text
stringlengths 1
3.65k
| source
stringlengths 15
79
|
|---|---|
we discuss the mean values of multiplicative functions over function fields. in particular, we adapt the authors ' new proof of halasz ' s theorem on mean values to this simpler setting. several of the technical difficulties that arise over the integers disappear in the function field setting, which helps bring out more clearly the main ideas of the proofs over number fields. we also obtain lipschitz estimates showing the slow variation of mean values of multiplicative functions over function fields, which display some features that are not present in the integer situation.
|
arxiv:1504.05409
|
we study by numerical simulations on a lattice the behaviour of the gauge - invariant two - point correlation functions of the gauge - field strengths across the deconfinement phase transition, both for the pure - gauge su ( 3 ) theory and for full qcd with two flavours. quenched data agree within errors with previous determinations, but have much higher statistics. a best - fit analysis of the data has been performed, both for the quenched and the full - qcd case, showing that the electric gluon condensate drops to zero at the deconfining phase transition.
|
arxiv:hep-lat/0205018
|
we show that the nonlinear response of a driven circuit quantum electrodynamics setup displays antiresonant multiphoton transitions, as recently observed in a transmon qubit device. by including photon leaking, we explain the lineshape by a perturbative and a semiclassical analysis. we derive a bistable semiclassical quasienergy surface whose lowest quasienergy eigenstate is squeezed, allowing for a squeezing - dependent local effective temperature. we study the escape dynamics out of the metastable state and find signatures of dynamical tunneling, similar as for the quantum duffing oscillator.
|
arxiv:0903.2338
|
spectroscopic and spectropolarimetric observations of the pre - main sequence early - g star hd 141943 were obtained at four observing epochs ( in 2006, 2007, 2009 and 2010 ). the observations were undertaken at the 3. 9 - m anglo - australian telescope using the ucles echelle spectrograph and the sempol spectropolarimeter visitor instrument. brightness and surface magnetic field topologies were reconstructed for the star using the technique of least - squares deconvolution to increase the signal - to - noise of the data. the reconstructed brightness maps show that hd 141943 had a weak polar spot and a significant amount of low latitude features, with little change in the latitude distribution of the spots over the 4 years of observations. the surface magnetic field was reconstructed at three of the epochs from a high order ( l < = 30 ) spherical harmonic expansion of the spectropolarimetric observations. the reconstructed magnetic topologies show that in 2007 and 2010 the surface magnetic field was reasonably balanced between poloidal and toroidal components. however we find tentative evidence of a change in the poloidal / toroidal ratio in 2009 with the poloidal component becoming more dominant. at all epochs the radial magnetic field is predominantly non - axisymmetric while the azimuthal field is predominantly axisymmetric with a ring of positive azimuthal field around the pole similar to that seen on other active stars.
|
arxiv:1101.5859
|
we revisit the scale evolution of the quark and gluon spin contributions to the proton spin, $ \ frac { 1 } { 2 } \ delta \ sigma $ and $ \ delta g $, using the three - loop results for the spin - dependent evolution kernels available in the literature. we argue that the evolution of the quark spin contribution may actually be extended to four - loop order, and that to all orders a single anomalous dimension governs the evolution of both $ \ delta \ sigma $ and $ \ delta g $. we present analytical solutions of the evolution equations for $ \ delta \ sigma $ and $ \ delta g $ and investigate their scale dependence both to large and down to lower " hadronic " scales. we find that the solutions remain perturbatively stable even to low scales, where they come closer to simple quark model expectations. we discuss a curious scenario for the proton spin, in which even the gluon spin contribution is essentially scale independent and has a finite asymptotic value as the scale becomes large. we finally also show that perturbative three - loop evolution leads to a larger spin contribution of strange anti - quarks than of strange quarks.
|
arxiv:1902.04636
|
we give a new description to obtain the shear viscosity in qcd at finite temperature. firstly, we obtain the correlation function of the renormalized energy - momentum tensor using the gradient flow method. secondly, we estimate the spectral function from the smeared correlation functions using the sparse modeling method. the combination of these two methods looks promising to determine the shear viscosity precisely.
|
arxiv:2110.13417
|
this work presents an optimal sampling - based method to solve the real - time motion planning problem in static and dynamic environments, exploiting the rapid - exploring random trees ( rrt ) algorithm and the model predictive path integral ( mppi ) algorithm. the rrt algorithm provides a nominal mean value of the random control distribution in the mppi algorithm, resulting in satisfactory control performance in static and dynamic environments without a need for fine parameter tuning. we also discuss the importance of choosing the right mean of the mppi algorithm, which balances exploration and optimality gap, given a fixed sample size. in particular, a sufficiently large mean is required to explore the state space enough, and a sufficiently small mean is required to guarantee that the samples reconstruct the optimal controls. the proposed methodology automates the procedure of choosing the right mean by incorporating the rrt algorithm. the simulations demonstrate that the proposed algorithm can solve the motion planning problem in real - time for static or dynamic environments.
|
arxiv:2301.13143
|
the existence of glueballs, bound states of gluons, is one of the basic predictions of qcd ; the lightest state is expected to be a scalar. the experimental situation, however, is still ambiguous. the existence of f _ 0 ( 1370 ) would point to a supernumerous state within the nonet classification of scalars and would therefore provide a hint towards a glueball. in this talk we summarize some arguments in favour and against the existence of f _ 0 ( 1370 ) and discuss schemes with and without this state included.
|
arxiv:1304.7634
|
we perform detailed study of the higgs production and decay, when higgs is emitted from the black holes produced in proton - proton collisions at the large hadron collider. we show that black hole production can significantly enhance the signal for the higgs search at the lhc. we evaluate rapidity distribution of diphotons and transverse momentum distribution of bottom quarks, photons, tau leptons, top quarks and w bosons from higgs decay, when higgs is emitted from the black hole and also in case when these particles are produced directly from the black hole evaporation. we compare our results with the standard model backgrounds. we find that higgs production from black holes is dominant over standard model production for $ p _ t ^ h > 100 $ gev, when $ m _ p = 1 $ tev. diphotons from higgs, when higgs is produced from evaporation of black holes, are dominant over the standard model prediction, for diphoton rapidity $ | y _ { \ gamma \ gamma } | \ leq 1 $, while bottom quarks are dominant over qcd background for large bottom quark transverse momentum, $ p _ t ^ b > 300 $ gev, when $ m _ p = 1 $ tev. we show that measurements of the photon and bottom quark transverse momentum distribution can provide valuable information about the value of the fundamental planck scale. we also propose a new signal for black hole production at the lhc, an onset of increasing transverse momentum distribution of bottom quarks with large transverse momentum.
|
arxiv:0904.0230
|
we analyze the effect of low dimensionality on the electrical conductivity ( { \ sigma } ) and seebeck coefficient ( s ) in ultra - narrow si nanowires ( nws ) by employing atomistic considerations for the electronic structures and linearized boltzmann transport theory. we show that changes in the geometrical features of the nws such as diameter and orientation, mostly affect { \ sigma } and s in two ways : i ) the distance of the band edges from the fermi level ( { \ eta } f ) changes, and ii ) quantum confinement in some cases strongly affect the effective mass of the subbands, which influences the conductivity of the nws and { \ eta } f. changes in eta _ f cause exponential changes in { \ sigma }, but linear changes in s. s seems to be only weakly dependent on the curvature of the bands, the strength of the scattering mechanisms, and the shape of the dos ( e ) function, contrary to current view. our results indicate that low dimensionality has a stronger influence on { \ sigma } than on s due to the stronger sensitivity of { \ sigma } on { \ eta } f. we identify cases where bandstructure engineering through confinement can improve { \ sigma } without significantly affecting s, which can result in power factor improvements.
|
arxiv:1307.8153
|
during inflation, there is a preferred reference frame in which the expansion of the background spacetime is spatially isotropic. in contrast to minkowski spacetime, observables can depend on the velocity of the system with respect to this cosmic rest frame. we derive new constraints from radiative stability and unitarity on effective field theories with such spontaneously broken lorentz symmetry. in addition to a maximum energy scale, there is now also a critical velocity at which the theory breaks down. the theory therefore has different resolving power in time and in space, and we show that these can only coincide if cubic lorentz - violating interactions are absent. applying these bounds to the effective field theory of inflation, we identify the region of parameter space in which inflation can be both single - field and weakly coupled on subhorizon scales. this can be implemented as a theoretical prior, and we illustrate this explicitly using planck observational constraints on the primordial bispectrum.
|
arxiv:2005.02366
|
high - efficiency video coding ( hevc ) surpasses its predecessors in encoding efficiency by introducing new coding tools at the cost of an increased encoding time - complexity. the coding tree unit ( ctu ) is the main building block used in hevc. in the hevc standard, frames are divided into ctus with the predetermined size of up to 64x64 pixels. each ctu is then divided recursively into a number of equally sized square areas, known as coding units ( cus ). although this diversity of frame partitioning increases encoding efficiency, it also causes an increase in the time complexity due to the increased number of ways to find the optimal partitioning. to address this complexity, numerous algorithms have been proposed to eliminate unnecessary searches during partitioning ctus by exploiting the correlation in the video. in this paper, existing ctu depth decision algorithms for hevc are surveyed. these algorithms are categorized into two groups, namely statistics and machine learning approaches. statistics approaches are further subdivided into neighboring and inherent approaches. neighboring approaches exploit the similarity between adjacent ctus to limit the depth range of the current ctu, while inherent approaches use only the available information within the current ctu. machine learning approaches try to extract and exploit similarities implicitly. traditional methods like support vector machines or random forests use manually selected features, while recently proposed deep learning methods extract features during training. finally, this paper discusses extending these methods to more recent video coding formats such as versatile video coding ( vvc ) and aomedia video 1 ( av1 ).
