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we describe the universal target of annular khovanov - rozansky link homology functors as the homotopy category of a free symmetric monoidal category generated by one object and one endomorphism. this categorifies the ring of symmetric functions and admits categorical analogues of plethystic transformations, which we use to characterize the annular invariants of coxeter braids. further, we prove the existence of symmetric group actions on the khovanov - rozansky invariants of cabled tangles and we introduce spectral sequences that aid in computing the homologies of generalized hopf links. finally, we conjecture a characterization of the horizontal traces of rouquier complexes of coxeter braids in other types. | arxiv:1904.04481 |
based on the nuclear attenuation data obtained by the hermes experiment on nitrogen and krypton nuclei, it is shown that the nuclear attenuation $ r _ m ^ { h } $ can be parametrised in a form of a linear polynomial $ p _ 1 = a _ { 11 } $ + $ \ tau a _ { 12 } $, where $ \ tau $ is the formation time, which depends on the energy of the virtual photon $ \ nu $ and fraction of that energy $ z $ carried by the final hadron. three widely known parameterizations for $ \ tau $ were used for the performed fit. the fit parameters $ a _ { 11 } $ and $ a _ { 12 } $ do not depend on $ \ nu $ and $ z $. | arxiv:hep-ph/0703124 |
coupling electromagnetic waves in a cavity and mechanical vibrations via the radiation pressure of the photons [ 1, 2 ] is a promising platform for investigations of quantum mechanical properties of motion of macroscopic bodies and thereby the limits of quantum mechanics [ 3, 4 ]. a drawback is that the effect of one photon tends to be tiny, and hence one of the pressing challenges is to substantially increase the interaction strength towards the scale of the cavity damping rate. a novel scenario is to introduce into the setup a quantum two - level system ( qubit ), which, besides strengthening the coupling, allows for rich physics via strongly enhanced nonlinearities [ 5 - 8 ]. addressing these issues, here we present a design of cavity optomechanics in the microwave frequency regime involving a josephson junction qubit. we demonstrate boosting of the radiation pressure interaction energy by six orders of magnitude, allowing to approach the strong coupling regime, where a single quantum of vibrations shifts the cavity frequency by more than its linewidth. we observe nonlinear phenomena at single - photon energies, such as an enhanced damping due to the two - level system. this work opens up nonlinear cavity optomechanics as a plausible tool for the study of quantum properties of motion. | arxiv:1412.5518 |
shared memory programming models usually provide worksharing and task constructs. the former relies on the efficient fork - join execution model to exploit structured parallelism ; while the latter relies on fine - grained synchronization among tasks and a flexible data - flow execution model to exploit dynamic, irregular, and nested parallelism. on applications that show both structured and unstructured parallelism, both worksharing and task constructs can be combined. however, it is difficult to mix both execution models without penalizing the data - flow execution model. hence, on many applications structured parallelism is also exploited using tasks to leverage the full benefits of a pure data - flow execution model. however, task creation and management might introduce a non - negligible overhead that prevents the efficient exploitation of fine - grained structured parallelism, especially on many - core processors. in this work, we propose worksharing tasks. these are tasks that internally leverage worksharing techniques to exploit fine - grained structured loop - based parallelism. the evaluation shows promising results on several benchmarks and platforms. | arxiv:2004.03258 |
the alcap experiment is a joint venture between the comet and mu2e collaborations that will measure the rate and spectrum of particles emitted after nuclear muon capture on aluminium. both collaborations will search for the charged lepton flavour violating process of neutrinoless muon - to - electron conversion by stopping muons in an aluminium target. knowledge of other particles emitted during this process is important. the alcap charged particle emission data was collected at the paul scherrer institut in switzerland over two runs in 2013 and 2015. in this talk, the experiment will be described and the current status will be presented. | arxiv:1809.10122 |
we discuss possible symmetries of effective theories describing spinless and spin 1 bosons, mainly to concentrate on an intriguing phenomenological possibility : that of a hardly noticeable strong electroweak sector at relatively low energies. specifically, a model with both vector and axial vector strong interacting bosons may possess a discrete symmetry imposing degeneracy of the two sets of bosons ( degenerate bess model ). in such a case its effects at low energies become almost invisible and the model easily passes all low energy precision tests. the reason lies essentially in the fact that the model automatically satisfies decoupling, contrary to models with only vectors. for large mass of the degenerate spin one bosons the model becomes identical at the classical level to the standard model taken in the limit of infinite higgs mass. for these reasons we have thought it worthwhile to fully develop the model, together with its possible generalizations, and to study the expected phenomenology. for instance, just because of its invisibility at low energy, it is conceivable that degenerate bess has low mass spin one states and gives quite visible signals at existing or forthcoming accelerators. | arxiv:hep-ph/9510431 |
in this article, we consider a dynamic epidemiology model for the spread of the covid - 19 infection. starting from the classical seir model, the model is modified so as to better describe characteristic features of the underlying pathogen and its infectious modes. in line with the large number of secondary infections not related to contact with documented infectious individuals, the model includes a cohort of asymptomatic or oligosymptomatic infectious individuals, not accounted for in the data of new daily counts of infections. a bayesian particle filtering algorithm is used to update dynamically the relevant cohort and simultaneously estimate the transmission rate as the new data on the number of new infections and disease related death become available. the underlying assumption of the model is that the infectivity rate is dynamically changing during the epidemics, either because of a mutation of the pathogen or in response to mitigation and containment measures. the sequential bayesian framework naturally provides a quantification of the uncertainty in the estimate of the model parameters, including the reproduction number, and of the size of the different cohorts. moreover, we introduce a dimensionless quantity, which is the equilibrium ratio between asymptomatic and symptomatic cohort sizes, and propose a simple formula to estimate the quantity. this ratio leads naturally to another dimensionless quantity that plays the role of the basic reproduction number $ r _ 0 $ of the model. when we apply the model and particle filter algorithm to covid - 19 infection data from several counties in northeastern ohio and southeastern michigan we found the proposed reproduction number $ r _ 0 $ to have a consistent dynamic behavior within both states, thus proving to be a reliable summary of the success of the mitigation measures. | arxiv:2005.04365 |
let $ \ mathcal { l } = \ sum _ { j = 1 } ^ { m } x _ { j } ^ { 2 } $ be a h \ " { o } rmander sum of squares of vector fields in $ \ mathbb { r } ^ { n } $, where any $ x _ { j } $ is homogeneous of degree $ 1 $ with respect to a family of non - isotropic dilations in $ \ mathbb { r } ^ { n } $. then $ \ mathcal { l } $ is known to admit a global fundamental solution $ \ gamma ( x ; y ) $, that can be represented as the integral of a fundamental solution of a sublaplacian operator on a lifting space $ \ mathbb { r } ^ { n } \ times \ mathbb { r } ^ { p } $, equipped with a carnot group structure. the aim of this paper is to prove global pointwise ( upper and lower ) estimates of $ \ gamma $, in terms of the carnot - carath \ ' { e } odory distance induced by $ x = \ { x _ { 1 }, \ ldots, x _ { m } \ } $ on $ \ mathbb { r } ^ { n } $, as well as global pointwise ( upper ) estimates for the $ x $ - derivatives of any order of $ \ gamma $, together with suitable integral representations of these derivatives. the least dimensional case $ n = 2 $ presents several peculiarities which are also investigated. applications to the potential theory for $ \ mathcal { l } $ and to singular - integral estimates for the kernel $ x _ { i } x _ { j } \ gamma $ are also provided. finally, most of the results about $ \ gamma $ are extended to the case of h \ " { o } rmander operators with drift $ \ sum _ { j = 1 } ^ { m } x _ { j } ^ { 2 } + x _ { 0 } $, where $ x _ { 0 } $ is $ 2 $ - homogeneous and $ x _ { 1 },..., x _ { m } $ are $ 1 $ - homogeneous. | arxiv:1906.07836 |
we study from first principles the emission linewidth of eu $ ^ { 2 + } $ - doped led phosphors. based on the one - dimensional configuration coordinate model, an analysis of first principles data obtained for fifteen compounds show that, at working temperature, the linewidth of eu $ ^ { 2 + } $ emission band in solids is negligibly affected by quantum effects, and can be extracted from the franck - condon energy shifts. for a fixed stokes shift, the difference of franck - condon energy shifts in the excited and ground states is the key factor for the fwhm determination. narrow emission eu $ ^ { 2 + } $ - doped led phosphors are expected for the case with large positive value of such difference. | arxiv:2109.05780 |
this work studies the statistical properties of the maximum penalized likelihood approach in a semi - parametric framework. we recall the penalized likelihood approach for estimating a function and review some asymptotic results. we investigate the properties of two estimators of the variance of maximum penalized likelihood estimators : sandwich estimator and a bayesian estimator. the coverage rates of confidence intervals based on these estimators are studied through a simulation study of survival data. in a first simulation the coverage rates for the survival function and the hazard function are evaluated. in a second simulation data are generated from a proportional hazard model with covariates. the estimators of the variances of the regression coefficients are studied. as for the survival and hazard functions, both sandwich and bayesian estimators exhibit relatively good properties, but the bayesian estimator seems to be more accurate. as for the regression coefficients, we focussed on the bayesian estimator and found that it yielded good coverage rates. | arxiv:1401.7893 |
inelastic photoproduction of $ j / \ psi $ particles at high energies is one of the processes to determine the gluon distribution in the nucleon. the qcd radiative corrections to the color - singlet model of this reaction have recently been calculated. they are large at moderate photon energies, but decrease with increasing energies. i compare the cross section and the $ { j / \ psi } $ energy spectrum with the available fixed - target photoproduction data. predictions for the hera energy range are given which demonstrate the sensitivity of the result to the parametrization of the gluon distribution in the small - $ x $ region. ( talk presented at the workshop on " heavy quark physics ", bad honnef, frg, dec. 1994 ) | arxiv:hep-ph/9504255 |
we investigate potential correlations between radio source counts ( after background corrections ) of 22 galactic globular clusters ( gcs ) from the maveric survey, and stellar encounter rates ( $ \ gamma $ ) and masses ( $ m $ ) of the gcs. applying a radio luminosity limit of $ l _ \ mathrm { lim } = 5. 0 \ times 10 ^ { 27 } ~ \ mathrm { erg ~ s ^ { - 1 } } $, we take a census of radio sources in the core and those within the half - light radius. by following a maximum likelihood method and adopting a simplified linear model, we find an unambiguous dependence of core radio source counts on $ \ gamma $ and / or $ m $ at 90 % confidence, but no clear dependence of source counts within the half - light radius on either $ \ gamma $ or $ m $. five of the identified radio sources in cores above our adopted limit are millisecond pulsars or neutron star x - ray binaries ( xrbs ), the dependence of which on $ \ gamma $ is well - known, but another is a published black hole ( bh ) xrb candidate, and ten others are not identified. accounting for the verified cluster members increases the significance of correlation with $ m $ and / or $ \ gamma $ ( to 99 % confidence ), for fits to core and half - light region source counts, while excluding a dependence on $ \ gamma $ alone at 90 % ( core ) and 68 % ( half - light ) confidence. this is consistent with published dynamical simulations of gc bh interactions that argue $ \ gamma $ will be a poor predictor of the distribution of accreting bhs in gcs. future multiwavelength follow - up to verify cluster membership will enable stronger constraints on the dependence of radio source classes on cluster properties, promising a new view on the dynamics of bhs in gcs. | arxiv:2104.12049 |
we consider the wilson loop expectation in su ( 2 ) lattice gauge theory in the presence of constraints. the constraints eliminate from the functional measure gauge field configurations whose physical interpretation is that of thick center vortices linking with the loop. we give a simple proof that, for dimension $ d \ geq 3 $, the so constrained wilson loop follows perimeter law, i. e. non - confining behavior, at weak coupling ( low temperature ). thus the presence of vortex configurations is a necessary condition for confinement. | arxiv:hep-lat/9806030 |
