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a sizeable difference in the differential production cross section of top - compared to antitop - quark production, denoted charge asymmetry, has been observed at the tevatron. the experimental results seem to exceed the theory predictions based on the standard model by a significant amount and have triggered a large number of suggestions for " new physics ". in the present paper the standard model predictions for tevatron and lhc experiments are revisited. this includes a reanalysis of electromagnetic as well as weak corrections, leading to a shift of the asymmetry by roughly a factor 1. 1 when compared to the results of the first papers on this subject. the impact of cuts on the transverse momentum of the top - antitop system is studied. restricting the ttbar system to a transverse momentum less than 20 gev leads to an enhancement of the asymmetries by factors between 1. 3 and 1. 5, indicating the importance of an improved understanding of the $ t \ bar t $ - momentum distribution. predictions for similar measurements at the lhc are presented, demonstrating the sensitivity of the large rapidity region both to the standard model contribution and effects from " new physics ". | arxiv:1109.6830 |
we analyze the extraction of weak phases from cp violation in $ b \ to \ pi ^ + \ pi ^ - $ decays. by combining the information on mixing induced cp violation in $ b \ to \ pi ^ + \ pi ^ - $, namely $ s _ { \ pi \ pi } $, with the precision observable $ \ sin 2 \ beta $ obtained from the ` ` gold - plated ' ' mode $ b \ to \ psi k _ s $, we propose the determination of the unitarity triangle. we also discuss alternative ways to analyze $ s _ { \ pi \ pi } $ which can be useful if new physics affects $ b _ d $ - - $ \ bar b _ d $ mixing. predictions and uncertainties for $ r $ and $ \ phi $ in qcd factorization are examined in detail. it is pointed out that a simultaneous expansion in $ 1 / m _ b $ and $ 1 / n _ c $ leads to interesting simplifications. at first order infrared divergences are absent, while the most important effects are retained. independent experimental tests of the factorization framework are briefly discussed. | arxiv:hep-ph/0311104 |
the natural cutoff scale for the quadratically divergent top quark contribution to the higgs mass parameter can be significantly raised above the surprisingly low standard model value, with important consequences for the lhc : the physics that cancels the top quark divergence may be out of reach, while an electroweak sector with " improved naturalness " may be discovered. such a sector, consistent with electroweak precision tests, arises in the two higgs doublet model with heavy higgs and top quark interactions that approach strong coupling. | arxiv:hep-ph/0510243 |
prior research states that frequencies below 75 hz in eye - tracking data represent the primary eye movement termed ` ` signal ' ' while those above 75 hz are deemed ` ` noise ' '. this study examines the biometric significance of this signal - noise distinction and its privacy implications. there are important individual differences in a person ' s eye movement, which lead to reliable biometric performance in the ` ` signal ' ' part. despite minimal eye - movement information in the ` ` noise ' ' recordings, there might be significant individual differences. our results confirm the ` ` signal ' ' predominantly contains identity - specific information, yet the ` ` noise ' ' also possesses unexpected identity - specific data. this consistency holds for both short - ( approx. 20 min ) and long - term ( approx. 1 year ) biometric evaluations. understanding the location of identity data within the eye movement spectrum is essential for privacy preservation. | arxiv:2305.04413 |
in this work i develop a new framework for anisotropic hydrodynamics that generalizes the leading order of the hydrodynamic expansion to the full ( 3 + 1 ) - dimensional anisotropic massive case. following previous works, my considerations are based on the boltzmann kinetic equation with the collisional term treated in the relaxation time approximation. the momentum anisotropy is included explicitly in the leading term, allowing for a large difference between the longitudinal and transverse pressures as well as for non trivial transverse dynamics. energy and momentum conservation is expressed by the first moment of the boltzmann equation. the system of equations is closed by using the zeroth and second moments of the boltzmann equation. the close - to - equilibrium matching with second - order viscous hydrodynamics is demonstrated. in particular, i show that the coupling between shear and bulk pressure corrections, recently proved to be important for an accurate description of momentum anisotropy and bulk viscous dynamics, does not vanish in the close - to - equilibrium limit. | arxiv:1411.7268 |
a kind of motivic stable homotopy theory of algebras is developed. explicit fibrant replacements for the $ s ^ 1 $ - spectrum and $ ( s ^ 1, \ mathbb g ) $ - bispectrum of an algebra are constructed. as an application, unstable, morita stable and stable universal bivariant theories are recovered. these are shown to be embedded by means of contravariant equivalences as full triangulated subcategories of compact generators of some compactly generated triangulated categories. another application is the introduction and study of the symmetric monoidal compactly generated triangulated category of $ k $ - motives. it is established that the triangulated category $ kk $ of corti \ ~ { n } as - - thom can be identified with the $ k $ - motives of algebras. it is proved that the triangulated category of $ k $ - motives is a localization of the triangulated category of $ ( s ^ 1, \ mathbb g ) $ - bispectra. also, explicit fibrant $ ( s ^ 1, \ mathbb g ) $ - bispectra representing stable algebraic kasparov $ k $ - theory and algebraic homotopy $ k $ - theory are constructed. | arxiv:1206.0178 |
aims. many recent observations of pulsars and magnetars can be interpreted in terms of neutron stars ( ns ) with multipole electromagnetic fields. as a first approximation, we investigate the multipole magnetic and electric fields in the environment of a rotating star when this environment is deprived of plasma. methods. we compute a multipole expansion of the electromagnetic field in vacuum for a given magnetic field on the conducting surface of the rotating star. then, we consider a few consequences of multipole fields of pulsars. results. we provide an explicit form of the solution. for each spherical harmonic of the magnetic field, the expansion contains a finite number of terms. a multipole magnetic field can provide an explanation for the stable sub - structures of pulses, and they offer a solution to the problem of current closure in pulsar magnetospheres. conclusions. this computation generalises the widely used model of a rotating star in vacuum with a dipole field. it can be especially useful as a first approximation to the electromagnetic environment of a compact star, for instance a neutron star, with an arbitrarily magnetic field. | arxiv:2007.02539 |
the invariant balanced hermitian geometry of nilmanifolds of dimension 6 is described. we prove that the holonomy group of the associated bismut connection reduces to a proper subgroup of su ( 3 ) if and only if the complex structure is abelian. as an application we show that if j is abelian then any invariant balanced j - hermitian structure provides solutions of the strominger system. | arxiv:1104.5524 |
co - simulation is commonly used for the analysis of complex cyber - physical energy systems ( cpes ). different domain - specific simulation tools and modeling approaches are used to simulate all or parts of the system. the co - simulation framework mosaik is a powerful tool to couple these simulation tools and models. this paper identifies the limitations of mosaik 2 for simulating systems that combine continuous and discrete behavior, and introduces the new version mosaik 3. 0 with improved event capabilities to efficiently combine time - stepped and discrete event simulation. here it is explained how these extensions and new features of mosaik can be applied and implemented for extended co - simulation scenarios. | arxiv:2410.16937 |
multispectral images contain many clues of surface characteristics of the objects, thus can be widely used in many computer vision tasks, e. g., recolorization and segmentation. however, due to the complex illumination and the geometry structure of natural scenes, the spectra curves of a same surface can look very different. in this paper, a low rank multispectral image intrinsic decomposition model ( lriid ) is presented to decompose the shading and reflectance from a single multispectral image. we extend the retinex model, which is proposed for rgb image intrinsic decomposition, for multispectral domain. based on this, a low rank constraint is proposed to reduce the ill - posedness of the problem and make the algorithm solvable. a dataset of 12 images is given with the ground truth of shadings and reflectance, so that the objective evaluations can be conducted. the experiments demonstrate the effectiveness of proposed method. | arxiv:1802.08793 |
adapted from biological sequence alignment, trace alignment is a process mining technique used to visualize and analyze workflow data. any analysis done with this method, however, is affected by the alignment quality. the best existing trace alignment techniques use progressive guide - trees to heuristically approximate the optimal alignment in o ( n2l2 ) time. these algorithms are heavily dependent on the selected guide - tree metric, often return sum - of - pairs - score - reducing errors that interfere with interpretation, and are computationally intensive for large datasets. to alleviate these issues, we propose process - oriented iterative multiple alignment ( pima ), which contains specialized optimizations to better handle workflow data. we demonstrate that pima is a flexible framework capable of achieving better sum - of - pairs score than existing trace alignment algorithms in only o ( nl2 ) time. we applied pima to analyzing medical workflow data, showing how iterative alignment can better represent the data and facilitate the extraction of insights from data visualization. | arxiv:1709.05440 |
in selection processes such as hiring, promotion, and college admissions, implicit bias toward socially - salient attributes such as race, gender, or sexual orientation of candidates is known to produce persistent inequality and reduce aggregate utility for the decision maker. interventions such as the rooney rule and its generalizations, which require the decision maker to select at least a specified number of individuals from each affected group, have been proposed to mitigate the adverse effects of implicit bias in selection. recent works have established that such lower - bound constraints can be very effective in improving aggregate utility in the case when each individual belongs to at most one affected group. however, in several settings, individuals may belong to multiple affected groups and, consequently, face more extreme implicit bias due to this intersectionality. we consider independently drawn utilities and show that, in the intersectional case, the aforementioned non - intersectional constraints can only recover part of the total utility achievable in the absence of implicit bias. on the other hand, we show that if one includes appropriate lower - bound constraints on the intersections, almost all the utility achievable in the absence of implicit bias can be recovered. thus, intersectional constraints can offer a significant advantage over a reductionist dimension - by - dimension non - intersectional approach to reducing inequality. | arxiv:2202.01661 |
in this paper, we show that chen - teboulle ' s proximal - based decomposition method can be interpreted as a proximal augmented lagrangian method. more precisely, it coincides with a linearized augmented lagrangian method. we then proposed three generalized methods based on this interpretation. by invoking recent work ( he et al., ima j. numer. anal., 32 ( 2020 ), pp. 227 - - 245 ), we show that the step size condition of chen - teboulle ' s method can be relaxed without adding any further assumptions. our analysis offers a new insight into this proximal - based decomposition method. | arxiv:2006.11255 |
