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arXiv research

A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,657 papers · 148 categories

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64129193257 · May 202619922001200920172026
48 results for constant energy density

Neural density estimators are flexible families of parametric models which have seen widespread use in unsupervised machine learning in recent years. Maximum-likelihood training typically dictates that these models be constrained to specify an explicit density. However, this limitation can be overcome by instead using …

2019-04-11abs ↗pdf ↗

The paper classifies biharmonic quadratic maps between spheres, proving their energy density properties.

problem Classifying non-harmonic biharmonic quadratic forms between spheres.
method Proving non-harmonic biharmonic quadratic forms have constant energy density and classifying them.
result Non-harmonic biharmonic quadratic forms have constant energy density (m+1)/2(m+1)/2.

Derives continuum model from discrete ε\varepsilon-graphs with connectivity functional.

problem Modeling diffusion in networks with varying connectivity.
method Energy-based continuum limit derivation, neural-network reconstruction of connectivity.
result Error between discrete and continuum energies is O(ε)O(\varepsilon), valid even with fluctuations.

Extends Penrose's method to null shells with pressure and energy flux.

problem Constructing null thin shells with arbitrary gravitational/matter content.
method Derive locally Lipschitz metric and coordinate transformation.
result Example of null shell with non-trivial energy density, flux, and pressure in Minkowski space.

In this paper, we introduce a new energy density function Y\mathscr Y on the projective bundle P(TM)M\mathbb{P}(T_M)\>M for a smooth map f:(M,h)(N,g)f:(M,h)\>(N,g) between Riemannian manifolds Y=gijfαifβjWαWβhγδWγWδ.\mathscr Y=g_{ij}f^i_αf^j_β\frac{W^αW^β}{\sum h_{γδ} W^γW^δ}. We get new Hessian estimates to this energy density and obtain various new…

2018-10-08abs ↗pdf ↗

We consider a vector bundle EE over a compact Riemannian manifold MM=MnM^{n},n4n\geq 4,and AA is a Yang-Mills connection with Ln2L^{\frac{n}{2}} curvature FAF_{A} on EE.Then we prove a mean value inequality for the density FAn2|F_{A}|^{\frac{n}{2}}.This inequality give rise to an energy concentrate principle for seque…

2015-02-11abs ↗pdf ↗

A new method normalizes EBM training by introducing a learnable parameter.

problem Training energy-based models with maximum likelihood is challenging due to intractable normalisation constants.
method Proposes a self-normalised log-likelihood (SNL) objective that introduces a learnable parameter representing the normalisation constant.
result The SNL objective is a lower bound of the log-likelihood and can be directly optimised using stochastic gradient techniques.

FNFs model parameter-dependent densities by combining a fixed flow with a polynomial parameter-dependent transformation.

problem Learning a separate flow for every parameter configuration is intractable.
method Factorizable Normalizing Flows (FNFs) represent the parameter-dependent density as a fixed flow for a reference configuration and a learnable polynomial transformation factorized over parameters.
result FNFs enable the recovery of the combined effect of multiple parameters without sampling their joint space, providing a scalable and interpretable solution.

This paper studies the convergence of penalized energy to harmonic maps in Riemannian manifolds.

problem Analyzing the convergence of penalized energy to harmonic maps in Riemannian manifolds.
method Using the penalized energy functional and weak convergence techniques, the paper proves the energy identity for Ginzburg-Landau approximation of harmonic maps.
result The defect measure ν can be expressed as the sum of energies of harmonic spheres for arbitrary manifolds.

In this paper, we analyzed the physical meaning of scalar curvatures for a generalized Riemannian space. It is developed the Madsen's formulae for pressures and energy-densities with respect to the corresponding energy-momentum tensors. After that, the energy-momentum tensors, pressures, energy-densities and state-para…

2019-11-13abs ↗pdf ↗

Quantum vacuum energy (Casimir energy) is reviewed for a mathematical audience as a topic in spectral theory. Then some one-dimensional systems are solved exactly, in terms of closed classical paths and periodic orbits. The relations among local spectral densities, energy densities, global eigenvalue densities, and tot…

2007-06-19abs ↗pdf ↗

We prove that at a finite singular time for the Harmonic Ricci Flow on a surface of positive genus both the energy density of the map component and the curvature of the domain manifold have to blow up simultaneously. As an immediate consequence, we obtain smooth long-time existence for the Harmonic Ricci Flow with larg…

2015-10-13abs ↗pdf ↗

Outlier detection amounts to finding data points that differ significantly from the norm. Classic outlier detection methods are largely designed for single data type such as continuous or discrete. However, real world data is increasingly heterogeneous, where a data point can have both discrete and continuous attribute…

2016-08-17abs ↗pdf ↗

Efficiently samples and learns densities with symmetries using equivariant methods.

problem Efficiently sampling and learning densities with symmetries.
method Equivariant Stein Variational Gradient Descent (SVGD) and equivariant energy based models.
result Improves and scales up training of energy based models.