|
arxiv:2104.08328
|
standardized tests play a crucial role in the detection of cognitive impairment. previous work demonstrated that automatic detection of cognitive impairment is possible using audio data from a standardized picture description task. the presented study goes beyond that, evaluating our methods on data taken from two standardized neuropsychological tests, namely the german skt and a german version of the cerad - nb, and a semi - structured clinical interview between a patient and a psychologist. for the tests, we focus on speech recordings of three sub - tests : reading numbers ( skt 3 ), interference ( skt 7 ), and verbal fluency ( cerad - nb 1 ). we show that acoustic features from standardized tests can be used to reliably discriminate cognitively impaired individuals from non - impaired ones. furthermore, we provide evidence that even features extracted from random speech samples of the interview can be a discriminator of cognitive impairment. in our baseline experiments, we use opensmile features and support vector machine classifiers. in an improved setup, we show that using wav2vec 2. 0 features instead, we can achieve an accuracy of up to 85 %.
|
arxiv:2206.05018
|
speaker verification is an established yet challenging task in speech processing and a very vibrant research area. recent speaker verification ( sv ) systems rely on deep neural networks to extract high - level embeddings which are able to characterize the users ' voices. most of the studies have investigated on improving the discriminability of the networks to extract better embeddings for performances improvement. however, only few research focus on improving the generalization. in this paper, we propose to apply the ladder network framework in the sv systems, which combines the supervised and unsupervised learning fashions. the ladder network can make the system to have better high - level embedding by balancing the trade - off to keep / discard as much useful / useless information as possible. we evaluated the framework on two state - of - the - art sv systems, d - vector and x - vector, which can be used for different use cases. the experiments showed that the proposed approach relatively improved the performance by 10 % at most without adding parameters and augmented data.
|
arxiv:2003.09125
|
we investigate a strong version of the integral tate conjecture for 1 - cycles on the product of a curve and a surface over a finite field, under the assumption that the surface is geometrically $ ch _ 0 $ - trivial. by this we mean that over any algebraically closed field extension, the degree map on the zero - dimensional chow group of the surface is an isomorphism. this applies to enriques surfaces. when the n \ ' eron - severi group has no torsion, we recover earlier results of a. pirutka. the results rely on a detailed study of the third unramified cohomology group of specific products of varieties.
|
arxiv:2001.10515
|
adversarial purification is a kind of defense technique that can defend various unseen adversarial attacks without modifying the victim classifier. existing methods often depend on external generative models or cooperation between auxiliary functions and victim classifiers. however, retraining generative models, auxiliary functions, or victim classifiers relies on the domain of the fine - tuned dataset and is computation - consuming. in this work, we suppose that adversarial images are outliers of the natural image manifold and the purification process can be considered as returning them to this manifold. following this assumption, we present a simple adversarial purification method without further training to purify adversarial images, called zeropur. zeropur contains two steps : given an adversarial example, guided shift obtains the shifted embedding of the adversarial example by the guidance of its blurred counterparts ; after that, adaptive projection constructs a directional vector by this shifted embedding to provide momentum, projecting adversarial images onto the manifold adaptively. zeropur is independent of external models and requires no retraining of victim classifiers or auxiliary functions, relying solely on victim classifiers themselves to achieve purification. extensive experiments on three datasets ( cifar - 10, cifar - 100, and imagenet - 1k ) using various classifier architectures ( resnet, wideresnet ) demonstrate that our method achieves state - of - the - art robust performance. the code will be publicly available.
|
arxiv:2406.03143
|
in this paper, we investigate the performance of lte multicast - broadcast single - frequency networks ( mbsfn ). lte - mbsfn is viewed as one of the most promising candidates for vehicular communications which can enhance reliability of vehicular application traffic. this is achieved due to the possibility to efficiently support message exchange in - between vehicles by multicasting information to several vehicles in parallel ( point - to - multipoint transmission ) employing an multimedia broadcast / multicast service ( mbms ). we investigate two metrics to gauge the performance of mbms / mbsfn transmissions in comparison with standard unicast transmissions for vehicular communications : latency of packet delivery and overhead caused by vehicular traffic, i. e., network utilization. additionally, we present technique of prediction of system behaviour and explore the influence of transmission bandwidth and transmission rate on mentioned metrics.
|
arxiv:1510.06547
|
the lack of a procedure to determine equilibrium thermodynamic properties of a small system interacting with a bath is frequently seen as a weakness of conventional statistical mechanics. a typical example for such a small system is a solute surrounded by an explicit solvation shell. one way to approach this problem is to enclose the small system of interest in a large bath of explicit solvent molecules, considerably larger than the system itself. the explicit inclusion of the solvent degrees of freedom is obviously limited by the available computational resources. a potential remedy to this problem is a microsolvation approach where only a few explicit solvent molecules are considered and surrounded by an implicit solvent bath. still, the sampling of the solvent degrees of freedom is challenging with conventional grand canonical monte carlo methods, since no single chemical potential for the solvent molecules can be defined in the realm of small - system thermodynamics. in this work, a statistical thermodynamic model based on the grand canonical ensemble is proposed that avoids the conventional system size limitations and accurately characterizes the properties of the system of interest subject to the thermodynamic constraints of the bath. we extend an existing microsolvation approach to a generalized multi - bath " micro - statistical " model and show that the previously derived approaches result as a limit of our model. the framework described here is universal and we validate our method numerically for a lennard - jones model fluid.
|
arxiv:2212.07544
|
learning surfaces from neural radiance field ( nerf ) became a rising topic in multi - view stereo ( mvs ). recent signed distance function ( sdf ) - based methods demonstrated their ability to reconstruct accurate 3d shapes of lambertian scenes. however, their results on reflective scenes are unsatisfactory due to the entanglement of specular radiance and complicated geometry. to address the challenges, we propose a gaussian - based representation of normals in sdf fields. supervised by polarization priors, this representation guides the learning of geometry behind the specular reflection and captures more details than existing methods. moreover, we propose a reweighting strategy in the optimization process to alleviate the noise issue of polarization priors. to validate the effectiveness of our design, we capture polarimetric information, and ground truth meshes in additional reflective scenes with various geometry. we also evaluated our framework on the pandora dataset. comparisons prove our method outperforms existing neural 3d reconstruction methods in reflective scenes by a large margin.
|
arxiv:2403.11899
|
identifying measurable genetic indicators ( or biomarkers ) of a specific condition of a biological system is a key element of precision medicine. indeed it allows to tailor diagnostic, prognostic and treatment choice to individual characteristics of a patient. in machine learning terms, biomarker discovery can be framed as a feature selection problem on whole - genome data sets. however, classical feature selection methods are usually underpowered to process these data sets, which contain orders of magnitude more features than samples. this can be addressed by making the assumption that genetic features that are linked on a biological network are more likely to work jointly towards explaining the phenotype of interest. we review here three families of methods for feature selection that integrate prior knowledge in the form of networks.
|
arxiv:1607.08161
|
in this article we will see some properties that guarantee that a product of an ergodic non - singular action and a probability preserving ergodic action is also an ergodic action. we will start by proving ' the multiplier theorem ' for locally compact abelian groups. then we will show that for certain locally compact polish groups ( moore groups, and minimally weakly mixing groups ), a non - singular g action is weakly mixing if and only if any finite dimensional g - invariant subspace of l _ \ infty is trivial. finally, we will show that the gaussian action associated to the infinite dimensional irreducible representation of the continuous heisenberg group, h _ 3, is weakly mixing but not mildly mixing.
|
arxiv:1306.3669
|
nolimits ( \ delta _ i ) $, where $ \ mathop { \ mathrm { ord } } \ nolimits \ ni \ theta _ i \ geq \ mathop { \ rm cf } \ nolimits ( \ delta _ i ) > \ mathop { \ rm cf } \ nolimits ( \ theta _ i ) = \ omega $ and $ \ theta _ i = \ lim _ { n \ rightarrow \ omega } \ delta _ n $, where $ \ mathop { \ rm cf } \ nolimits ( \ delta _ n ) = \ mathop { \ rm cf } \ nolimits ( \ delta _ i ) $, for all $ n \ in \ omega $.
|
arxiv:2401.00302
|
we reconsider the problem of the stability of the thermohaline circulation as described by a two - dimensional boussinesq model with mixed boundary conditions. we determine how the stability properties of the system depend on the intensity of the hydrological cycle. we define a two - dimensional parameters ' space descriptive of the hydrology of the system and determine, by considering suitable quasi - static perturbations, a bounded region where multiple equilibria of the system are realized. we then focus on how the response of the system to finite - amplitude surface freshwater forcings depends on their rate of increase. we show that it is possible to define a robust separation between slow and fast regimes of forcing. such separation is obtained by singling out an estimate of the critical growth rate for the anomalous forcing, which can be related to the characteristic advective time scale of the system.
|
arxiv:physics/0407147
|
clinical trial outcome prediction seeks to estimate the likelihood that a clinical trial will successfully reach its intended endpoint. this process predominantly involves the development of machine learning models that utilize a variety of data sources such as descriptions of the clinical trials, characteristics of the drug molecules, and specific disease conditions being targeted. accurate predictions of trial outcomes are crucial for optimizing trial planning and prioritizing investments in a drug portfolio. while previous research has largely concentrated on small - molecule drugs, there is a growing need to focus on biologics - a rapidly expanding category of therapeutic agents that often lack the well - defined molecular properties associated with traditional drugs. additionally, applying conventional methods like graph neural networks to biologics data proves challenging due to their complex nature. to address these challenges, we introduce the language interaction network ( lint ), a novel approach that predicts trial outcomes using only the free - text descriptions of the trials. we have rigorously tested the effectiveness of lint across three phases of clinical trials, where it achieved roc - auc scores of 0. 770, 0. 740, and 0. 748 for phases i, ii, and iii, respectively, specifically concerning trials involving biologic interventions.
|
arxiv:2405.06662
|
r - parity violation and extensions of the standard model gauge structure offer two non - minimal realizations of supersymmetry at low energies that can lead to similar new physics signatures at existing and future colliders. we discuss techniques that can be employed at the nlc below direct production threshold to distinguish these two new physics scenarios.