the canonical redshift - scale factor relation, 1 / a = 1 + z, is a key element in the standard lambdacdm model of the big bang cosmology. despite its fundamental role, this relation has not yet undergone any observational tests since lemaitre and hubble established the expansion of the universe. it is strictly based on the assumption of the friedmann - lemaitre - robertson - walker metric describing a locally homogeneous and isotropic universe and that photons move on null geodesics of the metric. thus any violation of this assumption, within general relativity or modified gravity, can yield a different mapping between the model redshift z = 1 / a - 1 and the actually observed redshift z _ obs, i. e. z _ obs neq z. here we perform a simple test of consistency for the standard redshift - scale factor relation by determining simultaneous observational constraints on the concordance lambdacdm cosmological parameters and a generalized redshift mapping z = f ( z _ obs ). using current baryon acoustic oscillations ( bao ) and type ia supernova ( sn ) data we demonstrate that the generalized redshift mapping is strongly degenerated with dark energy. marginalization over a class of monotonic functions f ( z _ obs ) changes substantially degeneracy between matter and dark energy density : the density parameters become anti correlated with nearly vertical axis of degeneracy. furthermore, we show that current sn and bao data, analysed in a framework with the generalized redshift mapping, do not constrain dark energy unless the bao data include the measurements from the ly - alpha forest of high - redshift quasars. | arxiv:1602.02231 |
we discuss perturbative o ( g ^ 2a ) matching with static heavy quarks and domain - wall light quarks for lattice operators relevant to b - meson decays and $ b ^ 0 $ - $ \ bar { b } ^ 0 $ mixing. the chiral symmetry of the light domain - wall quarks does not prohibit operator mixing at o ( a ) for these operators. the o ( a ) corrections to physical quantities are non - negligible and must be included to obtain high - precision simulation results for ckm physics. we provide results using plaquette, symanzik, iwasaki and dbw2 gluon actions and applying ape, hyp1 and hyp2 link - smearing for the static quark action. | arxiv:1101.1072 |
here, we present idnet, a user authentication framework from smartphone - acquired motion signals. its goal is to recognize a target user from their way of walking, using the accelerometer and gyroscope ( inertial ) signals provided by a commercial smartphone worn in the front pocket of the user ' s trousers. idnet features several innovations including : i ) a robust and smartphone - orientation - independent walking cycle extraction block, ii ) a novel feature extractor based on convolutional neural networks, iii ) a one - class support vector machine to classify walking cycles, and the coherent integration of these into iv ) a multi - stage authentication technique. idnet is the first system that exploits a deep learning approach as universal feature extractors for gait recognition, and that combines classification results from subsequent walking cycles into a multi - stage decision making framework. experimental results show the superiority of our approach against state - of - the - art techniques, leading to misclassification rates ( either false negatives or positives ) smaller than 0. 15 % with fewer than five walking cycles. design choices are discussed and motivated throughout, assessing their impact on the user authentication performance. | arxiv:1606.03238 |
we derive the equation for the evolution of the curvature perturbation on the comoving time slice, $ \ mathcal { r } _ c $, in the presence of anisotropic and non - adiabatic terms in the energy - momentum tensor of matter fields. the equation is obtained by manipulating the perturbed einstein ' s equations in the comoving time slice. it could be used to study the evolution of the comoving curvature perturbations for systems with an anisotropic energy - momentum tensor, such as in the presence of vector fields, in the presence of entropy, such as in a multi - field system, or in modified gravity theories. as a simple application, after checking that the comoving time slice for a multi - field system does not coincide with the uniform field time slice in general, we use the equation in the case of two minimally coupled scalar fields and derive a closed set of equations for the curvature and entropy perturbations on the comoving time slice. | arxiv:1804.05005 |
observations with space - borne x - ray telescopes revealed the existence of soft, diffuse x - ray emission from the inner regions of planetary nebulae. although the existing images support the idea that this emission arises from the hot shocked central - star wind which fills the inner cavity of a planetary nebula, existing models have difficulties to explain the observations consistently. we investigate how the inclusion of thermal conduction changes the physical parameters of the hot shocked wind gas and the amount of x - ray emission predicted by time - dependent hydrodynamical models of planetary nebulae with central stars of normal, hydrogen - rich surface composition. the radiation hydrodynamical models show that heat conduction leads to lower temperatures and higher densities within a bubble and brings the physical properties of the x - ray emitting domain into close agreement with the values derived from observations. depending on the central - star mass and the evolutionary phase, our models predict x - ray [ 0. 45 - - 2. 5 kev ] luminosities between $ 10 ^ { - 8 } $ and $ 10 ^ { - 4 } $ of the stellar bolometric luminosities, in good agreement with the observations. less than 1 % of the wind power is radiated away in this x - ray band. although temperature, density, and also the mass of the hot bubble is significantly altered by heat conduction, the dynamics of the whole system remains practically the same. heat conduction allows the construction of nebular models which predict the correct amount of x - ray emission and at the same time are fully consistent with the observed mass - loss rate and wind speed. thermal conduction must be considered as a viable physical process for explaining the diffuse x - ray emission from planetary nebulae with closed inner cavities. magnetic fields must then be absent or extremely weak. | arxiv:0807.3290 |
we numerically investigated how the nonlinear dynamics depends on the dimensionality and on the higher - order curvature corrections in the form of gauss - bonnet ( gb ) terms. we especially monitored the processes of appearances of a singularity ( or black hole ) in two models : ( i ) a perturbed wormhole throat in spherically symmetric space - time, and ( ii ) colliding scalar pulses in plane - symmetric space - time. we used a dual - null formulation for evolving the field equations, which enables us to locate the trapping horizons directly, and also enables us to follow close to the large - curvature region due to its causal integrating scheme. we observed that the fate of a perturbed wormhole is either a black hole or an expanding throat depending on the total energy of the structure, and its threshold depends on the coupling constant of the gb terms ( $ \ alpha _ { \ rm gb } $ ). we also observed that a collision of large scalar pulses will produce a large - curvature region, of which the magnitude also depends on $ \ alpha _ { \ rm gb } $. for both models, the normal corrections ( $ \ alpha _ { \ rm gb } > 0 $ ) work for avoiding the appearance of singularity, although it is inevitable. we also found that in the critical situation for forming a black hole, the existence of the trapped region in the einstein - gb gravity does not directly indicate the formation of a black hole. | arxiv:1706.02070 |
this paper considers the stress - induced phase transitions of shape memory alloy slender cylinder, and analytically studies the phase transition process and the associated instability. a three - dimensional ( 3d ) phenomenological model with an internal variable is adopted, which is simplified to a 1d system of two strains in three regions ( austenite, martensite and phase transition regions ). suitable boundary conditions and interface conditions are proposed. theoretically, it is a free boundary problem, as the position and shape of phase interfaces are unknown. we then focus on planar interfaces ( which are energetically favored ), and a symmetric case when phase transition occurs in the middle. for given applied stress, two - region solutions, three - region solutions and the connecting solutions between them are obtained analytically or semi - analytically, including many period - k solutions. two - region solutions show that phase transition does not take place at one point, but simultaneously in a small region. the width of phase transition region is found analytically, revealing the roles of the material and geometrical parameters. three - region solutions represent localized inhomogeneous deformations in experiments, and capture that the stress stays almost at the maxwell stress during propagation of transformation front. for displacement - controlled process, the transition process is demonstrated by the stress - strain curve, which captures the stress drop / rise and the transition from homogeneous deformations to period - 1 localized inhomogeneous deformations. when the radius is smaller than a critical value ( given by material constants ), the stress drop is very sharp due to transition of solutions in a snap - back bifurcation. these features show good agreement with experimental observations and shed light on the difficulties of numerical simulations. | arxiv:1905.10454 |
super - kamiokande uses neutrino - electron elastic scattering to measure the recoil electron spectrum and zenith - angle dependence of solar $ ^ 8 $ b neutrinos. sno has measured the $ ^ 8 $ b neutrino - - deuteron charged - current reaction rate. the elastic scattering rate, spectrum and zenith - angle dependence in conjunction with the charged - current reaction rate favors active neutrino oscillations at large mixing angles by about 3 $ \ sigma $ over the no - oscillation hypothesis and small mixing angles. the analysis is independent of the absolute $ ^ 8 $ b and { \ it hep } flux and assumes two - flavor oscillations described by mixing angle and mass $ ^ 2 $ difference. two allowed regions at large mixing are found. | arxiv:hep-ex/0108053 |
traditional artworks like paintings, photographs, or films can be reproduced by conventional media like printing or video. this makes visitors of museums possible to purchase postcards, posters, books, and dvds of pictures and / or movies shown at the exhibition. however, newly developing arts so called interactive art, or new media art, has not been able to be reproduced due to limitation of functionalities of the conventional media. in this article, the authors report a novel approach of sharing such interactive art outside the exhibition, so that the visitors of the museum can take a copy to home, and even share it with non - visitors. the authors build up their new projector - and - camera ( procam ) based interactive artwork for exhibition at museum of contemporary art tokyo ( mot ) by using apple ' s iphone. the exactly same software driving this artwork was downloadable from apple ' s app store - - thus all visitors or even non - visitors could enjoy the same experience at home or wherever they like. | arxiv:1411.2190 |
the inverse radon transform allows to obtain partonic double distributions from ( extended ) generalized parton distributions. we express the extension of generalized parton distributions by their dual parts, generalized distribution amplitudes and study some aspects of the filtered backprojection ( inverse radon transform ). we also show that single integral transforms, previously obtained in the context of wave function overlap representation, are valid for generalized parton distributions that do not possess such a representation. utilizing radyushkin ` s double distribution ansatz, we study and compare the numerical evaluation of double distributions within the filtered backprojection and single integral transforms along the imaginary and real axes. | arxiv:1906.01458 |
in this work we study travelling wave solutions to bistable reaction diffusion equations on bi - infinite $ k $ - ary trees in the continuum regime where the diffusion parameter is large. adapting the spectral convergence method developed by bates and his coworkers, we find an asymptotic prediction for the speed of travelling front solutions. in addition, we prove that the associated profiles converge to the solutions of a suitable limiting reaction - diffusion pde. finally, for the standard cubic nonlinearity we provide explicit formula ' s to bound the thin region in parameter space where the propagation direction undergoes a reversal. | arxiv:2401.12899 |
