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We propose a general strategy to discretize the Dyson series without applying direct numerical quadrature to high-dimensional integrals, and extend this framework to open quantum systems. The resulting discretization can also be interpreted…

Quantum Physics · Physics 2025-10-20 Zhenning Cai , Yixiao Sun , Geshuo Wang

The non-Markovian master equation for open quantum systems is obtained by generalization of the standard Zwanzig-Nakajima (ZN) projection technique. To this end, a coupled chain of equations for the reduced density matrices of the bath…

Quantum Physics · Physics 2022-03-29 V. V. Ignatyuk , V. G. Morozov

We develop a general framework for designing conservative numerical methods based on summation by parts operators and split forms in space, combined with relaxation Runge-Kutta methods in time. We apply this framework to create new classes…

Numerical Analysis · Mathematics 2021-03-09 Hendrik Ranocha , Dimitrios Mitsotakis , David I. Ketcheson

Given a set of Kohn-Sham orbitals from an insulating system, we present a simple, robust, efficient and highly parallelizable method to construct a set of, optionally orthogonal, localized basis functions for the associated subspace. Our…

Computational Physics · Physics 2014-11-05 Anil Damle , Lin Lin , Lexing Ying

We propose an approximation scheme to describe the dynamics of the spin-boson model when the spectral density of the environment shows a peak at a characteristic frequency $\Omega$ which can be very close (or even equal) to the spin Zeeman…

Quantum Physics · Physics 2008-12-11 Frederico Brito , Amir O. Caldeira

We introduce MENO (''Matrix Exponential-based Neural Operator''), a hybrid surrogate modeling framework for efficiently solving stiff systems of ordinary differential equations (ODEs) that exhibit a sparse nonlinear structure. In such…

Computational Physics · Physics 2025-07-22 Ivan Zanardi , Simone Venturi , Marco Panesi

Hidden Markov Models (HMMs) are powerful tools for modeling sequential data, where the underlying states evolve in a stochastic manner and are only indirectly observable. Traditional HMM approaches are well-established for linear sequences,…

Machine Learning · Statistics 2024-06-05 Farzan Vafa , Sahand Hormoz

A major challenge in open quantum dynamics is the inclusion of Matsubara-decay terms in the memory kernel, which arise from the quantum-Boltzmann delocalisation of the bath modes. This delocalisation can be quantified by the radius of…

Quantum Physics · Physics 2026-02-17 Andrew C. Hunt , Stuart C. Althorpe

We study a diffuse-interface model for thermally driven phase separation in viscous incompressible mixtures. The system couples a convective Cahn-Hilliard equation for the order parameter with a Stokes subsystem for the velocity-pressure…

Analysis of PDEs · Mathematics 2026-04-24 Maria Deliyianni , Boris Muha , Andrej Novak

The impact of randomness on model training is poorly understood. How do differences in data order and initialization actually manifest in the model, such that some training runs outperform others or converge faster? Furthermore, how can we…

Machine Learning · Computer Science 2024-01-23 Michael Y. Hu , Angelica Chen , Naomi Saphra , Kyunghyun Cho

Out-of-equilibrium dynamics of non-integrable Hamiltonian many-body quantum systems are characterized by highly entangled wave functions. Near-maximal entanglement arises in systems exhibiting thermalization or pre-thermalization, where the…

We introduce a new technique for the simulation of dissipative quantum systems. This method is composed of an approximate decomposition of the Lindblad equation into a Kraus map, from which one can define an ensemble of wavefunctions. Using…

Quantum Physics · Physics 2021-01-13 Gerard McCaul , Kurt Jacobs , Denys I. Bondar

We present a new efficient computational approach for time-dependent first-order Hamilton-Jacobi-Bellman PDEs. Since our method is based on a time-implicit Eulerian discretization, the numerical scheme is unconditionally stable, but…

Numerical Analysis · Mathematics 2013-06-18 Alexander Vladimirsky , Changxi Zheng

We investigate the quantum field aspects in flat spacetime for an uniformly accelerated observer moving in a thermal bath. In particular, we obtain an exact closed expression of the reduced density matrix for an uniformly accelerated…

General Relativity and Quantum Cosmology · Physics 2014-02-26 Sanved Kolekar

In this letter, we study the energy-optimal control of nonlinear port-Hamiltonian (pH) systems in discrete time. For continuous-time pH systems, energy-optimal control problems are strictly dissipative by design. This property, stating that…

Systems and Control · Electrical Eng. & Systems 2025-09-03 Arijit Sarkar , Vaibhav Kumar Singh , Manuel Schaller , Karl Worthmann

We consider a Hidden Markov Model (HMM) where the integrated continuous-time Markov chain can be observed at discrete time points perturbed by a Brownian motion. The aim is to derive a filter for the underlying continuous-time Markov chain.…

Probability · Mathematics 2021-07-21 Nicole Bäuerle , Igor Gilitschenski , Uwe D. Hanebeck

We present a deep learning model, DE-LSTM, for the simulation of a stochastic process with an underlying nonlinear dynamics. The deep learning model aims to approximate the probability density function of a stochastic process via numerical…

Computational Physics · Physics 2018-10-23 Kyongmin Yeo , Igor Melnyk

We review and compare numerical methods that simultaneously control temperature while preserving the momentum, a family of particle simulation methods commonly used for the modelling of complex fluids and polymers. The class of methods…

Computational Physics · Physics 2020-02-14 Benedict Leimkuhler , Xiaocheng Shang

We propose a nonperturbative quantum dissipation theory, in term of hierarchical quantum master equation. It may be used with a great degree of confidence to various dynamics systems in condensed phases. The theoretical development is…

Statistical Mechanics · Physics 2015-05-14 Rui-Xue Xu , Bao-Ling Tian , Jian Xu , Qiang Shi , YiJing Yan

Path-integral techniques are a powerful tool used in open quantum systems to provide an exact solution for the non-Markovian dynamics. However, the exponential scaling of the tensor size with quantum memory length of these techniques limits…

Quantum Physics · Physics 2025-08-25 L. M. J. Hall , A. Gisdakis , E. A. Muljarov