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We introduce a novel algorithm that leverages stochastic sampling techniques to compute the perturbative triples correction in the coupled-cluster (CC) framework. By combining elements of randomness and determinism, our algorithm achieves a…

Chemical Physics · Physics 2024-05-29 Yann Damour , Alejandro Gallo , Anthony Scemama

In complex and unknown processes, global models are initially generated over the entire experimental space but often fail to provide accurate predictions in local areas. A common approach is to use local models, which requires partitioning…

Machine Learning · Computer Science 2025-05-29 Dominik Polke , Tim Kösters , Elmar Ahle , Dirk Söffker

Polynomial chaos expansion (PCE) is a classical and widely used surrogate modeling technique in physical simulation and uncertainty quantification. By taking a linear combination of a set of basis polynomials - orthonormal with respect to…

Machine Learning · Computer Science 2026-04-01 Johannes Exenberger , Sascha Ranftl , Robert Peharz

The BCS and/or HFB theories are extended by treating the effect of four quasi-particle states perturbatively. The approach is tested on the pairing hamiltonian, showing that it combines the advantage of standard perturbation theory valid at…

Nuclear Theory · Physics 2015-06-05 Denis Lacroix , Danilo Gambacurta

In this paper we present new results on the preservation of polynomial stability of damped wave equations under addition of perturbing terms. We in particular introduce sufficient conditions for the stability of perturbed two-dimensional…

Analysis of PDEs · Mathematics 2021-12-08 D. Baidiuk , L. Paunonen

We develop a new generalized coupling approach to the study of stochastic delay equations with H\"older continuous coefficients, for which analytical PDE-based methods are not available. We prove that such equations possess unique weak…

Probability · Mathematics 2018-08-21 Alexei Kulik , Michael Scheutzow

We summarize the current status of our understanding of the structure of the perturbative QCD expressions for the QCD generalization of the Crewther relation.

High Energy Physics - Phenomenology · Physics 2007-05-23 A. L. Kataev

A new perturbation and continuation method is presented for computing and analyzing stellarator equilibria. The method is formally derived from a series expansion about the equilibrium condition $F \equiv J \times B - \nabla p = 0$, and an…

Plasma Physics · Physics 2023-04-05 Rory Conlin , Daniel W. Dudt , Dario Panici , Egemen Kolemen

Using a generalization of the moment problem and the extremal properties of spectral measures corresponding to the selfadjoint extensions of a regular symmetric operator, we study point mass perturbations of spectral measures. We obtain…

Mathematical Physics · Physics 2020-04-23 Rafael del Rio , Luis O. Silva , Julio H. Toloza

We propose a general framework for obtaining probabilistic solutions to PDE-based inverse problems. Bayesian methods are attractive for uncertainty quantification but assume knowledge of the likelihood model or data generation process. This…

Methodology · Statistics 2023-09-28 Youngsoo Baek , Wilkins Aquino , Sayan Mukherjee

We prove a general theorem providing smoothed analysis estimates for conic condition numbers of problems of numerical analysis. Our probability estimates depend only on geometric invariants of the corresponding sets of ill-posed inputs.…

Numerical Analysis · Mathematics 2015-06-26 Peter Buergisser , Felipe Cucker , Martin Lotz

This paper establishes a variant of Stewart's theorem (Theorem~6.4 of Stewart, {\em SIAM Rev.}, 15:727--764, 1973) for the singular subspaces associated with the SVD of a matrix subject to perturbations. Stewart's original version uses both…

Numerical Analysis · Mathematics 2024-06-12 Ren-Cang Li , Ninoslav Truhar , Lei-Hong Zhang

The stationary Gross-Pitaevskii equation in one dimension is considered with a complex periodic potential satisfying the conditions of the PT (parity-time reversal) symmetry. Under rather general assumptions on the potentials we prove…

Dynamical Systems · Mathematics 2018-12-31 Tomas Dohnal , Dmitry E. Pelinovsky

This paper introduces a new generalized polynomial chaos expansion (PCE) comprising multivariate Hermite orthogonal polynomials in dependent Gaussian random variables. The second-moment properties of Hermite polynomials reveal a weakly…

Numerical Analysis · Mathematics 2017-04-27 Sharif Rahman

In this paper, based on the theory of adjoint operators and dual norms, we define condition numbers for a linear solution function of the weighted linear least squares problem. The explicit expressions of the normwise and componentwise…

Numerical Analysis · Mathematics 2017-05-23 Huai-An Diao , Liming Liang , Sanzheng Qiao

The problem of determining the initial condition from noisy final observations in time-fractional parabolic equations is considered. This problem is well-known to be ill-posed and it is regularized by backward Sobolev-type equations. Error…

Numerical Analysis · Mathematics 2020-09-11 Dinh Nho Hao , Nguyen Van Duc , Nguyen Van Thang , Nguyen Trung Thanh

The Gross-Pitaevskii equation with white noise in time perturbations of the harmonic potential is considered. In this article we define a Crank-Nicolson scheme based on a spectral discretization and we show the convergence of this scheme in…

Probability · Mathematics 2017-01-23 Romain Poncet

This paper introduces a new generalized polynomial chaos expansion (PCE) comprising measure-consistent multivariate orthonormal polynomials in dependent random variables. Unlike existing PCEs, whether classical or generalized, no…

Probability · Mathematics 2018-04-17 Sharif Rahman

Various authors have shown that, near the onset of a period-doubling bifurcation, small perturbations in the control parameter may result in much larger disturbances in the response of the dynamical system. Such amplification of small…

Chaotic Dynamics · Physics 2007-05-23 Xiaopeng Zhao , David G. Schaeffer , Carolyn M. Berger , Daniel J. Gauthier

An outline is given of an extended perturbative solution of Euclidean QCD which systematically accounts for a class of nonperturbative effects, while allowing renormalization by the perturbative counterterms. Proper vertices Gamma are…

High Energy Physics - Theory · Physics 2014-11-18 M. Stingl