text
stringlengths 1
3.65k
| source
stringlengths 15
79
|
|---|---|
##ians, monetarists, new classical and new keynesian economists, a synthesis emerged by the 2000s, often given the name the new neoclassical synthesis. it integrated the rational expectations and optimizing framework of the new classical theory with a new keynesian role for nominal rigidities and other market imperfections like imperfect information in goods, labour and credit markets. the monetarist importance of monetary policy in stabilizing the economy and in particular controlling inflation was recognised as well as the traditional keynesian insistence that fiscal policy could also play an influential role in affecting aggregate demand. methodologically, the synthesis led to a new class of applied models, known as dynamic stochastic general equilibrium or dsge models, descending from real business cycles models, but extended with several new keynesian and other features. these models proved useful and influential in the design of modern monetary policy and are now standard workhorses in most central banks. = = = = after the 2008 financial crisis = = = = after the 2008 financial crisis, macroeconomic research has put greater emphasis on understanding and integrating the financial system into models of the general economy and shedding light on the ways in which problems in the financial sector can turn into major macroeconomic recessions. in this and other research branches, inspiration from behavioural economics has started playing a more important role in mainstream economic theory. also, heterogeneity among the economic agents, e. g. differences in income, plays an increasing role in recent economic research. = = = other schools and approaches = = = other schools or trends of thought referring to a particular style of economics practised at and disseminated from well - defined groups of academicians that have become known worldwide, include the freiburg school, the school of lausanne, the stockholm school and the chicago school of economics. during the 1970s and 1980s mainstream economics was sometimes separated into the saltwater approach of those universities along the eastern and western coasts of the us, and the freshwater, or chicago school approach. within macroeconomics there is, in general order of their historical appearance in the literature ; classical economics, neoclassical economics, keynesian economics, the neoclassical synthesis, monetarism, new classical economics, new keynesian economics and the new neoclassical synthesis. beside the mainstream development of economic thought, various alternative or heterodox economic theories have evolved over time, positioning themselves in contrast to mainstream theory. these include : austrian school, emphasizing human action, property rights and the freedom to contract and transact to have a thriving and successful economy. it also
|
https://en.wikipedia.org/wiki/Economics
|
the analysis of the output from a large scale computer simulation experiment can pose a challenging problem in terms of size and computation. we consider output in the form of simulated crop yields from the environmental policy integrated climate ( epic ) model, which requires a large number of inputs such as fertiliser levels, weather conditions, and crop rotations inducing a high dimensional input space. in this paper, we adopt a bayes linear approach to efficiently emulate crop yield as a function of the simulator fertiliser inputs. we explore emulator diagnostics and present the results from emulation of a subset of the simulated epic data output.
|
arxiv:2109.10208
|
thermal energy storage ( tes ) is increasingly recognized as an essential component of efficient combined heat and power ( chp ), concentrated solar power ( csp ), heating ventilation and air conditioning ( hvac ), and refrigeration as it reduces peak demand while helping to manage intermittent availability of energy ( e. g., from solar or wind ). latent heat thermal energy storage ( lhtes ) is a viable option because of its high energy storage density. parametric analysis of lhtes heat exchangers have been focused on obtaining data with laminar flow in the phase changing fluid and then fitting a functional form, such as a power law or polynomial, to those data. alternatively, in this paper we present a parametric framework to analyze lhtes devices by identifying all relevant fluid parameters and corresponding dimensionless numbers. we present 64 simulations of an lhtes device using the finite volume method at four values of the grashof, prandtl and reynolds numbers in the phase change material ( pcm ) and heat transfer fluid ( htf ). we observe that with sufficient energy available in the htf, the effects of the htf reynolds number and prandtl number on the heat transfer rate are negligible. under these conditions, we propose a time scale for the variation of energy stored ( or melt fraction ) of the lhtes device based on the fourier number ( $ fo $ ), grashof number ( $ gr _ p $ ) and prandtl number ( $ pr _ p $ ) and observe a $ gr _ p ^ 1 $ and $ pr _ p ^ { ( 1 / 3 ) } $ dependency. we also identify two distinct regions in the variation of the melt fraction with time, namely, the linear and the asymptotic region. we also predict the critical value of the melt fraction at the transition between the two regions. from these analyses, we draw some conclusions regarding the design procedure for lhtes devices.
|
arxiv:2009.10712
|
topic models are valuable for understanding extensive document collections, but they don ' t always identify the most relevant topics. classical probabilistic and anchor - based topic models offer interactive versions that allow users to guide the models towards more pertinent topics. however, such interactive features have been lacking in neural topic models. to correct this lacuna, we introduce a user - friendly interaction for neural topic models. this interaction permits users to assign a word label to a topic, leading to an update in the topic model where the words in the topic become closely aligned with the given label. our approach encompasses two distinct kinds of neural topic models. the first includes models where topic embeddings are trainable and evolve during the training process. the second kind involves models where topic embeddings are integrated post - training, offering a different approach to topic refinement. to facilitate user interaction with these neural topic models, we have developed an interactive interface. this interface enables users to engage with and re - label topics as desired. we evaluate our method through a human study, where users can relabel topics to find relevant documents. using our method, user labeling improves document rank scores, helping to find more relevant documents to a given query when compared to no user labeling.
|
arxiv:2311.09438
|
automated detection and segmentation of pulmonary nodules on lung computed tomography ( ct ) scans can facilitate early lung cancer diagnosis. existing supervised approaches for automated nodule segmentation on ct scans require voxel - based annotations for training, which are labor - and time - consuming to obtain. in this work, we propose a weakly - supervised method that generates accurate voxel - level nodule segmentation trained with image - level labels only. by adapting a convolutional neural network ( cnn ) trained for image classification, our proposed method learns discriminative regions from the activation maps of convolution units at different scales, and identifies the true nodule location with a novel candidate - screening framework. experimental results on the public lidc - idri dataset demonstrate that, our weakly - supervised nodule segmentation framework achieves competitive performance compared to a fully - supervised cnn - based segmentation method.
|
arxiv:1707.01086
|
in his previous papers ( math. res. letters 7 ( 2000 ), 123 - - 13 ; math. res. letters 8 ( 2001 ), 429 - - 435 ; moscow math. j. 2 ( 2002 ), issue 2, 403 - 431 ) the author proved that in characteristic $ \ ne 2 $ the jacobian $ j ( c ) $ of a hyperelliptic curve $ c : y ^ 2 = f ( x ) $ has only trivial endomorphisms over an algebraic closure $ k _ a $ of the ground field $ k $ if the galois group $ \ gal ( f ) $ of the irreducible polynomial $ f ( x ) \ in k [ x ] $ is either the symmetric group $ \ sn $ or the alternating group $ \ a _ n $. here $ n \ ge 9 $ is the degree of $ f $. the goal of this paper is to extend this result to the case of certain ` ` smaller ' ' doubly transitive simple galois groups. namely, we treat the infinite series $ n = 2 ^ m + 1, \ gal ( f ) = \ l _ 2 ( 2 ^ m ) : = \ psl _ 2 ( \ f _ { 2 ^ m } ) $, $ n = 2 ^ { 4m + 2 } + 1, \ gal ( f ) = \ sz ( 2 ^ { 2m + 1 } ) = { ^ 2 \ b _ 2 } ( 2 ^ { 2m + 1 } ) $ and $ n = 2 ^ { 3m } + 1, \ gal ( f ) = \ u _ 3 ( 2 ^ m ) : = \ psu _ 3 ( \ f _ { 2 ^ m } ) $.
|
arxiv:math/0301177
|
we develop a cluster dynamical mean field theory of the periodic anderson model in three dimensions, taking a cluster of two sites as a basic reference frame. the mean field theory displays the basic features of the doniach phase diagram : a paramagnetic fermi liquid state, an antiferromagnetic state and a transition between them. in contrast with spin density wave theories, the transition is accompanied by a large increase of the effective mass everywhere on the fermi surface and a substantial change of the fermi surface shape across the transition. to understand the nature and the origin of the phases near the transition, we investigate the paramagnetic solution underlying the antiferromagnetic state, and identify the transition as a point where the $ f $ electrons decouple from the conduction electrons undergoing an orbitally selective mott transition. this point turns out to be intimately related to the two impurity kondo model quantum critical point. in this regime, non local correlations become important and result in significant changes in the photoemission spectra and the de haas - van alphen frequencies. the transition involves considerable $ f $ spectral weight transfer from the fermi level to its immediate vicinity, rather than to the hubbard bands as in single site dmft.
|
arxiv:cond-mat/0702559
|
distributed control systems require high reliability and availability guarantees despite often being deployed at the edge of network infrastructure. edge computing resources are less secure and less reliable than centralized resources in data centers. replication and consensus protocols improve robustness to network faults and crashed or corrupted nodes, but these volatile environments can cause non - faulty nodes to temporarily diverge, increasing the time needed for replicas to converge on a consensus value, and give byzantine attackers too much influence over the convergence process. this paper proposes proximal byzantine consensus, a new approximate consensus protocol where clients use statistical models of streaming computations to decide a consensus value. in addition, it provides an interval around the decision value and the probability that the true ( non - faulty, noise - free ) value falls within this interval. proximal consensus ( pc ) tolerates unreliable network conditions, byzantine behavior, and other sources of noise that cause honest replica states to diverge. we evaluate our approach for scalar values, and compare pc simulations against a vector consensus ( vc ) protocol simulation. our simulations demonstrate that consensus values selected by pc have lower error and are more robust against byzantine attacks. we formally characterize the security guarantees against byzantine attacks and demonstrate attacker influence is bound with high probability. additionally, an informal complexity analysis suggests pc scales better to higher dimensions than convex hull - based protocols such as vc.
|
arxiv:2402.12577
|
a common issue when analyzing real - world complex systems is that the interactions between the elements often change over time : this makes it difficult to find optimal models that describe this evolution and that can be estimated from data, particularly when the driving mechanisms are not known. here we offer a new perspective on the development of models for time - varying interactions introducing a generalization of the well - known kinetic ising model ( kim ), a minimalistic pairwise constant interactions model which has found applications in multiple scientific disciplines. keeping arbitrary choices of dynamics to a minimum and seeking information theoretical optimality, the score - driven methodology lets us significantly increase the knowledge that can be extracted from data using the simple kim. in particular, we first identify a parameter whose value at a given time can be directly associated with the local predictability of the dynamics. then we introduce a method to dynamically learn the value of such parameter from the data, without the need of specifying parametrically its dynamics. finally, we extend our framework to disentangle different sources ( e. g. endogenous vs exogenous ) of predictability in real time. we apply our methodology to several complex systems including financial markets, temporal ( social ) networks, and neuronal populations. our results show that the score - driven kim produces insightful descriptions of the systems, allowing to predict forecasting accuracy in real time as well as to separate different components of the dynamics. this provides a significant methodological improvement for data analysis in a wide range of disciplines.