|
arxiv:hep-ph/9811440
|
in rare - earth - based frustrated magnets, the synergistic interplay between spin correlations, spin - orbit coupling and competing exchange interactions provide a promising route to realize exotic quantum states with nontrivial excitations. here, through thermodynamic and local - probe measurements down to 16 mk, we demonstrate the exotic magnetism and spin dynamics in the nearly perfect emergent honeycomb lattice antiferromagnet tbbo3. the latter embodies a frustrated lattice with a superimposed triangular lattice, constituted by additional tb3 + ions at the center of each hexagon. thermodynamic experiments reveal the presence of dominant antiferromagnetic interactions with no indications of either long - range order or spin freezing down to 50 mk. despite sizable antiferromagnetic exchange interactions between the tb3 + moments, muon - spin relaxation does not detect any signatures of long - range magnetic order or spin - freezing down to 16 mk. this suggests that the spin - orbit - driven anisotropic exchange interaction engenders a strong frustration, crucial to induce persistent spin dynamics. the specific - heat data exhibit a t ^ 2. 2 power - law behavior at low temperatures, suggesting gapless excitations consistent with theoretical predictions. the scaling of muon relaxation rate as a function of the characteristic energy scale for several spin - liquid candidates, including tbbo3, demonstrates a thermally activated behavior. this is consistent with nmr results on tbbo3 and reminiscent of a universal qsl behavior, here attributed to short - range spin correlations. our experimental results are supported by density functional theory + hubbard u and crystal electric - field calculations, which propose tbbo3 as a promising platform to realize the theoretically proposed quantum disorder state in an anisotropy - driven frustrated honeycomb lattice.
|
arxiv:2407.05867
|
the limit free energy of an enriched mixed $ p $ - spin spin glass model has been identified with the solution of a hamilton - jacobi equation. in this note, we remark that the aizenman - sims - starr scheme yields a subsolution to the equation.
|
arxiv:2212.09542
|
a general scheme is proposed for introduction of lattice and q - difference variables to integrable hierarchies in frame of $ \ bar { \ partial } $ - dressing method. using this scheme, lattice and q - difference darboux - zakharov - manakov systems of equations are derived. darboux, b \ " acklund and combescure transformations and exact solutions for these systems are studied.
|
arxiv:solv-int/9501007
|
we consider general field theories in six dimensions, with two of the dimensions compactified on a t _ { 2 } / z _ { 4 } orbifold. six - dimensional weyl fermions propagating on this background give rise to a chiral zero - mode, which makes them interesting for phenomenological applications. the compact two - dimensional space is flat and has three conical singularities. we consider the one - loop structure of these theories, and show that the presence of logarithmic divergences requires the introduction of counterterms precisely at these three singular points. we also show that the corresponding localized operators are rotationally symmetric in the plane of the two extra dimensions, as expected from the geometry about the singularities. we derive the propagators for spin - 0, spin - 1 / 2 and spin - 1 fields in momentum space, in such a way that the appropriate boundary conditions are satisfied. this allows us to efficiently calculate loop diagrams in any given model. we give general expressions for the mass splittings among kaluza - klein modes within a given level. our results can also be used to obtain interesting kk - parity preserving interactions among kaluza - klein modes. we pay special attention to the components of six - dimensional gauge fields that transform as scalars under the four - dimensional lorentz group. these states provide a characteristic signature for these scenarios. in particular, we find that they can easily be the lightest particles in the kaluza - klein spectrum.
|
arxiv:hep-ph/0512304
|
this volume contains the proceedings of the 13th international workshop on programmability and architectures for heterogeneous multicores. the workshop was held in conjunction with the 16th international conference on high - performance and embedded architectures and compilers ( hipeac ) in bologna, italy on january 20th, 2020.
|
arxiv:2005.07619
|
it has long been noticed that laudau - lifshitz theory can be used to study the fluctuation of a system that contains a black hole. since the black string can be constructed by extending n - dimensional black hole into one extra dimension. we study the fluctuation of black string flow with a schwarzschlid - like metric in d = n + 1 dimensional spacetime and a charged solution in d = 5 dimensional spacetime and get the second moments of the fluctuation of the mass flux and charge flux.
|
arxiv:1505.01943
|
this work explores conditional image generation with a new image density model based on the pixelcnn architecture. the model can be conditioned on any vector, including descriptive labels or tags, or latent embeddings created by other networks. when conditioned on class labels from the imagenet database, the model is able to generate diverse, realistic scenes representing distinct animals, objects, landscapes and structures. when conditioned on an embedding produced by a convolutional network given a single image of an unseen face, it generates a variety of new portraits of the same person with different facial expressions, poses and lighting conditions. we also show that conditional pixelcnn can serve as a powerful decoder in an image autoencoder. additionally, the gated convolutional layers in the proposed model improve the log - likelihood of pixelcnn to match the state - of - the - art performance of pixelrnn on imagenet, with greatly reduced computational cost.
|
arxiv:1606.05328
|
diamond colour centres are promising optically - addressable solid state spins that can be matter - qubits, mediate deterministic interaction between photons and act as single photon emitters. useful quantum computers will comprise millions of logical qubits. to become useful in constructing quantum computers, spin - photon interfaces must therefore become scalable and be compatible with mass - manufacturable photonics and electronics. here we demonstrate heterogeneous integration of nv centres in nanodiamond with low - fluorescence silicon nitride photonics from a standard 180 nm cmos foundry process. nanodiamonds are positioned over pre - defined sites in a regular array on a waveguide, in a single post - processing step. using an array of optical fibres, we excite nv centres selectively from an array of six integrated nanodiamond sites, and collect the photoluminescence ( pl ) in each case into waveguide circuitry on - chip. we verify single photon emission by an on - chip hanbury brown and twiss cross - correlation measurement, which is a key characterisation experiment otherwise typically performed routinely with discrete optics. our work opens up a simple and effective route to simultaneously address large arrays of individual optically - active spins at scale, without requiring discrete bulk optical setups. this is enabled by the heterogeneous integration of nv centre nanodiamonds with cmos photonics.
|
arxiv:2304.10227
|
the auto - importance sampling ( ais ) method is a monte carlo variance reduction technique proposed for deep penetration problems, which can significantly improve computational efficiency without pre - calculations for importance distribution. however, the ais method is only validated with several simple examples, and cannot be used for coupled neutron - photon transport. this paper presents the improved algorithms for the ais method, including particle transport, fictitious particles creation and adjustment, fictitious surface geometry, random number allocation and calculation of the estimated relative error. these improvements allow the ais method to be applicable to complicated deep penetration problems with complex geometry and multiple materials. a coupled neutron - photon auto - importance sampling ( np - ais ) method is proposed to solve the deep penetration problems of coupled neutron - photon transport using the improved algorithms. the nureg / cr - 6115 pwr benchmark was calculated by using the methods of np - ais, geometry splitting with russian roulette and the analog monte carlo, respectively. the calculation results of np - ais were in good agreement with those of geometry splitting with russian roulette and the benchmark solutions. the computational efficiency of np - ais for both neutron and photon was much better than that of geometry splitting with russian roulette in most cases, and increased by several orders of magnitude compared with that of the analog monte carlo.
|
arxiv:1603.01480
|
space time is described as a continuum four - dimensional medium similar to ordinary elastic continua. exploiting the analogy internal stress states are considered. the internal ' ' stress ' ' is originated by the presence of defects. the defects are described according to the typical volterra process. the case of a point defect in an otherwise isotropic four - dimensional medium is discussed showing that the resulting metric tensor corresponds to an expanding ( or contracting ) universe filled up with a non - zero energy - momentum density.
|
arxiv:gr-qc/0410145
|
rare - earth ion doped crystals are state - of - the - art platforms for processing quantum information, particularly thanks to their excellent optical and spin coherence properties at cryogenic temperatures. experimental observations have shown that the application of a static magnetic bias field significantly improves the coherence times in the rare - earth ions ensemble, but only a few studies have focused on its the dependency as a function of both magnetic field direction and amplitude. this is especially true for magnetic field amplitudes under the mt, and for low magnetic dipole moment ions. in this paper, we investigate the relationship between the magnetic field parameters and the decoherence caused by magnetic dipole - dipole coupling with the nearest neighbors nuclear spins in the crystal. the primary non - kramers rare - earth ions investigated here are europium and praseodymium, but we also extend our study to the ytterbium kramers ion due to its low magnetic dipole in the mt range. we perform theoretical investigations and simulations of the energy structure and coherence time evolution and identify good correspondences between experimental and simulated spin echo data. this work allows us to pinpoint the most relevant decoherence mechanisms in the considered magnetic field regime, and to predict favorable magnetic configurations.
|
arxiv:2408.01958
|
we analyze the dynamics of m - theory on a manifold of g _ 2 holonomy that is developing a conical singularity. the known cases involve a cone on cp ^ 3, where we argue that the dynamics involves restoration of a global symmetry, su ( 3 ) / u ( 1 ) ^ 2, where we argue that there are phase transitions among three possible branches corresponding to three classical spacetimes, and s ^ 3 x s ^ 3 and its quotients, where we recover and extend previous results about smooth continuations between different spacetimes and relations to four - dimensional gauge theory.
|
arxiv:hep-th/0107177
|
time series forecasting is a key component in many industrial and business decision processes and recurrent neural network ( rnn ) based models have achieved impressive progress on various time series forecasting tasks. however, most of the existing methods focus on single - task forecasting problems by learning separately based on limited supervised objectives, which often suffer from insufficient training instances. as the transformer architecture and other attention - based models have demonstrated its great capability of capturing long term dependency, we propose two self - attention based sharing schemes for multi - task time series forecasting which can train jointly across multiple tasks. we augment a sequence of paralleled transformer encoders with an external public multi - head attention function, which is updated by all data of all tasks. experiments on a number of real - world multi - task time series forecasting tasks show that our proposed architectures can not only outperform the state - of - the - art single - task forecasting baselines but also outperform the rnn - based multi - task forecasting method.
|
arxiv:2101.09645
|
we describe the density matrix renormalization group algorithms for time dependent and time independent hamiltonians. this paper is a brief but comprehensive introduction to the subject for anyone willing to enter in the field or write the program source code from scratch.
