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We propose a method for inference on moderately high-dimensional, nonlinear, non-Gaussian, partially observed Markov process models for which the transition density is not analytically tractable. Markov processes with intractable transition…

Methodology · Statistics 2020-04-02 Joonha Park , Edward L. Ionides

Understanding the behaviour of a quantum system coupled to its environment is of fundamental interest in the general field of quantum technologies. It also has important repercussions on foundational problems in physics, such as the process…

Quantum Physics · Physics 2021-11-01 Sapphire Lally , Nicholas Werren , Jim Al-Khalili , Andrea Rocco

We propose a convex variational approach to compute localized density matrices for both zero temperature and finite temperature cases, by adding an entry-wise $\ell_1$ regularization to the free energy of the quantum system. Based on the…

Numerical Analysis · Mathematics 2016-05-04 Rongjie Lai , Jianfeng Lu

By merging the Feynman-Vernon's approach with the out-of-equilibrium Keldysh-Schwinger formalism, we construct the reduced generating functional through which all the time-dependent correlation functions of an open fermionic system can be…

Quantum Physics · Physics 2024-07-09 A. I. Karanikas , G. E. Pavlou

Reduced-density-matrix-functional theory is applied to open-shell systems. We introduce a spin-restricted formulation by appropriately expressing approximate correlation-energy functionals in terms of spin-dependent occupation numbers and…

Strongly Correlated Electrons · Physics 2007-05-23 N. N. Lathiotakis , N. Helbig , E. K. U. Gross

Our ability to numerically model and understand the complex flow behavior of solid-bearing suspensions has increased significantly over the last couple of years, partly due to direct numerical simulations that compute flow around individual…

Computational Physics · Physics 2019-03-21 Zhipeng Qin , Kali Alison , Jenny Suckale

Simulating the nonequilibrium dynamics of thermal states is a fundamental problem across scales from high energy to condensed matter physics. Quantum computers may provide a way to solve this problem efficiently. Preparing a thermal state…

Quantum Physics · Physics 2023-11-03 Jason Saroni , Henry Lamm , Peter P. Orth , Thomas Iadecola

Time-independent quantum response calculations are performed using Tensor cores. This is achieved by mapping density matrix perturbation theory onto the computational structure of a deep neural network. The main computational cost of each…

A methodology for using random sketching in the context of model order reduction for high-dimensional parameter-dependent systems of equations was introduced in [Balabanov and Nouy 2019, Part I]. Following this framework, we here construct…

Numerical Analysis · Mathematics 2022-03-25 Oleg Balabanov , Anthony Nouy

The reduced density matrix (RDM) plays a key role in quantum entanglement and measurement, as it allows the extraction of almost all physical quantities related to the reduced degrees of freedom. However, restricted by the degrees of…

Quantum Physics · Physics 2025-03-27 Bin-Bin Mao , Yi-Ming Ding , Zhe Wang , Shijie Hu , Zheng Yan

At early times dark matter has a thermal velocity dispersion of unknown amplitude which, for warm dark matter models, can influence the formation of nonlinear structure on observable scales. We propose a new scheme to simulate cosmologies…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-10 Jens Stücker , Oliver Hahn , Raul E. Angulo , Simon D. M. White

The theoretical description of materials' properties driven out of equilibrium has important consequences in various fields such as semiconductor spintronics, nonlinear optics, continuous and discrete quantum information science and…

Materials Science · Physics 2025-09-18 Jacopo Simoni , Gabriele Riva , Yuan Ping

We study the effects of integrability breaking perturbations on the non-equilibrium evolution of many-particle quantum systems. We focus on a class of spinless fermion models with weak interactions. We employ equation of motion techniques…

Statistical Mechanics · Physics 2015-11-04 Bruno Bertini , Fabian H. L. Essler , Stefan Groha , Neil J. Robinson

We determine the exact time-dependent non-idempotent one-particle reduced density matrix and its spectral decomposition for a harmonically confined two-particle correlated one-dimensional system when the interaction terms in the…

Statistical Mechanics · Physics 2017-02-01 I. Nagy , J. Pipek , M. L. Glasser

A new approach is presented to compute entropy for massless scalar quantum fields. By perturbing a skewed correlation matrix composed of field operator correlation functions, the mutual information is obtained for disjoint spherical regions…

High Energy Physics - Theory · Physics 2025-01-15 Joseph Bramante , Andrew Buchanan

We present the non-Markovian generalization of the widely used stochastic Schrodinger equation. Our result allows to describe open quantum systems in terms of stochastic state vectors rather than density operators, without approximation.…

Quantum Physics · Physics 2009-10-30 Lajos Diosi , Walter T. Strunz

Efficient computation methods are devised for the perturbative solution of Schwinger--Dyson equations for propagators. We show how a simple computation allows to obtain the dominant contribution in the sum of many parts of previous…

High Energy Physics - Theory · Physics 2010-09-30 Marc Bellon

The deformation of an initially spherical capsule, freely suspended in simple shear flow, can be computed analytically in the limit of small deformations [D. Barthes-Biesel, J. M. Rallison, The Time-Dependent Deformation of a Capsule Freely…

Soft Condensed Matter · Physics 2010-08-10 Timm Krüger , Fathollah Varnik , Dierk Raabe

We demonstrate that the dynamics of an open quantum system can be calculated efficiently and with predefined error, provided a basis exists in which the system-environment interactions are local and hence obey the Lieb-Robinson bound. We…

Quantum Physics · Physics 2015-03-19 Giulia Gualdi , Christiane P. Koch

We present a quantum information-inspired framework for analyzing complex systems through multivariate time series. In this approach the system's state is encoded into a density matrix, providing a compact representation of higher-order…

Chaotic Dynamics · Physics 2025-12-17 Parsa Kafashi , Mozhgan Orujlu