|
arxiv:2007.15545
|
in this paper we define an intrinsic notion of principal for the hypoelliptic calculus on heisenberg manifolds. more precisely, the principal symbol of a \ psivdo appears as a homogeneous section over the linear dual of the tangent lie algebra bundle of the manifold. this definition is an important step towards using global $ k $ - theoretic tools in the heisenberg setting, such as those involved in the elliptic setting for proving the atiyah - singer index theorem or the regularity of the eta invariant. on the other hand, the intrinsic definition of the principal symbol enables us to give an intrinsic sense to the model operator of \ psivdo at point and to give a definitive proof that the heisenberg calculus is modelled at each point by the calculus of left - invariant \ psidos on the tangent group at the point. this also allows us to define an intrinsic rockland condition for \ psivdos which is shown to be equivalent to the invertibility of the principal symbol, provided that the levi form has constant rank. furthermore, we review the main hypoellipticity results on heisenberg manifolds in terms of the results of the paper. in particular, we complete the treatment of the kohn laplacian by beals - greiner and establish that for the horizontal sublaplacian the invertibility of the principal symbol is equivalent to some condition on the levi form, called condition $ x ( k ) $. incidentally, this paper provides us with a relatively up - to - date overview of the main facts about the heisenberg calculus.
|
arxiv:math/0504048
|
security proof of practical quantum key distribution ( qkd ) has attracted a lot of attentions in recent years. most of real - life qkd implementations are based on phase - coding bb84 protocol, which usually uses unbalanced mach - zehnder interferometer ( umzi ) as the information coder and decoder. however, the long arm and short arm of umzi will introduce different loss in practical experimental realizations, the state emitted by alice ' s side is nolonger standard bb84 states. in this paper, we will give a security analysis in this situation. counterintuitively, active compensation for this different loss will only lower the secret key bit rate.
|
arxiv:0911.2938
|
we give a combinatorial characterization of the identities holding in the semiring of all upper triangular boolean $ n \ times n $ - matrices and apply the characterization to computational complexity of identity checking, finite axiomatizability of equational theories, and algebraic descriptions of certain classes of recognizable languages.
|
arxiv:2412.16113
|
we construct a physics - agnostic approach to the neutron star ( ns ) equation of state ( eos ) based on a sound speed model, which connects both low - density information from nuclear theory and high - density constraints from perturbative qcd ( pqcd ). using this approach, we study the impact of pqcd calculations on ns eos that have been constrained by astrophysical observations. we find that pqcd affects the eos mainly beyond the densities realized in ns. furthermore, we observe an interesting interplay between pqcd and astrophysical constraints, with pqcd preferring softer eos for the heaviest ns while recent nicer observations suggest the eos to be stiffer. we explore the sensitivity of our findings to pqcd uncertainties and study the constraining power of pqcd if future observations of heavy ns were to suggest radii larger than 13 km.
|
arxiv:2204.14039
|
we investigate the prospects for indirect detection of right - handed sneutrino dark matter at the icecube neutrino telescope in a $ u ( 1 ) _ { b - l } $ extension of the mssm. the capture and annihilation of sneutrinos inside the sun reach equilibrium, and the flux of produced neutrinos is governed by the sneutrino - proton elastic scattering cross section, which has an upper bound of $ 8 \ times 10 ^ { - 9 } $ pb from the $ z ^ { \ prime } $ mass limits in the $ b - l $ model. despite the absence of any spin - dependent contribution, the muon event rates predicted by this model can be detected at icecube since sneutrinos mainly annihilate into leptonic final states by virtue of the fermion $ b - l $ charges. these subsequently decay to neutrinos with 100 % efficiency. the earth muon event rates are too small to be detected for the standard halo model irrespective of an enhanced sneutrino annihilation cross section that can explain the recent pamela data. for modified velocity distributions, the earth muon events increase substantially and can be greater than the icecube detection threshold of 12 events $ \ mathrm { km } ^ { - 2 } $ $ \ mathrm { yr } ^ { - 1 } $. however, this only leads to a mild increase of about 30 % for the sun muon events. the number of muon events from the sun can be as large as roughly 100 events $ \ mathrm { km } ^ { - 2 } $ $ \ mathrm { yr } ^ { - 1 } $ for this model.
|
arxiv:0907.1486
|
we consider the relativistic scattering of unequal - mass scalar particles through graviton exchange in the small - angle high - energy regime. we show the self - consistency of expansion around the eikonal limit and compute the scattering amplitude up to the next - to - leading power correction of the light particle energy, including gravitational effects of the same order. the first power correction is suppressed by a single power of the ratio of momentum transfer to the energy of the light particle in the rest frame of the heavy particle, independent of the heavy particle mass. we find that only gravitational corrections contribute to the exponentiated phase in impact parameter space in four dimensions. for large enough heavy - particle mass, the saddle point for the impact parameter is modified compared to the leading order by a multiple of the schwarzschild radius determined by the mass of the heavy particle, independent of the energy of the light particle.
|
arxiv:1308.5204
|
topological invariants are conventionally known to be responsible for protection of extended states against disorder. a prominent example is the presence of topologically protected extended - states in two - dimensional ( 2d ) quantum hall systems as well as on the surface of three - dimensional ( 3d ) topological insulators. distinct from such cases, here we introduce a new concept, that is, the topological protection of bound states against hybridization. this situation is shown to be realizable in a 2d quantum hall insulator put on a 3d trivial insulator. in such a configuration, there exist topologically protected bound states, localized along the normal direction of 2d plane, in spite of hybridization with the continuum of extended states. the one - dimensional edge states are also localized along the same direction as long as their energies are within the band gap. this finding demonstrates the dual role of topological invariants, as they can also protect bound states against hybridization in a continuum.
|
arxiv:1212.5598
|
the problem of the low - energy highly - anharmonic quantum dynamics of isolated impurities in solids is addressed by using path - integral monte carlo simulations. interstitial oxygen in silicon is studied as a prototypical example showing such a behavior. the assignment of a " geometry " to the defect is discussed. depending on the potential ( or on the impurity mass ), there is a " classical " regime, where the maximum probability - density for the oxygen nucleus is at the potential minimum. there is another regime, associated to highly anharmonic potentials, where this is not the case. both regimes are separated by a sharp transition. also, the decoupling of the many - nuclei problem into a one - body hamiltonian to describe the low - energy dynamics is studied. the adiabatic potential obtained from the relaxation of all the other degrees of freedom at each value of the coordinate associated to the low - energy motion, gives the best approximation to the full many - nuclei problem.
|
arxiv:cond-mat/9607115
|
3d sensing for monocular in - the - wild images, e. g., depth estimation and 3d object detection, has become increasingly important. however, the unknown intrinsic parameter hinders their development and deployment. previous methods for the monocular camera calibration rely on specific 3d objects or strong geometry prior, such as using a checkerboard or imposing a manhattan world assumption. this work solves the problem from the other perspective by exploiting the monocular 3d prior. our method is assumption - free and calibrates the complete $ 4 $ degree - of - freedom ( dof ) intrinsic parameters. first, we demonstrate intrinsic is solved from two well - studied monocular priors, i. e., monocular depthmap, and surface normal map. however, this solution imposes a low - bias and low - variance requirement for depth estimation. alternatively, we introduce a novel monocular 3d prior, the incidence field, defined as the incidence rays between points in 3d space and pixels in the 2d imaging plane. the incidence field is a pixel - wise parametrization of the intrinsic invariant to image cropping and resizing. with the estimated incidence field, a robust ransac algorithm recovers intrinsic. we demonstrate the effectiveness of our method by showing superior performance on synthetic and zero - shot testing datasets. beyond calibration, we demonstrate downstream applications in image manipulation detection & restoration, uncalibrated two - view pose estimation, and 3d sensing. codes, models, and data will be held in https : / / github. com / shngjz / wildcamera.
|
arxiv:2306.10988
|
in this paper, we consider two systems of type rao - nakra sandwich beam in the whole line r with a frictional damping or an infinite memory acting on the euler - bernoulli equation. when the speeds of propagation of the two wave equations are equal, we show that the solutions do not converge to zero when time goes to infinity. in the reverse situation, we prove some l2 ( r ) - norm and l1 ( r ) - norm decay estimates of solutions and theirs higher order derivatives with respect to the space variable. thanks to interpolation inequalities and carlson inequality, these l2 ( r ) - norm and l1 ( r ) - norm decay estimates lead to similar ones in the lq ( r ) - norm, for any q > 1. in our both l2 ( r ) - norm and l1 ( r ) - norm decay estimates, we specify the decay rates in terms of the regularity of the initial data and the nature of the control.
|
arxiv:2201.05881
|
the solution of systems of linear ( ized ) equations lies at the heart of many problems in scientific computing. in particular for systems of large dimension, iterative methods are a primary approach. stationary iterative methods are generally based on a matrix splitting, whereas for polynomial iterative methods such as krylov subspace iteration, the splitting matrix is the preconditioner. the smoother in a multigrid method is generally a stationary or polynomial iteration. here we consider real symmetric indefinite and complex hermitian indefinite coefficient matrices and prove that no splitting matrix can lead to a contractive stationary iteration unless the inertia is exactly preserved. this has consequences for preconditioning for indefinite systems and smoothing for multigrid as we further describe.
|
arxiv:2412.01554
|
it has been an open problem to identify classes of gibbs measures less regular then h \ " older continuous on the full shift which are closed under factor maps. in this article we show that in fact all of the classical uniqueness regimes ( bowen, walters, and h \ " older ) from thermodynamic formalism are closed under factor maps between full shifts. in fact we show more generally that the classical uniqueness regimes are closed under factors between shifts of finite type provided the factor map satisfies a suitable mixing in fibers condition.
|
arxiv:1905.03803
|
we study the analytic behaviour of adelic versions of igusa integrals given by integer polynomials defining elliptic curves. by applying results on the meromorphic continuation of symmetric power l - functions and the sato - tate conjectures we prove that these global igusa zeta functions have some meromorphic continuation until a natural boundary beyond which no continuation is possible.
|
arxiv:1509.04835
|
let f be a transcendental entire function in the eremenko - lyubich class b. we give a lower bound for the hausdorff dimension of the julia set of f that depends on the growth of f. this estimate is best possible and is obtained by proving a more general result concerning the size of the escaping set of a function with a logarithmic tract.
