Research
On-device research index

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.

168,742 papers · 148 categories

Trend · papers per month

68136204272 · May 202619922001200920172026
48 results for covariant Schrödinger operator

Paper introduces a new generative learning model using Schrödinger bridge diffusion in latent space.

problem Learning distributions from divergent data distributions.
method Pre-training with large-scale models, Schrödinger bridge diffusion model in latent space.
result Effective control of second-order Wasserstein distance between generated and target distributions.

Unified framework for robust, stable, and efficient density ratio estimation.

problem Density-chasm and support-chasm problems in density ratio estimation.
method Dequantified diffusion-Schrödinger bridge (D3RE) framework with DDBI and DSBI.
result Offers uniform approximation and bounded time scores in theory and empirical performance.

We give a new lower bound for the first gap λ2λ1λ_2 - λ_1 of the Dirichlet eigenvalues of the Schr{ö}dinger operator on a bounded convex domain ΩΩ in Rn^n or Sn^n and greatly sharpens the previous estimates. The new bound is explicit and computable.

2004-04-22abs ↗pdf ↗

The goal of this article is twofold: in a first part, we prove Gaussian estimates for the heat kernel of Schr{ö}dinger operators delta + V whose potential V is "small at infinity" in an integral sense. In a second part, we prove sharp boundedness result for the associated Riesz transform with potential d(delta+V) --1/2…

2015-03-02abs ↗pdf ↗

Study shows observability for Schrödinger equations on product manifolds with specific conditions.

problem Observability of Schrödinger equations on product manifolds with product metrics.
method Proof of observability in finite time on open subsets satisfying Vertical Geometric Control Condition, under gap condition on spectrum of F(g).
result Observability on ω for the Schrödinger equation is strictly weaker than Geometric Control Condition on product of spheres.

Suppose that G=(V,E)G=(V, E) is a finite graph with the vertex set VV and the edge set EE. Let ΔΔ be the usual graph Laplacian. Consider the following nonlinear Schro¨\ddot{o}dinger type equation of the form {Δuαu=f(x,u),uW1,2(V), \left \{ \begin{array}{lcr} -Δu-αu=f(x,u),\\ u\in W^{1,2}(V),\\ \end{array} \right. on graph GG, where $f(x…

2019-03-13abs ↗pdf ↗

CMCD sampler connects transport and variational inference for efficient sampling.

problem Efficient sampling and generative modeling in Bayesian computation.
method Developed a principled framework using divergences on path space, CMCD sampler with adaptive dynamics.
result CMCD sampler outperforms competing approaches across various experiments.

Study on estimating distances between covariance operators and Gaussian processes.

problem Estimating distances between covariance operators and Gaussian processes.
method Riemannian distances, concentration results for Hilbert space-valued random variables, RKHS covariance and cross-covariance operators.
result Both distances converge in the Hilbert-Schmidt norm and can be consistently and efficiently estimated.

Researchers create a family of conformally covariant operators.

problem Developing a comprehensive set of conformally covariant operators.
method Constructing a family of conformally covariant tridifferential operators as tangential operators in the Fefferman--Graham ambient space.
result Symmetrization of ambient operators is formally self-adjoint.

We introduce and study covariance fields of distributions on a Riemannian manifold. At each point on the manifold, covariance is defined to be a symmetric and positive definite (2,0)-tensor. Its product with the metric tensor specifies a linear operator on the respected tangent space. Collectively, these operators form…

2008-07-29abs ↗pdf ↗

We describe a set of conformally covariant boundary operators associated to the Paneitz operator, in the sense that they give rise to a conformally covariant energy functional for the Paneitz operator on a compact Riemannian manifold with boundary. These operators naturally give rise to a first- and third-order conform…

2015-09-28abs ↗pdf ↗

This study approximates distances between Gaussian processes and covariance operators using RKHS.

problem Approximating distances between Gaussian processes and covariance operators from finite samples.
method Using reproducing kernel Hilbert space (RKHS) covariance and cross-covariance operators, the study shows how to consistently and efficiently estimate Sinkhorn divergence from finite samples.
result Convergence rates are dimension-independent and of the same order as Hilbert-Schmidt distance.

In this paper, the Dirac, twistor and Killing equations on Weyl manifolds with CSpin structures are investigated. A conformal Schr"odinger-Lichnerowicz formula is presented and used to show integrability conditions for these equations. By introducing the Killing equation for spinors of arbitrary weight, the result of A…

1999-01-27abs ↗pdf ↗

Researchers solve Yamabe problems for specific operators, finding both uniqueness and nonuniqueness.

problem Prescribing scalar, Q-, or σ₂-curvatures in conformal classes.
method Formally self-adjoint, conformally covariant, polydifferential operators.
result Uniqueness results on the sphere, nonuniqueness in general.

Active data collection improves convergence rates in operator learning.

problem Improving convergence rates in operator learning with linear target and stochastic input.
method Active data collection strategies with mean-zero stochastic process and continuous covariance kernels.
result Achieves arbitrarily fast error convergence rates with eigenvalue decay of covariance kernels.