we first review the cosmological constant problem, and then mention a conjecture of feynman according to which the general relativistic theory of gravity should be reformulated in such a way that energy does not couple to gravity. we point out that our recent unification of gravitation and electromagnetism through a symmetric tensor has the property that the free electromagnetic energy and the vacuum energy do not contribute explicitly to the curvature of spacetime just like the free gravitational energy. therefore in this formulation of general relativity, the vacuum energy density has its very large value today as in the early universe, while the cosmological constant does not exist at all. | arxiv:gr-qc/0002061 |
we investigate the spectrum of stochastic gravitational wave background generated by hybrid topological defects : domain walls bounded by strings and monopoles connected by strings. such defects typically decay early in the history of the universe, and their mass scale is not subject to the constraints imposed by microwave background and millisecond pulsar observations. nonetheless, the intensity of the gravitational wave background from hybrid defects can be quite high at frequencies above $ 10 ^ { - 8 } hz $, and in particular in the frequency range of ligo, virgo and lisa detectors. | arxiv:astro-ph/9606022 |
we build on recent new evolutionary models of jupiter and saturn and here extend our calculations to investigate the evolution of extrasolar giant planets of mass 0. 15 to 3. 0 m _ j. our inhomogeneous thermal history models show that the possible phase separation of helium from liquid metallic hydrogen in the deep interiors of these planets can lead to luminosities ~ 2 times greater than have been predicted by homogeneous models. for our chosen phase diagram this phase separation will begin to affect the planets ' evolution at ~ 700 myr for a 0. 15 m _ j object and ~ 10 gyr for a 3. 0 m _ j object. we show how phase separation affects the luminosity, effective temperature, radii, and atmospheric helium mass fraction as a function of age for planets of various masses, with and without heavy element cores, and with and without the effect of modest stellar irradiation. this phase separation process will likely not affect giant planets within a few au of their parent star, as these planets will cool to their equilibrium temperatures, determined by stellar heating, before the onset of phase separation. we discuss the detectability of these objects and the likelihood that the energy provided by helium phase separation can change the timescales for formation and settling of ammonia clouds by several gyr. we discuss how correctly incorporating stellar irradiation into giant planet atmosphere and albedo modeling may lead to a consistent evolutionary history for jupiter and saturn. | arxiv:astro-ph/0402620 |
we analyze the emergence of wiggling temporal localized states in a passively mode - locked vertical external - cavity surface - emitting laser composed by a gain chip and a resonant saturable absorber mirror. we show that the wiggling instability stems from the interplay between the third - order dispersion induced by the micro - cavities and their frequency mismatch. the latter is identified as an experimentally crucial parameter defining the range of existence of stable emission. we reveal the homoclinic scenario underlying the wiggling phenomenon and we show how it allows to control the oscillation. | arxiv:2103.09788 |
ryu and takayanagi conjectured a formula for the entanglement ( von neumann ) entropy of an arbitrary spatial region in an arbitrary holographic field theory. the von neumann entropy is a special case of a more general class of entropies called renyi entropies. using euclidean gravity, fursaev computed the entanglement renyi entropies ( eres ) of an arbitrary spatial region in an arbitrary holographic field theory, and thereby derived the rt formula. we point out, however, that his eres are incorrect, since his putative saddle points do not in fact solve the einstein equation. we remedy this situation in the case of two - dimensional cfts, considering regions consisting of one or two intervals. for a single interval, the eres are known for a general cft ; we reproduce them using gravity. for two intervals, the rt formula predicts a phase transition in the entanglement entropy as a function of their separation, and that the mutual information between the intervals vanishes for separations larger than the phase transition point. by computing eres using gravity and cft techniques, we find evidence supporting both predictions. we also find evidence that large - $ n $ symmetric - product theories have the same eres as holographic ones. | arxiv:1006.0047 |
we investigate the free energy and entropy of the gaussian massive scalar field theory in the static de sitter space - time for arbitrary temperature. for the inverse temperatures of the form $ \ beta = 2 \ pi 2 ^ k, \ \ k \ in \ mathbf { z } $, in curvature units, we find the explicit form of the free energy and its derivatives with respect to the temperature. there are two types of contributions to the free energy : one is of the " area type " and can be attributed to the horizon, while the other is of the " volume type " and is associated with the interior of the space - time. the latter contribution in the odd - dimensional case in the limit of the week field ( large mass or small hubble constant ) significantly depends on the temperature. namely, for $ \ beta < 2 \ pi $, the free energy behaves as $ f ^ { bulk } _ { \ beta } \ sim e ^ { - \ beta \, m } $, while for $ \ beta > 2 \ pi $ it behaves as $ f ^ { bulk } _ { \ beta } \ sim e ^ { - 2 \, \ pi \, m } $. we also show that even the leading uv contributions to the free energy significantly depend on the state of the theory, which is very unusual. we explain the origin and physical meaning of these observations. as the model example we consider the situation in the rindler wedge of the flat space - time. | arxiv:2112.14794 |
infinite order differential equations have come to play an increasingly significant role in theoretical physics. field theories with infinitely many derivatives are ubiquitous in string field theory and have attracted interest recently also from cosmologists. crucial to any application is a firm understanding of the mathematical structure of infinite order partial differential equations. in our previous work we developed a formalism to study the initial value problem for linear infinite order equations with constant coefficients. our approach relied on the use of a contour integral representation for the functions under consideration. in many applications, including the study of cosmological perturbations in nonlocal inflation, one must solve linearized partial differential equations about some time - dependent background. this typically leads to variable coefficient equations, in which case the contour integral methods employed previously become inappropriate. in this paper we develop the theory of a particular class of linear infinite order partial differential equations with variable coefficients. our formalism is particularly well suited to the types of equations that arise in nonlocal cosmological perturbation theory. as an example to illustrate our formalism we compute the leading corrections to the scalar field perturbations in p - adic inflation and show explicitly that these are small on large scales. | arxiv:0809.4513 |
cui ( arxiv : 1405. 6441 ) has shown that the modified quantum affine algebra $ \ widetilde { \ mathbf u } $ ( more precisely its quotients, bln algebras ) is affine cellular in the sense of koenig and xi. the proof is based on the structure of cells of $ \ widetilde { \ mathbf u } $, studied previously in [ http : / / arxiv. org / abs / math / 0212253 ], the author ' s joint work with beck. we here give more direct proof based on lemma 6. 17 in [ http : / / arxiv. org / abs / math / 0212253 ], together with a property of the bilinear form introduced in [ http : / / arxiv. org / abs / math / 0204183 ]. we also prove that cell ideals are idempotent, and hence theorem 4. 4 in [ koenig - xi ] is applicable. | arxiv:1406.1298 |
self - consistent approach for interacting phonons description in lattice, which generalized debye model, is proposed. notion of " self - consistent " phonons is introduced, speed of which depends on temperature and is determined from non - linear equation. debye energy is also a function of temperature in this approach. thermodynamics of " self - consistent " phonon gas is constructed. it is shown, that at low temperatures there is a correction proportional to the seventh power of temperature to the cubic law of specific heat dependence on temperature. this may be one of the reasons why cubic law for specific heat is observed only at rather low temperatures. at high temperatures the theory predicts linear deviation from dulong - petit law, which is observed experimentally. | arxiv:1511.07011 |
we investigate the effect of disorder on a gapped crystalline system by introducing a class of local quantities for an energy band, which is referred as to band correlation function ( bcf ) and is the sum of correlation functions for all eigenstates of the band. we show that the bcfs are robust in the presence of disorder if the band gap is not collapse. the eigenstate set of an energy band can be almost completely mapped onto the perturbated eigenstate set, referred as to quasi - closed mapping, when it is sufficiently isolated from other bands. some features relate to translational symmetry may emerge in a randomly perturbed system. we demonstrate this by simulating numerically the pumping process for a 1d rice - mele ( rm ) model with disorders on the hopping strength and on - site potential. it is shown that the quantized pumping charge is robust against with the dynamic disorder. this result indicates the possibility of measuring the topological invariant in experimental system with imperfection. | arxiv:1905.12490 |
in this paper, we extend our work to the bayesian inverse problems for inferring unknown forcing and initial condition of the forward navier - stokes equation coupled with tracer equation with noisy lagrangian observation on the positions of the tracers. we consider the navier - stokes equations in the two dimensional periodic torus with a tracer equation which is a simple ordinary differential equation. we developed rigorously the theory for the case of the uniform prior where the forcing and the initial condition depend linearly on a countable set of random variables which are uniformly distributed in a compact interval. numerical experiment using the mlmcmc method produces approximations for posterior expectation of quantities of interest which are in agreement with the theoretical optimal convergence rate established. | arxiv:2403.12501 |
we generalize the recent work of viazovska by constructing infinite families of schwartz functions, suitable for cohn - elkies style linear programming bounds, using quasi - modular and modular forms. in particular for dimensions $ d \ equiv 0 \ pmod { 8 } $ we give the constructions that lead to the best sphere packing upper bounds via modular forms. in dimension $ 8 $ and $ 24 $ these exactly match the functions constructed by viazovska and cohn, kumar, miller, radchenko, and viazovska which resolved the sphere packing problem in those dimensions. | arxiv:1903.05737 |
deep learning is a state of the art method for a lot of applications. the main issue is that most of the real - time data is highly imbalanced in nature. in order to avoid bias in training, cost - sensitive approach can be used. in this paper, we propose cost - sensitive deep learning based frameworks and the performance of the frameworks is evaluated on three different cyber security use cases which are domain generation algorithm ( dga ), electronic mail ( email ), and uniform resource locator ( url ). various experiments were performed using cost - insensitive as well as cost - sensitive methods and parameters for both of these methods are set based on hyperparameter tuning. in all experiments, the cost - sensitive deep learning methods performed better than the cost - insensitive approaches. this is mainly due to the reason that cost - sensitive approach gives importance to the classes which have a very less number of samples during training and this helps to learn all the classes in a more efficient manner. | arxiv:2004.04812 |
