 0. 0004 $. the model is further tested by comparison with experimental data, qcd sum rules and lattice calculations.
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arxiv:hep-ph/9701388
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we study maurer - cartan moduli spaces of dg algebras and associated dg categories and show that, while not quasi - isomorphism invariants, they are invariants of strong homotopy type, a natural notion that has not been studied before. we prove, in several different contexts, schlessinger - stasheff type theorems comparing the notions of homotopy and gauge equivalence for maurer - cartan elements as well as their categorified versions. as an application, we re - prove and generalize block - smith ' s higher riemann - hilbert correspondence, and develop its analogue for simplicial complexes and topological spaces.
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arxiv:1802.02549
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this is an informal discussion on one of the basic problems in the theory of empirical processes, addressed in our preprint " combinatorics of random processes and sections of convex bodies ", which is available at arxiv and from our web pages.
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arxiv:math/0404193
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we examine the coupling of electromagnetic waves incident normal to a thin silver film that forms an oscillatory grating embedded between two otherwise uniform, semi - infinite half spaces. two grating structures are considered, in one of which the mid point of the ag film remains fixed whereas the thickness varies sinusoidally, while in the other the mid point oscillates sinusoidally whereas the film thicknesses remains fixed. on reducing the light wavelength from the long wavelength limit, we encounter signatures in the transmission, t, and reflection, r, coefficients associated with : i ) the short - range surface plasmon mode, ii ) the long - range surface plasmon mode, and iii ) electromagnetic diffraction tangent to the grating. the first two features can be regarded as generalized ( plasmon ) wood ' s anomalies whereas the third is the first - order conventional ( electromagnetic ) wood ' s anomaly. the energy density at the film surface is enhanced for wavelengths corresponding to these three anomalies, particularly for the long range plasmon mode in thin films. when exciting the silver film with a pair of waves incident from opposite directions, we find that by adjusting the grating oscillation amplitude and fixing the relative phase of the incoming waves to be even or odd, t + r can be made to vanish for one or the other of the plasmon modes ; this corresponds to perfect coupling ( impedance matching in the language of electrical engineering ) between the incoming light and these modes.
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arxiv:0808.1941
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large language models ( llms ) increasingly serve as knowledge interfaces, yet systematically assessing their reliability with conflicting information remains difficult. we propose an rdf - based framework to assess multilingual llm quality, focusing on knowledge conflicts. our approach captures model responses across four distinct context conditions ( complete, incomplete, conflicting, and no - context information ) in german and english. this structured representation enables the comprehensive analysis of knowledge leakage - where models favor training data over provided context - error detection, and multilingual consistency. we demonstrate the framework through a fire safety domain experiment, revealing critical patterns in context prioritization and language - specific performance, and demonstrating that our vocabulary was sufficient to express every assessment facet encountered in the 28 - question study.
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arxiv:2504.21605
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we prove that random groups in the gromov density model at any density $ d $ have with overwhelming probability no non - trivial left - orderable quotients. in particular, random groups at densities $ d < \ frac { 1 } { 2 } $ are not left - orderable.
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arxiv:1409.1289
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the contact of water with semiconductors typically changes its surface electronic structure by oxidation or corrosion processes. a detailed knowledge - or even control of - the surface structure is highly desirable, as it impacts the performance of opto - electronic devices from gas - sensing to energy conversion applications. it is also a prerequisite for density functional theory - based modelling of the electronic structure in contact with an electrolyte. the p - rich gap ( 100 ) surface is extraordinary with respect to its contact with gas - phase water, as it undergoes a surface reordering, but does not oxidise. we investigate the underlying changes of the surface in contact with water by means of theoretically derived reflection anisotropy spectroscopy ( ras ). a comparison of our results with experiment reveals that a water - induced hydrogen - rich phase on the surface is compatible with the boundary conditions from experiment, reproducing the optical spectra. we discuss potential reaction paths that comprise a water - enhanced hydrogen mobility on the surface. our results also show that computational ras - required for the interpretation of experimental signatures - is feasible for gap in contact with water double layers. here, ras is sensitive to surface electric fields, which are an important ingredient of the helmholtz - layer. this paves the way for future investigations of ras at the semiconductor - electrolyte interface.