we show that untwisted respectively twisted conjugacy classes of a compact and simply connected lie group which satisfy a certain integrality condition correspond naturally to irreducible highest weight representations of the corresponding affine lie algebra. along the way, review the classification of twisted conjugacy classes of a simply connected compact lie group $ g $ and give a description of their stabilizers in terms of the dynkin diagram of the corresponding twisted affine lie algebra. | arxiv:math/0303118 |
in this paper we explore the extent to which the algebraic structure of a monoid $ m $ determines the topologies on $ m $ that are compatible with its multiplication. specifically we study the notions of automatic continuity ; minimal hausdorff or polish semigroup topologies ; and we formulate a notion of the zariski topology for monoids. if $ m $ is a topological monoid such that every homomorphism from $ m $ to a second countable topological monoid $ n $ is continuous, then we say that $ m $ has \ emph { automatic continuity }. we show that many well - known monoids have automatic continuity with respect to a natural semigroup topology, namely : the full transformation monoid $ \ mathbb { n } ^ \ mathbb { n } $ ; the full binary relation monoid $ b _ { \ mathbb { n } } $ ; the partial transformation monoid $ p _ { \ mathbb { n } } $ ; the symmetric inverse monoid $ i _ { \ mathbb { n } } $ ; the monoid inj $ ( \ mathbb { n } ) $ consisting of the injective functions on $ \ mathbb { n } $ ; and the monoid $ c ( 2 ^ { \ mathbb { n } } ) $ of continuous functions on the cantor set. we show that the pointwise topology on $ \ mathbb { n } ^ \ mathbb { n } $, and its analogue on $ p _ { \ mathbb { n } } $, are the unique polish semigroup topologies on these monoids. the compact - open topology is the unique polish semigroup topology on $ c ( 2 ^ \ mathbb { n } ) $ and $ c ( [ 0, 1 ] ^ \ mathbb { n } ) $. there are at least 3 polish semigroup topologies on $ i _ { \ mathbb { n } } $, but a unique polish inverse semigroup topology. there are no polish semigroup topologies $ b _ { \ mathbb { n } } $ nor on the partitions monoids. at the other extreme, inj $ ( \ mathbb { n } ) $ and the monoid surj $ ( \ mathbb { n } ) $ of all surjective functions on $ \ mathbb { n } $ each have infinitely many distinct polish semigroup topologies. we prove that the zariski topologies on $ \ mathbb { n } | arxiv:1912.07029 |
geodesic orbit spaces ( or g. o. spaces ) are defined as those homogeneous riemannian spaces $ ( m = g / h, g ) $ whose geodesics are orbits of one - parameter subgroups of $ g $. the corresponding metric $ g $ is called a geodesic orbit metric. we study the geodesic orbit spaces of the form $ ( g / h, g ) $, such that $ g $ is one of the compact classical lie groups $ \ so ( n ) $, $ u ( n ) $, and $ h $ is a diagonally embedded product $ h _ 1 \ times \ cdots \ times h _ s $, where $ h _ j $ is of the same type as $ g $. this class includes spheres, stiefel manifolds, grassmann manifolds and real flag manifolds. the present work is a contribution to the study of g. o. spaces $ ( g / h, g ) $ with $ h $ semisimple. | arxiv:2103.02908 |
adiabatic effective action for vortices in neutral and charged superfluids at zero temperature are calculated using the topological landau - ginzburg theory recently proposed by hatsuda, yahikozawa, ao and thouless, and vortex dynamics are examined. the berry phase term arising in the effective action naturally yields the magnus force in both neutral and charged superfluids. it is shown that in neutral superfluid there is only one degree of freedom, namely the center of vorticities, and the vortex energy is proportinal to the sum of all vorticities so that it is finite only for the vanishing total vorticity of the system. on the other hand the effective mass and the vortex energy for a vortex in charged superfluids are defined individually as expected. the effects of the vortex core on these quantities are also estimated. the possible depinning scenario which is governed by the magnus force and the inertial mass is also discussed. | arxiv:cond-mat/9505158 |
we study thermodynamic properties of 2 + 1 flavor qcd applying the small flow - time expansion ( sftx ) method based on the gradient flow. the method provides us with a general way to compute correctly renormalized observables irrespective of explicit violation of symmetries due to the regularization, such as the poincare and chiral symmetries on the lattice. we report on the status of our on - going project to compute the energy - momentum tensor and the chiral condensate at the physical point with improved wilson quarks, extending our previous study with slightly heavy u and d quarks. we also report on our test of two - loop matching coefficients recently calculated by harlander et al., revisiting the case of qcd with slightly heavy u and d quarks. our results suggest that the sftx method is powerful in extracting physical observables on the lattice. | arxiv:1910.13036 |
in many methods of sound event detection ( sed ), a segmented time frame is regarded as one data sample to model training. the durations of sound events greatly depend on the sound event class, e. g., the sound event " fan " has a long duration, whereas the sound event " mouse clicking " is instantaneous. thus, the difference in the duration between sound event classes results in a serious data imbalance in sed. moreover, most sound events tend to occur occasionally ; therefore, there are many more inactive time frames of sound events than active frames. this also causes a severe data imbalance between active and inactive frames. in this paper, we investigate the impact of sound duration and inactive frames on sed performance by introducing four loss functions, such as simple reweighting loss, inverse frequency loss, asymmetric focal loss, and focal batch tversky loss. then, we provide insights into how we tackle this imbalance problem. | arxiv:2102.01927 |
the differential cross section of the process gamma gamma - > pi ^ 0 pi ^ 0 has been measured in the kinematical range 0. 6 gev < w < 4. 0 gev and | cos theta * | < 0. 8 in energy and pion scattering angle, respectively, in the gamma gamma center - of - mass system. we find at least four resonant structures including a peak from f _ 0 ( 980 ). in addition, there is evidence for chi _ { c0 } production. we also make a preliminary discussion of the angular dependence and cross section ratio to gamma gamma - > pi ^ + pi ^ -. | arxiv:0711.1926 |
the scattering amplitude for photoproduction of a large invariant mass diphoton in the generalized bjorken regime has a very peculiar and interesting analytical structure. the leading twist leading order amplitude is proportional to valence quark generalized parton distributions taken at the border value $ x = \ pm \ xi $. cross section estimates show that this process is measurable at jlab energies. the angular asymmetry triggered by a linearly polarized photon beam is large. | arxiv:1907.08431 |
we present a novel framework to regularize neural radiance field ( nerf ) in a few - shot setting with a geometry - aware consistency regularization. the proposed approach leverages a rendered depth map at unobserved viewpoint to warp sparse input images to the unobserved viewpoint and impose them as pseudo ground truths to facilitate learning of nerf. by encouraging such geometry - aware consistency at a feature - level instead of using pixel - level reconstruction loss, we regularize the nerf at semantic and structural levels while allowing for modeling view dependent radiance to account for color variations across viewpoints. we also propose an effective method to filter out erroneous warped solutions, along with training strategies to stabilize training during optimization. we show that our model achieves competitive results compared to state - of - the - art few - shot nerf models. project page is available at https : / / ku - cvlab. github. io / geconerf /. | arxiv:2301.10941 |
k. adaricheva and m. bolat have recently proved that if $ u _ 0 $ and $ u _ 1 $ are circles in a triangle with vertices $ a _ 0, a _ 1, a _ 2 $, then there exist $ j \ in \ { 0, 1, 2 \ } $ and $ k \ in \ { 0, 1 \ } $ such that $ u _ { 1 - k } $ is included in the convex hull of $ u _ k \ cup ( \ { a _ 0, a _ 1, a _ 2 \ } \ setminus \ { a _ j \ } ) $. one could say disks instead of circles. here we prove the existence of such a $ j $ and $ k $ for the more general case where $ u _ 0 $ and $ u _ 1 $ are compact sets in the plane such that $ u _ 1 $ is obtained from $ u _ 0 $ by a positive homothety or by a translation. also, we give a short survey to show how lattice theoretical antecedents, including a series of papers on planar semimodular lattices by g. gratzer and e. knapp, lead to our result. | arxiv:1807.03443 |
we have analyzed a dissipative two level quantum system ( tls ) which is continuously and simultaneously irradiated by a high and low frequency excitation. the interaction of the tls with a high frequency excitation is considered in the frame of the dressed state approach. a linear response of the coupled tls and corresponding photon field system to a signal whose frequency is of the order of the rabi frequency is found. the response exhibits undamped low frequency oscillations, whose amplitude has a clear resonance at the rabi frequency with the width being dependent on the damping rates of the tls. the method can be useful for low - frequency rabi spectroscopy in various physical systems described by a two - level hamiltonian, such as nuclei spins in nmr, double well quantum dots, superconducting flux and charge qubits, etc. the application of the method to a superconducting flux qubit and to the detection of nmr is considered in detail. | arxiv:cond-mat/0609144 |
1, 2 } ( \ mathbb { r } ^ { n } ), \ ] where $ 2 _ { n } ^ { \ ast } : = \ frac { 2n } { n - 2 } $ is the critical exponent in dimension $ n. $ \ medskip | arxiv:1703.02257 |
we present the quasar luminosity function ( lf ) at $ z = 7 $, measured with 35 spectroscopically confirmed quasars at $ 6. 55 < z < 7. 15 $. the sample of 22 quasars from the subaru high - $ z $ exploration of low - luminosity quasars ( shellqs ) project, combined with 13 brighter quasars in the literature, covers an unprecedentedly wide range of rest - frame ultraviolet magnitudes over $ - 28 < m _ { 1450 } < - 23 $. we found that the binned lf flattens significantly toward the faint end populated by the shellqs quasars. a maximum likelihood fit to a double power - law model has a break magnitude $ m ^ * _ { 1450 } = - 25. 60 ^ { + 0. 40 } _ { - 0. 30 } $, a characteristic density $ \ phi ^ * = 1. 35 ^ { + 0. 47 } _ { - 0. 30 } $ gpc $ ^ { - 3 } $ mag $ ^ { - 1 } $, and a bright - end slope $ \ beta = - 3. 34 ^ { + 0. 49 } _ { - 0. 57 } $, when the faint - end slope is fixed to $ \ alpha = - 1. 2 $ as observed at $ z \ le 6 $. the overall lf shape remains remarkably similar from $ z = 4 $ to $ 7 $, while the amplitude decreases substantially toward higher redshifts, with a clear indication of an accelerating decline at $ z \ ge 6 $. the estimated ionizing photon density, $ 10 ^ { 48. 2 \ pm 0. 1 } $ s $ ^ { - 1 } $ mpc $ ^ { - 3 } $, is less than 1 % of the critical rate to keep the intergalactic medium ionized at $ z = 7 $, and thus indicates that quasars are not a major contributor to cosmic reionization. | arxiv:2305.11225 |
in this article, we study the controllability issues of the landau - lifshitz - gilbert equations ( llges ), accompanied with non - zero exchange energy only, in an interval in one spatial dimension with neumann boundary conditions. the paper is of twofold. in the first part of the paper, we study the controllability issues of the llges. the control force acting here is degenerate i. e., it acts through a few numbers of low mode frequencies. we exploit the fourier series expansion of the solution. we borrow methods of differential geometric control theory ( lie bracket generating property ) to establish the global controllability of the finite - dimensional galerkin approximations of llges. we show $ l ^ 2 $ approximate controllability of the full system. in the second part, we consider the llges with lower - dimensional degenerate random forcing ( finite - dimensional brownian motions ) and study support theorems. | arxiv:2211.04204 |
there has been an increasing interest in 3d indoor navigation, where a robot in an environment moves to a target according to an instruction. to deploy a robot for navigation in the physical world, lots of training data is required to learn an effective policy. it is quite labour intensive to obtain sufficient real environment data for training robots while synthetic data is much easier to construct by rendering. though it is promising to utilize the synthetic environments to facilitate navigation training in the real world, real environment are heterogeneous from synthetic environment in two aspects. first, the visual representation of the two environments have significant variances. second, the houseplans of these two environments are quite different. therefore two types of information, i. e. visual representation and policy behavior, need to be adapted in the reinforcement model. the learning procedure of visual representation and that of policy behavior are presumably reciprocal. we propose to jointly adapt visual representation and policy behavior to leverage the mutual impacts of environment and policy. specifically, our method employs an adversarial feature adaptation model for visual representation transfer and a policy mimic strategy for policy behavior imitation. experiment shows that our method outperforms the baseline by 19. 47 % without any additional human annotations. | arxiv:1904.03895 |