|
arxiv:0807.2363
|
using g - structure language, a systematic, iterative formalism for computing neccessary and sufficient conditions for the existence of n arbitrary linearly independent killing spinors is presented. the key organisational tool is the common isotropy group of the killing spinors. the formalism is illustrated for configurations in gauged su ( 2 ) supergravity in seven dimensions admitting at least one null killing spinor, and the possible isotropy groups are shown to be $ ( su ( 2 ) \ ltimes \ mathbb { r } ^ 4 ) \ times \ mathbb { r } $, su ( 2 ), $ \ mathbb { r } ^ 5 $, or the identity. the constraints associated with the existence of certain additional killing spinors are computed, and used to derive numerous solutions. a discussion of the relevance of the formalism to the complete classification of all supersymmetric configurations in d = 11 is given.
|
arxiv:hep-th/0408203
|
linear nonautonomous / random parabolic partial differential equations are considered under the dirichlet, neumann or robin boundary conditions, where both the zero order coefficients in the equation and the coefficients in the boundary conditions are allowed to depend on time. the theory of the principal spectrum / principal lyapunov exponents is shown to apply to those equations. in the nonautonomous case, the main result states that the principal eigenvalue of any time - averaged equation is not larger than the supremum of the principal spectrum and that there is a time - averaged equation whose principal eigenvalue is not larger than the infimum of the principal spectrum. in the random case, the main result states that the principal eigenvalue of the time - averaged equation is not larger than the principal lyapunov exponent.
|
arxiv:1708.06533
|
critical fluctuations of some order parameter describing a fluid generates long - range forces between boundaries. here, we discuss fluctuation - induced forces associated to a disordered landau - ginzburg model defined in a $ d $ - dimensional slab geometry $ \ mathbb r ^ { d - 1 } \ times [ 0, l ] $. in the model the strength of the disordered field is defined by a non - thermal control parameter. we study a nearly critical scenario, using the distributional zeta - function method, where the quenched free energy is written as a series of the moments of the partition function. in the gaussian approximation, we show that, for each moment of the partition function, and for some specific strength of the disorder, the non - thermal fluctuations, associated to an order parameter - like quantity, becomes long - ranged. we demonstrate that the sign of the fluctuation induced force between boundaries, depend in a non - trivial way on the strength of the aforementioned non - thermal control parameter.
|
arxiv:2201.07400
|
by applying the basic concept of the density matrix in an open quantum system and modification of quantum mechanics, we derive kossakowski - lindblad equation and different properties of this equation are reviewed. next, a pedagogical approach is used to present ramsey ' s trick for linear modification of the quantum mechanics. we discuss how an open quantum mechanics or its modification changes the fraction of excited states in ramsey interferometers.
|
arxiv:1808.10244
|
we present revel, a partially neural reinforcement learning ( rl ) framework for provably safe exploration in continuous state and action spaces. a key challenge for provably safe deep rl is that repeatedly verifying neural networks within a learning loop is computationally infeasible. we address this challenge using two policy classes : a general, neurosymbolic class with approximate gradients and a more restricted class of symbolic policies that allows efficient verification. our learning algorithm is a mirror descent over policies : in each iteration, it safely lifts a symbolic policy into the neurosymbolic space, performs safe gradient updates to the resulting policy, and projects the updated policy into the safe symbolic subset, all without requiring explicit verification of neural networks. our empirical results show that revel enforces safe exploration in many scenarios in which constrained policy optimization does not, and that it can discover policies that outperform those learned through prior approaches to verified exploration.
|
arxiv:2009.12612
|
based on high quality observations of multiplet v1 of oii and the nlte atomic computations of oii we study the density and temperature of a sample of hii regions. we find that the signature for oxygen rich clumps of high density and low temperature is absent in all objects of our sample : one extragalactic and eight galactic hii regions. the temperatures derived from : a ) recombination lines of oii, and b ) recombination lines of hi together with balmer continua are lower than those derived from forbidden lines, while the densities derived from recombination lines of oii are similar or smaller than densities derived from forbidden lines. electron pressures derived from collisionally excited lines are about two times larger than those derived from recombination lines. these results imply that the proper abundances are those derived from recombination lines and suggest that other processes in addition to direct photoionization, such as dissipation of turbulent energy in shocks, magnetic reconnection, and shadowed regions, might be responsible for the large adf and t2 values observed in hii regions.
|
arxiv:1310.0089
|
various string theory realizations of three - dimensional gauge theories relate them to gravitational instantons, nahm equations and monopoles. we use this correspondence to model self - dual gravitational instantons of $ d _ k $ - type as moduli spaces of singular monopoles, find their twistor spaces and metrics.
|
arxiv:hep-th/9807237
|
quantum measurements affect the state of the observed systems via back - action. while projective measurements extract maximal classical information, they drastically alter the system. in contrast, weak measurements balance information extraction with the degree of disturbance. considering the prevalent use of projective measurements in quantum computing and communication protocols, the potential benefits of weak measurements in these fields remain largely unexplored. in this work, we demonstrate that incorporating weak measurements into a quantum machine - learning protocol known as quantum reservoir computing provides advantages in both execution time scaling and overall performance. we analyze different measurement settings by varying the measurement strength across two benchmarking tasks. our results reveal that carefully optimizing both the reservoir hamiltonian parameters and the measurement strength can significantly improve the quantum reservoir computing algorithm performance. this work provides a comprehensive and practical recipe to promote the implementation of weak measurement - based protocols in quantum reservoir computing. moreover, our findings motivate further exploration of experimental protocols that leverage the back - action effects of weak measurements.
|
arxiv:2411.03979
|
in this paper, we prove a sanov - type large deviation principle for the sequence of empirical measures of vectors chosen uniformly at random from an orlicz ball. from this level - $ 2 $ large deviation result, in a combination with gibbs conditioning, entropy maximization and an orlicz version of the poincar \ ' e - maxwell - borel lemma, we deduce a conditional limit theorem for high - dimensional orlicz balls. roughly speaking, the latter shows that if $ v _ 1 $ and $ v _ 2 $ are orlicz functions, then random points in the $ v _ 1 $ - orlicz ball, conditioned on having a small $ v _ 2 $ - orlicz radius, look like an appropriately scaled $ v _ 2 $ - orlicz ball. in fact, we show that the limiting distribution in our poincar \ ' e - maxwell - borel lemma, and thus the geometric interpretation, undergoes a phase transition depending on the magnitude of the $ v _ 2 $ - orlicz radius.
|
arxiv:2111.04691
|
the notion of ` pseudo algebraically closed ( pac ) extensions ' is a generalization of the classical notion of pac fields. it was originally motivated by hilbert ' s tenth problem, and recently had new applications. in this work we develop a basic machinery to study pac extensions. this machinery is based on a generalization of embedding problems to field extensions. the main goal is to prove that the galois closure of any proper separable algebraic pac extension is its separable closure. this vastly generalizes earlier works of jarden - razon, jarden, and jarden and the author. this also leads to a classification of all finite pac extensions which in turn proves the ` bottom conjecture ' for finitely generated infinite fields. the secondary goal of this work is to unify proofs of known results about pac extensions and to establish new basic properties of pac extensions, e. g. \ transitiveness of pac extensions.
|
arxiv:0806.3851
|
hirota ' s bilinear method ( " direct method " ) has been very effective in constructing soliton solutions to many integrable equations. the construction of one - and two - soliton solutions is possible even for non - integrable bilinear equations, but the existence of a generic three - soliton solution imposes severe constraints and is in fact equivalent to integrability. this property has been used before in searching for integrable partial differential equations, and in this paper we apply it to two dimensional partial difference equations defined on a 3x3 stencil. we also discuss how the obtained equations are related to projections and limits of the three - dimensional master equations of hirota and miwa, and find that sometimes a singular limit is needed.
|
arxiv:1210.4708
|
we report on some recent progress in understanding heterotic flux compactifications, from a worldsheet perspective mainly. we consider local models consisting in torus fibration over warped eguchi - hanson space and non - k \ " ahler resolved conifold geometries. we analyze the supergravity solutions and define a double - scaling limit of the resolved singularities, defined such that the geometry is smooth and weakly coupled. we show that, remarkably, the heterotic solutions admit solvable worldsheet cft descriptions in this limit. this allows in particular to understand the important role of worldsheet non - perturbative effects.
|
arxiv:1109.1534
|
in the loop approach to quantum gravity the spectra of operators corresponding to such geometrical quantities as length, area and volume become quantized. however, the size of arising quanta of geometry in planck units is not fixed by the theory itself : a free parameter, sometimes referred to as immirzi parameter, is known to affect the spectrum of all geometrical operators. in this paper i propose an argument that fixes the value of this parameter. i consider rotating black holes, in particular the extremal ones. for such black holes the ` ` no naked singularity condition ' ' bounds the total angular momentum j by a _ h / 8 pi g, where a _ h is the horizon area and g newton ' s constant. a similar bound on j comes from the quantum theory. the requirement that these two bounds are the same fixes the value of immirzi parameter to be unity. a byproduct of this argument is the picture of the quantum extremal rotating black hole in which all the spin entering the extremal hole is concentrated in a single puncture.
|
arxiv:gr-qc/9902015
|
we study the effects of fermiophobic scalar / pseudo - scalar oblique corrections on bound state energy levels in muonic atoms. to make the treatment sufficiently general we will consider unparticle scalars / pseudo - scalars which couple only to photons. we derive the relevant vacuum polarization functions and comment on the functional forms of the unparticle uehling potentials for various scaling dimensions in the point nucleus and finite nucleus approximations. it is estimated that for an infra - red fixed point near the scale of electroweak symmetry breaking, in the low tev range, the energy shifts in the low - lying muonic lead transitions could typically be of the order of a few times 0. 1 ev to a few times 0. 01 ev. it is shown that this conclusion is not changed even when scale invariance is broken and is in fact relatively insensitive to the scale at which it is broken. it is pointed out nevertheless that the estimated magnitude of the unparticle uehling shift is a factor of $ 10 ^ { 3 } - 10 ^ { 4 } $ below the discrepancy in qed / nuclear theory and precision muonic lead spectroscopy from about two decades ago. a minimum value for the conformal invariance breaking scale is also estimated for the fermiophobic scalar / pseudo - scalar sector to ensure consistency with astrophysics and cosmology. the energy level structure of the unparticle uehling shifts are inferred using general methods for the scalar and pseudo - scalar cases and it is shown that the two cases contribute to the energy shifts with the same sign.
|
arxiv:0906.4379
|
the task of generating natural images from 3d scenes has been a long standing goal in computer graphics. on the other hand, recent developments in deep neural networks allow for trainable models that can produce natural - looking images with little or no knowledge about the scene structure. while the generated images often consist of realistic looking local patterns, the overall structure of the generated images is often inconsistent. in this work we propose a trainable, geometry - aware image generation method that leverages various types of scene information, including geometry and segmentation, to create realistic looking natural images that match the desired scene structure. our geometrically - consistent image synthesis method is a deep neural network, called geometry to image synthesis ( gis ) framework, which retains the advantages of a trainable method, e. g., differentiability and adaptiveness, but, at the same time, makes a step towards the generalizability, control and quality output of modern graphics rendering engines. we utilize the gis framework to insert vehicles in outdoor driving scenes, as well as to generate novel views of objects from the linemod dataset. we qualitatively show that our network is able to generalize beyond the training set to novel scene geometries, object shapes and segmentations. furthermore, we quantitatively show that the gis framework can be used to synthesize large amounts of training data which proves beneficial for training instance segmentation models.