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arxiv:1710.08194
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the plebanski - demianski metric is commonly thought to describe the most general type d black hole in general relativity ( possibly coupled with maxwell electromagnetism ), but in the form we know at the moment, it fails to include the elusive accelerating spacetimes with gravitomagnetic mass without angular momentum. we propose a very general type d metric, stemming from a binary black hole system, which represents a novel branch of the type d spacetimes : accelerating kerr - newman - nut black hole with cosmological constant. it has straightforward limits to all the known type d black holes in the einstein - maxwell theory and in particular to the accelerating reissner - nordstrom - nut solution, yet unknown in the literature.
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arxiv:2404.06551
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this review explores the dynamics and the low - energy excitation spectra of bose - einstein condensates ( becs ) of interacting bosons in external potential traps putting particular emphasis on the emerging many - body effects beyond mean - field descriptions. to do so, methods have to be used that, in principle, can provide numerically exact results for both the dynamics and the excitation spectra in a systematic manner. numerically exact results for the dynamics are presented employing the well - established multicongurational time - dependent hartree for bosons ( mctdhb ) method. the respective excitation spectra are calculated utilizing the more recently introduced linear - response theory atop it ( lr - mctdhb ). the latter theory gives rise to an, in general, non - hermitian eigenvalue problem. the theory and its newly developed implementation are described in detail and benchmarked towards the exactly - solvable harmonic - interaction model. several applications to becs in one - and two - dimensional potential traps are discussed. with respect to dynamics, it is shown that both the out - of - equilibrium tunneling dynamics and the dynamics of trapped vortices are of many - body nature. furthermore, many - body effects in the excitation spectra are presented for becs in different trap geometries. it is demonstrated that even for essentially - condensed systems, the spectrum of the lowest - in - energy excitations computed at the many - body level can differ substantially from the standard mean - field description. in general, it is shown that bosons carrying angular momentum are more sensitive to many - body effects than bosons without. these effects are present in both the dynamics and the excitation spectrum.
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arxiv:2101.11615
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text classification has been one of the earliest problems in nlp. over time the scope of application areas has broadened and the difficulty of dealing with new areas ( e. g., noisy social media content ) has increased. the problem - solving strategy switched from classical machine learning to deep learning algorithms. one of the recent deep neural network architecture is the transformer. models designed with this type of network and its variants recently showed their success in many downstream natural language processing tasks, especially for resource - rich languages, e. g., english. however, these models have not been explored fully for bangla text classification tasks. in this work, we fine - tune multilingual transformer models for bangla text classification tasks in different domains, including sentiment analysis, emotion detection, news categorization, and authorship attribution. we obtain the state of the art results on six benchmark datasets, improving upon the previous results by 5 - 29 % accuracy across different tasks.
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arxiv:2011.04446
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in theories with a warped extra dimension, composite fermions, as e. g. the right - handed top quark, can be very strongly coupled to kaluza - klein ( kk ) fields. in particular, the kk gluons in the presence of such composite fields become very broad resonances, thus remarkably modifying their experimental signatures. we have computed the pole mass and the pole width of the kk gluon, triggered by its interaction with quarks, as well as the prediction for proton - proton cross - sections using the full propagator and compared it with that obtained from the usual breit - wigner approximation. we compare both approaches, along with the existing experimental data from atlas and cms, for the $ t \ bar t $, $ t \ bar t w $, $ t \ bar t z $, $ t \ bar t h $, and $ t \ bar t t \ bar t $ channels. we have found differences between the two approaches of up to about 100 %, highlighting that the effect of broad resonances can be dramatic on present, and mainly future, experimental searches. the channel $ t \ bar t t \ bar t $ is particularly promising because the size of the cross - section signal is of the same order of magnitude as the standard model prediction, and future experimental analyses in this channel, especially for broad resonances, can shed light on the nature of possible physics beyond the standard model.
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arxiv:2102.11241
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we consider the vlasov - poisson system with initial data a small, radial, absolutely continuous perturbation of a point charge. we show that the solution is global and disperses to infinity via a modified scattering along trajectories of the linearized flow. this is done by an exact integration of the linearized equation, followed by the analysis of the perturbed hamiltonian equation in action - angle coordinates.