Study magnetic Laplacians on hyperbolic surfaces, revealing three regimes of eigenfunction behavior.

problem Investigate semiclassical defect measures of magnetic Laplacians on hyperbolic surfaces.
method Analyze eigenfunctions in low, critical, and high energy regimes using quantum ergodicity and equidistribution.
result Eigenfunctions in different regimes converge to distinct measures: invariant, Liouville, or equidistributed.

The integral of the energy density function m\mathfrak m of a closed Robertson-Walker (RW) spacetime with source a perfect fluid and cosmological constant ΛΛ gives rise to an action functional on the space of scale functions of RW spacetime metrics. This paper studies closed RW spacetimes which are critical for this …

2019-04-18abs ↗pdf ↗

Kernel ridge regression is used to approximate the kinetic energy of non-interacting fermions in a one-dimensional box as a functional of their density. The properties of different kernels and methods of cross-validation are explored, and highly accurate energies are achieved. Accurate {\em constrained optimal densitie…

2014-04-04abs ↗pdf ↗

The paper establishes curvature inequalities and rigidity results for surfaces in Riemannian and Lorentzian geometry.

problem Curvature and rigidity of surfaces in Riemannian and Lorentzian geometries.
method Establishes curvature inequalities and rigidity results using stability conditions and extrinsic curvature sign conditions.
result Sharp inequality H216π/Σ|\vec{H}|^2\leq 16π/ |Σ| for spacetime constant mean curvature surfaces under the dominant energy condition.

We examine Generative Adversarial Networks (GANs) through the lens of deep Energy Based Models (EBMs), with the goal of exploiting the density model that follows from this formulation. In contrast to a traditional view where the discriminator learns a constant function when reaching convergence, here we show that it ca…

2019-10-29abs ↗pdf ↗

New method trains deep neural networks for non-interacting kinetic-energy functionals in DFT.

problem Lack of exact relationship between electron density and non-interacting kinetic energy.
method Variational principle to regularize machine-learned density functionals.
result Excellent results on kinetic-energy functionals for various systems.

New proof confirms De Giorgi's conjecture about phase-field approximation of Willmore functional.

problem Proving a conjecture about the phase-field approximation of the Willmore functional.
method Using Γ-convergence and properties of the Allen-Cahn energy and its variations.
result The original De Giorgi conjecture holds with k=0.

The study shows how energy density of harmonic maps dominates in nn-Fuchsian fibers, leading to unique minimal surfaces.

problem Understanding energy density and topological invariants in nn-Fuchsian fibers of Higgs bundles.
method Establishing an algebraic inequality generalizing a GIT theorem to prove energy density domination.
result Energy density of harmonic maps dominates in nn-Fuchsian fibers, leading to unique minimal surfaces.

The problem of continuous inverse optimal control (over finite time horizon) is to learn the unknown cost function over the sequence of continuous control variables from expert demonstrations. In this article, we study this fundamental problem in the framework of energy-based model, where the observed expert trajectori…

2019-04-10abs ↗pdf ↗

We give a derivation of the Einstein equation for gravity which employs a definition of the local energy density of the gravitational field as a symmetric second rank tensor whose value for each observer gives the trace of the spatial part of the energy-stress tensor as seen by that observer. We give a physical motivat…

2008-03-11abs ↗pdf ↗

RNE provides a flexible framework for diffusion models, enabling inference-time control and energy-based training.

problem Insufficient knowledge of marginal densities in diffusion models.
method Introduces Radon-Nikodym Estimator (RNE) to reveal the connection between marginal densities and transition kernels.
result RNE delivers strong results in inference-time control and energy-based diffusion training.

iDEM generates samples from Boltzmann densities without data.

problem Generating statistically independent samples from unnormalized distributions.
method Iterative algorithm using energy and gradient for diffusion-based sampler training.
result iDEM achieves state-of-the-art performance and trains faster than existing methods.

Study on helix curves and their Möbius energy asymptotics.

problem Understanding the asymptotic behavior of Möbius energy for helix curves.
method Investigation of helix curves with fixed radius, focusing on energy decay and blow-up.
result Proven asymptotics for both uncoiling and coiling helix curves, revealing distinct strategies for each.

Adaptive multi-stage density ratio estimation improves learning of latent space EBM.

problem Learning energy-based models in latent space is computationally expensive and challenging.
method Adaptive multi-stage density ratio estimation using NCE to bridge the gap between prior and posterior densities.
result The method enables more expressive prior models and sharpens the latent space EBM.

For Ginzburg-Landau vortices, energy quantization holds only when density is less than 2.

problem Energy quantization in Ginzburg-Landau vortices for higher dimensions.
method Analyzing normalized energy measures and vorticity sets.
result Energy quantization only holds when density is less than 2.

We study, using Mean Curvature Flow methods, 2+1 dimensional cosmologies with a positive cosmological constant and matter satisfying the dominant and the strong energy conditions. If the spatial slices are compact with non-positive Euler characteristic and are initially expanding everywhere, then we prove that the spat…

2019-02-01abs ↗pdf ↗