an action functional is developed for nonlinear dislocation dynamics. this serves as a first step towards the application of effective field theory in physics to evaluate its potential in obtaining a macroscopic description of dislocation dynamics describing the plasticity of crystalline solids. connections arise between the continuum mechanics and material science of defects in solids, effective field theory techniques in physics, and fracton tensor gauge theories. the scheme that emerges from this work for generating a variational principle for a nonlinear pde system is general, as is demonstrated by doing so for nonlinear elastostatics involving a stress response function that is not necessarily hyperelastic. | arxiv:2104.12568 |
motivated by community detection, we characterise the spectrum of the non - backtracking matrix $ b $ in the degree - corrected stochastic block model. specifically, we consider a random graph on $ n $ vertices partitioned into two equal - sized clusters. the vertices have i. i. d. weights $ \ { \ phi _ u \ } _ { u = 1 } ^ n $ with second moment $ \ phi ^ { ( 2 ) } $. the intra - cluster connection probability for vertices $ u $ and $ v $ is $ \ frac { \ phi _ u \ phi _ v } { n } a $ and the inter - cluster connection probability is $ \ frac { \ phi _ u \ phi _ v } { n } b $. we show that with high probability, the following holds : the leading eigenvalue of the non - backtracking matrix $ b $ is asymptotic to $ \ rho = \ frac { a + b } { 2 } \ phi ^ { ( 2 ) } $. the second eigenvalue is asymptotic to $ \ mu _ 2 = \ frac { a - b } { 2 } \ phi ^ { ( 2 ) } $ when $ \ mu _ 2 ^ 2 > \ rho $, but asymptotically bounded by $ \ sqrt { \ rho } $ when $ \ mu _ 2 ^ 2 \ leq \ rho $. all the remaining eigenvalues are asymptotically bounded by $ \ sqrt { \ rho } $. as a result, a clustering positively - correlated with the true communities can be obtained based on the second eigenvector of $ b $ in the regime where $ \ mu _ 2 ^ 2 > \ rho. $ in a previous work we obtained that detection is impossible when $ \ mu _ 2 ^ 2 < \ rho, $ meaning that there occurs a phase - transition in the sparse regime of the degree - corrected stochastic block model. as a corollary, we obtain that degree - corrected erd \ h { o } s - r \ ' enyi graphs asymptotically satisfy the graph riemann hypothesis, a quasi - ramanujan property. a by - product of our proof is a weak law of large numbers for local - functionals on degree - corrected stochastic block models, which could be of independent interest. | arxiv:1609.02487 |
we show that any self - complementary graph with $ n $ vertices contains a $ k _ { \ lfloor \ frac { n + 1 } { 2 } \ rfloor } $ minor. we derive topological properties of self - complementary graphs. | arxiv:1708.02309 |
we suggest a new correlation in diffractive production of 2 ` ` clusters ' ' $ a + b \ to a ^ \ ast b ^ \ ast $ with large intrinsic angular momenta for each $ a ^ \ ast $ and $ b ^ \ ast $ cluster. these correlations are expected in the context of the ` ` color dipole picture ' ' for high energy collision and reflect the approximate conservation of dipole direction during the collision. this conservation is in particular manifest when the two dipoles, $ \ vec d _ a $, $ \ vec d _ b $ and the impact vector $ \ undtilb $ are all parallel. the predicted positive triple correlation is between the momentum transfer $ \ undtildel $ and the planes of the $ a ^ \ ast $ and $ b ^ \ ast $ clusters. | arxiv:hep-ph/0009335 |
the cat state is shown to ` store ' a single photon through the superposition of its orthogonal counterpart with itself, and an excited oscillator state. photon addition leads to a $ \ pi $ phase shift at origin in the observed phase space interference of the wigner function, which also displays negativity, controlled by the average photon number ( $ | \ alpha | ^ 2 $ ) of coherent states comprising the cat state. the maxima and minima of the sub - planck tiles in the phase space of the kitten state are interchanged after photon addition, leading to their orthogonality. interestingly, photon addition to yurke - stoler state characterized by poissonian statistics leads to a sub - poissonian distribution. | arxiv:2011.00990 |
deep convolutional neural networks ( cnns ) have been actively adopted in the field of music information retrieval, e. g. genre classification, mood detection, and chord recognition. however, the process of learning and prediction is little understood, particularly when it is applied to spectrograms. we introduce auralisation of a cnn to understand its underlying mechanism, which is based on a deconvolution procedure introduced in [ 2 ]. auralisation of a cnn is converting the learned convolutional features that are obtained from deconvolution into audio signals. in the experiments and discussions, we explain trained features of a 5 - layer cnn based on the deconvolved spectrograms and auralised signals. the pairwise correlations per layers with varying different musical attributes are also investigated to understand the evolution of the learnt features. it is shown that in the deep layers, the features are learnt to capture textures, the patterns of continuous distributions, rather than shapes of lines. | arxiv:1607.02444 |
we propose one of the very few constructive consequences of the second law of thermodynamics. more specifically, we present protocols for secret - key establishment and multiparty computation the security of which is based fundamentally on landauer ' s principle. the latter states that the erasure cost of each bit of information is at least ktln2 ( where k is boltzmann ' s constant and t is the absolute temperature of the environment ). albeit impractical, our protocols explore the limits of reversible computation, and the only assumption about the adversary is her inability to access a quantity of free energy that is exponential in the one of the honest participants. our results generalize to the quantum realm. | arxiv:2206.01501 |
we analyse the physics of nonlinear gravitational processes inside a spherical charged black hole perturbed by a self - gravitating massless scalar field. for this purpose we created an appropriate numerical code. throughout the paper, in addition to investigation of the properties of the mathematical singularities where some curvature scalars are equal to infinity, we analyse the properties of the physical singularities where the kretschmann curvature scalar is equal to the planckian value. using a homogeneous approximation we analyse the properties of the spacetime near a spacelike singularity in spacetimes influenced by different matter contents namely a scalar field, pressureless dust and matter with ultrarelativistic isotropic pressure. we also carry out full nonlinear analyses of the scalar field and geometry of spacetime inside black holes by means of an appropriate numerical code with adaptive mesh refinement capabilities. we use this code to investigate the nonlinear effects of gravitational focusing, mass inflation, matter squeeze, and these effects dependence on the initial boundary conditions. it is demonstrated that the position of the physical singularity inside a black hole is quite different from the positions of the mathematical singularities. in the case of the existence of a strong outgoing flux of the scalar field inside a black hole it is possible to have the existence of two null singularities and one central $ r = 0 $ singularity simultaneously. | arxiv:gr-qc/0501015 |
providing elderly and people with special needs to retain their independence as long as possible is one of the biggest challenges of the society of tomorrow. teseo, a startup company spinoff from the university of genoa, aims at accelerating the transition towards a sustainable healthcare system. teseo ' s first concept and product, arianna, allows for the automated recognition of activities of daily living at home and acts as a wellbeing and healthcare personalized assistant. this abstract outlines the main concepts underlying its features and capabilities. | arxiv:1707.03988 |
the increasing success of deep neural networks has raised concerns about their inherent black - box nature, posing challenges related to interpretability and trust. while there has been extensive exploration of interpretation techniques in vision and language, interpretability in the audio domain has received limited attention, primarily focusing on post - hoc explanations. this paper addresses the problem of interpretability by - design in the audio domain by utilizing the recently proposed attention - free focal modulation networks ( focalnets ). we apply focalnets to the task of environmental sound classification for the first time and evaluate their interpretability properties on the popular esc - 50 dataset. our method outperforms a similarly sized vision transformer both in terms of accuracy and interpretability. furthermore, it is competitive against piq, a method specifically designed for post - hoc interpretation in the audio domain. | arxiv:2402.02754 |
bound states of heavy quarks are considered. using the path integral formalism we are able to rederive, in a gauge invariant way, the leutwyler - voloshin short distance analysis as well as a long distance linear potential. at all distances we describe the states in terms of nonperturbative field correlators, and we include radiative corrections at short and intermediate distances. for intermediate distance states ( particularly $ b \ bar { b } $ with $ n = 2 $ ) our results improve, qualitatively and quantitatively, standard analyses, thanks mostly to being able to take into account the finiteness of the correlation time. | arxiv:hep-ph/9504273 |
hyperspectral imaging ( hsi ) serves as an important technique in remote sensing. however, high dimensionality and data volume typically pose significant computational challenges. band selection is essential for reducing spectral redundancy in hyperspectral imagery while retaining intrinsic critical information. in this work, we propose a novel hyperspectral band selection model by decomposing the data into a low - rank and smooth component and a sparse one. in particular, we develop a generalized 3d total variation ( g3dtv ) by applying the $ \ ell _ 1 ^ p $ - norm to derivatives to preserve spatial - spectral smoothness. by employing the alternating direction method of multipliers ( admm ), we derive an efficient algorithm, where the tensor low - rankness is implied by the tensor cur decomposition. we demonstrate the effectiveness of the proposed approach through comparisons with various other state - of - the - art band selection techniques using two benchmark real - world datasets. in addition, we provide practical guidelines for parameter selection in both noise - free and noisy scenarios. | arxiv:2405.00951 |
in unknown cluttered and dynamic environments such as disaster scenes, mobile robots need to perform target - driven navigation in order to find people or objects of interest, while being solely guided by images of the targets. in this paper, we introduce navformer, a novel end - to - end transformer architecture developed for robot target - driven navigation in unknown and dynamic environments. navformer leverages the strengths of both 1 ) transformers for sequential data processing and 2 ) self - supervised learning ( ssl ) for visual representation to reason about spatial layouts and to perform collision - avoidance in dynamic settings. the architecture uniquely combines dual - visual encoders consisting of a static encoder for extracting invariant environment features for spatial reasoning, and a general encoder for dynamic obstacle avoidance. the primary robot navigation task is decomposed into two sub - tasks for training : single robot exploration and multi - robot collision avoidance. we perform cross - task training to enable the transfer of learned skills to the complex primary navigation task without the need for task - specific fine - tuning. simulated experiments demonstrate that navformer can effectively navigate a mobile robot in diverse unknown environments, outperforming existing state - of - the - art methods in terms of success rate and success weighted by ( normalized inverse ) path length. furthermore, a comprehensive ablation study is performed to evaluate the impact of the main design choices of the structure and training of navformer, further validating their effectiveness in the overall system. | arxiv:2402.06838 |