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arxiv:2008.08013
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understanding the properties of hypernuclei is crucial for constraining the nature of hyperon - nucleon ( $ y \ text { - } n $ ) interactions, which plays a key role in determining the inner structure of compact stars. the lightest hypernuclei and antihypernuclei are the hypertriton ( $ ^ 3 _ \ lambda \ text { h } $ ), which consists of a pair of nucleons and a $ \ lambda $ hyperon, and its antinucleus ( $ { ^ 3 _ { \ bar { \ lambda } } } \ overline { \ rm h } $ ). significant knowledge has recently been acquired regarding the mass, lifetime, and binding energy of $ ^ 3 _ \ lambda \ text { h } $. however, its exact spin, whether $ \ frac { 1 } { 2 } $ or $ \ frac { 3 } { 2 } $, remains undetermined in both experimental and theoretical studies. here, we present a novel method of using the hypertriton global polarization in heavy - ion collisions to decipher not only its total spin but also its internal spin structure. this method is based on the finding that its three different spin structures exhibit distinct beam energy dependence of its global polarization when it is produced in these collisions from the coalescence of proton, neutron and $ \ lambda $. future observations of the hypertriton and antihypertriton global polarizations thus provide the opportunity to unveil the spin structures of hypertriton and antihypertriton and their production mechanisms in heavy - ion collisions.
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arxiv:2405.12015
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financial engineering is a multidisciplinary field involving financial theory, methods of engineering, tools of mathematics and the practice of programming. it has also been defined as the application of technical methods, especially from mathematical finance and computational finance, in the practice of finance. financial engineering plays a key role in a bank ' s customer - driven derivatives business — delivering bespoke otc - contracts and " exotics ", and implementing various structured products — which encompasses quantitative modelling, quantitative programming and risk managing financial products in compliance with the regulations and basel capital / liquidity requirements. an older use of the term " financial engineering " that is less common today is aggressive restructuring of corporate balance sheets. mathematical finance is the application of mathematics to finance. computational finance and mathematical finance are both subfields of financial engineering. computational finance is a field in computer science and deals with the data and algorithms that arise in financial modeling. = = discipline = = financial engineering draws on tools from applied mathematics, computer science, statistics and economic theory. in the broadest sense, anyone who uses technical tools in finance could be called a financial engineer, for example any computer programmer in a bank or any statistician in a government economic bureau. however, most practitioners restrict the term to someone educated in the full range of tools of modern finance and whose work is informed by financial theory. it is sometimes restricted even further, to cover only those originating new financial products and strategies. despite its name, financial engineering does not belong to any of the fields in traditional professional engineering even though many financial engineers have studied engineering beforehand and many universities offering a postgraduate degree in this field require applicants to have a background in engineering as well. in the united states, the accreditation board for engineering and technology ( abet ) does not accredit financial engineering degrees. in the united states, financial engineering programs are accredited by the international association of quantitative finance. quantitative analyst ( " quant " ) is a broad term that covers any person who uses math for practical purposes, including financial engineers. quant is often taken to mean " financial quant ", in which case it is similar to financial engineer. the difference is that it is possible to be a theoretical quant, or a quant in only one specialized niche in finance, while " financial engineer " usually implies a practitioner with broad expertise. " rocket scientist " ( aerospace engineer ) is an older term, first coined in the development of rockets in wwii ( wernher von braun ), and later, the nasa space program ; it was adapted by the
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https://en.wikipedia.org/wiki/Financial_engineering
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astri ( " astrofisica con specchi a tecnologia replicante italiana " ) is a flagship project of the italian ministry of education, university and research. within this framework, inaf is currently developing a wide field of view ( 9. 6 degrees in diameter ) end - to - end prototype of the cta small - size telescope ( sst ), devoted to the investigation of the energy range from a fraction of tev up to tens of tevs, and scheduled to start data acquisition in 2014. for the first time, a dual - mirror schwarzschild - couder optical design will be adopted on a cherenkov telescope, in order to obtain a compact optical configuration. a second challenging, but innovative technical solution consists of a modular focal surface camera based on silicon photo - multipliers with a logical pixel size of 6. 2mm x 6. 2mm. here we describe the current status of the project, the expected performance, and its possible evolution in terms of an sst mini - array. this cta - sst precursor, composed of a few ssts and developed in collaboration with cta international partners, could not only peruse the technological solutions adopted by astri, but also address a few scientific test cases that are discussed in detail.