|
arxiv:cond-mat/0603842
|
let $ \ pi $ be a cuspidal automorphic representation of $ { \ mathrm { gl } } _ 2 ( \ mathbb { a } _ \ mathbb { q } ) $. newton and thorne have proved that for every $ n \ geq 1 $, the symmetric power lifting $ { { \ mathrm { sym } } ^ n ( \ pi ) } $ is automorphic if $ \ pi $ is attached to a non - cm hecke eigenform. in this article, we establish an asymptotic estimate of the number of cuspidal automorphic representations of $ { \ mathrm { gl } } _ { n + 1 } ( \ mathbb { a } _ \ mathbb { q } ) $ which contribute to the cuspidal cohomology of $ { \ mathrm { gl } } _ { n + 1 } $ and are obtained by symmetric $ n $ th transfer of cuspidal representations of $ { \ mathrm { gl } } _ 2 ( \ mathbb { a } _ \ mathbb { q } ) $. here we fix the weight and vary the level. this generalises the previous works done for $ { \ mathrm { gl } } _ 3 $ and $ { \ mathrm { gl } } _ 4 $.
|
arxiv:2308.06846
|
image saliency detection has recently witnessed rapid progress due to deep convolutional neural networks. however, none of the existing methods is able to identify object instances in the detected salient regions. in this paper, we present a salient instance segmentation method that produces a saliency mask with distinct object instance labels for an input image. our method consists of three steps, estimating saliency map, detecting salient object contours and identifying salient object instances. for the first two steps, we propose a multiscale saliency refinement network, which generates high - quality salient region masks and salient object contours. once integrated with multiscale combinatorial grouping and a map - based subset optimization framework, our method can generate very promising salient object instance segmentation results. to promote further research and evaluation of salient instance segmentation, we also construct a new database of 1000 images and their pixelwise salient instance annotations. experimental results demonstrate that our proposed method is capable of achieving state - of - the - art performance on all public benchmarks for salient region detection as well as on our new dataset for salient instance segmentation.
|
arxiv:1704.03604
|
we briefly survey recent results related to linear series on curves that are general in various moduli spaces, highlighting the interplay between algebraic geometry on a general curve and the combinatorics of its degenerations. breakthroughs include the proof of the maximal rank theorem, which determines the hilbert function of the general linear series of given degree and rank on the general curve in m _ g, and complete analogs of the standard brill - noether theorems for curves that are general in hurwitz spaces. other advances include partial results in a similar direction for linear series in the prym locus of a general unramified double cover of a general k - gonal curve and instances of the strong maximal rank conjecture.
|
arxiv:2111.00351
|
heavy axion - like particles ( alps ), with masses $ m _ a \ gtrsim 100 $ kev, coupled with photons, would be copiously produced in a supernova ( sn ) core via primakoff process and photon coalescence. using a state - of - the - art sn model, we revisit the energy - loss sn 1987a bounds on axion - photon coupling. moreover, we point out that heavy alps with masses $ m _ a \ gtrsim 100 $ mev and axion - photon coupling $ g _ { a \ gamma } \ gtrsim 4 \ times 10 ^ { - 9 } $ gev $ ^ { - 1 } $ would decay into photons behind the shock - wave producing a possible enhancement in the energy deposition that would boost the sn shock revival.
|
arxiv:2008.04918
|
within the $ t $ - $ j $ model, we study the doping dependence of antiferromagnetism in the copper oxide materials by considering quantum fluctuations of spinons in the random - phase - approximation. the staggered magnetization vanishes around doping $ \ delta = 5 % $ for a reasonable parameter value $ t / j = 5 $, which is in agreement with the experiments on copper oxide materials.
|
arxiv:cond-mat/9708176
|
the multi - commodity flow - cut gap is a fundamental parameter that affects the performance of several divide \ & conquer algorithms, and has been extensively studied for various classes of undirected graphs. it has been shown by linial, london and rabinovich and by aumann and rabani that for general $ n $ - vertex graphs it is bounded by $ o ( \ log n ) $ and the gupta - newman - rabinovich - sinclair conjecture asserts that it is $ o ( 1 ) $ for any family of graphs that excludes some fixed minor. we show that the multicommodity flow - cut gap on \ emph { directed } planar graphs is $ o ( \ log ^ 3 n ) $. this is the first \ emph { sub - polynomial } bound for any family of directed graphs of super - constant treewidth. we remark that for general directed graphs, it has been shown by chuzhoy and khanna that the gap is $ \ widetilde { \ omega } ( n ^ { 1 / 7 } ) $, even for directed acyclic graphs. as a direct consequence of our result, we also obtain the first polynomial - time polylogarithmic - approximation algorithms for the directed non - bipartite sparsest - cut, and the directed multicut problems for directed planar graphs, which extends the long - standing result for undirectd planar graphs by rao ( with a slightly weaker bound ). at the heart of our result we investigate low - distortion quasimetric embeddings into \ emph { directed } $ \ ell _ 1 $. more precisely, we construct $ o ( \ log ^ 2 n ) $ - lipschitz quasipartitions for the shortest - path quasimetric spaces of planar digraphs, which generalize the notion of lipschitz partitions from the theory of metric embeddings. this construction combines ideas from the theory of bi - lipschitz embeddings, with tools form data structures on directed planar graphs.
|
arxiv:2111.07974
|
training graph neural networks ( gnn ) on large graphs is resource - intensive and time - consuming, mainly due to the large graph data that cannot be fit into the memory of a single machine, but have to be fetched from distributed graph storage and processed on the go. unlike distributed deep neural network ( dnn ) training, the bottleneck in distributed gnn training lies largely in large graph data transmission for constructing mini - batches of training samples. existing solutions often advocate data - computation colocation, and do not work well with limited resources where the colocation is infeasible. the potentials of strategical task placement and optimal scheduling of data transmission and task execution have not been well explored. this paper designs an efficient algorithm framework for task placement and execution scheduling of distributed gnn training, to better resource utilization, improve execution pipelining, and expediting training completion. our framework consists of two modules : ( i ) an online scheduling algorithm that schedules the execution of training tasks, and the data transmission plan ; and ( ii ) an exploratory task placement scheme that decides the placement of each training task. we conduct thorough theoretical analysis, testbed experiments and simulation studies, and observe up to 67 % training speed - up with our algorithm as compared to representative baselines.
|
arxiv:2204.11224
|
given a network of routing nodes, represented as a directed graph, we prove the following necessary and sufficient condition for the existence of deadlock - free message routing : the directed graph must contain two edge - disjoint directed trees rooted at the same node, one tree directed into the root node and the other directed away from the root node. while the sufficiency of this condition is known, its necessity, to the best of our knowledge, has not been previously recognized or proven. although not directly applicable to the construction of deadlock - free routing schemes, this result provides a fundamental insight into the nature of deadlock - free networks and may lead to the development of improved tools for designing and verifying such schemes.
|
arxiv:2503.04583
|
invariant coordinate selection ( ics ) is a multivariate technique that relies on the simultaneous diagonalization of two scatter matrices. it serves various purposes, including its use as a dimension reduction tool prior to clustering or outlier detection. unlike methods such as principal component analysis, ics has a theoretical foundation that explains why and when the identified subspace should contain relevant information. these general results have been examined in detail primarily for specific scatter combinations within a two - cluster framework. in this study, we expand these investigations to include more clusters and scatter combinations. the case of three clusters in particular is studied at length. based on these expanded theoretical insights and supported by numerical studies, we conclude that ics is indeed suitable for recovering fisher ' s discriminant subspace under very general settings and cases of failure seem rare.
|
arxiv:2409.17631
|
recently, the weight - sharing technique has significantly speeded up the training and evaluation procedure of neural architecture search. however, most existing weight - sharing strategies are solely based on experience or observation, which makes the searching results lack interpretability and rationality. in addition, due to the negligence of fairness, current methods are prone to make misjudgments in module evaluation. to address these problems, we propose a novel neural architecture search algorithm based on dynamical isometry. we use the fix point analysis method in the mean field theory to analyze the dynamics behavior in the steady state random neural network, and how dynamic isometry guarantees the fairness of weight - sharing based nas. meanwhile, we prove that our module selection strategy is rigorous fair by estimating the generalization error of all modules with well - conditioned jacobian. extensive experiments show that, with the same size, the architecture searched by the proposed method can achieve state - of - the - art top - 1 validation accuracy on imagenet classification. in addition, we demonstrate that our method is able to achieve better and more stable training performance without loss of generality.
|
arxiv:2307.02263
|
we prove that if $ \ phi, \ psi \ in out ( f _ n ) $ are hyperbolic iwips ( irreducible with irreducible powers ) such that $ < \ phi, \ psi > \ le out ( f _ n ) $ is not virtually cyclic then some high powers of $ \ phi $ and $ \ psi $ generate a free subgroup of rank two, all of whose nontrivial elements are again hyperbolic iwips. being a hyperbolic iwip element of $ out ( f _ n ) $ is strongly analogous to being a pseudo - anosov element of a mapping class group, so the above result provides analogs of " purely pseudo - anosov " free subgroups of $ out ( f _ n ) $.
|
arxiv:0902.4017
|
in this paper, based on the previous work [ b. shi, z. guo, lattice boltzmann model for nonlinear convection - diffusion equations, phys. rev. e 79 ( 2009 ) 016701 ], we develop a general multiple - relaxation - time ( mrt ) lattice boltzmann model for nonlinear anisotropic convection - diffusion equation ( nacde ), and show that the nacde can be recovered correctly from the present model through the chapman - enskog analysis. we then test the mrt model through some classic cdes, and find that the numerical results are in good agreement with analytical solutions or some available results. besides, the numerical results also show that similar to the single - relaxation - time ( srt ) lattice boltzmann model or so - called bgk model, the present mrt model also has a second - order convergence rate in space. finally, we also perform a comparative study on the accuracy and stability of the mrt model and bgk model by using two examples. in terms of the accuracy, both the theoretical analysis and numerical results show that a \ emph { numerical } slip on the boundary would be caused in the bgk model, and cannot be eliminated unless the relaxation parameter is fixed to be a special value, while the \ emph { numerical } slip in the mrt model can be overcome once the relaxation parameters satisfy some constrains. the results in terms of stability also demonstrate that the mrt model could be more stable than the bgk model through tuning the free relaxation parameters.