|
arxiv:1809.04696
|
in this paper, we prove two improved versions of the finiteness principle for nonnegative $ c ^ 2 ( \ mathbb { r } ^ 2 ) $ interpolation, previously proven by fefferman, israel, and luli. the first version sharpens the finiteness constant to $ 64 $, and the second version carries better computational practicality. along the way, we also provide detailed construction of nonnegative $ c ^ 2 $ interpolants in one - dimension, and prove the nonexistence of a bounded linear $ c ^ 2 $ - extension operator that preserves nonnegativity.
|
arxiv:1901.09876
|
based on a combined charge and vector spin transport theory capable of imaging noncollinear magnetic textures on surfaces with spin - polarized scanning tunneling microscopy ( sp - stm ), the high - resolution tunneling electron charge and coupled spin transport properties of a variety of n \ ' eel - and bloch - type skyrmions are investigated. axially symmetric skyrmions are considered within the same topology class characterized by a vorticity value of $ m = 1 $, and their helicities are varied by taking $ \ gamma = 0 $ and $ \ pi $ values for the n \ ' eel skyrmions and $ \ gamma = - \ pi / 2 $ and $ \ pi / 2 $ values for the bloch skyrmions. depending on the orientation of the magnetization of the stm tip as well as on the helicity and the time - reversal of the skyrmionic spin structures, several relationships between their spin transport vector components, the in - plane and out - of - plane spin transfer torque and the longitudinal spin current, are identified. the magnitudes of the spin transport vector quantities show close relation to standard charge current sp - stm images. it is also demonstrated that the sp - stm images can be used to determine the helicity of the skyrmions. moreover, the modified spin polarization vectors of the conduction electrons due to the local chirality of the complex spin texture are incorporated into the tunneling model. it is found that this effect modifies the apparent size of the skyrmions. these results contribute to the proper identification of topological surface magnetic objects imaged by sp - stm, and deliver important parameters for current - induced spin dynamics.
|
arxiv:1804.09096
|
a graph $ g $ is antimagic if there exists a bijection $ f $ from $ e ( g ) $ to $ \ left \ { 1, 2, \ dots, | e ( g ) | \ right \ } $ such that the vertex sums for all vertices of $ g $ are distinct, where the vertex sum is defined as the sum of the labels of all incident edges. hartsfield and ringel conjectured that every connected graph other than $ k _ 2 $ admits an antimagic labeling. it is still a challenging problem to address antimagicness in the case of disconnected graphs. in this paper, we study antimagicness for the disconnected graph that is constructed as the direct product of a star and a path.
|
arxiv:2308.11663
|
data assimilation of observational data into full atmospheric states is essential for weather forecast model initialization. recently, methods for deep generative data assimilation have been proposed which allow for using new input data without retraining the model. they could also dramatically accelerate the costly data assimilation process used in operational regional weather models. here, in a central us testbed, we demonstrate the viability of score - based data assimilation in the context of realistically complex km - scale weather. we train an unconditional diffusion model to generate snapshots of a state - of - the - art km - scale analysis product, the high resolution rapid refresh. then, using score - based data assimilation to incorporate sparse weather station data, the model produces maps of precipitation and surface winds. the generated fields display physically plausible structures, such as gust fronts, and sensitivity tests confirm learnt physics through multivariate relationships. preliminary skill analysis shows the approach already outperforms a naive baseline of the high - resolution rapid refresh system itself. by incorporating observations from 40 weather stations, 10 % lower rmses on left - out stations are attained. despite some lingering imperfections such as insufficiently disperse ensemble da estimates, we find the results overall an encouraging proof of concept, and the first at km - scale. it is a ripe time to explore extensions that combine increasingly ambitious regional state generators with an increasing set of in situ, ground - based, and satellite remote sensing data streams.
|
arxiv:2406.16947
|
the need to estimate a particular quantile of a distribution is an important problem which frequently arises in many computer vision and signal processing applications. for example, our work was motivated by the requirements of many semi - automatic surveillance analytics systems which detect abnormalities in close - circuit television ( cctv ) footage using statistical models of low - level motion features. in this paper we specifically address the problem of estimating the running quantile of a data stream when the memory for storing observations is limited. we make several major contributions : ( i ) we highlight the limitations of approaches previously described in the literature which make them unsuitable for non - stationary streams, ( ii ) we describe a novel principle for the utilization of the available storage space, ( iii ) we introduce two novel algorithms which exploit the proposed principle in different ways, and ( iv ) we present a comprehensive evaluation and analysis of the proposed algorithms and the existing methods in the literature on both synthetic data sets and three large real - world streams acquired in the course of operation of an existing commercial surveillance system. our findings convincingly demonstrate that both of the proposed methods are highly successful and vastly outperform the existing alternatives. we show that the better of the two algorithms ( data - aligned histogram ) exhibits far superior performance in comparison with the previously described methods, achieving more than 10 times lower estimate errors on real - world data, even when its available working memory is an order of magnitude smaller.
|
arxiv:1411.2250
|
we present a bayesian formulation for deep speaker embedding, wherein the xi - vector is the bayesian counterpart of the x - vector, taking into account the uncertainty estimate. on the technology front, we offer a simple and straightforward extension to the now widely used x - vector. it consists of an auxiliary neural net predicting the frame - wise uncertainty of the input sequence. we show that the proposed extension leads to substantial improvement across all operating points, with a significant reduction in error rates and detection cost. on the theoretical front, our proposal integrates the bayesian formulation of linear gaussian model to speaker - embedding neural networks via the pooling layer. in one sense, our proposal integrates the bayesian formulation of the i - vector to that of the x - vector. hence, we refer to the embedding as the xi - vector, which is pronounced as / zai / vector. experimental results on the sitw evaluation set show a consistent improvement of over 17. 5 % in equal - error - rate and 10. 9 % in minimum detection cost.
|
arxiv:2108.05679
|
in this paper we study the problem of half - duplex active eavesdropping in fast fading channels. the active eavesdropper is a more powerful adversary than the classical eavesdropper. it can choose between two functional modes : eavesdropping the transmission between the legitimate parties ( ex mode ), and jamming it ( jx mode ) - - the active eavesdropper cannot function in full duplex mode. we consider a conservative scenario, when the active eavesdropper can choose its strategy based on the legitimate transmitter - receiver pair ' s strategy - - and thus the transmitter and legitimate receiver have to plan for the worst. we show that conventional physical - layer secrecy approaches perform poorly ( if at all ), and we introduce a novel encoding scheme, based on very limited and unsecured feedback - - the block - markov wyner ( bmw ) encoding scheme - - which outperforms any schemes currently available.
|
arxiv:1002.1313
|
born - again planetary nebulae ( pne ) allow investigating stellar evolution, dust production, and nebular shocks in human timescales. here we present an analysis of multi - epoch optical spectroscopic observations of the born - again pn a 58 around v605 aql, which experienced a very late thermal pulse ( vltp ) about a century ago. the h - deficient ejecta has experienced a considerable brightening in the time period considered, from 1996 to 2021, with notable changes also in many emission line ratios. neither the reduction of the extinction caused by the dilution of the ejecta nor the increase of the ionizing photon flux from the central star seem capable to produce these spectral changes, which are instead attributed to shocks in the bipolar h - poor outflow dissociating molecular material and propagating through the outer nebula.
|
arxiv:2206.10203
|
we analyze the results of recent measurements of galactic cosmic ray ( gcrs ) energy spectra and the spectra of nonthermal emission from supernova remnants ( snrs ) in order to determine their consistency with gcr origin in snrs. it is shown that the measured primary and secondary cr nuclei energy spectra as well as the observed positron - to - electron ratio are consistent with the origin of gcrs up to the energy 10 ^ 17 ev in snrs. existing snr emission data provide evidences for efficient cr production in snrs accompanied by significant magnetic field amplification. in some cases the nature of the detected gamma - ray emission is difficult to determine because key snr parameters are not known or poorly constrained.
|
arxiv:1412.7800
|
in recent years, deep neural networks ( dnns ) have gained remarkable achievement in computer vision tasks, and the success of dnns often depends greatly on the richness of data. however, the acquisition process of data and high - quality ground truth requires a lot of manpower and money. in the long, tedious process of data annotation, annotators are prone to make mistakes, resulting in incorrect labels of images, i. e., noisy labels. the emergence of noisy labels is inevitable. moreover, since research shows that dnns can easily fit noisy labels, the existence of noisy labels will cause significant damage to the model training process. therefore, it is crucial to combat noisy labels for computer vision tasks, especially for classification tasks. in this survey, we first comprehensively review the evolution of different deep learning approaches for noisy label combating in the image classification task. in addition, we also review different noise patterns that have been proposed to design robust algorithms. furthermore, we explore the inner pattern of real - world label noise and propose an algorithm to generate a synthetic label noise pattern guided by real - world data. we test the algorithm on the well - known real - world dataset cifar - 10n to form a new real - world data - guided synthetic benchmark and evaluate some typical noise - robust methods on the benchmark.
|
arxiv:2404.04159
|
we explore theoretically the novel superfluidity of harmonically - trapped polarized ultracold fermionic atoms in a two - dimensional ( 2d ) optical lattice by solving the bogoliubov - de gennes equations. the pairing amplitude is found to oscillate along the radial direction at low particle density and along the angular direction at high density. the former is consistent with the existing experiments and the latter is a newly predicted fulde - ferrell - larkin - ovchinnikov ( fflo ) state, which can be tested in experiments.
|
arxiv:0710.5484
|
for a two - dimensional canonical system $ y ' ( t ) = zjh ( t ) y ( t ) $ on the half - line $ ( 0, \ infty ) $ whose hamiltonian $ h $ is a. e. positive semidefinite, denote by $ q _ h $ its weyl coefficient. de branges ' inverse spectral theorem states that the assignment $ h \ mapsto q _ h $ is a bijection between trace - normalised hamiltonians and nevanlinna functions. we prove that $ q _ h $ has an asymptotics towards $ i \ infty $ whose leading coefficient is some ( complex ) multiple of a regularly varying function if and only if the primitive $ m $ of $ h $ is regularly or rapidly varying at $ 0 $ and its off - diagonal entries do not oscillate too much. the leading coefficient in the asymptotic of $ q _ h $ towards $ i \ infty $ is related to the behaviour of $ m $ towards $ 0 $ by explicit formulae. the speed of growth in absolute value depends only on the diagonal entries of $ m $, while the argument of the leading coefficient corresponds to the relative size of the off - diagonal entries.