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arxiv:1303.2024
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air - intake opening, fuel injection and auto - ignition. after sustaining hypersonic combustion for 20 seconds, cruise vehicle achieved velocity of nearly 2 km / s ( mach 5. 9 ). a ship was also deployed in the bay of bengal to study the missile trajectory. the missile ' s scramjet engine performed in a " text book manner. " this test flight validated aerodynamic configuration of vehicle, ignition and sustained combustion of scramjet engine at hypersonic flow, separation mechanisms and characterised thermo - structural materials. the hstdv is set to serve as the building block for next - generation hypersonic cruise missiles. = = = scramjet testing = = = = = gallery = = = = see also = = boeing x - 51 brahmos - ii hgv - 202f = = references = = = = external links = = hypersonic flight and ground testing activities in india media related to drdo hypersonic technology demonstrator vehicle at wikimedia commons
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https://en.wikipedia.org/wiki/Hypersonic_Technology_Demonstrator_Vehicle
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for a fixed prime p, the p - class tower f ( p, infinity, k ) of a number field k is considered to be known if a pro - p presentation of the galois group h = gal ( f ( p, infinity, k ) / k ) is given. in the last few years, it turned out that the artin pattern ap ( k ) = ( tau ( k ), kappa ( k ) ) consisting of targets tau ( k ) = ( cl ( p, l ) ) and kernels kappa ( k ) = ( ker ( j ( l / k ) ) of class extensions j ( l / k ) : cl ( p, k ) - - > cl ( p, l ) to unramified abelian subfields l / k of the hilbert p - class field f ( p, 1, k ) only suffices for determining the two - stage approximation g = h / h " of h. additional techniques had to be developed for identifying the group h itself : searching strategies in descendant trees of finite p - groups, iterated and multilayered ipads of second order, and the cohomological concept of shafarevich covers involving relation ranks. this enabled the discovery of three - stage towers of p - class fields over quadratic base fields k = q ( squareroot ( d ) ) for p = 2, 3, 5. these non - metabelian towers reveal the new phenomenon of various tree topologies expressing the mutual location of the groups h and g.
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arxiv:1605.09617
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cybercrime investigators face numerous challenges when policing online crimes. firstly, the methods and processes they use when dealing with traditional crimes do not necessarily apply in the cyber - world. additionally, cyber criminals are usually technologically - aware and constantly adapting and developing new tools that allow them to stay ahead of law enforcement investigations. in order to provide adequate support for cybercrime investigators, there needs to be a better understanding of the challenges they face at both technical and socio - technical levels. in this paper, we investigate this problem through an analysis of current practices and workflows of investigators. we use interviews with experts from government and private sectors who investigate cybercrimes as our main data gathering process. from an analysis of the collected data, we identify several outstanding challenges faced by investigators. these pertain to practical, technical, and social issues such as systems availability, usability, and in computer - supported collaborative work. importantly, we use our findings to highlight research areas where user - centric workflows and tools are desirable. we also define a set of recommendations that can aid in providing a better foundation for future research in the field and allow more effective combating of cybercrimes.