|
arxiv:1603.09577
|
we propose a new approximation scheme within equation of motion approach ( eom ) to spin polarized transport through a quantum dot coupled to ferromagnetic leads. it has some advantages over a widely used in the literature standard eom technique, in particular when we are interested in spin polarized quantities. namely, it gives the values of the dot spin polarization which are closer to the ones obtained within numerical renormalization group ( nrg ), than the standard eom approach. while restoring the kondo effect, the spin polarization vanishes and the transport becomes unpolarized, in agreement with nrg and a real time diagrammatic calculations. the standard eom procedure gives nonzero values of the spin polarization, and the transport is still spin polarized. both approximations give the same correct splitting of the kondo peaks due to ferromagnetism in the electrodes.
|
arxiv:0712.2414
|
azimuthal distributions of radial velocities of charged hadrons produced in nucleus - nucleus $ ( ab ) $ collisions are compared with the corresponding azimuthal distribution of charged hadron multiplicity in the framework of a multiphase transport ( ampt ) model at two different collision energies. the mean radial velocity seems to be a good probe for studying radial expansion. while the anisotropic part of the distributions indicates a kind of collective nature of radial expansion, the isotropic part characterizes a thermal motion. the present investigation is carried out keeping the upcoming compressed baryonic matter ( cbm ) experiment to be held at the facility for anti - proton ion research ( fair ) in mind. as far as high - energy heavy - ion interactions are concerned, cbm will supplement the relativistic heavy ion collider ( rhic ) and large hadron collider ( lhc ) experiments. in this context our simulation results at high baryochemical potential would be interesting, when scrutinized from the perspective of almost a baryon free environment achieved at rhic and lhc.
|
arxiv:1804.04957
|
multimodal hearing aids ( has ) aim to deliver more intelligible audio in noisy environments by contextually sensing and processing data in the form of not only audio but also visual information ( e. g. lip reading ). machine learning techniques can play a pivotal role for the contextually processing of multimodal data. however, since the computational power of ha devices is low, therefore this data must be processed either on the edge or cloud which, in turn, poses privacy concerns for sensitive user data. existing literature proposes several techniques for data encryption but their computational complexity is a major bottleneck to meet strict latency requirements for development of future multi - modal hearing aids. to overcome this problem, this paper proposes a novel real - time audio / visual data encryption scheme based on chaos - based encryption using the tangent - delay ellipse reflecting cavity - map system ( td - ercs ) map and non - linear chaotic ( nca ) algorithm. the results achieved against different security parameters, including correlation coefficient, unified averaged changed intensity ( uaci ), key sensitivity analysis, number of changing pixel rate ( npcr ), mean - square error ( mse ), peak signal to noise ratio ( psnr ), entropy test, and chi - test, indicate that the newly proposed scheme is more lightweight due to its lower execution time as compared to existing schemes and more secure due to increased key - space against modern brute - force attacks.
|
arxiv:2202.05662
|
the recent up to 2fb ^ { - 1 } of data from the atlas and cms experiments at the cern large hadron collider at 7tev put an upper bound on the production cross section of a higgs - like particle. we translate the results of the h - > ww - > l nu l nu and h - > gamma gamma as well as the combined analysis by the atlas and cms into an allowed region for the kaluza - klein ( kk ) mass m _ { kk } and the higgs mass $ m _ h $ for all the known universal extra dimension ( ued ) models in five and six dimensions. our bound is insensitive to the detailed kk mass splitting and mixing and hence complementary to all other known signatures.
|
arxiv:1108.1764
|
this paper contributes to the study of large data problems for $ c ^ 1 $ solutions of the relativistic euler equations. in the $ ( 1 + 1 ) $ - dimensional spacetime setting, if the initial data are away from vacuum, a key difficulty in proving the global well - posedness or finite time blow - up is coming up with a way to obtain sharp enough control on the lower bound of the mass - energy density function $ \ rho $. first, for $ c ^ 1 $ solutions of the 1 - dimensional classical isentropic compressible euler equations in the eulerian setting, we show a novel idea of obtaining a mass density time - dependent lower bound by studying the difference of the two riemann invariants, along with certain weighted gradients of them. furthermore, using an elaborate argument on a certain ode inequality and introducing some key artificial ( new ) quantities, we apply this idea to obtain the lower bound estimate for the mass - energy density of the ( 1 + 1 ) - dimensional relativistic euler equations. ultimately, for $ c ^ 1 $ solutions with uniformly positive initial mass - energy density of the ( 1 + 1 ) - dimensional relativistic euler equations, we give a necessary and sufficient condition for the formation of singularity in finite time, which gives a complete picture for the ( $ c ^ 1 $ ) large data problem in dimension $ ( 1 + 1 ) $. moreover, for the ( 3 + 1 ) - dimensional relativistic fluids, under the assumption that the initial mass - energy density vanishes in some open domain, we give two sufficient conditions for $ c ^ 1 $ solutions to blow up in finite time, no matter how small the initial data are. we also do some interesting studies on the asymptotic behavior of the relativistic velocity when vacuum appears at the far field, which tells us that one can not obtain any global regular solution whose $ l ^ \ infty $ norm of $ u $ decays to zero as time $ t $ goes to infinity.
|
arxiv:1903.03355
|
we investigate the structure of a digraph having a transitive automorphism group where every cutset of minimal cardinality consists of all successors or all predecessors of some vertex. we improve most of the existing results in this area.
|
arxiv:1006.5129
|
with google scholar, scientists can maintain their publications on personal profile pages, while the citations to these works are automatically collected and counted. maintenance of publications is done manually by the researcher herself, and involves deleting erroneous ones, merging ones that are the same but which were not recognized as the same, adding forgotten co - authors, and correcting titles of papers and venues. the publications are presented on pages with 20 or 100 papers in the web page interface from 2012 - - 2014. the interface does not allow a scientist to merge two version of a paper if they appear on different pages. this not only implies that a scientist who wants to merge certain subsets of publications will sometimes be unable to do so, but also, we show in this note that the decision problem to determine if it is possible to merge given subsets of papers is np - complete.
|
arxiv:1410.3820
|
a new derivation of surface charges for 3 + 1 gravity coupled to electromagnetism is obtained. gravity theory is written in the tetrad - connection variables. the general derivation starts from the lagrangian and uses the covariant symplectic formalism in the language of forms. for gauge theories surface charges disentangle physical from gauge symmetries through the use of noether identities and the exactness symmetry condition. the surface charges are quasilocal, explicitly coordinate independent, gauge invariant, and background independent. for a black hole family solution the surface charge conservation implies the first law of black hole mechanics. as a check we show the first law for black hole electrically charged, rotating, and with an asymptotically constant curvature ( the kerr - newman ( anti - ) de sitter family ). the charges, including the would - be mass term appearing in the first law, are quasilocal. it is not required a reference to the asymptotic structure of the spacetime nor boundary conditions, and therefore topological terms do not play a r \ ^ ole. finally, surface charges formulae for lovelock gravity coupled to electromagnetism are exhibited. it generalizes the one derived in a recent work by g. barnich, p. mao, and r. ruzziconi. the two different symplectic methods to define surface charges are compared and shown equivalent.
|
arxiv:1703.10120
|
we propose a single - shot approach to determining 6 - dof pose of an object with available 3d computer - aided design ( cad ) model from a single rgb image. our method, dubbed mrc - net, comprises two stages. the first performs pose classification and renders the 3d object in the classified pose. the second stage performs regression to predict fine - grained residual pose within class. connecting the two stages is a novel multi - scale residual correlation ( mrc ) layer that captures high - and - low level correspondences between the input image and rendering from first stage. mrc - net employs a siamese network with shared weights between both stages to learn embeddings for input and rendered images. to mitigate ambiguity when predicting discrete pose class labels on symmetric objects, we use soft probabilistic labels to define pose class in the first stage. we demonstrate state - of - the - art accuracy, outperforming all competing rgb - based methods on four challenging bop benchmark datasets : t - less, lm - o, ycb - v, and itodd. our method is non - iterative and requires no complex post - processing.
|
arxiv:2403.08019
|
we present a model - atmosphere analysis of ultraviolet echelle spectra of kpd0005 + 5106 taken with the space telescope imaging spectrograph aboard the hubble space telescope. the star is the hottest known pre - white dwarf ( teff = 200, 000 + - 20, 000 k, log g = 6. 7 + - 0. 3 ; wassermann et al. 2010 ). its atmosphere is composed of helium with trace amounts of metals. it is of the so - called o ( he ) spectral type that comprises very hot helium - rich pre - white dwarfs whose origin is debated. from neon and silicon ionisation balances, we derive tighter constraints on the effective temperature ( 195, 000 + - 15, 000 k ) and improve previous abundance determinations of these elements. we confirm the idea that kpd0005 + 5106 is the descendant of an r coronae borealis ( rcb ) star and, hence, is the outcome of a binary - white dwarf merger. we discuss the relation of kpd0005 + 5106 to other o ( he ) and rcb stars.
|
arxiv:1509.08938
|
the advent of the transformer has sparked a quick growth in the size of language models, far outpacing hardware improvements. ( dense ) transformers are expected to reach the trillion - parameter scale in the near future, for which training requires thousands or even tens of thousands of gpus. we investigate the challenges of training at this scale and beyond on commercially available hardware. in particular, we analyse the shortest possible training time for different configurations of distributed training, leveraging empirical scaling laws for language models to estimate the optimal ( critical ) batch size. contrary to popular belief, we find no evidence for a memory wall, and instead argue that the real limitation - - other than the cost - - lies in the training duration. in addition to this analysis, we introduce two new methods, \ textit { layered gradient accumulation } and \ textit { modular pipeline parallelism }, which together cut the shortest training time by half. the methods also reduce data movement, lowering the network requirement to a point where a fast infiniband connection is not necessary. this increased network efficiency also improve on the methods introduced with the zero optimizer, reducing the memory usage to a tiny fraction of the available gpu memory.