|
arxiv:2201.01522
|
origin of magnetic fields, its structure and effects on dynamical processes in stars to galaxies are not well understood. lack of a direct probe has hampered its study. the first phase of square kilometre array ( ska - i ), will have more than an order of magnitude higher sensitivity than existing radio telescopes. in this contribution, we discuss specific science cases that are of interest to the indian community concerned with astrophysical turbulence and magnetic fields. the ska - i will allow observations of a large number of background sources with detectable polarisation and measure their faraday depths ( fds ) through the milky way, other galaxies and their circum - galactic medium. this will probe line - of - sight magnetic fields in these objects well and provide field configurations. detailed comparison of observational data with models which consider various processes giving rise to field amplification and maintenance will then be possible. such observations will also provide the coherence scale of the fields and measure its random component. measuring the random component is important to characterise turbulence in the medium. observations of fds with redshift will provide important information on magnetic field evolution as a function of redshift. the background sources could also be used to probe magnetic fields and its coherent scale in galaxy clusters and in bridges formed between interacting galaxies. other than fds, sensitive observations of synchrotron emission from galaxies will provide complimentary information on their magnetic field strengths in the sky plane. the core shift measurements of agns can provide more precise measurements of magnetic field very close ( < pc ) to the black hole and its evolution. the low band of ska - i will also be useful to study circularly polarized emission from sun and comparing various models of field configurations with observations.
|
arxiv:1611.06966
|
##cey enrolled the next year and in 1965 became the university ' s first african american graduate. georgia tech became the first university in the deep south to desegregate without a court order. in the 1967 – 68 academic year 28 students out of 7, 526 were black. in 1968, william peace became the first black instructor and marle carter became the first black member of the homecoming court. in 1964, dr. calvin huey became the first black player to play at grant field when he took the field for navy. the first black person to play for georgia tech was eddie mcashan in 1970. similarly, there was little student reaction at georgia tech to the vietnam war and united states involvement in the cambodian civil war. the student council defeated a resolution supporting the vietnam moratorium, and the extent of the tech community ' s response to the kent state shooting was limited to a student - organized memorial service, though the institute was ordered closed for two days, along with all other university system of georgia schools. in 1988, president john patrick crecine pushed through a restructuring of the university. the institute at that point had three colleges : the college of engineering, the college of management, and the catch - all cosals, the college of sciences and liberal arts. crecine reorganized the latter two into the college of computing, the college of sciences, and the ivan allen college of management, policy, and international affairs. crecine never asked for input regarding the changes and, consequently, many faculty members disliked his top - down management style ; despite this, the changes passed by a slim margin. crecine was also instrumental in securing the 1996 summer olympics for atlanta. a large amount of construction occurred, creating most of what is now considered " west campus " for tech to serve as the olympic village, and significantly gentrifying midtown atlanta. the undergraduate living center, fourth street apartments, sixth street apartments, eighth street apartments, hemphill apartments ( now named crecine apartments ), and center street apartments housed athletes and journalists. the georgia tech aquatic center was built for swimming events, and the alexander memorial coliseum was renovated. the institute also erected the kessler campanile and fountain to serve as a landmark and symbol of the university on television broadcasts. in 1994, g. wayne clough became the first georgia tech alumnus to serve as the president of institution ; he was in office during the 1996 summer olympics. in 1998, he separated the ivan allen college of management, policy, and international affairs into the ivan allen college of
|
https://en.wikipedia.org/wiki/Georgia_Tech
|
j { \ ' o } nsson and tarski ' s notion of the perfect extension of a boolean algebra with operators has evolved into an extensive theory of canonical extensions of lattice - based algebras. after reviewing this evolution we make two contributions. first it is shown that the failure of a variety of algebras to be closed under canonical extensions is witnessed by a particular one of its free algebras. the size of the set of generators of this algebra can be made a function of a collection of varieties and is a kind of hanf number for canonical closure. secondly we study the complete lattice of stable subsets of a polarity structure, and show that if a class of polarities is closed under ultraproducts, then its stable set lattices generate a variety that is closed under canonical extensions. this generalises an earlier result of the author about generation of canonically closed varieties of boolean algebras with operators, which was in turn an abstraction of the result that a first - order definable class of kripke frames determines a modal logic that is valid in its so - called canonical frames.
|
arxiv:1709.09798
|
in the last decade, the order polytope of the zigzag poset has been thoroughly studied. a related poset, called \ emph { crown poset }, obtained by adding an extra relation between the endpoints of an even zigzag poset, is not so well understood. in this paper, we study the order polytopes of crown posets. we provide explicit formulas for their $ f $ - vectors. we provide recursive formulas for their ehrhart polynomial, giving a counterpart to formulas found in the zigzag case by petersen - - zhuang ( 2025 ). we use these formulas to simplify a computation by ferroni - - morales - - panova ( 2025 ) of the linear term of the order polynomial of these posets. furthermore, we provide a combinatorial interpretation for the coefficients of the $ h ^ * $ - polynomial in terms of the cyclic swap statistic on cyclically alternating permutations, which provides a circular version of a result by coons - - sullivant ( 2023 ).
|
arxiv:2504.05123
|
we consider the quantization of the midi - superspace associated with a class of spacetimes with toroidal isometries, but without the compact spatial hypersurfaces of the well - known gowdy models. by a symmetry reduction, the phase space for the system at the classical level can be identified with that of a free massless scalar field on a fixed background spacetime, thereby providing a simple route to quantization. we are then able to study certain non - perturbative features of the quantum gravitational system. in particular, we examine the quantum geometry of the asymptotic regions of the spacetimes involved and find some surprisingly large dispersive effects of quantum gravity.
|
arxiv:gr-qc/9801107
|
we discuss repulsive casimir forces between dielectric materials with non trivial magnetic susceptibility. it is shown that considerations based on naive pair - wise summation of van der waals and casimir polder forces may not only give an incorrect estimate of the magnitude of the total casimir force, but even the wrong sign of the force when materials with high dielectric and magnetic response are involved. indeed repulsive casimir forces may be found in a large range of parameters, and we suggest that the effect may be realized in known materials. the phenomenon of repulsive casimir forces may be of importance both for experimental study and for nanomachinery applications.
|
arxiv:quant-ph/0202114
|
autonomous quantum thermal machines do not require an external coherent drive or work input to perform the desired tasks, which makes them a promising candidate for thermal management in quantum systems. here, we propose an autonomous quantum thermal machine in which two uncoupled macroscopic mechanical resonators or microwave resonators achieve considerable entanglement via a hot thermal bath. this becomes possible by coupling the resonators to a common two - level system or third harmonic oscillator and driving it by the hot incoherent thermal bath. the critical step to make the entanglement involves suitable engineering of the hot bath, realized by bath spectrum filtering. our results suggest that the bath spectrum filtering can be an alternative to typical non - autonomous reservoir engineering schemes to create exotic quantum states.
|
arxiv:2203.06632
|
the two - higgs doublet model ( 2hdm ) is one of the most popular and natural extensions of the higgs sector ; but it has two potential fine - tuning problems, related to the electroweak ( ew ) breaking and the requirement of alignment with the sm higgs boson. we have quantified the fine - tunings obtaining analytical expressions, both in terms of the initial 2hdm parameters and the physical ones ( masses, mixing angles, etc. ). we also provide simple approximate expressions. we have taken into account that the fine - tunings are not independent and removed the " double counting " by projecting the variations of the alignment onto the constant - $ { \ rm v } ^ 2 $ hypersurface. the ew and the alignment fine - tunings become severe in different, even opposite, regions of the parameter space, namely in the regimes of large and small extra - higgs masses, respectively ; emerging an intermediate region, $ 500 \ { \ rm gev } \ leq \ { m _ h, m _ a, m _ { h ^ \ pm } \ } \ leq 700 \ { \ rm gev } $, where both are acceptably small. we also discuss a remarkable trend that is not obvious at first glance. namely, for large $ \ tan \ beta $ both the ew and the alignment fine - tunings become mitigated. in consequence, the 2hdm becomes quite natural for $ \ tan \ beta \ geq { \ cal o } ( 10 ) $, even if $ m _ h, m _ a, m _ { h ^ \ pm } $ are as large as 1500 gev. we explain why this is not the case for the 2hdm stemming from supersymmetry. we have illustrated all these trends by numerically analyzing several representative scenarios.
|
arxiv:2202.09103
|
we investigate the effects of an external magnetic helicity production on the evolution of the cosmic axion field. it is shown that a helicity larger than ( few \ times 10 ^ { - 15 } g ) ^ 2 mpc, if produced at temperatures above a few gev, is in contradiction with the existence of the axion, since it would produce too much of an axion relic abundance.
|
arxiv:astro-ph/0512458
|
multi - messenger astronomy is a vast and expanding field as electromagnetic observations ( em ) are no longer the only way of exploring the universe. due to the new messengers, astrophysical events with both gravitational waves ( gws ) and em emission are no longer a dream of the astronomical community. a breakthrough for gw multi - messenger astronomy came when the ligo - virgo network detected a gw signal of two low - mass compact objects consistent with a binary neutron star ( bns, gw170817 ) an event that generated a short gamma - ray burst ( grbs ) and a kilonova. while gw170817 represents the testimony to bns mergers being the progenitor of at least some grbs, a wide range of highly energetic astrophysical phenomena is expected to be accompanied by the emission of gws and photons. here we present an unmodelled method to search for gws having gamma and radio counterparts, using the ligo - virgo data and observations of partner telescopes. we also discuss the most recent results of the unmodelled coherent searches targeting astrophysical events during the first part of the ligo - virgo third observing run ( o3a ) : 105 grbs detected by the fermi and swift satellites.
|
arxiv:2206.14014
|
we give algebraic characterizations of the properties of autonomy and of controllability of behaviours of spatially invariant dynamical systems, consisting of distributional solutions, that are periodic in the spatial variables, to a system pf partial differential equations corresponding to a polynomial matrix m in ( c [ \ xi _ 1,..., \ xi _ d, \ tau ] ) ^ { m \ times n }.