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arxiv:1902.06961
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we present deep 350 - and 1200 - micron imaging of the region around 4c41. 17 - - one of the most distant ( z = 3. 792 ) and luminous known radio galaxies - - obtained with the submillimeter high angular resolution camera ( sharc - ii ) and the max planck millimeter bolometer array ( mambo ). the radio galaxy is robustly detected at 350 - and 1200 - micron, as are two nearby 850 - micron - selected galaxies ; a third 850 - micron source is detected at 350 - micron and coincides with a ~ 2 - sigma feature in the 1200 - micron map. further away from the radio galaxy an additional nine sources are detected at 1200 - micron, bringing the total number of detected ( sub ) millimeter selected galaxies ( smgs ) in this field to 14. using radio images from the very large array ( vla ) and spitzer mid - infrared ( mid - ir ) data, we find statistically robust radio and / or 24 - micron counterparts to eight of the 14 smgs in the field around 4c41. 17. follow - up spectroscopy with keck / lris has yielded redshifts for three of the eight robustly identified smgs, placing them in the redshift range 0. 5 < z < 2. 7, i. e. well below that of 4c41. 17. we infer photometric redshifts for a further four sources using their 1. 6 - micron ( rest - frame ) stellar feature as probed by the irac bands ; only one of them is likely to be at the same redshift as 4c41. 17. thus at least four, and as many as seven, of the smgs within the 4c41. 17 field are physically unrelated to the radio galaxy. with the redshift information at hand we are able to constrain the observed over - densities of smgs within radial bins stretching to r = 50 and 100 " ( ~ 0. 4 and ~ 0. 8mpc at z ~ 3. 8 ) from the radio galaxy to ~ 5x and ~ 2x that of the field, dropping off to the background value at r = 150 ". [ abridged ]
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arxiv:0707.4482
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to understand the underlying degrees of freedom, near horizon symmetry analysis of a black has gain significant interest in the recent past. in this paper we generalized those analysis first by taking into account a generic null surface carrying $ u ( 1 ) $ electromagnetic charge. with the appropriate boundary conditions near the surface under study, we identified the symmetry algebra among the subset of diffeomporphism and gauge generators which preserve the metric of the null surface and the form of the gauge field configuration. with the knowledge of those symmetries we further derived the algebra among the associated charges considering general lanczos - lovelock gravity theory and gauge theory. importantly while computing the charges we not only considered general theory, but also used off - shell formalism which is believed to play crucial role in understanding quantum gravity. both the non - extremal and extremal cases are addressed here.
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arxiv:1802.07108
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we study the furstenberg - entropy realization problem for stationary actions. it is shown that for finitely supported probability measures on free groups, any a - priori possible entropy value can be realized as the entropy of an ergodic stationary action. this generalizes results of bowen. the stationary actions we construct arise via invariant random subgroups ( irss ), based on ideas of bowen and kaimanovich. we provide a general framework for constructing a continuum of ergodic irss for a discrete group under some algebraic conditions, which gives a continuum of entropy values. our tools apply for example, for certain extensions of the group of finitely supported permutations and lamplighter groups, hence establishing full realization results for these groups. for the free group, we construct the irss via a geometric construction of subgroups, by describing their schreier graphs. the analysis of the entropy of these spaces is obtained by studying the random walk on the appropriate schreier graphs.
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arxiv:1701.08350
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we consider the $ m $ - dimensional modified helmholtz equation and establish two relations between its solutions in a bounded domain and harmonic functions. both relations essentially rely on properties of the newtonian potential. some other characteristics of these solutions are also obtained.
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arxiv:2207.11729
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by using the york canonical basis of adm tetrad gravity, in a formulation using radar 4 - coordinates for the parametrization of the 3 + 1 splitting of the space - time, it is possible to write the 4 - riemann tensor of a globally hyperbolic, asymptotically minkowskian space - time as a hamiltonian tensor, whose components are 4 - scalars with respect to the ordinary world 4 - coordinates, plus terms vanishing due to einstein ' s equations. therefore " on - shell " we find the expression of the hamiltonian 4 - riemann tensor. moreover, the 3 + 1 splitting of the space - time used to define the phase space allows us to introduce a hamiltonian set of null tetrads and to find the hamiltonian expression of the 4 - ricci scalars of the newman - penrose formalism. this material will be used in the second paper to study the 4 - weyl tensor, the 4 - weyl scalars and the four weyl eigenvalues and to clarify the notions of dirac and bergmann observables.
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arxiv:1401.1370
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the na62 experiment at cern collected a large sample of charged kaon decays with a highly efficient trigger for decays into electrons in 2007. the kaon beam represents a source of tagged neutral pion decays in vacuum. a measurement of the electromagnetic transition form factor slope of the neutral pion in the time - like region from $ 1. 05 \ times10 ^ 6 $ fully reconstructed $ \ pi ^ 0 $ dalitz decay is presented. the limits on dark photon production in $ \ pi ^ 0 $ decays from the earlier kaon experiment at cern, na48 / 2, are also reported.