|
arxiv:2106.02679
|
verifying the integrity of embedded device characteristics is required to ensure secure operation of a device. one central challenge is to securely extract and store device - specific configurations for future verification. existing device attestation schemes suffer from notable limitations, including a lack of standardization and a failure to encompass all hardware and software aspects inherent to a platform. this paper proposes an extension of the nsa cybersecurity directorate ' s platform attribute certificate creator ( paccor ) for the esp32, a widely - used microcontroller series. platform attribute certificates store device characteristics as per the trusted computing group ' s platform certificate profile. as of today, there is little research on hybrid attestation schemes utilizing platform attribute certificates on embedded devices, which this work addresses. this paper presents a collection of attacks that can be detected using paccor4esp. the toolkit extracts security - relevant information from an esp32 - s3, such as the firmware hash, bootloader hash, gpio pin configuration, and a reference to the endorsement key of the secure element, and automatically embeds it into a platform attribute certificate. lastly, this work shows how paccor4esp can be integrated with existing embedded device attestation frameworks, such as ras, craft, and seda.
|
arxiv:2407.14286
|
recent advancements in large language models ( llms ), particularly those built on transformer architectures, have significantly broadened the scope of natural language processing ( nlp ) applications, transcending their initial use in chatbot technology. this paper investigates the multifaceted applications of these models, with an emphasis on the gpt series. this exploration focuses on the transformative impact of artificial intelligence ( ai ) driven tools in revolutionizing traditional tasks like coding and problem - solving, while also paving new paths in research and development across diverse industries. from code interpretation and image captioning to facilitating the construction of interactive systems and advancing computational domains, transformer models exemplify a synergy of deep learning, data analysis, and neural network design. this survey provides an in - depth look at the latest research in transformer models, highlighting their versatility and the potential they hold for transforming diverse application sectors, thereby offering readers a comprehensive understanding of the current and future landscape of transformer - based llms in practical applications.
|
arxiv:2403.18969
|
we investigate the monotone representation and measurability of generalized $ \ psi $ - estimators introduced by the authors in 2022. our first main result, applying the unique existence of a generalized $ \ psi $ - estimator, allows us to construct this estimator in terms of a function $ \ psi $, which is decreasing in its second variable. we then interpret this result as a bridge from a nonconvex optimization problem to a convex one. further, supposing that the underlying measurable space ( sample space ) has a measurable diagonal and some additional assumptions on $ \ psi $, we show that the measurability of a generalized $ \ psi $ - estimator is equivalent to the measurability of the corresponding function $ \ psi $ in its first variable.
|
arxiv:2412.02783
|
we present a correspondence between two - dimensional $ \ mathcal { n } = ( 2, 2 ) $ supersymmetric gauge theories and rational integrable $ \ mathfrak { gl } ( m | n ) $ spin chains with spin variables taking values in verma modules. to explain this correspondence, we realize the gauge theories as configurations of branes in string theory and map them by dualities to brane configurations that realize line defects in four - dimensional chern - simons theory with gauge group $ \ mathrm { gl } ( m | n ) $. the latter configurations embed the superspin chains into superstring theory. we also provide a string theory derivation of a similar correspondence, proposed by nekrasov, for rational $ \ mathfrak { gl } ( m | n ) $ spin chains with spins valued in finite - dimensional representations.
|
arxiv:2110.15112
|
following sanchez ' s approach we investigate the effect of scalar mass in the absorption and emission problems of 4d schwarzschild black hole. the absorption cross sections for arbitrary angular momentum of the scalar field are computed numerically in the full range of energy by making use of the analytic near - horizon and asymptotic solutions and their analytic continuations. the scalar mass makes an interesting effect in the low - energy absorption cross section for s - wave. unlike the massless case, the cross section decreases with increasing energy in the extremely low - energy regime. as a result the universality, { \ it i. e. } low - energy cross section for s - wave is equal to the horizon area, is broken in the presence of mass. if the scalar mass is larger than a critical mass, the absorption cross section becomes monotonically decreasing function in the entire range of energy. the hawking emission is also calculated numerically. it turns out that the planck factor generally suppresses the contribution of higher partial waves except s - wave. the scalar mass in general tends to reduce the emission rate.
|
arxiv:hep-th/0403251
|
the detection of brown dwarfs in globular star clusters will allow us to break the degeneracies in age, mass and composition that affect our current models, and therefore to constrain the physics of their atmospheres and interiors. furthermore, detecting brown dwarfs will help us constrain the properties of the clusters themselves, as they carry information about the clusters ' age and dynamics. great advancements in this field are to be expected in the next ten years, thanks to the extraordinary sensitivity in the infrared of upcoming telescopes like jwst and the elts.
|
arxiv:1903.06769
|
we present a rigorous mathematical analysis of the modeling of inviscid water waves. the free - surface is described as a parametrized curve. we introduce a numerically stable algorithm which accounts for its evolution with time. the method is shown to converge using approximate solutions, such as stokes waves and green - naghdi solitary waves. it is finally tested on a wave breaking problem, for which an odd - even coupling suffices to achieve numerical convergence up to the splash without the need for additional filtering.
|
arxiv:2306.02363
|
the quasar oj ~ 287 has shown large flares since 1888, following a pattern that arises in a supermassive black hole binary when the secondary hits the accretion disk of the primary, and releases a hot bubble of gas at every disk crossing. a complete mathematical solution of the flare sequence produced a list of future flares, the latest happening in the summer of 2022. here i look into the origin of the idea that the lack of seeing the 2022 flare is a theoretical problem. during the summer oj ~ 287 cannot be observed by ground - based optical telescopes. in a paper published in 2021, ahead of the 2022 observing campaign, this was clearly stated. the often repeated claim that there is a " missing flare problem ", is a misunderstanding, as no detection was possible with the current instrumentation.
|
arxiv:2411.00908
|
for an investigation of the physical properties of gravitational fields the observation of massive test particles and light is very useful. the characteristic features of a given space - time may be decoded by studying the complete set of all possible geodesic motions. such a thorough analysis can be accomplished most effectively by using analytical methods to solve the geodesic equation. in this contribution, the use of elliptic functions and their generalizations for solving the geodesic equation in a wide range of well known space - times, which are part of the general pleba \ ' nski - demia \ ' nski family of solutions, will be presented. in addition, the definition and calculation of observable effects like the perihelion shift will be presented and further applications of the presented methods will be outlined.
|
arxiv:1506.00804
|
we derive several lubrication approximation models, using shikhmurzaev ' s approach to the contact line problem, obtained in \ cite { gnv }. the first two lubrication models describe thin film flow of incompressible fluids on solid substrates, based on different orders of magnitude of the slip length parameter. the third lubrication model describes a meniscus formation where a wedge - shaped solid immerses in a thin film of fluid.
|
arxiv:2112.12040
|
generative models are nowadays widely used to generate graphical content used for multiple purposes, e. g. web, art, advertisement. however, it has been shown that the images generated by these models could reinforce societal biases already existing in specific contexts. in this paper, we focus on understanding if this is the case when one generates images related to various software engineering tasks. in fact, the software engineering ( se ) community is not immune from gender and ethnicity disparities, which could be amplified by the use of these models. hence, if used without consciousness, artificially generated images could reinforce these biases in the se domain. specifically, we perform an extensive empirical evaluation of the gender and ethnicity bias exposed by three versions of the stable diffusion ( sd ) model ( a very popular open - source text - to - image model ) - sd 2, sd xl, and sd 3 - towards se tasks. we obtain 6, 720 images by feeding each model with two sets of prompts describing different software - related tasks : one set includes the software engineer keyword, and one set does not include any specification of the person performing the task. next, we evaluate the gender and ethnicity disparities in the generated images. results show how all models are significantly biased towards male figures when representing software engineers. on the contrary, while sd 2 and sd xl are strongly biased towards white figures, sd 3 is slightly more biased towards asian figures. nevertheless, all models significantly under - represent black and arab figures, regardless of the prompt style used. the results of our analysis highlight severe concerns about adopting those models to generate content for se tasks and open the field for future research on bias mitigation in this context.
|
arxiv:2501.09014
|
we prove the existence of s - integral solutions of simultaneous diophantine inequalities for pairs ( q, l ) involving one quadratic form and one linear form satisfying some arithmetico - geometric conditions. the proof uses strong approximation in algebraic groups and ratner ' s topological rigidity of unipotent actions on homogeneous spaces.
|
arxiv:1307.3761
|
computation of derivatives ( gradient and hessian ) of a fidelity function is one of the most crucial steps in many optimization algorithms. having access to accurate methods to calculate these derivatives is even more desired where the optimization process requires propagation of these calculations over many steps, which is in particular important in optimal control of spin systems. here we propose a novel numerical approach, escalade ( efficient spin control using analytical lie algebraic derivatives ) that offers the exact first and second derivatives of the fidelity function by taking advantage of the properties of the lie group of $ 2 \ times 2 $ hermitian matrices, $ \ mathrm { su } ( 2 ) $, and its lie algebra, the lie algebra of skew - hermitian matrices, $ \ mathfrak { su } ( 2 ) $. a full mathematical treatment of the proposed method along with some numerical examples are presented.
|
arxiv:2003.02011
|
many man - made and natural phenomena, including the intensity of earthquakes, population of cities and size of international wars, are believed to follow power - law distributions. the accurate identification of power - law patterns has significant consequences for correctly understanding and modeling complex systems. however, statistical evidence for or against the power - law hypothesis is complicated by large fluctuations in the empirical distribution ' s tail, and these are worsened when information is lost from binning the data. we adapt the statistically principled framework for testing the power - law hypothesis, developed by clauset, shalizi and newman, to the case of binned data. this approach includes maximum - likelihood fitting, a hypothesis test based on the kolmogorov - - smirnov goodness - of - fit statistic and likelihood ratio tests for comparing against alternative explanations. we evaluate the effectiveness of these methods on synthetic binned data with known structure, quantify the loss of statistical power due to binning, and apply the methods to twelve real - world binned data sets with heavy - tailed patterns.
|
arxiv:1208.3524
|
magnetisation of superconductors are often measured under isothermal and uniform magnetic fields. magnetisation measurements in an unrestricted thermodynamic state and in non uniform magnetic fields naturally emerge from permanent magnets in comparison with size of superconducting bulk are needed for practical applications. a stationary type ii superconductor bulk sample is magnetised ( fc and zfc ) at liquid nitrogen temperatures in the presence of a stationary permanent magnet. magnetic field produced by magnetised superconductor and permanent magnet as a function of distance are measured along a straight line, a supposed path of another moving permanent magnet. a moving magnet is introduced and moved along the same straight line. force acting on moving magnet as a function of distance are measured due to magnetisation in superconductor and stationary magnet. both field and force measurements are quasi static. these experimental results combined with simulation results show insight in to the transfer of energy stored in magnetisation to thermal energy and the effect of rate of this energy transfer in ac response of superconductors which are otherwise not possible with isothermal studies. a possible application of reversible braking with bulk superconductors for motors and generators is explored. future similar measurements with type i superconductor would provide more insights in to this study.