recent findings of large anomalous hall signal in nonferromagnetic and nonferrimagnetic materials suggest that the magnetization of the system is not a critical component for the realization of the anomalous hall effect ( ahe ). here, we present a combined theoretical and experimental study demonstrating the evolution of different mechanisms of ahe in a cubic heusler system mnpt $ _ { 1 - x } $ ir $ _ x $ sn. with the help of magnetization and neutron diffraction studies, we show that the substitution of nonmagnetic ir in place of pt significantly reduces the net magnetic moment from 4. 17 $ \ mu _ b $ / f. u. in mnptsn to 2. 78 $ \ mu _ b $ / f. u. for mnpt $ _ { 0. 5 } $ ir $ _ { 0. 5 } $ sn. in contrast, the anomalous hall resistivity is enhanced by nearly three times from 1. 6 $ \ mu \ omega $ cm in mnptsn to about 5 $ \ mu \ omega $ cm for mnpt $ _ { 0. 5 } $ ir $ _ { 0. 5 } $ sn. the power law analysis of the hall resistivity data suggests that the extrinsic contribution of ahe that dominates in the case of the parent mnptsn almost vanishes for mnpt $ _ { 0. 5 } $ ir $ _ { 0. 5 } $ sn, where the intrinsic mechanism plays the major role. the experimental results are well supported by our theoretical study, which shows a considerable enhancement of the spin - orbit coupling when ir is introduced into the system. our finding of a crossover of the anomalous hall effect with chemical engineering is a major contribution toward the recent interest in controlling the band topology of topological materials, both in bulk and thin - film forms. | arxiv:2212.00360 |
dosimetry cross sections are fundamental quantities essential in determination of neutron fluences in points of interest in technologies under heavy radiation load. the most common is their application to reactor pressure vessel aging management, relating to correct estimation of its residual lifetime. the neutron spectrum in various reactor positions has a similar character as the fission spectrum. due to this fact, the validation of the neutron dosimetry cross sections in reactor fields, or in a very well - known neutron field of 252cf ( s. f. ) is sufficient for ensuring their validity in estimations of neutron fluxes in reactor physics. with an increasing field of applications, as in neutron dosimetry in accelerator - based fields or space applications, requests occurred on detailed validation in spectra different from fission ones. this paper presents the testing of a new methodology for the use of quasi monoenergetic neutron fields, where different sensitivity allows validations of the cross - section in different energy regions than in the fission spectrum. the exact shape of the neutron spectrum in the tested fields is determined by stilbene spectrometry and corrected to scattering by calculation, where applicable. the total flux is determined from ni and al flux monitors. the evaluated neutron flux in the target set of activation foils is used for calculation of theoretical reaction rate, which is compared with the experimental value determined from gamma activity. this kind of comparison can be understood as validation. it is worth noting, this methodology applied to the irdff - ii library shows satisfactory agreement for selected reactions. | arxiv:2306.09353 |
motivated by the nonlinear star formation efficiency found in recent numerical simulations by a number of workers, we perform high - resolution adaptive mesh refinement simulations of star formation in self - gravitating turbulently driven gas. as we follow the collapse of this gas, we find that the character of the flow changes at two radii, the disk radius $ r _ d $, and the radius $ r _ * $ where the enclosed gas mass exceeds the stellar mass. accretion starts at large scales and works inwards. in line with recent analytical work, we find that the density evolves to a fixed attractor, $ \ rho ( r, t ) \ rightarrow \ rho ( r ) $, for $ r _ d < r < r _ * $ ; mass flows through this structure onto a sporadically gravitationally unstable disk, and from thence onto the star. in the bulk of the simulation box we find that the random motions $ v _ t \ sim r ^ p $ with $ p \ sim 0. 5 $, in agreement with larson ' s size - linewidth relation. in the vicinity of massive star forming regions we find $ p \ sim 0. 2 - 0. 3 $, as seen in observations. for $ r < r _ * $, $ v _ t $ increases inward, with $ p = - 1 / 2 $. finally, we find that the total stellar mass $ m _ * ( t ) \ sim t ^ 2 $ in line with previous numerical and analytic work that suggests a nonlinear rate of star formation. | arxiv:1509.05910 |
the ramsey - tur \ ' an problem for $ k _ p $ asks for the maximum number of edges in an $ n $ - vertex $ k _ p $ - free graph with independence number $ o ( n ) $. in a natural generalization of the problem, cliques larger than the edge $ k _ 2 $ are counted. let { \ bf rt } $ ( n, \ # k _ q, k _ p, o ( n ) ) $ denote the maximum number of copies of $ k _ q $ in an $ n $ - vertex $ k _ p $ - free graph with independence number $ o ( n ) $. balogh, liu and sharifzadeh determined the asymptotics of { \ bf rt } $ ( n, \ # k _ 3, k _ p, o ( n ) ) $. in this paper we will establish the asymptotics for counting copies of $ k _ 4 $, $ k _ 5 $, and for the case $ p \ geq 5q $. we also provide a family of counterexamples to a conjecture of balogh, liu and sharifzadeh. | arxiv:2405.01804 |
renaissance technology was the set of european artifacts and inventions which spread through the renaissance period, roughly the 14th century through the 16th century. the era is marked by profound technical advancements such as the printing press, linear perspective in drawing, patent law, double shell domes and bastion fortresses. sketchbooks from artisans of the period ( taccola and leonardo da vinci, for example ) give a deep insight into the mechanical technology then known and applied. renaissance science spawned the scientific revolution ; science and technology began a cycle of mutual advancement. = = renaissance technology = = some important renaissance technologies, including both innovations and improvements on existing techniques : mining and metallurgy blast furnace enabled iron to be produced in significant quantities finery forge enabled pig iron ( from the blast furnace ) into bar iron ( wrought iron ) slitting mill mechanized the production of iron rods for nailmaking smeltmill increased the output of lead over previous methods ( bole hill ) = = = late 14th century = = = some of the technologies were the arquebus and the musket. = = = 15th century = = = the technologies that developed in europe during the second half of the 15th century were commonly associated by authorities of the time with a key theme in renaissance thought : the rivalry of the moderns and the ancients. three inventions in particular — the printing press, firearms, and the nautical compass — were indeed seen as evidence that the moderns could not only compete with the ancients, but had surpassed them, for these three inventions allowed modern people to communicate, exercise power, and finally travel at distances unimaginable in earlier times. crank and connecting rod the crank and connecting rod mechanism which converts circular into reciprocal motion is of utmost importance for the mechanization of work processes ; it is first attested for roman water - powered sawmills. during the renaissance, its use is greatly diversified and mechanically refined ; now connecting - rods are also applied to double compound cranks, while the flywheel is employed to get these cranks over the ' dead - spot '. early evidence of such machines appears, among other things, in the works of the 15th - century engineers anonymous of the hussite wars and taccola. from then on, cranks and connecting rods become an integral part of machine design and are applied in ever more elaborate ways : agostino ramelli ' s the diverse and artifactitious machines of 1588 depicts eighteen different applications, a number which rises in the 17th - century theatrum machinarum novum by georg andreas bo | https://en.wikipedia.org/wiki/Renaissance_technology |
the galactic globular cluster system is incomplete, especially in the low latitude regions of the galactic bulge and disk. we report the physical characterization of twelve star clusters in the milky way, most of which are explored here for the first time. our aim is determining their main physical parameters, such as reddening and extinction, metallicity, age, total luminosity, mean cluster proper motions ( pms ), distances, in order to unveil their physical nature. we study the clusters using optical and near - infrared ( nir ) datasets. we use the gaia early data release 3 ( edr3 ) pms in order to perform a pm - decontamination procedure and build final catalogues. we match the gaia edr3 with the vista variables in the v \ ' ia l \ ' actea extended ( vvvx ) survey and two micron all sky survey ( 2mass ) in the nir, in order to construct complete colour - magnitude diagrams ( cmds ) and investigate the clusters properties. the extinctions are evaluated using existing reddening maps, spanning $ 0. 09 \ lesssim a _ { ks } \ lesssim 0. 86 $ mag and $ 0. 89 \ lesssim a _ { g } \ lesssim 4. 72 $ mag in the nir and optical, respectively. we obtain their heliocentric distances, that range from about 4 to 20 kpc, placing these clusters at $ 3 \ lesssim r _ { g } \ lesssim 14 $ kpc from the galactic centre. the best parsec isochrone fit yields a metallicity range of $ - 1. 8 < $ [ fe / h ] $ < + 0. 3 $ and an approximative age range of $ 2 < $ age $ < 14 $ gyr. we find that all clusters have low - luminosities, with $ - 6. 9 < m _ { v } < - 3. 5 $ mag. based on our photometric analysis, we confirm the oc nature for kronberger100, while we classify patchick125 as a metal - poor gc, ferrero54 as a metal - rich gc, and eso92 - 18 as a possible old oc or young gc. the classification as gc candidates is also suggested for kronberger99, patchick122, patchick126, riddle15, fsr190 and | arxiv:2112.13591 |
we compute the upper characteristic rank of the projective stiefel manifolds over $ \ mathbb r, \ mathbb c $ and $ \ mathbb h $ and of the flip stiefel manifolds. we provide bounds for the cup lengths of these spaces. we also provide necessary conditions for existence of $ s ^ 3 $ - map between quaternionic stiefel manifolds using fadell - husseini index. | arxiv:2403.14207 |
in recent years, 3d vision has become a crucial field within computer vision, powering a wide range of applications such as autonomous driving, robotics, augmented reality, and medical imaging. this field relies on accurate perception, understanding, and reconstruction of 3d scenes from 2d images or text data sources. diffusion models, originally designed for 2d generative tasks, offer the potential for more flexible, probabilistic methods that can better capture the variability and uncertainty present in real - world 3d data. in this paper, we review the state - of - the - art methods that use diffusion models for 3d visual tasks, including but not limited to 3d object generation, shape completion, point - cloud reconstruction, and scene construction. we provide an in - depth discussion of the underlying mathematical principles of diffusion models, outlining their forward and reverse processes, as well as the various architectural advancements that enable these models to work with 3d datasets. we also discuss the key challenges in applying diffusion models to 3d vision, such as handling occlusions and varying point densities, and the computational demands of high - dimensional data. finally, we discuss potential solutions, including improving computational efficiency, enhancing multimodal fusion, and exploring the use of large - scale pretraining for better generalization across 3d tasks. this paper serves as a foundation for future exploration and development in this rapidly evolving field. | arxiv:2410.04738 |
random boolean networks, originally invented as models of genetic regulatory networks, are simple models for a broad class of complex systems that show rich dynamical structures. from a biological perspective, the most interesting networks lie at or near a critical point in parameter space that divides ` ` ordered ' ' from ` ` chaotic ' ' attractor dynamics. in the ordered regime, we show rigorously that the average number of relevant nodes ( the ones that determine the attractor dynamics ) remains constant with increasing system size n. for critical networks, our analysis and numerical results show that the number of relevant nodes scales like n ^ { 1 / 3 }. numerical experiments also show that the median number of attractors in critical networks grows faster than linearly with n. the calculations explain why the correct asymptotic scaling is observed only for very large n. | arxiv:cond-mat/0212306 |
the existence of standing high frequency electromagnetic ( em ) solitons in a fully degenerate overdense electron plasma is studied applying relativistic hydrodynamics and maxwell equations. the stable soliton solutions are found in both relativistic and nonrelativistic degenerate plasmas. | arxiv:1504.04305 |
for the large family of arma models with variable coefficients ( tv - arma ), either deterministic or stochastic, we provide an explicit and computationally tractable representation based on the general solution of the associated linear difference equation. analogous representations are established for the fundamental properties of such processes, including the wold - cram \ ' { e } r decomposition and their covariance structure as well as explicit optimal linear forecasts based on a finite set of past observations. these results are grounded on the principal determinant, that is a banded hessenbergian representation of a restriction of the green function involved in the solution of the linear difference equation associated with tv - arma models, built up solely of the autoregressive coefficients of the model. the $ l _ 2 $ convergence properties of the model are a consequence of the absolute summability of the aforementioned hessenbergian representation, which is in line with the asymptotic stability and efficiency of such processes. the invertibility of the model is also a consequence of an analogous condition, but now the green function is built up of the moving average coefficients. the structural asymmetry between constant and deterministically time - varying coefficient models, that is the backward and forward asymptotic efficiency differ in an essential manner, is formally demonstrated. an alternative approach to the hessenbergian solution representation is described by an equivalent procedure for manipulating time - varying polynomials. the practical significance of the theoretical results in this work is illustrated with an application to u. s. inflation data. the main finding is that inflation persistence increased after 1976, whereas from 1986 onwards the persistence declines and stabilizes to even lower levels than the pre - 1976 period. | arxiv:2110.06168 |