|
arxiv:1208.6496
|
electronics engineers are just as varied as the types of work they do. electronics engineers may be found in the pristine laboratory environment of a fabrication plant, the offices of a consulting firm or in a research laboratory. during their working life, electronics engineers may find themselves supervising a wide range of individuals including scientists, electricians, programmers, and other engineers. obsolescence of technical skills is a serious concern for electronics engineers. membership and participation in technical societies, regular reviews of periodicals in the field, and a habit of continued learning are therefore essential to maintaining proficiency, which is even more crucial in the field of consumer electronics products. = = see also = = comparison of eda software electrical engineering technology glossary of electrical and electronics engineering index of electrical engineering articles information engineering list of electrical engineers timeline of electrical and electronics engineering = = references = = = = external links = =
|
https://en.wikipedia.org/wiki/Electronic_engineering
|
spatiotemporal coordination of chromatin and subnuclear compartments is crucial for cells. numerous enzymes act inside nucleus \ textemdash some of those transiently link and pass two chromatin segments. here we study how such an active perturbation affects fluctuating dynamics of an inclusion in the chromatic medium. using numerical simulations and a versatile effective model, we categorize inclusion dynamics into three distinct modes. the transient - link - and - pass activity speeds up inclusion dynamics by affecting a slow mode related to chromatin remodeling, viz., size and shape of the chromatin meshes.
|
arxiv:2305.05521
|
lsi + 61 303 is one of the few x - ray binaries with be star companion from which both radio and high - energy gamma - ray emission have been observed. we present xmm - newton and integral observations which reveal variability of the x - ray spectral index of the system. the x - ray spectrum is hard ( photon index ~ 1. 5 ) during the orbital phases of both high and low x - ray flux. however, the spectrum softens at the moment of transition from high to low x - ray state. the spectrum of the system in the hard x - ray band does not reveal the presence of a cut - off ( or, at least a spectral break ) at 10 - 60 kev energies, expected if the compact object is an accreting neutron star. the observed spectrum and spectral variability can be explained if the compact object in the system is a rotation powered pulsar.
|
arxiv:astro-ph/0606070
|
we have prepared the oxyhydrate na03rho206h2o by extracting na + cations from narho2 and intercalating water molecules using an aqueous solution of na2s2o8. synchrotron x - ray powder diffraction, thermogravimetric analysis ( tga ), and energy - dispersive x - ray analysis ( edx ) reveal that a non - stoichiometric na03 ( h2o ) 06 network separates layers of edge - sharing rho6 octahedra containing rh3 + ( 4d6, s = 0 ) and rh4 + ( 4d5, s = 1 / 2 ). the resistivities of narho2 and na03rho206h2o ( t < 300 ) reveal insulating and semi - conducting behavior with activation gaps of 134 mev and 7. 8 mev, respectively. both na03rho206h2o and narho2 show paramagnetism at room temperature, however, the sodium - deficient sample exhibits simultaneously a weak but experimentally reproducible ferromagnetic component. both samples exhibit a temperature - independent pauli paramagnetism, for narho2 at t > 50 k and for na03rho206h2o at t > 25 k. the relative magnitudes of the temperature - independent magnetic susceptibilities, that of the oxide sample being half that of the oxyhydrate, is consistent with a higher density of thermally accessible electron states at the fermi level in the hydrated sample. at low temperatures the magnetic moments rise sharply, providing evidence of localized and weakl - ordered electronic spins.
|
arxiv:cond-mat/0504007
|
developing upon the ideas of ref. \ ref { 6 }, it is shown how the theory of classical $ w $ algebras can be formulated on a higher genus riemann surface in the spirit of krichever and novikov. the basic geometric object is the drinfeld - - sokolov principal bundle $ l $ associated to a simple complex lie group $ g $ equipped with an $ sl ( 2, \ bbb c ) $ subgroup $ s $, whose properties are studied in detail. on a multipunctured riemann surface, the drinfeld - - sokolov - - krichever - - novikov spaces are defined, as a generalization of the customary krichever - - novikov spaces, their properties are analyzed and standard bases are written down. finally, a wzwn chiral phase space based on the principal bundle $ l $ with a km type poisson structure is introduced and, by the usual procedure of imposing first class constraints and gauge fixing, a classical $ w $ algebra is produced. the compatibility of the construction with the global geometric data is highlighted.
|
arxiv:hep-th/9403036
|
the steady growth of graph data from social networks has resulted in wide - spread research in finding solutions to the influence maximization problem. in this paper, we propose a holistic solution to the influence maximization ( im ) problem. ( 1 ) we introduce an opinion - cum - interaction ( oi ) model that closely mirrors the real - world scenarios. under the oi model, we introduce a novel problem of maximizing the effective opinion ( meo ) of influenced users. we prove that the meo problem is np - hard and cannot be approximated within a constant ratio unless p = np. ( 2 ) we propose a heuristic algorithm osim to efficiently solve the meo problem. to better explain the osim heuristic, we first introduce easyim - the opinion - oblivious version of osim, a scalable algorithm capable of running within practical compute times on commodity hardware. in addition to serving as a fundamental building block for osim, easyim is capable of addressing the scalability aspect - memory consumption and running time, of the im problem as well. empirically, our algorithms are capable of maintaining the deviation in the spread always within 5 % of the best known methods in the literature. in addition, our experiments show that both osim and easyim are effective, efficient, scalable and significantly enhance the ability to analyze real datasets.
|
arxiv:1602.03110
|
the optical manipulation of nanoparticles on superlubricity surfaces is investigated. the research revealed that, due to the near - zero static friction and extremely low dynamic friction at superlubricity interfaces, the maximum intensity for controlling the optical field can be less than 100 w / cm $ ^ 2 $, which is nine orders of magnitude lower than controlling nanoparticles on traditional interfaces. the controlled nanoparticle radius can be as small as 5 nm, which is more than one order of magnitude smaller than nanoparticles controlled through traditional optical manipulation. manipulation can be achieved in sub - microsecond to microsecond timescales. furthermore, the manipulation takes place on solid surfaces and in non - liquid environments, with minimal impact from brownian motion. by appropriately increasing dynamic friction, controlling light intensity, or reducing pressure, the effects of brownian motion can be eliminated, allowing for the construction of microstructures with a size as small as 1 / 75 of the wavelength of light. this enables the control of super - resolution optical microstructures. the optical super - resolution manipulation of nanoparticles on superlubricity surfaces will find important applications in fields such as nanofabrication, photolithography, optical metasurface, and biochemical analysis.
|
arxiv:2401.03486
|
in this paper, we present photometry for young star clusters in m31, which are selected from caldwell et al. these star clusters have been observed as part of the beijing - - arizona - - taiwan - - connecticut ( batc ) multicolor sky survey from 1995 february to 2008 march. the batc images including these star clusters are taken with 15 intermediate - band filters covering 3000 - - 10000 \ aa. combined with photometry in the { \ sl galex } far - and near - ultraviolet, broad - band $ ubvri $, sdss $ ugriz $, and infrared $ jhk _ { \ rm s } $ of two micron all sky survey, we obtain their accurate spectral energy distributions ( seds ) from 1538 - 20000 \ aa. we derive these star clusters ' ages and masses by comparing their seds with stellar population synthesis models. our results are in good agreement with previous determinations. the mean value of age and mass of young clusters ( $ < 2 $ gyr ) is about 385 myr and $ 2 \ times 10 ^ 4 { m _ \ odot } $, respectively. there are two distinct peaks in the age distribution, a highest peak at age $ \ sim $ 60 myr and a secondary peak around 250 myr, while the mass distribution shows a single peak around $ 10 ^ 4 { m _ \ odot } $. a few young star clusters have two - body relaxation times greater than their ages, indicating that those clusters have not been well dynamically relaxed and therefore have not established the thermal equilibrium. there are several regions showing aggregations of young star clusters around the 10 kpc ring and the outer ring, indicating that the distribution of the young star clusters is well correlated with m31 ' s star - forming regions. the young massive star clusters ( age $ \ leq 100 $ myr and mass $ \ geq 10 ^ 4 { m _ \ odot } $ ) show apparent concentration around the ring splitting region, suggesting a recent passage of a satellite galaxy ( m32 ) through m31 disk.
|
arxiv:1208.6419
|
a subshift with linear block complexity has at most countably many ergodic measures, and we continue of the study of the relation between such complexity and the invariant measures. by constructing minimal subshifts whose block complexity is arbitrarily close to linear but has uncountably many ergodic measures, we show that this behavior fails as soon as the block complexity is superlinear. with a different construction, we show that there exists a minimal subshift with an ergodic measure whose slow entropy grows slower than any given rate tending to infinitely but faster than any other rate majorizing this one yet still growing subexponentially. these constructions lead to obstructions in using subshifts in applications to properties of the prime numbers and in finding a measurable version of the complexity gap that arises for shifts of sublinear complexity.
|
arxiv:1902.08645
|
the k = 3 read - rezayi ( rr ) parafermion quantum hall state hosts non - abelian excitations which provide a platform for the universal topological quantum computation. although the rr state may be realized at the filling factor \ nu = 12 / 5 in gaas - based two - dimensional electron systems, the corresponding quantum hall state is weak and at present nearly impossible to study experimentally. here we argue that the rr state can alternatively be realized in a class of chiral materials with massless and massive dirac - like band structure. this family of materials encompasses monolayer and bilayer graphene, as well as topological insulators. we show that, compared to gaas, these systems provide several important advantages in realizing and studying the rr state. most importantly, the effective interactions can be tuned { \ it in situ } by varying the external magnetic field, and by designing the dielectric environment of the sample. this tunability enables the realization of rr state with controllable energy gaps in different landau levels. it also allows one to probe the quantum phase transitions to other compressible and incompressible phases.
|
arxiv:1201.6598
|
in the cosmological context, for the standard model to be valid up to the scale of inflation, the top quark yukawa coupling $ y _ t $ should not exceed the critical value $ y _ t ^ { crit } $, coinciding with good precision ( about 0. 02 % ) with the requirement of the stability of the electroweak vacuum. so, the exact measurements of $ y _ t $ may give an insight on the possible existence and the energy scale of new physics above 100 gev, which is extremely sensitive to $ y _ t $. we overview the most recent theoretical computations of $ y _ t ^ { crit } $ and the experimental measurements of $ y _ t $. within the theoretical and experimental uncertainties in $ y _ t $ the required scale of new physics varies from $ 10 ^ 7 $ gev to the planck scale, urging for precise determination of the top quark yukawa coupling.