|
arxiv:1908.10297
|
in this chapter we provide an overview of the science enabled by radio continuum surveys in the ska era, focusing on galaxy / galaxy cluster physics and evolution studies, and other relevant continuum science in the > 2020 scientific framework. we outline a number of ' reference ' radio - continuum surveys for ska1 that can address such topics, and comprehensively discuss the most critical science requirements that we have identified. we highlight what should be achieved by ska1, to guarantee a major leap forwards with respect to the pre - ska era, considering the science advances expected in the coming years with existing and upcoming telescopes ( jvla, lofar, emerlin, and the three ska precursors : mwa, askap and meerkat ). in this exercise we take in due account also the other waveband facilities coming online at the same time ( e. g. euclid, lsst, etc. ), which tackle overlapping scientific goals, but in a different manner. in this respect particular attention has been payed to ensure that the proposed reference surveys are able to exploit the existing synergies with such facilities, so as to generate strong involvement from all astronomical communities, and leave a lasting legacy value. it is clear that a certain degree of freedom is allowed to some of the observational parameters. we believe it is very important to best fine - tune such parameters taking into proper account existing commensalities with ska1 surveys addressing other science areas ( hi galaxy science, magnetism, cosmology ).
|
arxiv:1412.6512
|
a model is presented based on a dipole picture with a hard and a soft pomeron. it is assumed that large dipoles couple to the soft pomeron and small dipoels couple to the hard pomeron. most of the parameters of the model are predetermined from proton - proton scattering and the only free parameter is the radius rc, defining the transition from small to large dipoles. this is fixed by the proton structure function. the model then successfully predicts the proton charm and longitudinal structure functions, j / psi photoproduction, the dvcs cross section, the total gamma - p and gamma - gamma cross sections and the photon structure function.
|
arxiv:hep-ph/0508261
|
in 1999 thomas appelquist, andrew g. cohen, and martin schmaltz ( acs ) proposed a constraint on the structure of asymptotically - free field theories. this constraint limits the number of degrees of freedom of asymptotically - free gauge theories in the infrared ( $ ir $ ) region relative to those in the ultra - violet ( $ uv $ ) region. in their paper acs checked various examples, both supersymmetric and non - supersymmetric, but checked only one case of interacting $ ir $ fixed point with superpotential - the case of seiberg - dual of $ su ( n _ { c } ) $ gauge theory. here we will verify the conjecture for two new cases - $ so ( n _ { c } ) $ and $ sp ( 2n _ { c } ) $ gauge groups around the banks - zaks fixed points. in addition, we subject the acs inequality to a series of nontrivial tests in theories with conjectured accidental symmetries in the $ ir $ and dramatically different dynamics caused by superpotential deformations. we start with $ ade $ - type deformations then move on to check three chiral theories by estimating their decoupled invariants from the chiral ring using a - maximization and unitarity considerations. remarkably, we found no violation of the acs conjecture.
|
arxiv:1401.3963
|
the two - loop invariant ( running ) coupling of qcd is written in terms of the lambert w function. the analyticity structure of the coupling in the complex q ^ 2 - plane is established. the corresponding analytic coupling is reconstructed via a dispersion relation. we also consider some other approximations to the qcd beta - function, when the corresponding couplings are solved in terms of the lambert function. the landau gauge gluon propagator has been considered in the renormalization group invariant analytic approach ( iaa ). it is shown that there is a nonperturbative ambiguity in determination of the anomalous dimension function of the gluon field. several analytic solutions for the propagator at the one - loop order are constructed. properties of the obtained analytical solutions are discussed.
|
arxiv:hep-ph/9911456
|
we study a class of nonlinear eigenvalue problems of schr \ " { o } dinger type, where the potential is singular on a set of points. such problems are widely present in physics and chemistry, and their analysis is of both theoretical and practical interest. in particular, we study the regularity of the eigenfunctions of the operators considered, and we propose and analyze the approximation of the solution via an isotropically refined $ hp $ discontinuous galerkin ( dg ) method. we show that, for weighted analytic potentials and for up - to - quartic polynomial nonlinearities, the eigenfunctions belong to analytic - type non homogeneous weighted sobolev spaces. we also prove quasi optimal a priori estimates on the error of the dg finite element method ; when using an isotropically refined $ hp $ space the numerical solution is shown to converge with exponential rate towards the exact eigenfunction. we conclude with a series of numerical tests to validate the theoretical results.
|
arxiv:1912.07483
|
contributions to b - \ bar b mixing from physics beyond the standard model may be detected from cp - violating asymmetries in b decays. there exists the possibility of large new contributions that cannot be detected by first generation experiments because of a discrete ambiguity. some possible strategies for resolving this are discussed.
|
arxiv:hep-ph/9801386
|
in this paper, we establish the well - posedness and stability of distributed parameter systems, focusing on linear positive control systems in a banach lattice setting. we characterize well - posedness and derive a sufficient condition for admissibility based on a lower norm estimate of the resolvent operator on the positive cone. furthermore, we analyze input - to - state stability ( iss ) under boundary perturbations within the domain of the semigroup generator. notably, we provide necessary and sufficient conditions for the robustness of iss under desch - schappacher perturbations. our theoretical results are demonstrated through a boundary value - controlled transport equation with non - local boundary conditions.
|
arxiv:2503.04097
|
for an undirected simple graph $ g $, we write $ g \ rightarrow ( h _ 1, h _ 2 ) ^ v $ if and only if for every red - blue coloring of its vertices there exists a red $ h _ 1 $ or a blue $ h _ 2 $. the generalized vertex folkman number $ f _ v ( h _ 1, h _ 2 ; h ) $ is defined as the smallest integer $ n $ for which there exists an $ h $ - free graph $ g $ of order $ n $ such that $ g \ rightarrow ( h _ 1, h _ 2 ) ^ v $. the generalized edge folkman numbers $ f _ e ( h _ 1, h _ 2 ; h ) $ are defined similarly, when colorings of the edges are considered. we show that $ f _ e ( k _ { k + 1 }, k _ { k + 1 } ; k _ { k + 2 } - e ) $ and $ f _ v ( k _ k, k _ k ; k _ { k + 1 } - e ) $ are well defined for $ k \ geq 3 $. we prove the nonexistence of $ f _ e ( k _ 3, k _ 3 ; h ) $ for some $ h $, in particular for $ h = b _ 3 $, where $ b _ k $ is the book graph of $ k $ triangular pages, and for $ h = k _ 1 + p _ 4 $. we pose three problems on generalized folkman numbers, including the existence question of edge folkman numbers $ f _ e ( k _ 3, k _ 3 ; b _ 4 ) $, $ f _ e ( k _ 3, k _ 3 ; k _ 1 + c _ 4 ) $ and $ f _ e ( k _ 3, k _ 3 ; \ overline { p _ 2 \ cup p _ 3 } ) $. our results lead to some general inequalities involving two - color and multicolor folkman numbers.
|
arxiv:1705.06268
|
we propose generalized equilibria of a three - dimensional color - gradient lattice boltzmann model for two - component two - phase flows using higher - order hermite polynomials. although the resulting equilibrium distribution function, which includes a sixth - order term on the velocity, is computationally cumbersome, its equilibrium central moments ( cms ) are velocity - independent and have a simplified form. numerical experiments show that our approach, as in wen et al. [ phys. rev. e 100, 023301 ( 2019 ) ] who consider terms up to third order, improves the galilean invariance compared to that of the conventional approach. dynamic problems can be solved with high accuracy at a density ratio of 10 ; however, the accuracy is still limited to a density ratio of $ 1 \, 000 $. for lower density ratios, the generalized equilibria benefit from the cm - based multiple - relaxation - time model, especially at very high reynolds numbers, significantly improving the numerical stability.
|
arxiv:2309.07801
|
we address the parallelization of the lu factorization of hierarchical matrices ( $ \ mathcal { h } $ - matrices ) arising from boundary element methods. our approach exploits task - parallelism via the ompss programming model and runtime, which discovers the data - flow parallelism intrinsic to the operation at execution time, via the analysis of data dependencies based on the memory addresses of the tasks ' operands. this is especially challenging for $ \ mathcal { h } $ - matrices, as the structures containing the data vary in dimension during the execution. we tackle this issue by decoupling the data structure from that used to detect dependencies. furthermore, we leverage the support for weak operands and early release of dependencies, recently introduced in ompss - 2, to accelerate the execution of parallel codes with nested task - parallelism and fine - grain tasks.
|
arxiv:1906.00874
|
this decade is marked by the introduction of vision transformer, a radical paradigm shift in broad computer vision. a similar trend is followed in medical imaging, unet, one of the most influential architectures, has been redesigned with transformers. recently, the efficacy of convolutional models in vision is being reinvestigated by seminal works such as convnext, which elevates a resnet to swin transformer level. deriving inspiration from this, we aim to improve a purely convolutional unet model so that it can be on par with the transformer - based models, e. g, swin - unet or uctransnet. we examined several advantages of the transformer - based unet models, primarily long - range dependencies and cross - level skip connections. we attempted to emulate them through convolution operations and thus propose, acc - unet, a completely convolutional unet model that brings the best of both worlds, the inherent inductive biases of convnets with the design decisions of transformers. acc - unet was evaluated on 5 different medical image segmentation benchmarks and consistently outperformed convnets, transformers, and their hybrids. notably, acc - unet outperforms state - of - the - art models swin - unet and uctransnet by $ 2. 64 \ pm 2. 54 \ % $ and $ 0. 45 \ pm 1. 61 \ % $ in terms of dice score, respectively, while using a fraction of their parameters ( $ 59. 26 \ % $ and $ 24. 24 \ % $ ). our codes are available at https : / / github. com / kiharalab / acc - unet.
