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We investigate a reformulation of the dynamics of interacting fermion systems in terms of a stochastic extension of Time Dependent Hartree-Fock equations. The noise is found from a path-integral representation of the evolution operator and…

Nuclear Theory · Physics 2009-11-07 O. Juillet , Ph. Chomaz , D. Lacroix , F. Gulminelli

The exact evolution of a system coupled to a complex environment can be described by a stochastic mean-field evolution of the reduced system density. The formalism developed in Ref. [D.Lacroix, Phys. Rev. E77, 041126 (2008)] is illustrated…

Nuclear Theory · Physics 2009-11-13 Denis Lacroix , Guillaume Hupin

The mean field approximation is numerically validated in the bosonic case by considering the time evolution of quantum states and their associated reduced density matrices by many-body Schr\"odinger dynamics. The model phase-space is…

Mathematical Physics · Physics 2015-08-04 Boris Pawilowski

The exact dynamics of a system coupled to an environment can be described by an integro-differential stochastic equation of its reduced density. The influence of the environment is incorporated through a mean-field which is both stochastic…

Quantum Physics · Physics 2009-11-13 Denis Lacroix

We show that the dynamics of interacting fermions can be exactly replaced by a quantum jump theory in the many-body density matrix space. In this theory, jumps occur between densities formed of pairs of Slater determinants, $D_{ab}=| \Phi_a…

Quantum Physics · Physics 2009-11-10 Denis Lacroix

A Gaussian operator basis provides a means to formulate phase-space simulations of the real- and imaginary-time evolution of quantum systems. Such simulations are guaranteed to be exact while the underlying distribution remains…

Computational Physics · Physics 2012-04-04 M. Ogren , K. V. Kheruntsyan , J. F. Corney

The dynamics of the spin-boson Hamiltonian is considered in the stochastic approximation. The Hamiltonian describes a two-level system coupled to an environment and is widely used in physics, chemistry and the theory of quantum measurement.…

Quantum Physics · Physics 2016-09-08 L. Accardi , S. V. Kozyrev , I. V. Volovich

In this paper we study the dynamics of fermionic mixed states in the mean-field regime. We consider initial states which are close to quasi-free states and prove that, under suitable assumptions on the inital data and on the many-body…

Mathematical Physics · Physics 2015-02-12 Niels Benedikter , Vojkan Jaksic , Marcello Porta , Chiara Saffirio , Benjamin Schlein

We introduce a positive phase-space representation for fermions, using the most general possible multi-mode Gaussian operator basis. The representation generalizes previous bosonic quantum phase-space methods to Fermi systems. We derive…

Other Condensed Matter · Physics 2009-11-10 J. F. Corney , P. D. Drummond

A dynamical model of an ecological community is analyzed within a "mean-field approximation" in which one of the species interacts with the combination of all of the other species in the community. Within this approximation the model may be…

Adaptation and Self-Organizing Systems · Physics 2009-10-31 Alan McKane , David Alonso , Ricard V. Sole

We study the dynamics of many-body Fermi systems, for a class of initial data which are close to quasi-free states exhibiting a nonvanishing pairing matrix. We focus on the mean-field scaling, which for fermionic systems is naturally…

Mathematical Physics · Physics 2024-10-01 Stefano Marcantoni , Marcello Porta , Julien Sabin

Finite lattice models are a prototype for strongly correlated quantum systems and capture essential properties of condensed matter systems. With the dramatic progress in ultracold atoms in optical lattices, finite fermionic Hubbard systems…

Strongly Correlated Electrons · Physics 2014-09-10 Denis Lacroix , S. Hermanns , C. M. Hinz , M. Bonitz

In this work, we establish formally exact stochastic equations of motion (SEOM) theory to describe the dissipative dynamics of fermionic open systems. The construction of the SEOM is based on a stochastic decoupling of the dissipative…

Statistical Mechanics · Physics 2020-06-24 Lu Han , Arif Ullah , Yun-An Yan , Xiao Zheng , YiJing Yan , Vladimir Chernyak

We study translation-invariant quasi-free states for a system of fermions with two-particle interactions. The associated energy functional is similar to the BCS functional but includes also direct and exchange energies. We show that for…

Mathematical Physics · Physics 2015-06-16 Gerhard Bräunlich , Christian Hainzl , Robert Seiringer

We derive stochastic master equations for a quantum system interacting with a Bose field prepared in a superposition of continuous-mode coherent states. To determine a conditional evolution of the quantum system we use a collision model…

Quantum Physics · Physics 2020-02-11 Anita Dabrowska

We present exact solutions for the non-equilibrium steady states of a class of dissipative spinless fermionic systems with arbitrary Hamiltonian pairing terms, global charging energy interactions, and uniform single particle loss on every…

Quantum Physics · Physics 2026-05-12 Andrew Lingenfelter , Aashish A. Clerk

We use a combinatorial approach to obtain exact expressions for the many-body density of states of fermionic and bosonic gases with equally spaced single-particle spectra. We identify a mapping that reveals a remarkable property, namely,…

Quantum Gases · Physics 2025-02-11 Carolyn Echter , Georg Maier , Juan-Diego Urbina , Caio Lewenkopf , Klaus Richter

We investigate an $N$-particle Bose-Hubbard dimer with an additional effective decay term in one of the sites. A mean-field approximation for this non-Hermitian many-particle system is derived, based on a coherent state approximation. The…

Quantum Physics · Physics 2008-10-10 E. M. Graefe , H. J. Korsch , A. E. Niederle

The dynamics of fermionic many-body systems is investigated in the framework of Boltzmann-Langevin (BL) stochastic one-body approaches. Within the recently introduced BLOB model, we examine the interplay between mean-field effects and…

Nuclear Theory · Physics 2017-11-27 P. Napolitani , M. Colonna

We examine distinct measures of fermionic entanglement in the exact ground state of a finite superconducting system. It is first shown that global measures such as the one-body entanglement entropy, which represents the minimum relative…

Quantum Physics · Physics 2018-06-20 M. Di Tullio , N. Gigena , R. Rossignoli
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