we consider an open model possessing a markovian quantum stochastic limit and derive the limit stochastic schrodinger equations for the wave function conditioned on indirect observations using only the von neumann projection postulate. we show that the diffusion ( gaussian ) situation is universal as a result of the central limit theorem with the quantum jump ( poissonian ) situation being an exceptional case. it is shown that, starting from the correponding limiting open systems dynamics, the theory of quantum filtering leads to the same equations, therefore establishing consistency of the quantum stochastic approach for limiting markovian models. | arxiv:quant-ph/0406055 |
this report summarizes the activities of the nlm working group of the workshop " physics at tev colliders ", les houches, france, 11 - 29 june, 2007. | arxiv:0803.0494 |
we consider an intersection zone where autonomous vehicles ( avs ) and human - driven vehicles ( hdvs ) can be present. as a new vehicle arrives, the traffic controller needs to decide and impose an optimal sequence of the vehicles that will exit the intersection zone. the traffic controller can send information regarding the time at which an av can cross the intersection ; however, the traffic controller can not communicate with the hdvs, rather the hdvs can only be controlled using the traffic lights. we formulate the problem as an integer constrained non - linear optimization problem where the traffic - intersection controller only communicates with a subset of the avs. since the number of possible combinations increases exponentially with the number of vehicles in the system, we relax the original problem and proposes an algorithm that gives the optimal solution of the relaxed problem and yet only scales linearly with the number of vehicles in the system. the numerical evaluation shows that our algorithm outperforms the first - in - first - out ( fifo ) algorithm. | arxiv:2108.12695 |
we prove rietsch ' s mirror conjecture that the dubrovin quantum connection for minuscule flag varieties is isomorphic to the character d - module of the berenstein - kazhdan geometric crystal. the idea is to recognize the quantum connection as galois and the geometric crystal as automorphic. we reveal surprising relations with the works of frenkel - gross, heinloth - ng \ ^ o - yun, and zhu on kloosterman sheaves. the isomorphism comes from global rigidity results where hecke eigensheaves are determined by their local ramification. as corollaries we obtain combinatorial identities for counts of rational curves and the peterson variety presentation of the small quantum cohomology ring. | arxiv:1705.00758 |
a } ^ { c \! p } = ( 1. 42 \ pm 0. 43 \ pm 0. 08 ) \ times 10 ^ { - 2 } $ and $ \ mathcal { r } _ { \ pi / k } = ( 3. 846 \ pm 0. 018 \ pm 0. 018 ) \ times 10 ^ { - 2 } $. the combined $ \ delta \ mathcal { a } ^ { c \! p } $ value deviates from zero by 3. 2 standard deviations, providing the first evidence for direct $ c \! p $ violation in the amplitudes of beauty decays to charmonium final states. | arxiv:2411.12178 |
consider a decision maker who is responsible to collect observations so as to enhance his information in a speedy manner about an underlying phenomena of interest. the policies under which the decision maker selects sensing actions can be categorized based on the following two factors : i ) sequential vs. non - sequential ; ii ) adaptive vs. non - adaptive. non - sequential policies collect a fixed number of observation samples and make the final decision afterwards ; while under sequential policies, the sample size is not known initially and is determined by the observation outcomes. under adaptive policies, the decision maker relies on the previous collected samples to select the next sensing action ; while under non - adaptive policies, the actions are selected independent of the past observation outcomes. in this paper, performance bounds are provided for the policies in each category. using these bounds, sequentiality gain and adaptivity gain, i. e., the gains of sequential and adaptive selection of actions are characterized. | arxiv:1211.2291 |
it is shown that, given any finite dimensional, split basic algebra $ \ lambda = k \ gamma / i $ ( where $ \ gamma $ is a quiver and $ i $ an admissible ideal in the path algebra $ k \ gamma $ ), there is a finite list of affine algebraic varieties, the points of which correspond in a natural fashion to the isomorphism types of uniserial left $ \ lambda $ - modules, and the geometry of which faithfully reflects the constraints met in constructing such modules. a constructive coordinatized access to these varieties is given, as well as to the accompanying natural surjections from the varieties onto families of uniserial modules with fixed composition series. the fibres of these maps are explored, one of the results being a simple algorithm to resolve the isomorphism problem for uniserial modules. moreover, new invariants measuring the complexity of the uniserial representation theory are derived from the geometric viewpoint. finally, it is proved that each affine algebraic variety arises as a variety of uniserial modules over a suitable finite dimensional algebra, in a setting where the points are in one - one correspondence with the isomorphism classes of uniserial modules. | arxiv:1407.2384 |
we consider how microlocal methods developed for tomographic problems can be used to detect singularities of the lorentzian metric of the universe using measurements of the cosmic microwave background radiation. the physical model we study is mathematically rigorous but highly idealized. | arxiv:1505.03123 |
the hyperbolic dispersion relation of phonon - polaritons ( phpol ) provides high - momentum states, highly directional propagation, subdiffractional confinement, large optical density of states, and enhanced light - matter interactions. in this work, we use raman spectroscopy in the convenient backscattering configuration to probe phpol in gase, a 2d material presenting two hyperbolic regions separated by a \ textit { double } reststrahlen band. by varying the incidence angle, dispersion relations are revealed. raman spectra calculations confirm the observation of one surface and two extraordinary guided polaritons and matches the evolution of phpol frequency as a function of confinement. resonant excitation close to the excitonic state singularly exalts the scattering efficiency of phpol. raman spectroscopy of phpol in non - centrosymmetry 2d materials does not require any wavevector matching strategies. widely available, it may accelerate the development of mir nanophotonic devices and applications. | arxiv:2208.13208 |
the relaxation in a vacuum capacitor - resistor circuit is comprised of two exponential decays, one caused by surface charge and the other by the decay of energy stored between the capacitor plates. a simple phenomenological model of this relaxation is shown to be supported by measurements even though maxwell ' s equations are difficult to apply in this case. similar behavior is also observed for polypropylene capacitors, indicating that this surface charge effect is applicable to all capacitors and potentially other circuit components. | arxiv:2405.19545 |
haircutting non - cash collateral has become a key element of the post - crisis reform of the shadow banking system and otc derivatives markets. this article develops a parametric haircut model by expanding haircut definitions beyond the traditional value - at - risk measure and employing a double - exponential jump - diffusion model for collateral market risk. haircuts are solved to target credit risk measurements, including probability of default, expected loss or unexpected loss criteria. comparing to data - driven approach typically run on proxy data series, the model enables sensitivity analysis and stress test, captures market liquidity risk, allows idiosyncratic risk adjustments, and incorporates relevant market information. computational results for main equities, securitization, and corporate bonds show potential for uses in collateral agreements, e. g. csas, and for regulatory capital calculations. | arxiv:1708.07585 |
solid state qubits from paramagnetic point defects in solids are promising platforms to realize quantum networks and novel nanoscale sensors. recent advances in materials engineering make possible to create proximate qubits in solids that might interact with each other, leading to electron spin / charge fluctuation. here we develop a method to calculate the tunneling - mediated charge diffusion between point defects from first principles, and apply it to nitrogen - vacancy ( nv ) qubits in diamond. the calculated tunneling rates are in quantitative agreement with previous experimental data. our results suggest that proximate neutral and negatively charged nv defect pairs can form an nv - - nv molecule. a tunneling - mediated model for the source of decoherence of the near - surface nv qubits is developed based on our findings on the interacting qubits in diamond. | arxiv:1708.08626 |
executive order ( eo ) 14028, " improving the nation ' s cybersecurity ", 12 may 2021, directs the national institute of standards and technology ( nist ) to recommend minimum standards for software testing within 60 days. this document describes eleven recommendations for software verification techniques as well as providing supplemental information about the techniques and references for further information. it recommends the following techniques : threat modeling to look for design - level security issues automated testing for consistency and to minimize human effort static code scanning to look for top bugs heuristic tools to look for possible hardcoded secrets use of built - in checks and protections " black box " test cases code - based structural test cases historical test cases fuzzing web app scanners, if applicable address included code ( libraries, packages, services ) the document does not address the totality of software verification, but instead, recommends techniques that are broadly applicable and form the minimum standards. the document was developed by nist in consultation with the national security agency ( nsa ). additionally, we received input from numerous outside organizations through papers submitted to a nist workshop on the executive order held in early june 2021, discussion at the workshop, as well as follow up with several of the submitters. | arxiv:2107.12850 |
comparing competing mathematical models of complex natural processes is a shared goal among many branches of science. the bayesian probabilistic framework offers a principled way to perform model comparison and extract useful metrics for guiding decisions. however, many interesting models are intractable with standard bayesian methods, as they lack a closed - form likelihood function or the likelihood is computationally too expensive to evaluate. with this work, we propose a novel method for performing bayesian model comparison using specialized deep learning architectures. our method is purely simulation - based and circumvents the step of explicitly fitting all alternative models under consideration to each observed dataset. moreover, it requires no hand - crafted summary statistics of the data and is designed to amortize the cost of simulation over multiple models and observable datasets. this makes the method particularly effective in scenarios where model fit needs to be assessed for a large number of datasets, so that per - dataset inference is practically infeasible. finally, we propose a novel way to measure epistemic uncertainty in model comparison problems. we demonstrate the utility of our method on toy examples and simulated data from non - trivial models from cognitive science and single - cell neuroscience. we show that our method achieves excellent results in terms of accuracy, calibration, and efficiency across the examples considered in this work. we argue that our framework can enhance and enrich model - based analysis and inference in many fields dealing with computational models of natural processes. we further argue that the proposed measure of epistemic uncertainty provides a unique proxy to quantify absolute evidence even in a framework which assumes that the true data - generating model is within a finite set of candidate models. | arxiv:2004.10629 |