in this two - part study we develop a general approach to the design and analysis of exact penalty functions for various optimal control problems, including problems with terminal and state constraints, problems involving differential inclusions, as well as optimal control problems for linear evolution equations. this approach allows one to simplify an optimal control problem by removing some ( or all ) constraints of this problem with the use of an exact penalty function, thus allowing one to reduce optimal control problems to equivalent variational problems, apply numerical methods for solving, e. g. problems without state constraints, to problems including such constraints, etc. in the first part of our study we strengthen some existing results on exact penalty functions for optimisation problems in infinite dimensional spaces and utilise them to study exact penalty functions for free - endpoint optimal control problems, which reduce these problems to equivalent variational ones. we also prove several auxiliary results on integral functionals and nemytskii operators that are helpful for verifying the assumptions under which the proposed penalty functions are exact. | arxiv:1903.00236 |
a model of the heart tissue as a conductive system with two interacting pacemakers and a refractory time, is proposed. in the parametric space of the model the phase locking areas are investigated in detail. obtained results allow us to predict the behaviour of excitable systems with two pacemakers depending on the type and intensity of their interaction and the initial phase. comparison of the described phenomena with intrinsic pathologies of cardiac rhythms is presented. | arxiv:nlin/0212025 |
at qingdao city, shandong province. = = = department of mathematical sciences = = = the department of mathematical sciences ( dms ) was established in 1927. in 1952, tsinghua dms was merged with the peking university department of mathematical sciences. then in 1979 it was renamed " department of applied mathematics ", and renamed again in 1999 to its current title. tsinghua dms has three institutes at present, the institute of pure mathematics which has 27 faculty members, the institute of applied mathematics and probability and statistics which has 27 faculty members, and the institute of computational mathematics and operations research which has 20 faculty members. there are currently about 400 undergraduate students and 200 graduate students. = = = department of precision instrument = = = the department of precision instrument was called the department of precision instrument and machine manufacturing in 1960 when it was separated out from the department of machine manufacturing to be an independent department. later, in 1971, it was renamed the department of precision instrument. the mission of the department of precision instrument at tsinghua university, as its dean said, is " supporting the national development and improving the people ' s well - being. " = = = = research = = = = research in the department of precision instrument is divided to four main parts, led by its four research institutes : the institute of opto - electronic engineering, the institute of instrument science and technology, the engineering research center for navigation technology, and the center for photonics and electronics. at the same time, the department of precision instrument has three key laboratories : the state key laboratory of tribology, the state key laboratory of precision measurement technology and instruments, and the key laboratory of high - accuracy inertial instrument and system. it also has two national engineering research centers, which are the national engineering research center of optical disk and the cims national engineering research center. the institute of opto - electronic engineering the institute of opto - electronic engineering ( ioee ) was established in 1958. it obtained the chinese government ' s authorization to offer phd program in 1981 and the approval to build the post - doctoral research site in 1988. the research of the ioee covers opto - electronic instruments, precision metrology and measurement, modern optical information processing, the theory and components of binary optics, and the birefringent frequency - splitting lasers. several famous scientists work in the ioee, including professor guofan jin, an academician of the chinese academy of engineering, and professor kegong zhao, formerly the president of the chinese national institute of | https://en.wikipedia.org/wiki/Tsinghua_University |
foundation models ( fms ) currently dominate news headlines. they employ advanced deep learning architectures to extract structural information autonomously from vast datasets through self - supervision. the resulting rich representations of complex systems and dynamics can be applied to many downstream applications. therefore, fms can find uses in electric power grids, challenged by the energy transition and climate change. in this paper, we call for the development of, and state why we believe in, the potential of fms for electric grids. we highlight their strengths and weaknesses amidst the challenges of a changing grid. we argue that an fm learning from diverse grid data and topologies could unlock transformative capabilities, pioneering a new approach in leveraging ai to redefine how we manage complexity and uncertainty in the electric grid. finally, we discuss a power grid fm concept, namely gridfm, based on graph neural networks and show how different downstream tasks benefit. | arxiv:2407.09434 |
method comparisons are essential to provide recommendations and guidance for applied researchers, who often have to choose from a plethora of available approaches. while many comparisons exist in the literature, these are often not neutral but favour a novel method. apart from the choice of design and a proper reporting of the findings, there are different approaches concerning the underlying data for such method comparison studies. most manuscripts on statistical methodology rely on simulation studies and provide a single real - world data set as an example to motivate and illustrate the methodology investigated. in the context of supervised learning, in contrast, methods are often evaluated using so - called benchmarking data sets, i. e. real - world data that serve as gold standard in the community. simulation studies, on the other hand, are much less common in this context. the aim of this paper is to investigate differences and similarities between these approaches, to discuss their advantages and disadvantages and ultimately to develop new approaches to the evaluation of methods picking the best of both worlds. to this aim, we borrow ideas from different contexts such as mixed methods research and clinical scenario evaluation. | arxiv:2208.01457 |
entropy and free - energy estimation are key in thermodynamic characterization of simulated systems ranging from spin models through polymers, colloids, protein structure, and drug - design. current techniques suffer from being model specific, requiring abundant computation resources and simulation at conditions far from the studied realization. here, we present a universal scheme to calculate entropy using lossless compression algorithms and validate it on simulated systems of increasing complexity. our results show accurate entropy values compared to benchmark calculations while being computationally effective. in molecular - dynamics simulations of protein folding, we exhibit unmatched detection capability of the folded states by measuring previously undetectable entropy fluctuations along the simulation timeline. such entropy evaluation opens a new window onto the dynamics of complex systems and allows efficient free - energy calculations. | arxiv:1709.10164 |
in this paper, we are concerned with the boundary value problem in a slab for the stationary relativistic bgk model of marle type, which is a relaxation model of the relativistic boltzmann equation. in the case of fixed inflow boundary conditions, we establish the existence of unique stationary solutions. | arxiv:1801.08382 |
models with two scalar doublets are among the simplest extensions of the standard model which fulfill the relation $ \ rho = 1 $ at lowest order for the $ \ rho $ parameter as favored by experimental data for electroweak observables allowing only small deviations from unity. such small deviations $ \ delta \ rho $ originate exclusively from quantum effects with special sensitivity to mass splittings between different isospin components of fermions and scalars. in this paper the dominant two - loop electroweak corrections to $ \ delta \ rho $ are calculated in the $ cp $ - conserving thdm, resulting from the top - yukawa coupling and the self - couplings of the higgs bosons in the gauge - less limit. the on - shell renormalization scheme is applied. with the assumption that one of the $ cp $ - even neutral scalars represents the scalar boson observed by the lhc experiments, with standard properties, the two - loop non - standard contributions in $ \ delta \ rho $ can be separated from the standard ones. these contributions are of particular interest since they increase with mass splittings between non - standard higgs bosons and can be additionally enhanced by $ \ tan \ beta $ and $ \ lambda _ 5 $, an additional free coefficient of the higgs potential, and can thus modify the one - loop result substantially. numerical results are given for the dependence on the various non - standard parameters, and the influence on the calculation of electroweak precision observables is discussed. | arxiv:1607.04610 |
in this paper we shall address this problem : is quantum gravity constraints algebra closed and what are the quantum einstein equations. we shall investigate this problem in the de - broglie - - bohm quantum theory framework. it is shown that the constraint algebra is weakly closed and the quantum einstein ' s equations are derived. | arxiv:gr-qc/0109052 |
early experiments on spin - blockaded double quantum dots revealed surprising robust, large - amplitude current oscillations in the presence of a static ( dc ) source - drain bias [ see e. g. k. ono, s. tarucha, phys. rev. lett. 92, 256803 ( 2004 ) ]. experimental evidence strongly indicates that dynamical nuclear polarization plays a central role, but the mechanism has remained a mystery. here we introduce a minimal albeit realistic model of coupled electron and nuclear spin dynamics which supports robust self - sustained oscillations. our mechanism relies on a nuclear - spin analog of the tunneling magnetoresistance phenomenon ( spin - dependent tunneling rates in the presence of an inhomogeneous overhauser field ) and nuclear spin diffusion, which governs dynamics of the spatial profile of nuclear polarization. the extremely long oscillation periods ( up to hundreds of seconds ) observed in experiments as well as the differences in phenomenology between vertical and lateral quantum dot structures are naturally explained in the proposed framework. | arxiv:1209.2997 |
it is well - known that magnetic moments are very harmful to superconductivity. a typical example is the element mn whose compounds usually exhibit strong magnetism. thus, it is very hard to achieve superconductivity in materials containing mn. here, we report enhanced superconductivity with the superconducting transition temperature ( $ t _ \ text { c } $ ) up to a record high - value of about 26 k in a beta - phase ti $ _ { 1 - x } $ mn $ _ x $ alloy containing rich magnetic element mn under high pressures. this is contrary to the intuition that the magnetic moments always suppress superconductivity. under high pressures, we also found that in the middle - pressure regime, the pauli limit of the upper critical field is surpassed. the synchrotron x - ray diffraction data shows an unchanged beta - phase with a continuous contraction of the cell volume, which is well supported by the first - principles calculations. although the theoretical results based on electron - phonon coupling ( epc ) can interpret the $ t _ \ text { c } $ value in a certain pressure region, the monotonic enhancement of superconductivity by pressure cannot seek support from the theory. our results show a surprising enhancement of superconductivity in ti $ _ { 1 - x } $ mn $ _ x $ alloy with a considerable mn content. | arxiv:2404.14182 |
the critical fluctuations of superconductors are discussed in a fixed dimension scaling suited to describe the type ii regime. the gauge dependence of the anomalous dimension of the scalar field is stablished exactly from the ward - takahashi identities. its fixed point value gives the $ \ eta $ critical exponent and it is shown that $ \ eta $ is gauge independent, as expected on physical grounds. in the scaling considered, $ \ eta $ is found to be zero at 1 - loop order, while $ \ nu \ approx 0. 63 $. this result is just the 1 - loop values for the xy model obtained in the fixed dimension renormalization group approach. it is shown that this xy behavior holds at all orders. the result $ \ eta = \ eta _ { xy } $ should be contrasted with the negative values frequently reported in the literature. | arxiv:cond-mat/9808097 |