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arxiv:1611.04972
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in this paper we have analyzed the production of pair charmonium mesons in the reactions $ e ^ + e ^ - \ to j / \ psi \ chi _ { c0 }, e ^ + e ^ - \ to \ psi ( 2s ) \ chi _ { c0 } $ at energy $ \ sqrt s = 10. 6 $ gev in the framework of the light cone formalism. in comparison with nrqcd the numerical results for the cross sections are in better agreement with experiment.
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arxiv:hep-ph/0602047
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this study focuses on the impact of digital finance on households. while digital finance has brought financial inclusion, it has also increased the risk of households falling into a debt trap. we provide evidence that supports this notion and explain the channel through which digital finance increases the likelihood of financial distress. our results show that the widespread use of digital finance increases credit market participation. the broadened access to credit markets increases household consumption by changing the marginal propensity to consume. however, the easier access to credit markets also increases the risk of households falling into a debt trap.
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arxiv:2201.09221
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the gillespie algorithm is commonly used to simulate and analyze complex chemical reaction networks. here, we leverage recent breakthroughs in deep learning to develop a fully differentiable variant of the gillespie algorithm. the differentiable gillespie algorithm ( dga ) approximates discontinuous operations in the exact gillespie algorithm using smooth functions, allowing for the calculation of gradients using backpropagation. the dga can be used to quickly and accurately learn kinetic parameters using gradient descent and design biochemical networks with desired properties. as an illustration, we apply the dga to study stochastic models of gene promoters. we show that the dga can be used to : ( i ) successfully learn kinetic parameters from experimental measurements of mrna expression levels from two distinct $ \ textit { e. coli } $ promoters and ( ii ) design nonequilibrium promoter architectures with desired input - output relationships. these examples illustrate the utility of the dga for analyzing stochastic chemical kinetics, including a wide variety of problems of interest to synthetic and systems biology.
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arxiv:2407.04865
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novae are the observational manifestations of thermonuclear runaways on the surface of accreting white dwarfs ( wds ). although novae are an ubiquitous phenomenon, their properties at low metallicity are not well understood. using the publicly - available stellar evolution code modules for experiments in stellar astrophysics ( mesa ), we model the evolution of accreting carbon - oxygen wds and consider models which accrete matter with metallicity z = 0. 02 or $ 10 ^ { - 4 } $. we consider both models without mixing and with matter enriched by co - elements assuming that mixing occurs in the process of accretion ( with mixing fraction 0. 25 ). we present and contrast ignition mass, ejected mass, recurrence period and maximum luminosity of novae for different wd masses and accretion rates for these metallicities and mixing cases. we find that models with z = 0. 02 have ignition masses and recurrence periods smaller than models with low z, while the ejected mass and maximum luminosity are larger. retention efficiency during novae outbursts decreases with increasing metallicity. in our implementation, inclusion of mixing at the h / he interface reduces accreted mass, ejected mass and recurrence period as compared to the no - mixing case, while the maximum luminosity becomes larger. retention efficiency is significantly reduced, becoming negative in most of our models. for ease of use, we provide a tabular summary of our results.
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arxiv:1909.07643
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a significant amount of work is invested in human - machine teaming ( hmt ) across multiple fields. accurately and effectively measuring system performance of an hmt is crucial for moving the design of these systems forward. metrics are the enabling tools to devise a benchmark in any system and serve as an evaluation platform for assessing the performance, along with the verification and validation, of a system. currently, there is no agreed - upon set of benchmark metrics for developing hmt systems. therefore, identification and classification of common metrics are imperative to create a benchmark in the hmt field. the key focus of this review is to conduct a detailed survey aimed at identification of metrics employed in different segments of hmt and to determine the common metrics that can be used in the future to benchmark hmts. we have organized this review as follows : identification of metrics used in hmts until now, and classification based on functionality and measuring techniques. additionally, we have also attempted to analyze all the identified metrics in detail while classifying them as theoretical, applied, real - time, non - real - time, measurable, and observable metrics. we conclude this review with a detailed analysis of the identified common metrics along with their usage to benchmark hmts.