|
arxiv:1411.1923
|
in this paper, we study the problem of text - to - image person re - identification ( tireid ), which aims to find images of the same identity described by a text sentence from a pool of candidate images. benefiting from vision - language pre - training, such as clip ( contrastive language - image pretraining ), the tireid techniques have achieved remarkable progress recently. however, most existing methods only focus on instance - level matching and ignore identity - level matching, which involves associating multiple images and texts belonging to the same person. in this paper, we propose a novel prototypical prompting framework ( propot ) designed to simultaneously model instance - level and identity - level matching for tireid. our propot transforms the identity - level matching problem into a prototype learning problem, aiming to learn identity - enriched prototypes. specifically, propot works by ' initialize, adapt, enrich, then aggregate '. we first use clip to generate high - quality initial prototypes. then, we propose a domain - conditional prototypical prompting ( dpp ) module to adapt the prototypes to the tireid task using task - related information. further, we propose an instance - conditional prototypical prompting ( ipp ) module to update prototypes conditioned on intra - modal and inter - modal instances to ensure prototype diversity. finally, we design an adaptive prototype aggregation module to aggregate these prototypes, generating final identity - enriched prototypes. with identity - enriched prototypes, we diffuse its rich identity information to instances through prototype - to - instance contrastive loss to facilitate identity - level matching. extensive experiments conducted on three benchmarks demonstrate the superiority of propot compared to existing tireid methods.
|
arxiv:2409.09427
|
it was recently suggested that the error with respect to experimental data in nuclear mass calculations is due to the presence of chaotic motion. the theory was tested by analyzing the typical error size. a more sensitive quantity, the correlations of the mass error between neighboring nuclei, is studied here. the results provide further support to this physical interpretation.
|
arxiv:nucl-th/0602041
|
it is shown how to take advantage of the frequent occurrence of double - strand breaks in the genome of prokaryotic cells, in order to reduce their high efficient reproductive capability. the analysis examines the physical status of the free ends of each break and considers how this status can interfere with an external physical apparatus, with the aim of undermining the repair processes. we indicate the biological consequences of this interaction and we give an approximate evaluation of the topological and dynamical effects that arise on the genomic material involved. the overall result suggests a significant reduction of the dynamics of the repair.
|
arxiv:1505.08014
|
facility location games provide an abstract model of mechanism design. in such games, a mechanism takes a profile of $ n $ single - peaked preferences over an interval as an input and determines the location of a facility on the interval. in this paper, we restrict our attention to distance - based single - peaked preferences and focus on a well - known class of parameterized mechanisms called ordered weighted average methods, which is proposed by yager in 1988 and contains several practical implementations such as the standard average and the olympic average. we comprehensively analyze their performance in terms of both incentives and fairness. more specifically, we provide necessary and sufficient conditions on their parameters to achieve strategy - proofness, non - obvious manipulability, individual fair share, and proportional fairness, respectively.
|
arxiv:2410.12884
|
_ { y }, } that is, if f has a right inverse. the axiom of choice is needed, because, if f is surjective, one defines g by g ( y ) = x, { \ displaystyle g ( y ) = x, } where x { \ displaystyle x } is an arbitrarily chosen element of f − 1 ( y ). { \ displaystyle f ^ { - 1 } ( y ). } the function f is bijective ( or is a bijection or a one - to - one correspondence ) if it is both injective and surjective. that is, f is bijective if, for every y ∈ y, { \ displaystyle y \ in y, } the preimage f − 1 ( y ) { \ displaystyle f ^ { - 1 } ( y ) } contains exactly one element. the function f is bijective if and only if it admits an inverse function, that is, a function g : y → x { \ displaystyle g : y \ to x } such that g ∘ f = id x { \ displaystyle g \ circ f = \ operatorname { id } _ { x } } and f ∘ g = id y. { \ displaystyle f \ circ g = \ operatorname { id } _ { y }. } ( contrarily to the case of surjections, this does not require the axiom of choice ; the proof is straightforward ). every function f : x → y { \ displaystyle f : x \ to y } may be factorized as the composition i ∘ s { \ displaystyle i \ circ s } of a surjection followed by an injection, where s is the canonical surjection of x onto f ( x ) and i is the canonical injection of f ( x ) into y. this is the canonical factorization of f. " one - to - one " and " onto " are terms that were more common in the older english language literature ; " injective ", " surjective ", and " bijective " were originally coined as french words in the second quarter of the 20th century by the bourbaki group and imported into english. as a word of caution, " a one - to - one function " is one that is injective, while a " one - to - one correspondence " refers to a bijective function. also, the statement " f maps x
|
https://en.wikipedia.org/wiki/Function_(mathematics)
|
aligning large language models ( llm ) to address subjectivity and nuanced preference levels requires adequate flexibility and control, which can be a resource - intensive and time - consuming procedure. existing training - time alignment methods require full re - training when a change is needed and inference - time ones typically require access to the reward model at each inference step. to address these limitations, we introduce inference - time model alignment method that learns encoded representations of preference dimensions, called \ textit { alignment vectors } ( av ). these representations are computed by subtraction of the base model from the aligned model as in model editing enabling dynamically adjusting the model behavior during inference through simple linear operations. even though the preference dimensions can span various granularity levels, here we focus on three gradual response levels across three specialized domains : medical, legal, and financial, exemplifying its practical potential. this new alignment paradigm introduces adjustable preference knobs during inference, allowing users to tailor their llm outputs while reducing the inference cost by half compared to the prompt engineering approach. additionally, we find that avs are transferable across different fine - tuning stages of the same model, demonstrating their flexibility. avs also facilitate multidomain, diverse preference alignment, making the process 12x faster than the retraining approach.
|
arxiv:2410.19206
|
the linear canonical transformations of geometric optics on two - dimensional screens form the group $ sp ( 4, r ) $, whose maximal compact subgroup is the fourier group $ u ( 2 ) _ f $ ; this includes isotropic and anisotropic fourier transforms, screen rotations and gyrations in the phase space of ray positions and optical momenta. deforming classical optics into a hamiltonian system whose positions and momenta range over a finite set of values, leads us to the finite oscillator model, which is ruled by the lie algebra $ so ( 4 ) $. two distinct subalgebra chains are used to model arrays of $ n ^ 2 $ points placed along cartesian or polar ( radius and angle ) coordinates, thus realizing one case of separation in two discrete coordinates. the $ n ^ 2 $ - vectors in this space are digital ( pixellated ) images on either of these two grids, related by a unitary transformation. here we examine the unitary action of the analogue fourier group on such images, whose rotations are particularly visible.
|
arxiv:1106.0093
|
we study the scattering equations recently proposed by cachazo, he and yuan in the special kinematics where their solutions can be identified with the zeros of the jacobi polynomials. this allows for a non - trivial two parameter family of kinematics. we present explicit and compact formulae for the n - gluon and n - graviton partial scattering amplitudes for our special kinematics in terms of jacobi polynomials. we also provide alternative expressions in terms of gamma functions. we give an interpretation of the common reduced determinant appearing in the amplitudes as the product of the squares of the eigenfrequencies of small oscillations of a system whose equilibrium is the solutions of the scattering equations.
|
arxiv:1312.7743
|
we present the design of a low - power 4 - bit 1gs / s folding - flash adc with a folding factor of two. the design of a new unbalanced double - tail dynamic comparator affords an ultra - low power operation and a high dynamic range. unlike the conventional approaches, this design uses a fully matched input stage, an unbalanced latch stage, and a two - clock operation scheme. a combination of these features yields significant reduction of the kick - back noise, while allowing the design flexibility for adjusting the trip points of the comparators. as a result, the adc achieves sndr of 22. 3 db at 100mhz and 21. 8 db at 500mhz ( i. e. the nyquist frequency ). the maximum inl and dnl are about 0. 2 lsb. the converter consumes about 700uw from a 1 - v supply yielding a figure of merit of 65fj / conversion step. these attributes make the proposed folding - flash adc attractive for the next - generation wireless applications.
|
arxiv:1612.04855
|
agriculture faces critical challenges from population growth, resource scarcity, and climate change, driving a shift toward advanced, technology - integrated farming. mechanization has transformed agriculture, enhancing sustainability and crop productivity. now, technologies like artificial intelligence ( ai ), robotics, biotechnology, blockchain, and the internet of things ( iot ) are advancing precision agriculture. the concept of the internet of everything ( ioe ) has gained traction due to its holistic approach to integrating various iot specializations, called ioxs with x referring to a specific domain. this paper explores the transformative role of ioe in agriculture, expanding beyond traditional iot applications to integrate niche subdomains like molecular communication ( mc ), the internet of nano things ( iont ), the internet of bio - nano things ( iobnt ), designer phages, and the internet of fungus ( iof ). our study provides a detailed review of how these ioe subdomains, in conjunction with 6g, blockchain, and machine learning ( ml ), can enhance precision farming in areas like crop monitoring, resource management, and disease control. unlike prior iot centric reviews, this work uniquely focuses on ioes potential to advance agriculture at molecular and biological scales, achieving more precise resource utilization and resilience. key contributions include an exploration of these technologies applicability, associated challenges, and recommendations for future research directions within precision agriculture.
|
arxiv:2404.06341
|
time - crystals are nonequilibrium many - body phases in which the state of the system dynamically approaches a limit cycle. while these phases are recently in the focus of intensive research, it is still far from clear whether they can host quantum correlations. in fact, mostly classical correlations have been observed so far and time - crystals appear to be effectively classical high - entropy phases. here, we consider the nonequilibrium behavior of an open quantum light - matter system, realizable in current experiments, which maps onto a paradigmatic time - crystal model after an adiabatic elimination of the light field. the system displays a bistable regime, with coexistent time - crystal and stationary phases, terminating at a tricritical point from which a second - order phase transition line departs. while light and matter are uncorrelated in the stationary phase, the time - crystal phase features bipartite correlations, both of quantum and classical nature. our work unveils that time - crystal phases in collective open quantum systems can sustain quantum correlations, including entanglement, and are thus more than effectively classical many - body phases.
|
arxiv:2303.07725
|
while finite automata have minimal dfas as a simple and natural normal form, deterministic omega - automata do not currently have anything similar. one reason for this is that a normal form for omega - regular languages has to speak about more than acceptance - for example, to have a normal form for a parity language, it should relate every infinite word to some natural color for this language. this raises the question of whether or not a concept such as a natural color of an infinite word ( for a given language ) exists, and, if it does, how it relates back to automata. we define the natural color of a word purely based on an omega - regular language, and show how this natural color can be traced back from any deterministic parity automaton after two cheap and simple automaton transformations. the resulting streamlined automaton does not necessarily accept every word with its natural color, but it has a ' co - run ', which is like a run, but can once move to a language equivalent state, whose color is the natural color, and no co - run with a higher color exists. the streamlined automaton defines, for every color c, a good - for - games co - b \ " uchi automaton that recognizes the words whose natural colors w. r. t. the represented language are at least c. this provides a canonical representation for every $ \ omega $ - regular language, because good - for - games co - b \ " uchi automata have a canonical minimal ( and cheap to obtain ) representation for every co - b \ " uchi language.
|
arxiv:2207.11000
|
entringer, jackson, and schatz conjectured in 1974 that every infinite cubefree binary word contains arbitrarily long squares. in this paper we show this conjecture is false : there exist infinite cubefree binary words avoiding all squares xx with | x | > = 4, and the number 4 is best possible. however, the entringer - jackson - schatz conjecture is true if " cubefree " is replaced with " overlap - free ".