metric spaces of generalized roundness zero have interesting non - embedding properties. for instance, we note that no metric space of generalized roundness zero is isometric to any metric subspace of any $ l _ { p } $ - space for which $ 0 < p \ leq 2 $. lennard, tonge and weston gave an indirect proof that $ \ ell _ { \ infty } ^ { ( 3 ) } $ has generalized roundness zero by appealing to highly non - trivial isometric embedding theorems of bretagnolle dacunha - castelle and krivine, and misiewicz. in this paper we give a direct proof that $ \ ell _ { \ infty } ^ { ( 3 ) } $ has generalized roundness zero. this provides insight into the combinatorial geometry of $ \ ell _ { \ infty } ^ { ( 3 ) } $ that causes the generalized roundness inequalities to fail. we complete the paper by noting a characterization of real quasi - normed spaces of generalized roundness zero. | arxiv:1401.4095 |
the qcd corrections for the box diagrams are revisited for the case of a heavy top quark with $ \ mt = 174 \ gev $. we resolve first a longstanding discrepancy between two methods of calculation by showing that they give the same results when the threshold factors are treated correctly. using this observation we refine our earlier results and derive formulae valid for the $ k $ - and $ b $ - meson systems. our formulae are given in terms of integrals to be evaluated numerically, as well as approximate analytical formulae. these calculations include the evolution above $ \ mw $ which has been neglected by other authors. | arxiv:hep-ph/9509420 |
in this work we consider quantum cascade networks in which quantum systems are connected through unidirectional channels that can mutually interact giving rise to interference effects. in particular we show how to compute master equations for cascade systems in an arbitrary interferometric configuration by means of a collisional model. we apply our general theory to two specific examples : the first consists in two systems arranged in a mach - zender - like configuration ; the second is a three system network where it is possible to tune the effective chiral interactions between the nodes exploiting interference effects. | arxiv:1702.05359 |
walk on spheres algorithms leverage properties of brownian motion to create monte carlo estimates of solutions to a class of elliptic partial differential equations. we propose a new caching strategy which leverages the continuity of paths of brownian motion. in the case of laplace ' s equation with dirichlet boundary conditions, our algorithm has improved asymptotic runtime compared to previous approaches. until recently, estimates were constructed pointwise and did not use the relationship between solutions at nearby points within a domain. instead, our results are achieved by passing information from a cache of fixed size. we also provide bounds on the performance of our algorithm and demonstrate its performance on example problems of increasing complexity. | arxiv:2404.17692 |
large language models ( llms ) have become increasingly pivotal across various domains, especially in handling complex data types. this includes structured data processing, as exemplified by chartqa and chatgpt - ada, and multimodal unstructured data processing as seen in visual question answering ( vqa ). these areas have attracted significant attention from both industry and academia. despite this, there remains a lack of unified evaluation methodologies for these diverse data handling scenarios. in response, we introduce babelbench, an innovative benchmark framework that evaluates the proficiency of llms in managing multimodal multistructured data with code execution. babelbench incorporates a dataset comprising 247 meticulously curated problems that challenge the models with tasks in perception, commonsense reasoning, logical reasoning, and so on. besides the basic capabilities of multimodal understanding, structured data processing as well as code generation, these tasks demand advanced capabilities in exploration, planning, reasoning and debugging. our experimental findings on babelbench indicate that even cutting - edge models like chatgpt 4 exhibit substantial room for improvement. the insights derived from our comprehensive analysis offer valuable guidance for future research within the community. the benchmark data can be found at https : / / github. com / ffd8ffe / babelbench. | arxiv:2410.00773 |
the orbital angular momentum of electrons offers a promising, yet largely unexplored, degree of freedom for ultrafast, energy - efficient information processing. as the foundation of orbitronics, understanding how orbital currents propagate and convert into charge currents is essential - but remains elusive due to the challenge in disentangling orbital and spin dynamics in ultrathin films. although orbital currents have been predicted to propagate over long distances in materials, recent theoretical studies argue that lattice symmetry may constrain their mean free paths ( mfps ) to the scale of a single atomic layer. in this work, we provide the first direct experimental evidence for ultrashort orbital mfps in heavy metals ( hms ) - w, ta, pt - revealed by femtosecond terahertz emission spectroscopy. this is enabled by sub - nanometer - precision control of thin - film thickness using wedge - shaped hm | ni heterostructures. by employing a multi - component terahertz - emission model, we quantitatively extract the orbital mfps, consistently finding them shorter than their spin counterparts. furthermore, control experiments rule out interfacial orbital - to - charge conversion as the dominant mechanism, confirming that the process is governed by the bulk inverse orbital hall effect. our findings resolve a central controversy in orbitronics and provide key insights into orbital transport and conversion mechanisms. | arxiv:2504.15553 |
we introduce cvss, a massively multilingual - to - english speech - to - speech translation ( s2st ) corpus, covering sentence - level parallel s2st pairs from 21 languages into english. cvss is derived from the common voice speech corpus and the covost 2 speech - to - text translation ( st ) corpus, by synthesizing the translation text from covost 2 into speech using state - of - the - art tts systems. two versions of translation speeches are provided : 1 ) cvss - c : all the translation speeches are in a single high - quality canonical voice ; 2 ) cvss - t : the translation speeches are in voices transferred from the corresponding source speeches. in addition, cvss provides normalized translation text which matches the pronunciation in the translation speech. on each version of cvss, we built baseline multilingual direct s2st models and cascade s2st models, verifying the effectiveness of the corpus. to build strong cascade s2st baselines, we trained an st model on covost 2, which outperforms the previous state - of - the - art trained on the corpus without extra data by 5. 8 bleu. nevertheless, the performance of the direct s2st models approaches the strong cascade baselines when trained from scratch, and with only 0. 1 or 0. 7 bleu difference on asr transcribed translation when initialized from matching st models. | arxiv:2201.03713 |
the risk minimizing problem $ \ mathbf { e } [ l ( ( h - x _ t ^ { x, \ pi } ) ^ { + } ) ] \ overset { \ pi } { \ longrightarrow } \ min $ in the multidimensional black - scholes framework is studied. specific formulas for the minimal risk function and the cost reduction function for basket derivatives are shown. explicit integral representations for the risk functions for $ l ( x ) = x $ and $ l ( x ) = x ^ p $, with $ p > 1 $ for digital, quantos, outperformance and spread options are derived. | arxiv:1102.3928 |
herophilos ( 335 – 280 bce ) was the first to base his conclusions on dissection of the human body and to describe the nervous system. galen ( 129 – c. 200 ce ) performed many audacious operations — including brain and eye surgeries — that were not tried again for almost two millennia. = = = greek mathematics = = = in hellenistic egypt, the mathematician euclid laid down the foundations of mathematical rigor and introduced the concepts of definition, axiom, theorem and proof still in use today in his elements, considered the most influential textbook ever written. archimedes, considered one of the greatest mathematicians of all time, is credited with using the method of exhaustion to calculate the area under the arc of a parabola with the summation of an infinite series, and gave a remarkably accurate approximation of pi. he is also known in physics for laying the foundations of hydrostatics, statics, and the explanation of the principle of the lever. = = = other developments = = = theophrastus wrote some of the earliest descriptions of plants and animals, establishing the first taxonomy and looking at minerals in terms of their properties, such as hardness. pliny the elder produced one of the largest encyclopedias of the natural world in 77 ce, and was a successor to theophrastus. for example, he accurately describes the octahedral shape of the diamond and noted that diamond dust is used by engravers to cut and polish other gems owing to its great hardness. his recognition of the importance of crystal shape is a precursor to modern crystallography, while notes on other minerals presages mineralogy. he recognizes other minerals have characteristic crystal shapes, but in one example, confuses the crystal habit with the work of lapidaries. pliny was the first to show amber was a resin from pine trees, because of trapped insects within them. the development of archaeology has its roots in history and with those who were interested in the past, such as kings and queens who wanted to show past glories of their respective nations. the 5th - century - bce greek historian herodotus was the first scholar to systematically study the past and perhaps the first to examine artifacts. = = = greek scholarship under roman rule = = = during the rule of rome, famous historians such as polybius, livy and plutarch documented the rise of the roman republic, and the organization and histories of other nations, while statesmen like julius caesar, cicero, and others provided examples of the politics of the republic | https://en.wikipedia.org/wiki/History_of_science |
the emergence of propositions - as - sessions, a curry - howard correspondence between propositions of linear logic and session types for concurrent processes, has settled the logical foundations of message - passing concurrency. central to this approach is the resource consumption paradigm heralded by linear logic. in this paper, we investigate a new point in the design space of session type systems for message - passing concurrent programs. we identify o ' hearn and pym ' s logic of bunched implications ( bi ) as a fruitful basis for an interpretation of the logic as a concurrent programming language. this leads to a treatment of non - linear resources that is radically different from existing approaches based on linear logic. we introduce a new $ { \ pi } $ - calculus with sessions, called $ { \ pi } $ bi ; its most salient feature is a construct called spawn, which expresses new forms of sharing that are induced by structural principles in bi. we illustrate the expressiveness of $ { \ pi } $ bi and lay out its fundamental theory : type preservation, deadlock - freedom, and weak normalization results for well - typed processes ; an operationally sound and complete typed encoding of an affine $ { \ lambda } $ - calculus ; and a non - interference result for access of resources. | arxiv:2209.05421 |
this survey paper examines the work of j. von neumann and m. h. stone as it relates to the abstract theory of wavelets. in particular, we discuss the direct integral theory of von neumann and how it can be applied to representations of certain discrete groups to study the existence of normalized tight frames in the setting of gabor systems and wavelets, via the use of group representations and von neumann algebras. then the extension of stone ' s theorem due to m. naimark, w. ambrose and r. godement is reviewed, and its relationship to the multiresolution analyses of s. mallat and y. meyer and the generalized multiresolution analyses of l. baggett, h. medina, and k. merrill. finally, the paper ends by discussing some recent work due to the author, baggett, p. jorgensen and merrill, and its relationship to operator theory. | arxiv:math/0407037 |
in human - computer interaction, speech emotion recognition ( ser ) plays an essential role in understanding the user ' s intent and improving the interactive experience. while similar sentimental speeches own diverse speaker characteristics but share common antecedents and consequences, an essential challenge for ser is how to produce robust and discriminative representations through causality between speech emotions. in this paper, we propose a gated multi - scale temporal convolutional network ( gm - tcnet ) to construct a novel emotional causality representation learning component with a multi - scale receptive field. gm - tcnet deploys a novel emotional causality representation learning component to capture the dynamics of emotion across the time domain, constructed with dilated causal convolution layer and gating mechanism. besides, it utilizes skip connection fusing high - level features from different gated convolution blocks to capture abundant and subtle emotion changes in human speech. gm - tcnet first uses a single type of feature, mel - frequency cepstral coefficients, as inputs and then passes them through the gated temporal convolutional module to generate the high - level features. finally, the features are fed to the emotion classifier to accomplish the ser task. the experimental results show that our model maintains the highest performance in most cases compared to state - of - the - art techniques. | arxiv:2210.15834 |