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arxiv:2008.04855
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let $ ( \ { 1, 2, \ ldots, n \ }, d ) $ be a metric space. we analyze the expected value and the variance of $ \ sum _ { i = 1 } ^ { \ lfloor n / 2 \ rfloor } \, d ( { \ boldsymbol { \ pi } } ( 2i - 1 ), { \ boldsymbol { \ pi } } ( 2i ) ) $ for a uniformly random permutation $ { \ boldsymbol { \ pi } } $ of $ \ { 1, 2, \ ldots, n \ } $, leading to the following results : ( i ) consider the problem of finding a point in $ \ { 1, 2, \ ldots, n \ } $ with the minimum sum of distances to all points. we show that this problem has a randomized algorithm that ( 1 ) always outputs a $ ( 2 + \ epsilon ) $ - approximate solution in expected $ o ( n / \ epsilon ^ 2 ) $ time and that ( 2 ) inherits indyk ' s ~ \ cite { ind99, ind00 } algorithm to output a $ ( 1 + \ epsilon ) $ - approximate solution in $ o ( n / \ epsilon ^ 2 ) $ time with probability $ \ omega ( 1 ) $, where $ \ epsilon \ in ( 0, 1 ) $. ( ii ) the average distance in $ ( \ { 1, 2, \ ldots, n \ }, d ) $ can be approximated in $ o ( n / \ epsilon ) $ time to within a multiplicative factor in $ [ \, 1 / 2 - \ epsilon, 1 \, ] $ with probability $ 1 / 2 + \ omega ( 1 ) $, where $ \ epsilon > 0 $. ( iii ) assume $ d $ to be a graph metric. then the average distance in $ ( \ { 1, 2, \ ldots, n \ }, d ) $ can be approximated in $ o ( n ) $ time to within a multiplicative factor in $ [ \, 1 - \ epsilon, 1 + \ epsilon \, ] $ with probability $ 1 / 2 + \ omega ( 1 ) $, where $ \ epsilon = \ omega ( 1 / n ^ { 1 / 4 } ) $.
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arxiv:1703.08433
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three - dimensional van der waals ferromagnet fe $ _ 3 $ gete $ _ 2 $ ( fgt ) is regarded as a candidate for the magnetic topological nodal line semimetal. we investigate lateral electron transport between two 3 ~ $ \ mu $ m spaced superconducting in leads beneath a thick three - dimensional fgt exfoliated flake. at low 30 ~ mk temperature, we observe josephson supercurrent that exhibits unusual critical current $ i _ c $ suppression by the magnetic field $ b $. the overall $ i _ c ( b ) $ pattern is asymmetric in respect to the b sign. we demonstrate, that the asymmetry is defined by the magnetic field sweep direction, so the $ i _ c ( b ) $ pattern is strictly reversed ( as $ b $ to $ - b $ inversion ) for the opposite sweeps. we also observe an interplay between maximum and minimum in $ i _ c ( b ) $ in normal magnetic fields, while there are fast aperiodic $ i _ c ( b ) $ fluctuations for the in - plane ones. these effects can not be expected for homogeneous superconductor - ferromagnet - superconductor junctions, while they are known for josephson spin valves. the mostly possible scenario for josephson spin valve realization in fgt is the misalignment of spin polarizations of the fermi arc surface states and ferromagnetic fgt bulk, but we also discuss possible influence of spin - dependent transport between magnetic domains.
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arxiv:2108.13761
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using a proposal of maldacena one describes the large n limit of gauge theories in terms of supergravity solutions on anti - de sitter space. from this point of view we discuss a possible scenario for quark confinement in gauge theory by describing hadrons as strongly curved universes. in particular an interpretation of black hole as a bag model in sqcd is discussed. one relates the mystery of curvature singularities in classical general relativity with the mystery of quark confinement. the ads bag model is defined by computing the probe membrane action in supergravity background. it naturally implies the " cheshire cat bag " principle. the confining pressure in the mit bag model is related with the cosmological constant in the ads bag model. the skyrme model is interpreted as an effective theory describing black holes.
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arxiv:hep-th/9803174
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