|
arxiv:math/0302303
|
we construct a new family of distance - biregular graphs related to hyperovals and a new sporadic example of a distance - biregular graph related to mathon ' s perp system. the infinite family can be explained using 2 - y - homogeneity, while the sporadic example belongs to a generalization of a construction by delorme. additionally, we give a new non - existence criteria for distance - biregular graphs.
|
arxiv:2504.21488
|
the berezinskii - kosterlitz - thouless ( bkt ) mechanism describes the breakdown of superfluidity in a two - dimensional bose gas or a two - dimensional gas of paired fermions. in the latter case, a population imbalance between the two pairing partners in the fermi mixture is known to influence pairing characteristics. here, we investigate the effects of imbalance on the two - dimensional bkt superfluid transition, and show that superfluidity is even more sensitive to imbalance than for three dimensional systems. finite - temperature phase diagrams are derived using the functional integral formalism in combination with a hydrodynamic action functional for the phase fluctuations. this allow to identify a phase separation region and tricritical points due to imbalance. in contrast to superfluidity in the three - dimensional case, the effect of imbalance is also pronounced in the strong - coupling regime.
|
arxiv:0903.1931
|
parametric down - conversion is a widely exploited technique in optics to produce entangled states of photons for quantum information processing and quantum sensing. in the microwave domain, devices based on josephson junctions, such as josephson parametric amplifiers ( jpas ) and voltage - biased josephson junctions, have been successfully utilized to generate such states. however, their high susceptibility to magnetic fields has posed challenges in many applications. here we demonstrate the generation of two - mode squeezed states via four - wave - mixing in a superconducting nanowire resonator patterned from nbn. the nbn nanowire exhibits a strong kerr nonlinearity, resulting in the emission of a signal - idler pair with a cross - correlation of $ g ^ { ( 2 ) } ( 0 ) = 11. 9 $. owing to the magnetic resilience and high critical temperature ( $ t _ c $ ) of nbn, our microwave parametric sources based on kinetic inductance promise an expanded range of potential applications.
|
arxiv:2308.02109
|
we present two different paradoxes related to the length contraction in special relativity and explain their resolution.
|
arxiv:1203.5333
|
the metro as a form of public transportation is an important urban infrastructure that takes a large population from place a to b every day. to achieve that, it is primarily designed for extreme functionality and efficiency. however, in terms of experiential aesthetics, the metro is seldom people s favourite place. when this modern infrastructure succeeds in serving urban mobility with high performance and efficiency, passengers seem to want more than the guaranteed functional performance. recently, with the emergence of vr technologies, increasing efforts from design and hci communities look at the value of vr technology in enhancing commuting experiences, bringing new possibilities of interaction and activities, and potentially transforming social public spaces. this study investigates how and why vr technology could be integrated with a metro ride. we experimented with ten passengers by showing them three 360 videos during their metro ride. the results show the narrative driven scene is most desirable. despite wearing a vr headset might cause anxiety, our findings indicate a high level of acceptance towards vr experiences based on the finding that it does not challenge the normative behaviours of being a passenger inattentive in social, active in mind and further can enhance the experience. as the takeaway, we propose three strategies of vr content tailored for the metro context in which passengers would find a role participating in the virtual scene and turn the scene to one s own story, and at the same time, maintain physically constrained.
|
arxiv:2210.00724
|
we examine the dependence of the deformation obtained by bending quasi - fuchsian structures on the bending lamination. we show that when we consider bending quasi - fuchsian structures on a closed surface, the conditions obtained by epstein and marden to relate weak convergence of arbitrary laminations to the convergence of bending cocycles are not necessary. bending may not be continuous on the set of all measured laminations. however we show that if we restrict our attention to laminations with non negative real and imaginary parts then the deformation depends continuously on the lamination.
|
arxiv:math/9810195
|
stochastic gradient descent ( sgd ) type optimization schemes are fundamental ingredients in a large number of machine learning based algorithms. in particular, sgd type optimization schemes are frequently employed in applications involving natural language processing, object and face recognition, fraud detection, computational advertisement, and numerical approximations of partial differential equations. in mathematical convergence results for sgd type optimization schemes there are usually two types of error criteria studied in the scientific literature, that is, the error in the strong sense and the error with respect to the objective function. in applications one is often not only interested in the size of the error with respect to the objective function but also in the size of the error with respect to a test function which is possibly different from the objective function. the analysis of the size of this error is the subject of this article. in particular, the main result of this article proves under suitable assumptions that the size of this error decays at the same speed as in the special case where the test function coincides with the objective function.
|
arxiv:2007.02723
|
we investigate the scalar resonances in the processes of $ d ^ { 0 } \ rightarrow \ pi ^ { 0 } \ pi ^ { 0 } \ pi ^ { 0 }, \ pi ^ { 0 } \ pi ^ { 0 } \ eta, \ pi ^ { 0 } \ eta \ eta $ decays based on the chiral unitary approach for the final state interaction. we start from singly cabibbo - suppressed production diagrams which provide a primary quark pair to hadronize two pseudoscalar mesons in $ d ^ { 0 } $ decays. the resonances $ f _ { 0 } ( 500 ) $, $ f _ { 0 } ( 980 ) $ and $ a _ { 0 } ( 980 ) $ are dynamically produced from the final state interactions of the meson pairs. in our results, the experimental data for the $ \ pi ^ { 0 } \ eta $ invariant mass spectrum of the $ d ^ { 0 } \ rightarrow \ pi ^ { 0 } \ eta \ eta $ decay can be described well. we also make the predictions for the $ \ pi ^ { 0 } \ pi ^ { 0 } $ invariant mass spectrum of the $ d ^ { 0 } \ rightarrow \ pi ^ { 0 } \ pi ^ { 0 } \ pi ^ { 0 } $, where the $ f _ { 0 } ( 980 ) $ can be found, and for the $ \ pi ^ { 0 } \ pi ^ { 0 } $, $ \ pi ^ { 0 } \ eta $ invariant mass spectrum of the $ d ^ { 0 } \ rightarrow \ pi ^ { 0 } \ pi ^ { 0 } \ eta $, where the $ f _ { 0 } ( 500 ) $, $ f _ { 0 } ( 980 ) $ and $ a _ { 0 } ( 980 ) $ appear. furthermore, the branching ratios of each decay channel are predicted. we expect more accurate measurements of these decays to better understand the nature of the states $ f _ { 0 } ( 500 ) $, $ f _ { 0 } ( 980 ) $ and $ a _ { 0 } ( 980 ) $.
|
arxiv:2110.05359
|
the atom - photon entanglement of dressed atom and its spontaneous emission in a double - lambda closed - loop atomic system is studied in multi - photon resonance condition. it is shown that, even in the absence of quantum interference due to the spontaneous emission, the von neumann entropy is phase - sensitive and it can be controlled by either intensity or relative phase of the applied fields. it is demonstrated that, for the special case of rabi frequency of the applied fields the system is maximally entangled. moreover, the open - loop configuration is considered and it is shown that the degree of entanglement measure ( dem ) can be controlled by intensity of the applied fields. furthermore, in electromagnetically induced transparency condition, the system is disentangled. such a system can be used for quantum information processing via entanglement using optical switching.
|
arxiv:1407.4090
|
given any deep fully connected neural network, initialized with random gaussian parameters, we bound from above the quadratic wasserstein distance between its output distribution and a suitable gaussian process. our explicit inequalities indicate how the hidden and output layers sizes affect the gaussian behaviour of the network and quantitatively recover the distributional convergence results in the wide limit, i. e., if all the hidden layers sizes become large.
|
arxiv:2203.07379
|
the problem of predicting the upper cut - off of the cosmic ray spectrum is re - examined. some aspects of extremely high energy interactions and their implications for the interpretation of giant air showers are also discussed.
|
arxiv:astro-ph/9812445
|
we study the use of hypermodels to represent epistemic uncertainty and guide exploration. this generalizes and extends the use of ensembles to approximate thompson sampling. the computational cost of training an ensemble grows with its size, and as such, prior work has typically been limited to ensembles with tens of elements. we show that alternative hypermodels can enjoy dramatic efficiency gains, enabling behavior that would otherwise require hundreds or thousands of elements, and even succeed in situations where ensemble methods fail to learn regardless of size. this allows more accurate approximation of thompson sampling as well as use of more sophisticated exploration schemes. in particular, we consider an approximate form of information - directed sampling and demonstrate performance gains relative to thompson sampling. as alternatives to ensembles, we consider linear and neural network hypermodels, also known as hypernetworks. we prove that, with neural network base models, a linear hypermodel can represent essentially any distribution over functions, and as such, hypernetworks are no more expressive.
|
arxiv:2006.07464
|
we consider the influence on the surface critical behaviour of a quantum ising chain of quenched random surface perturbations decaying as a power of the distance from the surface ( random hilhorst - van leeuwen models ). we study, analytically and numerically, the multiscaling behaviour of the surface magnetization and the surface energy density in the case of marginal perturbations.
|
arxiv:cond-mat/0110403
|
in an idealized system where four current channels interact in a two - dimensional periodic setting, we follow the detailed evolution of current sheets ( css ) forming in between the channels, as a result of a large - scale merging. a central x - point collapses and a gradually extending cs marks the site of continuous magnetic reconnection. using grid - adaptive, non - relativistic, resistive magnetohydrodynamic ( mhd ) simulations, we establish that slow, near - steady sweet - parker reconnection transits to a chaotic, multi - plasmoid fragmented state, when the lundquist number exceeds about ten to the fourth power, well in the range of previous studies on plasmoid instability. the extreme resolution employed in the mhd study shows significant magnetic island substructures. with relativistic test - particle simulations, we explore how charged particles can be accelerated in the vicinity of an o - point, either at embedded tiny - islands within larger " monster " - islands or near the centers of monster - islands. while the planar mhd setting artificially causes strong acceleration in the ignored third direction, it also allows for the full analytic study of all aspects leading to the acceleration and the in - plane - projected trapping of particles in the vicinities of o - points. our analytic approach uses a decomposition of the particle velocity in slow - and fast - changing components, akin to the reynolds decomposition in turbulence studies. our analytic description is validated with several representative test - particle simulations. we find that after an initial non - relativistic motion throughout a monster island, particles can experience acceleration in the vicinity of an o - point beyond 0. 7c, at which speed the acceleration is at its highest efficiency
|
arxiv:2108.13508
|
the partition function of rational conformal field theories ( cfts ) on riemann surfaces is expected to satisfy odes of gauss - manin type. we investigate the case of hyperelliptic surfaces and derive the ode system for the $ ( 2, 5 ) $ minimal model.
|
arxiv:1705.07627
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.