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We investigate the application of the density-matrix renormalization group (DMRG) algorithm to a one-dimensional harmonic oscillator chain and compare the results with exact solutions, aiming to improve the algorithm efficiency. It has been…

Quantum Physics · Physics 2015-06-19 Yongjun Ma , Jiaxiang Wang , Xinye Xu , Qi Wei , Sabre Kais

Configuration-interaction-type calculations on electronic and vibrational structure are often the method of choice for the reliable approximation of many-particle wave functions and energies. The exponential scaling, however, limits their…

Computational Physics · Physics 2019-05-24 Alberto Baiardi , Christopher J. Stein , Vincenzo Barone , Markus Reiher

This work is on a user-friendly reduced basis method for solving a family of parametric PDEs by preconditioned Krylov subspace methods including the conjugate gradient method, generalized minimum residual method, and bi-conjugate gradient…

Numerical Analysis · Mathematics 2026-02-24 Yuwen Li , Ludmil T. Zikatanov , Cheng Zuo

Transcorrelation (TC) techniques effectively enhance convergence rates in strongly correlated fermionic systems by embedding electron-electron cusp into the Jastrow factor of similarity transformations, yielding a non-Hermitian, yet…

Quantum Physics · Physics 2025-03-19 Bruna G. M. Araújo , Antonio M S Macedo

In the previous paper [arXiv:2210.10435], the nonlinear perturbation theory of cosmological density field is generalized to include the tensor-valued bias of astronomical objects, such as spins and shapes of galaxies and any other tensors…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-23 Takahiko Matsubara

Regularized kernel methods such as support vector machines (SVM) and support vector regression (SVR) constitute a broad and flexible class of methods which are theoretically well investigated and commonly used in nonparametric…

Methodology · Statistics 2013-05-07 Robert Hable

We implement an efficient numerical method to calculate response functions of complex impurities based on the Density Matrix Renormalization Group (DMRG) and use it as the impurity-solver of the Dynamical Mean Field Theory (DMFT). This…

Strongly Correlated Electrons · Physics 2017-11-27 Y. Núñez Fernández , K. Hallberg

A systematic and easy-to-use method is developed to calculate directly the doubly heavy hadron spectral density in the coordinate space. The correlation function is expressed in terms of hypergeometric functions, and the spectral density is…

High Energy Physics - Phenomenology · Physics 2012-08-31 Zhi-Wei Huang , Jueping Liu

Problems in machine learning (ML) can involve noisy input data, and ML classification methods have reached limiting accuracies when based on standard ML data sets consisting of feature vectors and their classes. Greater accuracy will…

Machine Learning · Statistics 2013-12-31 Yue Fan , Louise Raphael , Mark Kon

An efficient Krylov subspace algorithm for computing actions of the $\varphi$ matrix function for large matrices is proposed. This matrix function is widely used in exponential time integration, Markov chains and network analysis and many…

Numerical Analysis · Mathematics 2020-10-20 Mike A. Botchev , Leonid A. Knizhnerman , Eugene E. Tyrtyshnikov

This paper presents a method for computing local mean, variance, standard deviation, and effective sample count on incomplete gridded data using boundary-aware spectral operators. The framework combines normalized convolution with explicit…

Atmospheric and Oceanic Physics · Physics 2026-04-27 Jairo M. Valdivia-Prado , William E. Chapman , Katja Friedrich

The reconstruction of spectral function from correlation function in Euclidean space is a challenging task. In this paper, we employ the Machine Learning techniques in terms of the radial basis functions networks to reconstruct the spectral…

High Energy Physics - Phenomenology · Physics 2021-10-27 Meng Zhou , Fei Gao , Jingyi Chao , Yu-Xin Liu , Huichao Song

Quantum Krylov subspace diagonalization is a prominent candidate for early fault tolerant quantum simulation of many-body and molecular systems, but so far the focus has been mainly on computing ground-state energies. We go beyond this by…

Functional linear regression is one of the fundamental and well-studied methods in functional data analysis. In this work, we investigate the functional linear regression model within the context of reproducing kernel Hilbert space by…

Statistics Theory · Mathematics 2024-12-12 Naveen Gupta , S. Sivananthan , Bharath K. Sriperumbudur

We implement and apply time-dependent density matrix renormalization group (TD-DMRG) algorithms at zero and finite temperature to compute the linear absorption and fluorescence spectra of molecular aggregates. Our implementation is within a…

Chemical Physics · Physics 2019-07-30 Jiajun Ren , Zhigang Shuai , Garnet Kin-Lic Chan

We describe a low cost alternative to the standard variational DMRG (density matrix renormalization group) algorithm that is analogous to the combination of selected configuration interaction plus perturbation theory (SCI+PT). We denote the…

Chemical Physics · Physics 2018-03-28 Sheng Guo , Zhendong Li , Garnet Kin-Lic Chan

Among randomized numerical linear algebra strategies, so-called sketching procedures are emerging as effective reduction means to accelerate the computation of Krylov subspace methods for, e.g., the solution of linear systems, eigenvalue…

Numerical Analysis · Mathematics 2024-08-02 Davide Palitta , Marcel Schweitzer , Valeria Simoncini

A variational formulation for the calculation of interacting fermion systems based on the density-matrix functional theory is presented. Our formalism provides for a natural integration of explicit many-particle effects into standard…

Strongly Correlated Electrons · Physics 2013-05-29 Peter E. Bloechl , Christian F. J. Walther , Thomas Pruschke

We present an implementation of the relativistic quantum-chemical density matrix renormalization group (DMRG) approach based on a matrix-product formalism. Our approach allows us to optimize matrix product state (MPS) wave functions…

Chemical Physics · Physics 2017-10-24 Stefano Battaglia , Sebastian Keller , Stefan Knecht

We present for the first time time-dependent density-matrix renormalization-group simulations (t-DMRG) at finite temperatures. It is demonstrated how a combination of finite-temperature t-DMRG and time-series prediction allows for an easy…

Strongly Correlated Electrons · Physics 2009-07-28 Thomas Barthel , Ulrich Schollwöck , Steven R. White