|
arxiv:2308.13680
|
a monte carlo simulation of the $ o ( 4 ) $ $ \ lambda \ phi ^ 4 $ theory in the broken phase is performed on a hypercubic lattice in search of an $ i = 1 $, $ j = 1 $ resonance. we investigate the region of the cutoff theory where the interaction is strong as it is there that a resonance would be expected to have a better chance to form. in that region the presence of an $ i = 1 $, $ j = 1 $ resonance with mass below the cutoff is excluded. note : the full ps file is also available via anonymous ftp to ftp. scri. fsu. edu. to get the ps file, ftp to this address and use for username " anonymous " and for password your name. the file is in the directory pub / vranas ( to go to that directory type : cd pub / vranas ) and is called lat92 _ proc _ rho. ps ( to get it type : get lat92 _ proc _ rho. ps )
|
arxiv:hep-lat/9210034
|
, boom acquired a former reactionengines hypersonic test facility at colorado air and space port, to serve as the dedicated test site for the symphony engine. = = = mach 4 airliner concept = = = boom supersonic is participating in a nasa - led study to develop concept designs and technology roadmaps for a mach 4 airliner. boom is part of a team led by northrop grumman aeronautics systems, alongside blue ridge research and consulting and rolls - royce north american technologies. = = see also = = supersonic business jet aerion concorde exosonic spike s - 512 = = references = =
|
https://en.wikipedia.org/wiki/Boom_Technology
|
galaxy cluster mergers that exhibit clear dissociation between their dark matter, intracluster gas, and stellar components are great laboratories for probing dark matter properties. mergers that are binary and in the plane of the sky have the additional advantage of being simpler to model, allowing for a better understanding of the merger dynamics. we report the discovery of a galaxy cluster merger with all these characteristics and present a multiwavelength analysis of the system, which was found via a search in the redmapper optical cluster catalog. we perform a galaxy redshift survey to confirm the two subclusters are at the same redshift ( 0. 541, with $ 368 \ pm519 $ km s $ ^ { - 1 } $ line - of - sight velocity difference between them ). the x - ray morphology shows two surface - brightness peaks between the bcgs. we construct weak lensing mass maps that reveal a mass peak associated with each subcluster. fitting nfw profiles to the lensing data, we find masses of $ m _ { \ rm 200c } = 36 \ pm11 \ times10 ^ { 13 } $ and $ 38 \ pm11 \ times10 ^ { 13 } $ m $ _ \ odot / h $ for the southern and northern subclusters respectively. from the mass maps, we infer that the two mass peaks are separated by $ 520 ^ { + 162 } _ { - 125 } $ kpc along the merger axis, whereas the two bcgs are separated by 697 kpc. we also present deep gmrt 650 mhz data to search for a radio relic or halo, and find none. using the observed merger parameters, we find analog systems in cosmological n - body simulations and infer that this system is observed between 96 - 236 myr after pericenter, with the merger axis within $ 28 ^ { \ circ } $ of the plane of the sky.
|
arxiv:2307.10174
|
prostate cancer is a dominant health concern calling for advanced diagnostic tools. utilizing digital pathology and artificial intelligence, this study explores the potential of 11 deep neural network architectures for automated gleason grading in prostate carcinoma focusing on comparing traditional and recent architectures. a standardized image classification pipeline, based on the aucmedi framework, facilitated robust evaluation using an in - house dataset consisting of 34, 264 annotated tissue tiles. the results indicated varying sensitivity across architectures, with convnext demonstrating the strongest performance. notably, newer architectures achieved superior performance, even though with challenges in differentiating closely related gleason grades. the convnext model was capable of learning a balance between complexity and generalizability. overall, this study lays the groundwork for enhanced gleason grading systems, potentially improving diagnostic efficiency for prostate cancer.
|
arxiv:2403.16695
|
we show the existence of the so - called semiclassical states $ \ mathbf { u } : \ mathbb { r } ^ 3 \ to \ mathbb { r } ^ 3 $ to the following curl - curl problem $ $ \ varepsilon ^ 2 \ ; \ nabla \ times ( \ nabla \ times \ mathbf { u } ) + v ( x ) \ mathbf { u } = g ( \ mathbf { u } ), $ $ for sufficiently small $ \ varepsilon > 0 $. we study the asymptotic behaviour of solutions as $ \ varepsilon \ to 0 ^ + $ and we investigate also a related nonlinear schr \ " odinger equation involving a singular potential. the problem models large permeability nonlinear materials satisfying the system of maxwell equations.
|
arxiv:2312.03658
|
automated classification of metadata of research data by their discipline ( s ) of research can be used in scientometric research, by repository service providers, and in the context of research data aggregation services. openly available metadata of the datacite index for research data were used to compile a large training and evaluation set comprised of 609, 524 records, which is published alongside this paper. these data allow to reproducibly assess classification approaches, such as tree - based models and neural networks. according to our experiments with 20 base classes ( multi - label classification ), multi - layer perceptron models perform best with a f1 - macro score of 0. 760 closely followed by long short - term memory models ( f1 - macro score of 0. 755 ). a possible application of the trained classification models is the quantitative analysis of trends towards interdisciplinarity of digital scholarly output or the characterization of growth patterns of research data, stratified by discipline of research. both applications perform at scale with the proposed models which are available for re - use.
|
arxiv:1910.09313
|
superconducting quantum computing technology has ushered in a new era of computational possibilities. while a considerable research effort has been geared toward improving the quantum technology and building the software stack to efficiently execute quantum algorithms with reduced error rate, effort toward optimizing how quantum output states are defined and classified for the purpose of reducing the error rate is still limited. to this end, this paper proposes disq, a quantum output state classification approach which reduces error rates of quantum programs on nisq devices.
|
arxiv:2102.01153
|
heavy flavor particles provide important probes of the microscopic structure and thermodynamic properties of the quark - gluon plasma ( qgp ) produced in high - energy nucleus - nucleus collisions. we study the energy loss and flow of charm and bottom quarks inside the qgp via the nuclear modification factor ( $ r _ \ mathrm { aa } $ ) and elliptic flow coefficient ( $ v _ 2 $ ) of their decayed leptons in heavy - ion collisions at the lhc. the dynamical evolution of the qgp is performed using the ( 3 + 1 ) - dimensional viscous hydrodynamics model clvisc ; the evolution of heavy quarks inside the qgp is simulated with our improved langevin model that takes into account both collisional and radiative energy loss of heavy quarks ; the hadronization of heavy quarks is simulated via our hybrid coalescence - fragmentation model ; and the semi - leptonic decay of $ d $ and $ b $ mesons is simulated via pythia. by using the same spatial diffusion coefficient for charm and bottom quarks, we obtain smaller $ r _ \ mathrm { aa } $ and larger $ v _ 2 $ of charm decayed leptons than bottom decayed leptons, indicating stronger energy loss of charm quarks than bottom quarks inside the qgp within our current model setup.
|
arxiv:2403.07419
|
we study real time dynamics of a dp - brane orbiting a stack of ns5 - branes. it is generally known that a bps d - brane moving in the vicinity of ns5 - branes becomes unstable due to the presence of tachyonic degree of freedom induced on the d - brane. indeed, the d - brane necessarily falls into the fivebranes due to gravitational attraction and eventually collapses into a pressureless fluid. such a decay of the d - brane is known to be closely related to the rolling tachyon problem. in this paper we show that in special cases the decay of d - brane caused by gravitational attraction can be avoided. namely for certain values of energy and angular momentum the d - brane orbits around the fivebranes, maintaining certain distance from the fivebranes all the time, and the process of tachyon condensation is suppressed. we show that the tachyonic degree of freedom induced on such a d - brane really disappears and the brane returns to a stable d - brane.
|
arxiv:0911.4557
|
we use symbolic dynamics to study discrete - time dynamical systems with multiple time delays. we exploit the concept of avoiding sets, which arise from specific non - generating partitions of the phase space and restrict the occurrence of certain symbol sequences related to the characteristics of the dynamics. in particular, we show that the resulting forbidden sequences are closely related to the time delays in the system. we present two applications to coupled map lattices, namely ( 1 ) detecting synchronization and ( 2 ) determining unknown values of the transmission delays in networks with possibly directed and weighted connections and measurement noise. the method is applicable to multi - dimensional as well as set - valued maps, and to networks with time - varying delays and connection structure.
|
arxiv:0805.1837
|
the macwilliams identity, which relates the weight distribution of a code to the weight distribution of its dual code, is useful in determining the weight distribution of codes. in this paper, we derive the macwilliams identity for linear codes with the rank metric, and our identity has a different form than that by delsarte. using our macwilliams identity, we also derive related identities for rank metric codes. these identities parallel the binomial and power moment identities derived for codes with the hamming metric.
|
arxiv:0706.1751
|
the exclusive photoproduction of j / psi mesons, gamma p - > j / psi p, has been studied in ep collisions with the zeus detector at hera, in the kinematic range 20 < w < 290 gev, where w is the photon - proton centre - of - mass energy. the j / psi mesons were reconstructed in the muon and the electron decay channels using integrated luminosities of 38 pb ^ - 1 and 55 pb ^ - 1, respectively. the helicity structure of j / psi production shows that the hypothesis of s - channel helicity conservation is satisfied at the two standard - deviation level. the total cross section and the differential cross - section dsigma / dt, where t is the squared four - momentum transfer at the proton vertex, are presented as a function of w, for | t | < 1. 8 gev ^ 2. the t distribution exhibits an exponential shape with a slope parameter increasing logarithmically with w with a value b = 4. 15 \ pm 0. 05 ( stat. ) ^ { + 0. 30 } _ { - 0. 18 } ( syst. ) gev ^ - 2 at w = 90 gev. the effective parameters of the pomeron trajectory are alphapom ( 0 ) = 1. 200 \ pm 0. 009 ( stat. ) ^ { + 0. 004 } _ { - 0. 010 } ( syst. ) and alphappom = 0. 115 \ pm 0. 018 ( stat. ) ^ { + 0. 008 } _ { - 0. 015 } ( syst. ) gev ^ - 2.
|
arxiv:hep-ex/0201043
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.