adaptive filters are applied in several electronic and communication devices like smartphones, advanced headphones, dsp chips, smart antenna, and teleconference systems. also, they have application in many areas such as system identification, channel equalization, noise reduction, echo cancellation, interference cancellation, signal prediction, and stock market. therefore, reducing the energy consumption of the adaptive filtering algorithms has great importance, particularly in green technologies and in devices using battery. in this thesis, data - selective adaptive filters, in particular the set - membership ( sm ) adaptive filters, are the tools to reach the goal. there are well known sm adaptive filters in literature. this work introduces new algorithms based on the classical ones in order to improve their performances and reduce the number of required arithmetic operations at the same time. therefore, firstly, we analyze the robustness of the classical sm adaptive filtering algorithms. secondly, we extend the sm technique to trinion and quaternion systems. thirdly, by combining sm filtering and partial - updating, we introduce a new improved set - membership affine projection algorithm with constrained step size to improve its stability behavior. fourthly, we propose some new least - mean - square ( lms ) based and recursive least - squares based adaptive filtering algorithms with low computational complexity for sparse systems. finally, we derive some feature lms algorithms to exploit the hidden sparsity in the parameters. | arxiv:1909.03891 |
we show within the slave - boson mean field approximation that the two - dimensional t - j model has an intrinsic instability toward forming a quasi - one - dimensional ( q - 1d ) fermi surface. this q - 1d state competes with, and is overcome by, the d - wave pairing state for a realistic parameter choice. however, we find that a small spatial anisotropy in t and j exposes the q - 1d instability which has been hidden behind the d - wave pairing state, and brings about the coexistence with the d - wave pairing. we argue that this coexistence can be realized in la _ { 2 - x } sr _ { x } cuo _ 4 systems | arxiv:2104.10467 |
a significant fraction of local galaxies show evidence of nuclear activity. i argue that the bulk of this activity, while energetically not remarkable, derives from accretion onto a central massive black hole. the statistics of nearby active galactic nuclei thus provide an effective probe of black hole demography. consistent with the picture emerging from direct dynamical studies, the local census of nuclear activity strongly suggests that most, perhaps all, galaxies with a significant bulge component contain a central massive black hole. although late - type galaxies appear to be generally deficient in nuclear black holes, there are important exceptions to this rule. i highlight two examples of dwarf, late - type galaxies that contain active nuclei powered by intermediate - mass black holes. | arxiv:astro-ph/0401527 |
we have studied polycrystalline yb4lige4, a ternary variant of the r5t4 family of layered compounds characterized by a very strong coupling between the magnetic and crystallographic degrees of freedom. the system is mixed valent, with non - magnetic yb2 + and magnetic yb3 + present, and is characterized by coexisting ferromagnetic and antiferromagnetic correlations. we present measurements of resistivity, ac - susceptibility, specific heat, and muon spin relaxation ( musr ), below 1 k. the low temperature measurements suggest a transition to a mesoscopically inhomogeneous magnetically ordered state below 2 k characterized by fluctuations well below the ordering temperature. this unusual state is believed to result from the enhanced two - dimensionality produced by li substitution and frustration effects inherent in the yb sub - lattice geometry. | arxiv:1110.0118 |
cr invariant differential operators on densities with leading part a power of the sub - laplacian are derived. one family of such operators is constructed from the ` ` conformally invariant powers of the laplacian ' ' via the fefferman metric ; the powers which arise for these operators are bounded in terms of the dimension. a second family is derived from a cr tractor calculus which is developed here ; this family includes operators for every positive power of the sub - laplacian. this result together with work of cap, slovak and soucek imply in three dimensions the existence of a curved analogue of each such operator in flat space. | arxiv:math/0301092 |
neutron stars can appear as sources of different nature. in this paper we address observability of a hypothetical class of neutron stars - - hot and fast non accreting rotators, hofnars. these objects are heated due to the r - mode instability. with surface temperatures $ \ sim 10 ^ 6 $ ~ k they are expected to be thermal soft x - ray emitters. we perform a population synthesis modeling of hofnars to predict the number of potentially detectable sources in the erosita all - sky survey. for surface temperatures $ \ sim 10 ^ 6 $ ~ k we obtain $ \ sim 500 $ sources above the detection limit 0. 01 ~ cts ~ s $ ^ { - 1 } $ and $ \ sim 100 $ easier identifiable sources with $ > 0. 1 $ ~ cts ~ s $ ^ { - 1 } $. temperatures $ \ gtrsim 1. 2 \ times 10 ^ 6 $ ~ k start to be in contradiction with non - detection of hofnars by rosat. only for $ t \ lesssim 5 \ times 10 ^ 5 $ ~ k numbers predicted for erosita turn out to be so low that identification does not look possible. we conclude that erosita has good chances to discover hofnars, if they exist. non - detection will put very stringent limits on the properties of this type of neutron stars. | arxiv:2206.07957 |
the non - detection of dark matter ( dm ) particles in increasingly stringent laboratory searches has encouraged alternative gravity theories where gravity is sourced only from visible matter. here, we consider whether such theories can pass a two - dimensional test posed by gravitational lensing - - to reproduce a particularly detailed einstein ring in the core of the galaxy cluster abell 3827. we find that when we require the lensing mass distribution to strictly follow the shape ( ellipticity and position angle ) of the light distribution of cluster member galaxies, intracluster stars, and the x - ray emitting intracluster medium, we cannot reproduce the einstein ring, despite allowing the mass - to - light ratios of these visible components to freely vary with radius to mimic alternative gravity theories. alternatively, we show that the detailed features of the einstein ring are accurately reproduced by allowing a smooth, freely oriented dm halo in the lens model, with relatively small contributions from the visible components at a level consistent with their observed brightnesses. this dominant dm component is constrained to have the same orientation as the light from the intracluster stars, indicating that the intracluster stars trace the gravitational potential of this component. the einstein ring of abell 3827 therefore presents a new challenge for alternative gravity theories : not only must such theories find agreement between the total lensing mass and visible mass, but they must also find agreement between the projected sky distribution of the lensing mass and that of the visible matter, a more stringent test than has hitherto been posed by lensing data. | arxiv:2007.05603 |
multi - head attention advances neural machine translation by working out multiple versions of attention in different subspaces, but the neglect of semantic overlapping between subspaces increases the difficulty of translation and consequently hinders the further improvement of translation performance. in this paper, we employ capsule networks to comb the information from the multiple heads of the attention so that similar information can be clustered and unique information can be reserved. to this end, we adopt two routing mechanisms of dynamic routing and em routing, to fulfill the clustering and separating. we conducted experiments on chinese - to - english and english - to - german translation tasks and got consistent improvements over the strong transformer baseline. | arxiv:1909.00188 |
the noether currents are derived in a generic metric - affine theory of gravity, and the holographic nature of the gravitational entropy and energy - momentum is clarified. the main result is the verification of the canonical resolution to the energy - momentum problem in the noether formalism. | arxiv:2111.04716 |
in this paper, we propose a new convex approach to stability analysis of nonlinear systems with polynomial vector fields. first, we consider an arbitrary convex polytope that contains the equilibrium in its interior. then, we decompose the polytope into several convex sub - polytopes with a common vertex at the equilibrium. then, by using handelman ' s theorem, we derive a new set of affine feasibility conditions - solvable by linear programming - on each sub - polytope. any solution to this feasibility problem yields a piecewise polynomial lyapunov function on the entire polytope. this is the first result which utilizes handelman ' s theorem and decomposition to construct piecewise polynomial lyapunov functions on arbitrary polytopes. in a computational complexity analysis, we show that for large number of states and large degrees of the lyapunov function, the complexity of the proposed feasibility problem is less than the complexity of certain semi - definite programs associated with alternative methods based on sum - of - squares or polya ' s theorem. using different types of convex polytopes, we assess the accuracy of the algorithm in estimating the region of attraction of the equilibrium point of the reverse - time van der pol oscillator. | arxiv:1408.5189 |
this paper concerns boolean satisfiability ( sat ) solvers based on ordered binary decision diagrams ( bdds ), especially those that can generate proofs of unsatisfiability. mengel ( arxiv : 2306. 00886 ) has presented a theoretical analysis that a bdd - based sat solver can generate a proof of unsatisfiability for the pigeonhole problem ( php $ _ n $ ) in polynomial time, even when the problem is encoded in the standard ` ` direct ' ' form. his approach is based on bucket elimination, using different orderings for the variables in the bdds than in the buckets. we show experimentally that these proofs scale as $ o ( n ^ 5 ) $. we also confirm the exponential scaling that occurs when the same variable ordering is used for the bdds as for the buckets. | arxiv:2306.10337 |
the interface - enhanced superconductivity in monolayer iron selenide ( fese ) films on srtio3 has been actively pursued in the past decade. although a synergistic effect between interfacial charge transfer and interfacial electron - phonon coupling ( epc ) is proposed to be responsible for the mechanism, the microscopic nature of the interfacial epc in the enhancement of superconductivity remains highly controversial. herein we experimentally reveal that a coherent optical phonon mode at 4. 2 thz from the srtio3 substrate couples to fese electrons and modulates the quasiparticle relaxations using ultrafast pump - probe spectroscopy. this mode originates from the antiferrodistortive ( afd ) transition in srtio3 and is significantly stronger in the presence of monolayer fese than that in purely fete - capped nb - doped srtio3. pump fluence and temperature - dependent spectroscopy measurements suggest that srtio3 substrate facilitates the stabilization of fese structure and possibly prevents the occurrence of nematic phase transition, supporting that srtio3 substrate modifies the electronic structure of monolayer fese through a strong interfacial epc strength as large as 0. 77. our results provide unprecedented direct evidence that the strong coupling of srtio3 coherent phonon to fese electrons is indeed responsible for the high - temperature superconductivity in monolayer fese and srtio3 heterostructure. | arxiv:2401.16163 |
we study the effects of the tensor force, present in modern effective nucleon - nucleon interactions, in the spin instability of nuclear and neutron matter. stability conditions of the system against certain very low energy excitation modes are expressed in terms of landau parameters. it is shown that in the spin case, the stability conditions are equivalent to the condition derived from the spin susceptibility, which is obtained as the zero - frequency and long - wavelength limit of the spin response function calculated in the random phase approximation. zero - range forces of the skyrme type and finite - range forces of m3y and gogny type are analyzed. it is shown that for the skyrme forces considered, the tensor effects are sizeable, and tend to increase the spin instability which appears at smaller densities than in the case that the tensor is not taken into account. on the contrary, the tensor contribution of finite range forces to the spin susceptibility is small or negligible for both isospin channels of symmetric nuclear matter as well as for neutron matter. a comparison with the spin susceptibility provided by realistic interactions is also presented. | arxiv:1304.2663 |
