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The initial stages of the evolution of an open quantum system encode the key information of its underlying dynamical correlations, which in turn can predict the trajectory at later stages. We propose a general approach based on…

Quantum Physics · Physics 2015-10-20 Javier Cerrillo , Jianshu Cao

The simulation of quantum transport in a realistic, many-particle system is a nontrivial problem with no quantitatively satisfactory solution. While real-time propagation has the potential to overcome the shortcomings of conventional…

Mesoscale and Nanoscale Physics · Physics 2015-10-16 Justin E. Elenewski , Yanxiang Zhao , Hanning Chen

With the development of low order scaling methods for performing Kohn-Sham Density Functional Theory, it is now possible to perform fully quantum mechanical calculations of systems containing tens of thousands of atoms. However, with an…

Chemical Physics · Physics 2020-04-03 William Dawson , Stephan Mohr , Laura E. Ratcliff , Takahito Nakajima , Luigi Genovese

In these notes I explain how to describe one-dimensional quantum systems that are simultaneously near to, but not exactly at, a critical point, and in a far-from-equilibrium steady state. This description uses a density matrix on scattering…

Statistical Mechanics · Physics 2012-12-06 Benjamin Doyon

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

A first-principles approach to describe electron dynamics in open quantum systems driven far from equilibrium via external time-dependent stimuli is introduced. Within this approach, the driven Liouville von Neumann methodology is used to…

Mesoscale and Nanoscale Physics · Physics 2023-05-10 Annabelle Oz , Abraham Nitzan , Oded Hod , Juan E. Peralta

Dynamical maps are the principal subject of the open system theory. Formally, the dynamical map of a given open quantum system is a density matrix transformation that takes any initial state and sends it to the state at a later time.…

Quantum Physics · Physics 2025-09-03 Piotr Szańkowski

We develop analytical tools and numerical methods for time evolving the total density matrix of the finite-size Anderson model. The model is composed of two finite metal grains, each prepared in canonical states of differing chemical…

Mesoscale and Nanoscale Physics · Physics 2015-06-11 Manas Kulkarni , Kunal L Tiwari , Dvira Segal

Motivated by cosmological Hartle-Hawking and microcanonical density matrix prescriptions for the quantum state of the Universe we develop Schwinger-Keldysh in-in formalism for generic nonequilibrium dynamical systems with the initial…

High Energy Physics - Theory · Physics 2023-09-08 Andrei O. Barvinsky , Nikita Kolganov

We develop an exact framework to describe the non-Markovian dynamics of an open quantum system interacting with an environment modeled by a generalized spectral density function. The approach relies on mapping the initial system onto an…

Quantum Physics · Physics 2020-10-22 Graeme Pleasance , Barry M. Garraway , Francesco Petruccione

In this paper Quantum Mechanics with Fundamental Length is built as a deformation of Quantum Mechanics. To this aim an approach is used which does not take into account commutator deformation as usually it is done, but density matrix…

General Relativity and Quantum Cosmology · Physics 2007-05-23 A. E. Shalyt-Margolin , J. G. Suarez

A general method for numerical computation of the thermal density matrix of a single-particle quantum system is presented. The Schrodinger equation in imaginary time tau is solved numerically by the finite difference time domain (FDTD)…

Computational Physics · Physics 2009-02-12 I. Wayan Sudiarta , D. J. Wallace Geldart

We provide a brief overview of approaches for calculating the density of states of quantum systems and random matrix Hamiltonians using the tools of free probability theory. For a given Hamiltonian of a quantum system or a generic random…

Quantum Physics · Physics 2025-12-04 Keun-Young Kim , Kuntal Pal

The path integral approach offers not only an exact expression for the non- equilibrium dynamics of dissipative quantum systems, but is also a convenient starting point for perturbative treatments. An alternative way to explore the…

Statistical Mechanics · Physics 2022-09-21 Joachim Ankerhold

Understanding and simulating how a quantum system interacts and exchanges information or energy with its surroundings is a ubiquitous problem, one which must be carefully addressed in order to establish a coherent framework to describe the…

Quantum Physics · Physics 2021-05-25 Steve Campbell , Bassano Vacchini

In this paper I investigate the usability of the characteristic functions for the description of the dynamics of open quantum systems focussing on non-Lindblad-type master equations. I consider, as an example, a non-Markovian generalized…

Quantum Physics · Physics 2009-11-11 Sabrina Maniscalco

Pendry and MacKinnon meaningful discretization of Maxwell's equations was put forward specifically as part of a finite-element numerical algorithm. By contrast with a numerical approach, in the same spirit evoked by the relationships…

Optics · Physics 2023-03-14 Ovidiu-Zeno Lipan , Aldo De Sabata

Quantum Field Theory (QFT) makes predictions by combining assumptions about (1) quantum dynamics, typically a Schrodinger or Liouville equation; (2) quantum measurement, usually via a collapse formalism. Here I define a "classical density…

Quantum Physics · Physics 2007-05-23 Paul J. Werbos

This paper introduces a novel approach to probabilistic deep learning, kernel density matrices, which provide a simpler yet effective mechanism for representing joint probability distributions of both continuous and discrete random…

Machine Learning · Computer Science 2024-05-01 Fabio A. González , Raúl Ramos-Pollán , Joseph A. Gallego-Mejia

Recent advances in quantum technologies and related experiments have created a need for highly accurate, versatile, and computationally efficient simulation techniques for the dynamics of open quantum systems. Long-lived correlation effects…

Quantum Physics · Physics 2026-01-09 Meng Xu , Vasilii Vadimov , J. T. Stockburger , J. Ankerhold