Model predicts operational risk using HMMs with economic covariates.

problem Predicting operational risk losses with time-dependent structures and economic covariates.
method Hidden Markov Models extended to multivariate observations with an auxiliary economic variable.
result Calibration results show relevance of including economic covariates.

Improved 2-bit covariance estimator with reduced operator norm error and no tuning needed.

problem Improving 2-bit covariance estimation with reduced operator norm error and no tuning needed.
method Proposed a new 2-bit covariance matrix estimator using triangular dithering scales.
result Improved operator norm error rate that depends on effective rank of covariance matrix, closing theoretical gap.

CASP improves portfolio optimization by considering asset covariance.

problem Infeasibility in cardinality-constrained portfolio optimization.
method CASP uses volatility-normalized selection and covariance-aware projection.
result CASP-Basic delivers lower portfolio variance than standard Euclidean repair.

The well known conformal covariance of the Dirac operator acting on spinor fields over a semi Riemannian spin manifold does not extend to powers thereof in general. For odd powers one has to add lower order curvature correction terms in order to obtain conformal covariance. We derive an algorithmic construction in term…

2013-11-17abs ↗pdf ↗

Extends Gaussian process theory to Banach spaces.

problem Extending Gaussian process theory to Banach spaces.
method Investigates the connection between Gaussian processes and Gaussian random elements in reproducing kernel Banach spaces.
result Characterizes positive definite functions that arise from covariance operators in Banach space setting.

Algorithm solves covariant exterior derivative equations in small regions.

problem Solving covariant exterior derivative equations in geometric and algorithmic ways.
method Linear homotopy operator of the Poincare lemma, constraints for parallel transport equations.
result Solves covariant constant and related equations in a geometric and algorithmic way.

We describe a set of conformally covariant boundary operators associated to the sixth-order GJMS operator on a conformally invariant class of manifolds which includes compactifications of Poincaré--Einstein manifolds. This yields a conformally covariant energy functional for the sixth-order GJMS operator on such manifo…

2018-10-18abs ↗pdf ↗

The study bounds Riesz transforms on manifolds with controlled curvature.

problem Bounding Riesz transforms on manifolds with controlled curvature.
method Established LpL^p-boundedness of local covariant Riesz transforms for differential forms.
result Calderón-Zygmund estimates for manifolds with bounded Riemannian curvature.

The article defines conditions for a manifold to be conformal to an Einstein space.

problem Determining when a manifold is conformal to an Einstein space.
method Algorithmic conditions based on the metric tensor and the Weyl endomorphism.
result General necessary and sufficient conditions for a pseudo-Riemannian manifold to be conformal to an Einstein space.

We study the problem of structured output learning from a regression perspective. We first provide a general formulation of the kernel dependency estimation (KDE) problem using operator-valued kernels. We show that some of the existing formulations of this problem are special cases of our framework. We then propose a c…

2012-05-10abs ↗pdf ↗

A regular normal parabolic geometry of type G/PG/P on a manifold MM gives rise to sequences DiD_i of invariant differential operators, known as the curved version of the BGG resolution. These sequences are constructed from the normal covariant derivative $\na^\om$ on the corresponding tractor bundle V,V, where $\om$ is…

2010-03-31abs ↗pdf ↗

A new method uses Gram matrix for efficient multivariate functional principal components.

problem Efficiently estimating eigencomponents of multidimensional functional datasets.
method Proposes using inner-product matrix to estimate eigenelements of multivariate and multidimensional functional datasets.
result Established relationship between eigenelements of covariance operator and inner-product matrix.

New phase harmonic covariance models capture non-Gaussian properties of stationary processes.

problem Capturing non-Gaussian properties of stationary processes using Fourier phase.
method Introduce phase harmonic covariance moments and maximum entropy models conditioned by these moments.
result Maximum entropy models from phase harmonic covariances improve image synthesis of turbulent flows.

We prove an explicit residue formula for a meromorphic continuation of conformally covariant integral operators between differential forms on Rn{\bf R}^n and on its hyperplane. The results provide a simple and new construction of the conformally covariant differential symmetry breaking operators between differential fo…

2017-09-15abs ↗pdf ↗

The paper introduces boundary operators for Poincaré-Einstein manifolds and proves higher order trace inequalities.

problem Proving higher order trace inequalities on Poincaré-Einstein manifolds.
method Introducing conformally covariant boundary operators and using them to set up higher order Dirichlet problems.
result Sharp higher order Sobolev trace inequalities on the ball are obtained.

Study on stochastic covariant derivatives in curved space-time.

problem Analyzing covariant derivatives in curved space-time under stochastic processes.
method Using Itô-Wiener processes and stochastic calculus, including Besov spaces, Schrödinger operators, and white noise.
result Developed a framework for stochastic geodesics and white noise in fractoid spaces.

We study conformal SpinSpin-subgeometry of submanifolds in a semi-Riemannian SpinSpin-manifold, focusing on conformal SpinSpin-manifolds (M,[h])(M,[h]) and their Poincaré-Einstein metrics (X,g+)(X,g_+). Our approach is based on the spectral theory of Dirac operator in the ambient SpinSpin-manifold, and associated spinor valued meromorp…

2014-02-03abs ↗pdf ↗