of as the infinitesimal vectors generating the group, at least locally, by means of the exponential map, but the lie algebra does not form a generating set in the strict sense. in stochastic analysis, an ito diffusion or more general ito process has an infinitesimal generator. the generator of any continuous symmetry implied by noether ' s theorem, the generators of a lie group being a special case. in this case, a generator is sometimes called a charge or noether charge, examples include : angular momentum as the generator of rotations, linear momentum as the generator of translations, electric charge being the generator of the u ( 1 ) symmetry group of electromagnetism, the color charges of quarks are the generators of the su ( 3 ) color symmetry in quantum chromodynamics, more precisely, " charge " should apply only to the root system of a lie group. = = see also = = free object generating function lie theory symmetry ( physics ) supersymmetry gauge theory field ( physics ) = = references = = = = external links = = generating sets, k. conrad | https://en.wikipedia.org/wiki/Generator_(mathematics) |
a novel dose calculation approach was designed based on the application of lstm network that processes the 3d patient / phantom geometry as a sequence of 2d computed tomography input slices yielding a corresponding sequence of 2d slices that forms the respective 3d dose distribution. lstm networks can propagate information effectively in one direction, resulting in a model that can properly imitate the mechanisms of proton interaction in matter. the study is centered on predicting dose on a single pencil beam level, avoiding the averaging effects in treatment plans comprised of thousands pencil beams. moreover, such approach allows straightforward integration into today ' s treatment planning systems ' inverse planning optimization process. the ground truth training data was prepared with monte carlo simulations for both phantom and patient studies by simulating different pencil beams impinging from random gantry angles through the patient geometry. for model training, 10 ' 000 monte carlo simulations were prepared for the phantom study, and 4 ' 000 simulations were prepared for the patient study. the trained lstm model was able to achieve a 99. 29 % gamma - index pass rate ( [ 0. 5 %, 1 mm ] ) accuracy on the set - aside test set for the phantom study, and a 99. 33 % gamma - index pass rate ( [ 0. 5 %, 2 mm ] ) for the set - aside test set for the patient study. these results were achieved for each pencil beam in 6 - 23 ms. the average monte carlo simulation run - time using topas was 1160 s. the generalization of the model was verified by testing for 5 previously unseen lung cancer patients. lstm networks are well suited for proton therapy dose calculation tasks. however, further work needs to be performed to generalize the proposed approach to clinical applications, primarily to be implemented for various energies, patient sites, and ct resolutions / scanners. | arxiv:2006.06085 |
the effect of a scale dependent newton coupling, which is a crucial ingredient of many quantum gravity theories, is investigated in this paper. for case of non - rotating black holes, and using the null energy condition, we show that newtons scale dependent coupling can actually be obtained without solving the full quantum gap equations. | arxiv:1705.02729 |
aims. this series of papers aims at building a new formalism specifically tailored to study the impact of turbulence on the global modes of oscillation in solar - like stars. this first paper aims at deriving a linear wave equation that directly and consistently contains the turbulence as an input to the model, and therefore naturally contains the information on the coupling between the turbulence and the modes, through the stochasticity of the equations. methods. we use a lagrangian stochastic model of turbulence based on probability density function methods to describe the evolution of the properties of individual fluid particles through stochastic differential equations. we then transcribe these stochastic differential equations from a lagrangian frame to an eulerian frame, more adapted to the analysis of stellar oscillations. we combine this method with smoothed particle hydrodynamics, where all the mean fields appearing in the lagrangian stochastic model are estimated directly from the set of fluid particles themselves, through the use of a weighting kernel function allowing to filter the particles present in any given vicinity. the resulting stochastic differential equations on eulerian variables are then linearised. results. we obtain a stochastic, linear wave equation governing the time evolution of the relevant wave variables, while at the same time containing the effect of turbulence. the wave equation generalises the classical, unperturbed propagation of acoustic waves in a stratified medium to a form that, by construction, accounts for the impact of turbulence on the mode in a consistent way. the effect of turbulence consists in a non - homogeneous forcing term, responsible for the stochastic driving of the mode, and a stochastic perturbation to the homogeneous part of the wave equation, responsible for both the damping of the mode and the modal surface effects. | arxiv:2109.05983 |
lorentz invariance of the current operators implies that they satisfy the well - known commutation relations with the representation operators of the lorentz group. it is shown that if the standard construction of the current operators in quantum field theory is used then the commutation relations are broken by the schwinger terms. | arxiv:hep-th/9508158 |
engineering notation or engineering form ( also technical notation ) is a version of scientific notation in which the exponent of ten is always selected to be divisible by three to match the common metric prefixes, i. e. scientific notation that aligns with powers of a thousand, for example, 531×103 instead of 5. 31×105 ( but on calculator displays written without the ×10 to save space ). as an alternative to writing powers of 10, si prefixes can be used, which also usually provide steps of a factor of a thousand. on most calculators, engineering notation is called " eng " mode as scientific notation is denoted sci. = = history = = an early implementation of engineering notation in the form of range selection and number display with si prefixes was introduced in the computerized hp 5360a frequency counter by hewlett - packard in 1969. based on an idea by peter d. dickinson the first calculator to support engineering notation displaying the power - of - ten exponent values was the hp - 25 in 1975. it was implemented as a dedicated display mode in addition to scientific notation. in 1975, commodore introduced a number of scientific calculators ( like the sr4148 / sr4148r and sr4190r ) providing a variable scientific notation, where pressing the ee↓ and ee↑ keys shifted the exponent and decimal point by ±1 in scientific notation. between 1976 and 1980 the same exponent shift facility was also available on some texas instruments calculators of the pre - lcd era such as early sr - 40, ti - 30 and ti - 45 model variants utilizing ( inv ) ee↓ instead. this can be seen as a precursor to a feature implemented on many casio calculators since 1978 / 1979 ( e. g. in the fx - 501p / fx - 502p ), where number display in engineering notation is available on demand by the single press of a ( inv ) eng button ( instead of having to activate a dedicated display mode as on most other calculators ), and subsequent button presses would shift the exponent and decimal point of the number displayed by ±3 in order to easily let results match a desired prefix. some graphical calculators ( for example the fx - 9860g ) in the 2000s also support the display of some si prefixes ( f, p, n, μ, m, k, m, g, t, p, e ) as suffixes in engineering mode. = | https://en.wikipedia.org/wiki/Engineering_notation |
given a logic presented in a sequent calculus, a natural question is that of equivalence of proofs : to determine whether two given proofs are equated by any denotational semantics, ie any categorical interpretation of the logic compatible with its cut - elimination procedure. this notion can usually be captured syntactically by a set of rule permutations. very generally, proofnets can be defined as combinatorial objects which provide canonical representatives of equivalence classes of proofs. in particular, the existence of proof nets for a logic provides a solution to the equivalence problem of this logic. in certain fragments of linear logic, it is possible to give a notion of proofnet with good computational properties, making it a suitable representation of proofs for studying the cut - elimination procedure, among other things. it has recently been proved that there cannot be such a notion of proofnets for the multiplicative ( with units ) fragment of linear logic, due to the equivalence problem for this logic being pspace - complete. we investigate the multiplicative - additive ( without unit ) fragment of linear logic and show it is closely related to binary decision trees : we build a representation of proofs based on binary decision trees, reducing proof equivalence to decision tree equivalence, and give a converse encoding of binary decision trees as proofs. we get as our main result that the complexity of the proof equivalence problem of the studied fragment is logspace - complete. | arxiv:1707.00991 |
phagocytosis is the process of engulfment and internalization of comparatively large particles by the cell, that plays a central role in the functioning of our immune system. we study the process of phagocytosis by considering a simplified coarse grained model of a three - dimensional vesicle, having uniform adhesion interaction with a rigid particle, in the presence of curved membrane proteins and active cytoskeletal forces. complete engulfment is achieved when the bending energy cost of the vesicle is balanced by the gain in the adhesion energy. the presence of curved ( convex ) proteins reduces the bending energy cost by self - organizing with higher density at the highly curved leading edge of the engulfing membrane, which forms the circular rim of the phagocytic cup that wraps around the particle. this allows the engulfment to occur at much smaller adhesion strength. when the curved proteins exert outwards protrusive forces, representing actin polymerization, at the leading edge, we find that engulfment is achieved more quickly and at lower protein density. we consider spherical as well as non - spherical particles, and find that non - spherical particles are more difficult to engulf in comparison to the spherical particles of the same surface area. for non - spherical particles, the engulfment time crucially depends upon the initial orientation of the particles with respect to the vesicle. our model offers a mechanism for the spontaneous self - organization of the actin cytoskeleton at the phagocytic cup, in good agreement with recent high - resolution experimental observations. | arxiv:2201.01133 |
energy - energy correlators are constructed by averaging the number of charged particle pairs within jets, weighted by the product of their transverse momenta, as a function of the angular separation of the particles within a pair. they are sensitive to a multitude of perturbative and nonperturbative quantum chromodynamics phenomena in high - energy particle collisions. using lead - lead data recorded with the cms detector, energy - energy correlators inside high transverse momentum jets are measured in heavy ion collisions for the first time. the data are obtained at a nucleon - nucleon center - of - mass energy of 5. 02 tev and correspond to an integrated luminosity of 1. 70 nb $ ^ { - 1 } $. a similar analysis is done for proton - proton collisions at the same center - of - mass energy to establish a reference. the ratio of lead - lead to proton - proton energy - energy correlators reveals significant jet substructure modifications in the quark - gluon plasma. the results are compared to different models that incorporate either color coherence or medium response effects, where the two effects predict similar substructure modifications. | arxiv:2503.19993 |