we discuss various aspects of hkll bulk reconstruction for the free scalar field in ads $ _ { d + 1 } $. first, we consider the spacelike reconstruction kernel for the non - normalizable mode in global coordinates. we construct it as a mode sum. in even bulk dimensions, this can be reproduced using a chordal green ' s function approach that we propose. this puts the global ads results for the non - normalizable mode on an equal footing with results in the literature for the normalizable mode. in poincar \ ' e ads, we present explicit mode sum results in general even and odd dimensions for both normalizable and non - normalizable kernels. for generic scaling dimension $ \ delta $, these can be re - written in a form that matches with the global ads results via an antipodal mapping, plus a remainder. we are not aware of a general argument in the literature for dropping these remainder terms, but we note that a slight complexification of a boundary spatial coordinate ( which we call an $ i \ epsilon $ prescription ) allows us to do so in cases where $ \ delta $ is ( half - ) integer. since the non - normalizable mode turns on a source in the cft, our primary motivation for considering it is as a step towards understanding linear wave equations in general spacetimes from a holographic perspective. but when the scaling dimension $ \ delta $ is in the breitenlohner - freedman window, we note that the construction has some interesting features within ads / cft. | arxiv:2209.01130 |
the polemical term " interaction - free measurement " ( ifm ) is analyzed in its interpretative nature. two seminal works proposing the term are revisited and their underlying interpretations are assessed. the role played by nonlocal quantum correlations ( entanglement ) is formally discussed and some controversial conceptions in the original treatments are identified. as a result the term ifm is shown to be consistent neither with the standard interpretation of quantum mechanics nor with the lessons provided by the epr debate. | arxiv:0802.3853 |
the successive ionization potentials ( ips ) and electron affinities ( eas ) for superheavy elements with $ 111 \ leq z \ leq 114 $, namely, rg, cn, nh, and fl are reexamined using the relativistic fock - space coupled - cluster method with nonperturbative single ( s ), double ( d ), and triple ( t ) cluster amplitudes ( fs - ccsdt ). for the most of considered quantities, the triple - amplitude contributions turn out to be important. the breit and frequency - dependent breit corrections are evaluated by means of the configuration - interaction method. the quantum - electrodynamics corrections to the ips and eas are taken into account within the model - qed - operator approach. the obtained results are within 0. 10 ev uncertainty. | arxiv:2202.08304 |
we present a systematic study of involutions on the moduli space of $ g $ - higgs bundles over an elliptic curve $ x $, where $ g $ is complex reductive affine algebraic group. the fixed point loci in the moduli space of $ g $ - higgs bundles on $ x $, and in the moduli space of representations of the fundamental group of $ x $ into $ g $, are described. this leads to an explicit description of the moduli spaces of pseudo - real $ g $ - higgs bundles over $ x $. | arxiv:1612.08364 |
the circumnuclear disk ( cnd ) is a torus of dust and molecular gas rotating about the galactic centre and extending from approximately 1. 6pc to 7pc from the central massive black hole, sgra *. large velocity gradient modelling of the intensities of the hcn 1 - 0, 3 - 2 and 4 - 3 transitions is used to infer hydrogen density and hcn optical depth. from hcn observations we find the molecular hydrogen density ranges from 0. 1 to 2 $ \ times $ 10 $ ^ { 6 } $ cm $ ^ { - 3 } $, about an order of magnitude less than inferred previously. the 1 - 0 line is weakly inverted with line - centre optical depth approx $ - $ 0. 1, in stark contrast to earlier estimates of 4. the estimated mass of the ring is approximately 3 $ - $ 4 $ \ times $ 10 $ ^ { 5 } $ m $ _ { \ odot } $ consistent with estimates based on thermal dust emission. the tidal shear in the disk implies that star formation is not expected to occur without some significant triggering event. | arxiv:1310.8429 |
we have observed the autler - townes effect in single - and suspected double - photon magnetic - dipole transitions in the cesium ground - state magnetic - sublevel manifold. experiments were performed in a cesium vapor cell. the d $ _ 1 $ line was excited by laser radiation to create ground - state optical polarization, and transitions between the ground - state magnetic sublevels were excited by radio - frequency ( rf ) radiation. two different excitation geometries were studied : in one case the electric field vector of the linearly polarized laser radiation was parallel to the static magnetic field, whereas in the other case these vectors were perpendicular. the oscillating magnetic field produced by the rf coils was in the plane perpendicular to the electric field vector of the laser radiation. the autler - townes effect was confirmed by its linear dependence on the rf magnetic field amplitude, which is proportional to the rabi frequency, in the case of single - photon transitions. we also observed peaks that by their position appeared to correspond to double and even triple photon transitions, which were more pronounced when the dc magnetic field and optical electric field vectors were perpendicular. in the peak at an energy that corresponds to two photons, splitting with a quadratic dependence on the rf magnetic field amplitude could be observed. the experimental measurements are supplemented by theoretical calculations of a model $ j = 1 \ longrightarrow j = 0 $ system. | arxiv:2411.10327 |
this paper has been withdrawn by the authors. | arxiv:quant-ph/9807090 |
with extensive variational simulations, dissipative quantum phase transitions in the sub - ohmic spin - boson model are numerically studied in a dense limit of environmental modes. by employing a generalized trial wave function composed of coherent - state expansions, transition points and critical exponents are accurately determined for various spectral exponents, demonstrating excellent agreement with those obtained by other sophisticated numerical techniques. besides, the quantum - to - classical correspondence is fully confirmed over the entire sub - ohmic range, compared with theoretical predictions of the long - range ising model. mean - field and non - mean - field critical behaviors are found in the deep and shallow sub - ohmic regimes, respectively, and distinct physical mechanisms of them are uncovered. | arxiv:2309.00797 |
this paper studies a novel pre - training technique with unpaired speech data, speech2c, for encoder - decoder based automatic speech recognition ( asr ). within a multi - task learning framework, we introduce two pre - training tasks for the encoder - decoder network using acoustic units, i. e., pseudo codes, derived from an offline clustering model. one is to predict the pseudo codes via masked language modeling in encoder output, like hubert model, while the other lets the decoder learn to reconstruct pseudo codes autoregressively instead of generating textual scripts. in this way, the decoder learns to reconstruct original speech information with codes before learning to generate correct text. comprehensive experiments on the librispeech corpus show that the proposed speech2c can relatively reduce the word error rate ( wer ) by 19. 2 % over the method without decoder pre - training, and also outperforms significantly the state - of - the - art wav2vec 2. 0 and hubert on fine - tuning subsets of 10h and 100h. we release our code and model at https : / / github. com / microsoft / speecht5 / tree / main / speech2c. | arxiv:2203.17113 |
), and two nullary operations ( the constants 0 and 1 ). these operations are then subject to the conditions above. avoiding existential quantifiers is important in constructive mathematics and computing. one may equivalently define a field by the same two binary operations, one unary operation ( the multiplicative inverse ), and two ( not necessarily distinct ) constants 1 and −1, since 0 = 1 + ( −1 ) and −a = ( −1 ) a. = = examples = = = = = rational numbers = = = rational numbers have been widely used a long time before the elaboration of the concept of field. they are numbers that can be written as fractions a / b, where a and b are integers, and b = 0. the additive inverse of such a fraction is −a / b, and the multiplicative inverse ( provided that a = 0 ) is b / a, which can be seen as follows : b a ⋅ a b = b a a b = 1. { \ displaystyle { \ frac { b } { a } } \ cdot { \ frac { a } { b } } = { \ frac { ba } { ab } } = 1. } the abstractly required field axioms reduce to standard properties of rational numbers. for example, the law of distributivity can be proven as follows : a b ⋅ ( c d + e f ) = a b ⋅ ( c d ⋅ f f + e f ⋅ d d ) = a b ⋅ ( c f d f + e d f d ) = a b ⋅ c f + e d d f = a ( c f + e d ) b d f = a c f b d f + a e d b d f = a c b d + a e b f = a b ⋅ c d + a b ⋅ e f. { \ displaystyle { \ begin { aligned } & { \ frac { a } { b } } \ cdot \ left ( { \ frac { c } { d } } + { \ frac { e } { f } } \ right ) \ \ [ 6pt ] = { } & { \ frac { a } { b } } \ cdot \ left ( { \ frac { c } { d } } \ cdot { \ frac { f } { f } } + { \ frac { e } { f } } \ cdot { | https://en.wikipedia.org/wiki/Field_(mathematics) |
we report on broadband x - ray properties of the rabbit pulsar wind nebula ( pwn ) associated with the pulsar psr j1418 - 6058 using archival chandra and xmm - newton data, and a new nustar observation. nustar data above 10 kev allowed us to detect the 110 - ms spin period of the pulsar, characterize its hard x - ray pulse profile, and resolve hard x - ray emission from the pwn after removing contamination from the pulsar and other overlapping point sources. the extended pwn was detected up to $ \ sim $ 20 kev and is well described by a power - law model with a photon index $ \ gamma \ approx $ 2. the pwn shape does not vary significantly with energy, and its x - ray spectrum shows no clear evidence of softening away from the pulsar. we modeled the spatial profile of x - ray spectra and broadband spectral energy distribution in the radio to tev band to infer the physical properties of the pwn. we found that a model with low magnetic field strength ( $ b \ sim 10 $ $ \ mu $ g ) and efficient diffusion ( $ d \ sim 10 ^ { 27 } $ cm $ ^ 2 $ s $ ^ { - 1 } $ ) fits the pwn data well. the extended hard x - ray and tev emission, associated respectively with synchrotron radiation and inverse compton scattering by relativistic electrons, suggests that particles are accelerated to very high energies ( $ \ gtrsim500 $ tev ), indicating that the rabbit pwn is a galactic pevatron candidate. | arxiv:2302.03277 |
we consider the strongly - coupled standard model ( abbott - farhi model ) including an isotriplet of w ' vector bosons. first we calculate the corrections to the low - energy theory, which can be effectively summarized in terms of the parameters s, t and u. then we use high - precision electroweak measurements to constrain the mass and couplings of the w '. the w ' couplings are restricted to be unnaturally small, and we conclude that this model is no longer compelling as a theory of the electroweak interactions. | arxiv:hep-ph/9502331 |
any z _ 2 - graded c * - dynamical system with a self - adjoint graded - kms functional on it can be represented ( canonically ) as a z _ 2 - graded algebra of bounded operators on a z _ 2 - graded hilbert space, so that the grading of the latter is compatible with the functional. the modular conjugation operator plays a crucial role in this reconstruction. the results are generalized to the case of an unbounded graded - kms functional having as dense domain the union of a net of c * - subalgebras. it is shown that the modulus of such an unbounded graded - kms functional is kms. | arxiv:math-ph/0608044 |
the requirement that their gravitational binding self - energy density must at least equal the background repulsive dark energy density for large scale cosmic structures implies a mass - radius relation of m / r ^ 2 ~ 1g / cm ^ 2, as pointed out earlier. this relation seems to hold true for primeval galaxies as well as those at present epoch. this could set constraints on the nature and evolution of dark energy. besides, we also set constraints on the size of galaxy clusters and superclusters due to the repulsive cosmological dark energy. this could indicate as to why large scale cosmic structures much larger than ~ 200mpc are not seen. | arxiv:1806.07706 |
measures of local and global spatial association are key tools for exploratory spatial data analysis. many such measures exist including moran ' s $ i $, geary ' s $ c $, and the getis - ord $ g $ and $ g ^ * $ statistics. a parametric approach to testing for significance relies on strong assumptions, which are often not met by real world data. alternatively, the most popular nonparametric approach, the permutation test, imposes a large computational burden especially for massive graphical networks. hence, we propose a computation - free approach to nonparametric permutation testing for local and global measures of spatial autocorrelation stemming from generalizations of the khintchine inequality from functional analysis and the theory of $ l ^ p $ spaces. our methodology is demonstrated on the results of the 2019 federal canadian election in the province of alberta. we recorded the percentage of the vote gained by the conservative candidate in each riding. this data is not normal, and the sample size is fixed at $ n = 34 $ ridings making the parametric approach invalid. in contrast, running a classic permutation test for every riding, for multiple test statistics, with various neighbourhood structures, and multiple testing correction would require the simulation of millions of permutations. we are able to achieve similar statistical power on this dataset to the permutation test without the need for tedious simulation. we also consider data simulated across the entire electoral map of canada. | arxiv:2012.08647 |
various earth anomalies have destroyed the stable, balanced state, resulting in fatalities and serious destruction of property. with the advantages of large - scale and precise observation, high - resolution remote sensing images have been widely used for anomaly monitoring and localization. powered by the deep representation, the existing methods have achieved remarkable advances, primarily in classification and change detection techniques. however, labeled samples are difficult to acquire due to the low probability of anomaly occurrence, and the trained models are limited to fixed anomaly categories, which hinders the application for anomalies with few samples or unknown anomalies. in this paper, to tackle this problem, we propose the anomaly change detection ( anomalycd ) technique, which accepts time - series observations and learns to identify anomalous changes by learning from the historical normal change pattern. compared to the existing techniques, anomalycd processes an unfixed number of time steps and can localize the various anomalies in a unified manner, without human supervision. to benchmark anomalycd, we constructed a high - resolution dataset with time - series images dedicated to various earth anomalies ( the anomalycdd dataset ). anomalycdd contains high - resolution ( from 0. 15 to 2. 39 m / pixel ), time - series ( from 3 to 7 time steps ), and large - scale images ( 1927. 93 km2 in total ) collected globally furthermore, we developed a zero - shot baseline model ( anomalycdm ), which implements the anomalycd technique by extracting a general representation from the segment anything model ( sam ) and conducting temporal comparison to distinguish the anomalous changes from normal changes. anomalycdm is designed as a two - stage workflow to enhance the efficiency, and has the ability to process the unseen images directly, without retraining for each scene. | arxiv:2409.05679 |
light ( sub - gev ) dark matter has gained increasing interest in terms of direct detection. accelerated dark matter is a promising candidate that can generate detectable nuclear recoil energy within the sub - gev range. because of the large kinetic energy, its interactions with the nucleus are predominantly governed by inelastic scattering, including quasi - elastic and deep inelastic scattering. in this work, we calculated the inelastic effects in dark matter - - earth scattering mediated by a vector particle. our analysis revealed that the impact of inelastic scattering relies on the mediator mass and the kinetic energy spectrum of dark matter. the results exhibited considerable disparity : the upper bounds of the exclusion limit for the spin - independent cross - section between accelerated dark matter and nuclei via a heavy mediator differ by several tens of times when inelastic scattering is considered. | arxiv:2308.02204 |
antiferromagnetism and high - temperature superconductivity. jacob appelbaum ( 1983 – ) : american computer security researcher and hacker. he is a core member of the tor project. francois arago ( 1786 – 1853 ) : french mathematician, physicist, astronomer and politician. svante arrhenius ( 1859 – 1927 ) : swedish scientist and the first swedish nobel prize winner. abhay ashtekar ( 1949 – ) : indian theoretical physicist. as the creator of ashtekar variables, he is one of the founders of loop quantum gravity and its subfield loop quantum cosmology. larned b. asprey ( 1919 – 2005 ) : american chemist noted for his work on actinide, lanthanide, rare earth, and fluorine chemistry, and for his contributions to nuclear chemistry on the manhattan project and later at the los alamos national laboratory. peter atkins ( 1940 – ) : english quantum chemist and professor of chemistry at lincoln college, oxford, in england. scott atran ( 1952 – ) : american - french cultural anthropologist who is emeritus director of research in anthropology at the centre national de la recherche scientifique in paris, research professor at the university of michigan, and cofounder of artis international and of the centre for the resolution of intractable conflict archived 2018 - 05 - 14 at the wayback machine at oxford university. julius axelrod ( 1912 – 2004 ) : american nobel prize – winning biochemist, noted for his work on the release and reuptake of catecholamine neurotransmitters and major contributions to the understanding of the pineal gland and how it is regulated during the sleep - wake cycle. = = b = = sir edward battersby bailey frs ( 1881 – 1965 ) : british geologist, director of the british geological survey. gregory bateson ( 1904 – 1980 ) : english anthropologist, social scientist, linguist, visual anthropologist, semiotician and cyberneticist whose work intersected that of many other fields. sir patrick bateson frs ( 1938 – 2017 ) : english biologist and science writer, emeritus professor of ethology at the university of cambridge and president of the zoological society of london. william bateson ( 1861 – 1926 ) : english geneticist, a fellow of st. john ' s college, cambridge, where he eventually became master. he was the first person to use the term " genetics " to describe the study of heredity and biological inheritance, and the chief populariser of the ideas of gregor | https://en.wikipedia.org/wiki/List_of_atheists_in_science_and_technology |
we present the data reduction pipeline for the hi - gal survey. hi - gal is a key project of the herschel satellite which is mapping the inner part of the galactic plane ( | l | < = 70 \ cdot and | b | < = 1 \ cdot ), using 2 pacs and 3 spire frequency bands, from 70 { \ mu } m to 500 { \ mu } m. our pipeline relies only partially on the herschel interactive standard environment ( hipe ) and features several newly developed routines to perform data reduction, including accurate data culling, noise estimation and minimum variance map - making, the latter performed with the romagal algorithm, a deep modification of the roma code already tested on cosmological surveys. we discuss in depth the properties of the hi - gal science demonstration phase ( sdp ) data. | arxiv:1106.0698 |
we consider the ways in which a 4 - tangle t inside a unit cube can be extended outside the cube into a knot or link l. we present two links n ( t ) and d ( t ) such that the greatest common divisor of the determinants of these two links always divides the determinant of the link l. in order to prove this result we give a two - integer invariant of 4 - tangles. calculations are facilitated by viewing the determinant as the kauffman bracket at a fourth root of - 1, which sets the loop factor to zero. for rational tangles, our invariant coincides with the value of the associated continued fraction. | arxiv:math/9902119 |
we present keck interferometer observations of the three prototypical fu orionis stars, fu ori, v1057 cyg, and v1515 cyg. with a spatial resolution of a few milli - arcseconds and a spectral resolution of 2000, our near - infrared observations spatially resolve gas and dust emission extending from stellocentric radii of ~ 0. 05 au to several au. we fit these data with accretion disk models where each stellocentric radius of the disk is represented by a supergiant - type stellar emission spectrum at the disk temperature. a disk model is consistent with the data for fu ori, although we require some local asymmetry in the disk. for v1057 cyg the disk model does not fit our data well, especially compared to the fit quality achieved for fu ori. we speculate that a disk wind may be contributing substantially to the observed near - ir emission in this source. the data for v1515 cyg are noisier than the data obtained for the other two objects, and do not strongly constrain the validity of an accretion disk model. | arxiv:1106.1440 |
one challenge in condensed - matter physics is to unravel the interplay between magnetism and superconductivity in copper oxides with a high critical temperature ( tc ). kang et al. claim to have revealed a quantum phase transition from the superconducting to an antiferromagnetic state in the electron - doped material nd2 - xcexcuo4 ( ncco ) based on the observation of magnetic - field - induced neutron scattering intensity at ( 1 / 2, 1 / 2, 0 ), ( 1 / 2, 0, 0 ), and related reflections. here we argue that the observed magnetic intensity is due to a secondary phase of ( nd, ce ) 2o3. we therefore contend that the effect is spurious and not intrinsic to superconducting ncco. | arxiv:cond-mat/0308607 |
0103 $ - $ 72. 6, the second brightest x - ray supernova remnant ( snr ) in the small magellanic cloud ( smc ), has been observed with the { \ it chandra x - ray observatory }. our { \ it chandra } observation unambiguously resolves the x - ray emission into a nearly complete, remarkably circular shell surrounding bright clumpy emission in the center of the remnant. the observed x - ray spectrum for the central region is evidently dominated by emission from reverse shock - heated metal - rich ejecta. elemental abundances in this ejecta material are particularly enhanced in oxygen and neon, while less prominent in the heavier elements si, s, and fe. we thus propose that 0103 $ - $ 72. 6 is a new ` ` oxygen - rich ' ' snr, making it only the second member of the class in the smc. the outer shell is the limb - brightened, soft x - ray emission from the swept - up smc interstellar medium. the presence of o - rich ejecta and the snr ' s location within an h { \ small ii } region attest to a massive star core - collapse origin for 0103 $ - $ 72. 6. the elemental abundance ratios derived from the ejecta suggest an $ \ sim $ 18 m $ _ { \ odot } $ progenitor star. | arxiv:astro-ph/0309271 |
we study the algebraic properties of plethystic vertex operators, introduced in j. phys. a : math. theor. 43 405202 ( 2010 ), underlying the structure of symmetric functions associated with certain generalized universal character rings of subgroups of the general linear group, defined to stabilize tensors of young symmetry type characterized by a partition of arbitrary shape \ pi. here we establish an extension of the well - known boson - fermion correspondence involving schur functions and their associated ( bernstein ) vertex operators : for each \ pi, the modes generated by the plethystic vertex operators and their suitably constructed duals, satisfy the anticommutation relations of a complex clifford algebra. the combinatorial manipulations underlying the results involve exchange identities exploiting the hopf - algebraic structure of certain symmetric function series and their plethysms. | arxiv:1606.01695 |
we compactify the classical moduli variety $ a _ g $ of principally polarized abelian varieties of complex dimension $ g $ by attaching the moduli of flat tori of real dimensions at most $ g $ in an explicit manner. equivalently, we explicitly determine the gromov - hausdorff limits of principally polarized abelian varieties. this work is analogous to the first of our series ( available at arxiv : 1406. 7772v2 ), which compactified the moduli of curves by attaching the moduli of metrized graphs. then, we also explicitly specify the gromov - hausdorff limits along holomorphic family of abelian varieties and show that they form special non - trivial subsets of the whole boundary. we also do it for algebraic curves case and observe a crucial difference with the case of abelian varieties. | arxiv:1705.05545 |
research data and software are widely accepted as an outcome of scientific work. however, in comparison to text - based publications, there is not yet an established process to assess and evaluate quality of research data and research software publications. this paper presents an attempt to fill this gap. initiated by the working group open science of the helmholtz association the task group helmholtz quality indicators for data and software publications currently develops a quality indicator for research data and research software publications to be used within the association. this report summarizes the vision of the group of what all contributes to such an indicator. the proposed approach relies on generic well - established concepts for quality criteria, such as the fair principles and the cobit maturity model. it does - on purpose - not limit itself to technical implementation possibilities to avoid using an existing metric for a new purpose. the intention of this paper is to share the current state for further discussion with all stakeholders, particularly with other groups also working on similar metrics but also with entities that use the metrics. | arxiv:2401.08804 |
arbitrary - oriented object detection ( aood ) is a challenging task to detect objects in the wild with arbitrary orientations and cluttered arrangements. existing approaches are mainly based on anchor - based boxes or dense points, which rely on complicated hand - designed processing steps and inductive bias, such as anchor generation, transformation, and non - maximum suppression reasoning. recently, the emerging transformer - based approaches view object detection as a direct set prediction problem that effectively removes the need for hand - designed components and inductive biases. in this paper, we propose an arbitrary - oriented object detection transformer framework, termed ao2 - detr, which comprises three dedicated components. more precisely, an oriented proposal generation mechanism is proposed to explicitly generate oriented proposals, which provides better positional priors for pooling features to modulate the cross - attention in the transformer decoder. an adaptive oriented proposal refinement module is introduced to extract rotation - invariant region features and eliminate the misalignment between region features and objects. and a rotation - aware set matching loss is used to ensure the one - to - one matching process for direct set prediction without duplicate predictions. our method considerably simplifies the overall pipeline and presents a new aood paradigm. comprehensive experiments on several challenging datasets show that our method achieves superior performance on the aood task. | arxiv:2205.12785 |