the rs cvn binary system hr 1099 was extensively observed by the xmm - newton observatory in february 2000 as its first - light target. a total of 570 ks of exposure time was accumulated with the reflection grating spectrometers ( rgs ). the integrated x - ray spectrum between 5 - 35 angstrom is of unprecedented quality and shows numerous features attributed to transitions of the elements c, n, o, ne, mg, si, s, fe, and ni. we perform an in - depth study of the elemental composition of the average corona of this system, and find that the elemental abundances strongly depend on the first ionisation potential ( fip ) of the elements. but different from the solar coronal case, we find an inverse fip effect, i. e., the abundances ( relative to oxygen ) increase with increasing fip. possible scenarios, e. g., selective enrichment due to ne - rich flare - like events, are discussed. | arxiv:astro-ph/0011018 |
zeilberger proved the refined alternating sign matrix theorem, which gives a product formula, first conjectured by mills, robbins and rumsey, for the number of alternating sign matrices with given top row. stroganov proved an explicit formula for the number of alternating sign matrices with given top and bottom rows. fischer and romik considered a different kind of " doubly - refined enumeration " where one counts alternating sign matrices with given top two rows, and obtained partial results on this enumeration. in this paper we continue the study of the doubly - refined enumeration with respect to the top two rows, and use stroganov ' s formula to prove an explicit formula for these doubly - refined enumeration numbers. | arxiv:0906.3405 |
scheduling with testing is a recent online problem within the framework of explorable uncertainty motivated by environments where some preliminary action can influence the duration of a task. jobs have an unknown processing time that can be explored by running a test. alternatively, jobs can be executed for the duration of a given upper limit. we consider this problem within the setting of multiple identical parallel machines and present competitive deterministic algorithms and lower bounds for the objective of minimizing the makespan of the schedule. in the non - preemptive setting, we present the sbs algorithm whose competitive ratio approaches $ 3. 1016 $ if the number of machines becomes large. we compare this result with a simple greedy strategy and a lower bound which approaches $ 2 $. in the case of uniform testing times, we can improve the sbs algorithm to be $ 3 $ - competitive. for the preemptive case we provide a $ 2 $ - competitive algorithm and a tight lower bound which approaches the same value. | arxiv:2105.02052 |
the parisi - wu scheme of quantization opens up the possibility of using anomalous fermionic gauge theories. an analysis of ultra - violet divergences reveals that the structure of counter terms is different from what is expected in conventional quantization schemes. in this letter it is argued that there exists a possible mechanism of cp violation that requires at least three generations of quarks, a result well known from a phenomenological analysis of mass mixing of quarks. a few observations on possible ways of going beyond the standard model are included. | arxiv:2401.04137 |
filters were introduced by j. b. wilson in 2013 to generalize work of lazard with associated graded lie rings. it holds promise in improving isomorphism tests, but the formulas introduced then were impractical for computation. here, we provide an efficient algorithm for these formulas, and we demonstrate their usefulness on several examples of $ p $ - groups. | arxiv:1607.01344 |
by a covering of a group g we mean an epimorphism from a group f to g. introducing the notion of strong covering as a covering pi : f - - > g such that every automorphism of g is a projection via pi of an automorphism of f, the main aim of this paper is to characterise double coverings which are strong. this is done in details for metacyclic groups, rotary platonic groups and some finite simple groups. | arxiv:math/0610556 |
the first - ever ukraine cyberattack on power grid has proven its devastation by hacking into their critical cyber assets. with administrative privileges accessing substation networks / local control centers, one intelligent way of coordinated cyberattacks is to execute a series of disruptive switching executions on multiple substations using compromised supervisory control and data acquisition ( scada ) systems. these actions can cause significant impacts to an interconnected power grid. unlike the previous power blackouts, such high - impact initiating events can aggravate operating conditions, initiating instability that may lead to system - wide cascading failure. a systemic evaluation of " nightmare " scenarios is highly desirable for asset owners to manage and prioritize the maintenance and investment in protecting their cyberinfrastructure. this survey paper is a conceptual expansion of real - time monitoring, anomaly detection, impact analyses, and mitigation ( raim ) framework that emphasizes on the resulting impacts, both on steady - state and dynamic aspects of power system stability. hypothetically, we associate the combinatorial analyses of steady state on substations / components outages and dynamics of the sequential switching orders as part of the permutation. the expanded framework includes ( 1 ) critical / noncritical combination verification, ( 2 ) cascade confirmation, and ( 3 ) combination re - evaluation. this paper ends with a discussion of the open issues for metrics and future design pertaining the impact quantification of cyber - related contingencies. | arxiv:1801.01048 |
software interfaces today generally fall at either end of a spectrum. on one end are programmable systems, which allow expert users ( i. e. programmers ) to write software artifacts that describe complex abstractions, but programs are disconnected from their eventual output. on the other end are domain - specific graphical user interfaces ( guis ), which allow end users ( i. e. non - programmers ) to easily create varied content but present insurmountable walls when a desired feature is not built - in. both programmatic and direct manipulation have distinct strengths, but users must typically choose one over the other or use some ad - hoc combination of systems. our goal, put simply, is to bridge this divide. we envision novel software systems that tightly couple programmatic and direct manipulation - - - a combination we dub prodirect manipulation - - - for a variety of use cases. this will require advances in a broad range of software engineering disciplines, from program analysis and program synthesis technology to user interface design and evaluation. in this extended abstract, we propose two general strategies - - - real - time program synthesis and domain - specific synthesis of general - purpose programs - - - that may prove fruitful for overcoming the technical challenges. we also discuss metrics that will be important in evaluating the usability and utility of prodirect manipulation systems. | arxiv:1510.06788 |
learning quantum states is a crucial task for realizing quantum information technology. recently, neural approaches have emerged as promising methods for learning quantum states. we propose a meta - learning model that utilizes reinforcement learning ( rl ) to optimize the process of learning quantum states. to improve the data efficiency of the rl, we introduce an action repetition strategy inspired by curriculum learning. the rl agent significantly improves the sample efficiency of learning random quantum states, and achieves infidelity scaling close to the heisenberg limit. we also show that the rl agent trained using 3 - qubit states can generalize to learning up to 5 - qubit states. these results highlight the utility of rl - driven meta - learning to enhance the efficiency and generalizability of learning quantum states. our approach can be applied to improve quantum control, quantum optimization, and quantum machine learning. | arxiv:2412.02334 |
the effectiveness of data - driven techniques heavily depends on the input signal used to generate the estimation data. however, a significant research gap exists in the field of input design for nonlinear dynamic system identification. in particular, existing methods largely overlook the minimization of the generalization error, i. e., model inaccuracies in regions not covered by the estimation dataset. this work addresses this gap by proposing an input design method that embeds a novel optimality criterion within a receding horizon control ( rhc ) - based optimization framework. the distance - based optimality criterion induces a space - filling design within a user - defined region of interest in a surrogate model ' s input space, requiring only minimal prior knowledge. additionally, the method is applicable both online, where model parameters are continuously updated based on process observations, and offline, where a fixed model is employed. the space - filling performance of the proposed strategy is evaluated on an artificial example and compared to state - of - the - art methods, demonstrating superior efficiency in exploring process operating spaces. | arxiv:2504.02653 |
damped ly _ alpha galaxies provide a sample of young galaxies where chemical abundances can be derived throughout the whole universe with an accuracy comparable to that for the local universe. despite a large spread in redshift, hi column density and metallicity, dla galaxies show a remarkable uniformity in the elemental ratios rather suggestive of similar chemical evolution if not of an unique population. these galaxies are characterized by a moderate, if any, enhancement of alpha - elements over fe - peak elemental abundance with [ s / zn ] about 0 and [ o / zn ] about 0. 2, rather similarly to the dwarfs galaxies in the local group. nitrogen shows a peculiar behaviour with a bimodal distribution and possibly two plateaux. in particular, the plateau at low n abundances ( [ n / h ] < - 3 ), is not observed in other atrophysical sites and might be evidence for primary n production by massive stars. | arxiv:astro-ph/0503214 |
we study the upper and the lower densities of complete and minimal gabor gaussians systems. in contrast to the classical lattice case when they are both equal to $ 1 $, we prove that the lower density may reach $ 0 $ while the upper density may vary at least from $ \ frac { 1 } { \ pi } $ to $ e $. in the case when the upper density exceeds $ 1 $, we establish a sharp inequality relating the upper and the lower densities. | arxiv:2003.08702 |
pedal and contrapedal curves are important study objects of plane curves. as for a mixed - type minkowski plane curve, since the definitions of the pedal and contrapedal curves at lightlike points can not always be given, the investigation of them is difficult. we have done some research on the pedal curves of a mixed - type curve. in this paper, we discuss when the contrapedal curves of a mixed - type curve exist and give the definition of them when they exist. then, we study when the contrapedal curves of the mixed - type curve have singular points. meanwhile, we consider the types of the points on the contrapedal curves. moreover, we investigate the relationship between the pedal and contrapedal curves of a mixed - type curve, as well as the relationship among them and the evolute of the base curve. | arxiv:2401.13915 |
in this paper, we first use the " complexity equals action " conjecture to discuss the complexity growth rate in both perturbation einsteinian cubic gravity and non - perturbation einstein - weyl gravity. we find that the ca complexity rate in these cases is divergent. to avoid this divergence, we modify the original conjecture, where we assume that the complexity of the boundary state equals the boundary actions contributed by the null segments as well as the joints of the wheeler - dewitt patch. then, the late time growth rate of this modified holographic complexity is given by entropy $ s $ times temperature $ t $, which is quite in agreement with the circuit analysis. finally, to test its rationality, we also investigate the switchback effect by evaluating it in a vaidya geometry and analyze the results in circuit models. | arxiv:1903.05476 |
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