ensuring the safety of generated content remains a fundamental challenge for text - to - image ( t2i ) generation. existing studies either fail to guarantee complete safety under potentially harmful concepts or struggle to balance safety with generation quality. to address these issues, we propose safety - constrained direct preference optimization ( sc - dpo ), a novel framework for safety alignment in t2i models. sc - dpo integrates safety constraints into the general human preference calibration, aiming to maximize the likelihood of generating human - preferred samples while minimizing the safety cost of the generated outputs. in sc - dpo, we introduce a safety cost model to accurately quantify harmful levels for images, and train it effectively using the proposed contrastive learning and cost anchoring objectives. to apply sc - dpo for effective t2i safety alignment, we constructed scp - 10k, a safety - constrained preference dataset containing rich harmful concepts, which blends safety - constrained preference pairs under both harmful and clean instructions, further mitigating the trade - off between safety and sample quality. additionally, we propose a dynamic focusing mechanism ( dfm ) for sc - dpo, promoting the model ' s learning of difficult preference pair samples. extensive experiments demonstrate that sc - dpo outperforms existing methods, effectively defending against various nsfw content while maintaining optimal sample quality and human preference alignment. additionally, sc - dpo exhibits resilience against adversarial prompts designed to generate harmful content. | arxiv:2504.14290 |
by simulating the finite temperatures magnetized background in the rhic and lhc energies, we systematically study the characteristics of thermal widths and potentials of heavy quarkonia. it is found that the magnetic field has less influence on the real potential, but has a significant influence on the imaginary potential, especially in the low deconfined temperature. extracted from the effect of thermal worldsheet fluctuations about the classical configuration, the thermal width of $ \ upsilon ( 1s ) $ in the finite temperature magnetized background is investigated. it is found that at the low deconfined temperature the magnetic field can generate a significant thermal fluctuation of the thermal width of $ \ upsilon ( 1s ) $, but with the increase of temperature, the effect of magnetic field on the thermal width becomes less important, which means the effect of high temperature completely exceeds that of magnetic field and magnetic field become less important at high temperature. the thermal width decreases with the increasing rapidity at the finite temperature magnetized background. it is also observed that the effect of the magnetic field on the thermal width when dipole moving parallel to the magnetic field direction are larger than that moving perpendicular to the magnetic field direction, which implies that the magnetic field tends to enhance thermal fluctuation when dipole moving parallel to the direction of magnetic field. the thermal width of $ \ upsilon ( 1s ) $ hardly changes with the increasing temperature when dipole moving perpendicular to the magnetic field. but when dipole moving parallel to the magnetic field, the thermal width at low temperature is obviously larger than that at high temperature. | arxiv:1910.05668 |
accurate and precise control of large quantum systems is paramount to achieve practical advantages on quantum devices. therefore, benchmarking the hardware errors in quantum computers has drawn significant attention lately. existing benchmarks for digital quantum computers involve averaging the global fidelity over a large set of quantum circuits and are therefore unsuitable for specific multi - qubit gates used in analog quantum operations. moreover, average global fidelity is not the optimal figure - of - merit for some of the applications specific to multi - qubit gates and analog devices, such as the study of many - body physics, which often use local observables. in this two - part paper, we develop a new figure - of - merit suitable for multi - qubit quantum gates based on the reduced choi matrix of the operation. in the first part, we develop an efficient, scalable protocol to completely characterize the reduced choi matrix. we identify two sources of sampling errors in measurements of the reduced choi matrix and we show that there are fundamental limits to the rate of convergence of the sampling errors, analogous to the standard quantum limit and heisenberg limit. a slow convergence rate of sampling errors would mean that we need a large number of experimental shots. we develop protocols using quantum information scrambling, which has been observed in disordered systems for e. g., to speed up the rate of convergence of the sampling error at state preparation moreover, we develop protocols using squeezed and entangled initial states to enhance the convergence rate of the sampling error at measurement, which results in a metrologically enhanced reduced process tomography protocol. | arxiv:2210.04330 |
without specifying a matter field nor imposing energy conditions, we study killing horizons in $ n ( \ ge 3 ) $ - dimensional static solutions in general relativity with an $ ( n - 2 ) $ - dimensional einstein base manifold. assuming linear relations $ p _ { \ rm r } \ simeq \ chi _ { \ rm r } \ rho $ and $ p _ 2 \ simeq \ chi _ { \ rm t } \ rho $ near a killing horizon between the energy density $ \ rho $, radial pressure $ p _ { \ rm r } $, and tangential pressure $ p _ 2 $ of the matter field, we prove that any non - vacuum solution satisfying $ \ chi _ { \ rm r } < - 1 / 3 $ ( $ \ chi _ { \ rm r } \ ne - 1 $ ) or $ \ chi _ { \ rm r } > 0 $ does not admit a horizon as it becomes a curvature singularity. for $ \ chi _ { \ rm r } = - 1 $ and $ \ chi _ { \ rm r } \ in [ - 1 / 3, 0 ) $, non - vacuum solutions admit killing horizons, on which there exists a matter field only for $ \ chi _ { \ rm r } = - 1 $ and $ - 1 / 3 $, which are of the hawking - ellis type ~ i and type ~ ii, respectively. differentiability of the metric on the horizon depends on the value of $ \ chi _ { \ rm r } $, and non - analytic extensions beyond the horizon are allowed for $ \ chi _ { \ rm r } \ in [ - 1 / 3, 0 ) $. in particular, solutions can be attached to the schwarzschild - tangherlini - type vacuum solution at the killing horizon in at least a $ c ^ { 1, 1 } $ regular manner without a lightlike thin shell. we generalize some of those results in lovelock gravity with a maximally symmetric base manifold. | arxiv:2402.11012 |
we theoretically and numerically study the quantum dynamics of two degenerate optical parametric oscillators with mutual injections. the cavity mode in the optical coupling path between the two oscillator facets is explicitly considered. stochastic equations for the oscillators and mutual injection path based on the positive $ p $ representation are derived. the system of two gradually pumped oscillators with out - of - phase mutual injections is simulated, and its quantum state is investigated. when the incoherent loss of the oscillators other than the mutual injections is small, the squeezed quadratic amplitudes $ \ hat { p } $ in the oscillators are positively correlated near the oscillation threshold. it indicates finite quantum correlation, estimated via gaussian quantum discord, and the entanglement between the intracavity subharmonic fields. when the loss in the injection path is low, each oscillator around the phase transition point forms macroscopic superposition even under a small pump noise. it suggests that the squeezed field stored in the low - loss injection path weakens the decoherence in the oscillators. | arxiv:1506.00135 |
faced with a considerable lack of resources in african languages to carry out work in natural language processing ( nlp ), natural language understanding ( nlu ) and artificial intelligence, the research teams of ntealan association has set itself the objective of building open - source platforms for the collaborative construction of lexicographic data in african languages. in this article, we present our first reports after 2 years of collaborative construction of lexicographic resources useful for african nlp tools. | arxiv:2103.16712 |
we report on the appearance of magnetic stripes in mnas / gaas ( 100 ) epilayers at temperatures well below the ferromagnetic transition of the system. the study has been performed by ferromagnetic resonance experiments ( fmr ) on mnas epilayers grown on ( 100 ) and ( 111 ) gaas substrates. the fmr spectra of the mnas / gaas ( 100 ) samples at 180 k reveal the appearance of zones of different magnetic behavior with respect to the low - temperature homogeneous ferromagnetic phase. the angular and the temperature dependence of the spectra serve us to detect the inter - growth of the non - magnetic phase into the ferromagnetic phase at a very early stage of the process. the experimental data show that the new phase nucleates in a self - arranged array of stripes in mnas / gaas ( 100 ) thin films while it grows randomly in the same films grown on gaas ( 111 ). | arxiv:0707.0703 |
we report on the development of a systematic variational perturbation theory for the euclidean path integral representation of the density matrix based on new smearing formulas for harmonic correlation functions. as a first application, we present the lowest - order approximation for the radial distribution function of an electron in a hydrogen atom. | arxiv:1107.0289 |
of schools and colleges since 1929. mit operates on a 4 – 1 – 4 academic calendar with the fall semester beginning after labor day and ending in mid - december, a 4 - week " independent activities period " in the month of january, and the spring semester commencing in early february and ceasing in late may. mit students refer to both their majors and classes using numbers or acronyms alone. departments and their corresponding majors are numbered in the approximate order of their foundation ; for example, civil and environmental engineering is course 1, while linguistics and philosophy is course 24. students majoring in electrical engineering and computer science ( eecs ), the most popular department, collectively identify themselves as " course 6 ". mit students use a combination of the department ' s course number and the number assigned to the class to identify their subjects ; for instance, the introductory calculus - based classical mechanics course is simply " 8. 01 " ( pronounced eight - oh - one ) at mit. = = = undergraduate program = = = the four - year, full - time undergraduate program maintains a balance between professional majors and those in the arts and sciences. in 2010, it was dubbed " most selective " by u. s. news, admitting few transfer students and 4. 1 % of its applicants in the 2020 – 2021 admissions cycle. it is need - blind for both domestic and international applicants. mit offers 44 undergraduate degrees across its five schools. in the 2017 – 2018 academic year, 1, 045 bachelor of science degrees ( abbreviated " sb " ) were granted, the only type of undergraduate degree mit now awards. in the 2011 fall term, among students who had designated a major, the school of engineering was the most popular division, enrolling 63 % of students in its 19 degree programs, followed by the school of science ( 29 % ), school of humanities, arts, & social sciences ( 3. 7 % ), sloan school of management ( 3. 3 % ), and school of architecture and planning ( 2 % ). the largest undergraduate degree programs were in electrical engineering and computer science ( course 6 – 2 ), computer science and engineering ( course 6 – 3 ), mechanical engineering ( course 2 ), physics ( course 8 ), and mathematics ( course 18 ). all undergraduates are required to complete a core curriculum called the general institute requirements ( girs ). the science requirement, generally completed during freshman year as prerequisites for classes in science and engineering majors, comprises two semesters of physics, two semesters of calculus, one | https://en.wikipedia.org/wiki/Massachusetts_Institute_of_Technology |
we report on the results of an xmm - newton observation of the supergiant fast x - ray transient ( sfxt ) igr j08408 - 4503 performed in june 2020. the source is composed by a compact object ( likely a neutron star ) orbiting around an o8. 5ib - ii ( f ) p star, lm vel. the x - ray light curve shows a very low level of emission, punctuated by a single, faint flare. analysis of spectra measured during the flare and during quiescence is performed. the quiescent state shows a continuum spectrum well deconvolved to three spectral models : two components are from a collisionally - ionized plasma ( with temperatures kt1 = 0. 24 kev and kt2 = 0. 76 kev ), together with a power law model ( photon index of 2. 55 ), dominating above 2 kev. the x - ray flux emitted at this lowest level is 3. 2 $ \ times10 ^ { - 13 } $ erg / cm2 / s ( 0. 5 - 10 kev, corrected for the interstellar absorption ), implying an x - ray luminosity of 1. 85 $ \ times10 ^ { 32 } $ erg / s ( at 2. 2 kpc ). the two temperature collisionally - ionized plasma is intrinsic to the stellar wind of the donor star, while the power law can be interpreted as emission due to residual, low level accretion onto the compact object. the x - ray luminosity contributed by the power law component only, in the lowest state, is ( 4. 8 $ \ pm { 1. 4 } ) \ times10 ^ { 31 } $ erg / s, the lowest quiescent luminosity detected from the compact object in an sfxt. thanks to this very faint x - ray state caught by xmm - newton, x - ray emission from the wind of the donor star lm vel could be well - established and studied in detail for the first time, as well as a very low level of accretion onto the compact object. the residual accretion rate onto the compact object in igr j08408 - 4503 can be interpreted as the bohm diffusion of ( possibly magnetized ) plasma entering the neutron star magnetosphere at low bondi capture rates from the supergiant donor wind at the quasi - spherical radiation - driven settling accretion stage. | arxiv:2106.14909 |
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