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Approximate expressions for correlation functions in binary inhomogeneous mixtures are derived in a framework of the mesoscopic theory [Ciach A., Mol. Phys., 2011, {\textbf{109}}, 1101]. Fluctuation contribution is taken into account in a…

Soft Condensed Matter · Physics 2020-05-26 A. Ciach , O. Patsahan , A. Meyra

The long-time dynamics of the $d$-dimensional spherical model with a non-conserved order parameter and quenched from an initial state with long-range correlations is studied through the exact calculation of the two-time autocorrelation and…

Statistical Mechanics · Physics 2008-11-26 Alan Picone , Malte Henkel

The late-time equilibrium behavior of generic interacting models is determined by the coupled hydrodynamic equations associated with the globally conserved quantities. In the presence of an external time-dependent drive, non-integrable…

Strongly Correlated Electrons · Physics 2025-06-10 Haoyu Guo , Rohit Mukherjee , Debanjan Chowdhury

Classical and quantum correlation functions are derived for a system of non-interacting particles moving on a circle. It is shown that the decaying behaviour of the classical expression for the correlation function can be recovered from the…

Quantum Physics · Physics 2021-07-06 B. Buck , C. V. Sukumar

The study by Glauber of the time-dependent statistics of the Ising chain is extended to the case where each spin is influenced unequally by its nearest neighbours. The asymmetry of the dynamics implies the failure of the detailed balance…

Statistical Mechanics · Physics 2015-05-27 Claude Godreche

The theory of real-time quantum many-body dynamics as put forward in Ref. [arXiv:0710.4627] is evaluated in detail. The formulation is based on a generating functional of correlation functions where the Keldysh contour is closed at a given…

Quantum Gases · Physics 2011-02-09 Thomas Gasenzer , Stefan Kessler , Jan M. Pawlowski

Recent experimental results point to the existence of coherent quantum phenomena in systems made of a large number of particles, despite the fact that for many-body systems the presence of decoherence is hardly negligible and emerging…

Quantum Physics · Physics 2017-09-21 F. Benatti , F. Carollo , R. Floreanini , H. Narnhofer

Working within the Nonequilibrium Green's Function (NEGF) formalism, a formula for the two-time current correlation function is derived for the case of transport through a nanojunction in response to an arbitrary time-dependent bias. The…

Mesoscale and Nanoscale Physics · Physics 2017-05-03 Michael Ridley , Angus MacKinnon , Lev Kantorovich

We derive exact expressions for a number of aging functions that are scaling limits of non-equilibrium correlations, R(tw,tw+t) as tw --> infinity with t/tw --> theta, in the 1D homogenous q-state Potts model for all q with T=0 dynamics…

Disordered Systems and Neural Networks · Physics 2009-11-07 L. R. Fontes , M. Isopi , C. M. Newman , D. L. Stein

We propose a new approximation-technique to deal with the exact macroscopic integro-differential evolution equations of statistical systems which self-consistently accounts for dissipative effects. Concentrating on one and two point…

High Energy Physics - Phenomenology · Physics 2007-05-23 Herbert Nachbagauer

We present a method to compute the many-body real-time Green's function using an adaptive variational quantum dynamics simulation approach. The real-time Green's function involves the time evolution of a quantum state with one additional…

Quantum Physics · Physics 2023-02-08 Niladri Gomes , David B. Williams-Young , Wibe A. de Jong

In a semi-infinite geometry, a 1D, M-component model of biological evolution realizes microscopically an inhomogeneous branching process for $M \to \infty$. This implies in particular a size distribution exponent $\tau'=7/4$ for avalanches…

Statistical Mechanics · Physics 2009-10-31 E. Montevecchi , A. L. Stella

A general method is introduced for verifying multitime quantum correlations through the characteristic function of the time-dependent P functional that generalizes the Glauber-Sudarshan P function. Quantum correlation criteria are derived…

Quantum Physics · Physics 2016-06-30 F. Krumm , J. Sperling , W. Vogel

We propose a description of nonequilibrium systems via a simple protocol that combines exchange-correlation potentials from density functional theory with self-energies of many-body perturbation theory. The approach, aimed to avoid double…

Strongly Correlated Electrons · Physics 2016-06-15 M. Hopjan , D. Karlsson , S. Ydman , C. Verdozzi , C. -O. Almbladh

We investigate the behavior of correlations dynamics in a dissipative gain-loss system. First, we consider a setup made of two coupled lossy oscillators, with one of them subject to a local gain. This provides a more realistic platform to…

Quantum Physics · Physics 2023-05-24 Federico Roccati , Archak Purkayastha , G. Massimo Palma , Francesco Ciccarello

This article traces the development of fluctuation theory and its deep connection to irreversibility, from equilibrium to near-equilibrium, and finally to far-from-equilibrium systems. Classical fluctuation theorems, which capture the…

Quantum Physics · Physics 2025-12-30 Sounak Bandyopadhyay , Arnab Ghosh

The quantum dynamics of fermionic or bosonic many-body systems following external excitation can be successfully studied using two-time nonequilibrium Green's functions (NEGF) or single-time reduced density matrix methods. Approximations…

Strongly Correlated Electrons · Physics 2022-07-12 Erik Schroedter , Jan-Philip Joost , Michael Bonitz

One of the main questions of research on quantum many-body systems following unitary out of equilibrium dynamics is to find out how local expectation values equilibrate in time. For non-interacting models, this question is rather well…

Quantum Physics · Physics 2017-04-24 H. Wilming , M. Goihl , C. Krumnow , J. Eisert

We present a diagrammatic formulation of a theory for the time dependence of density fluctuations in equilibrium systems of interacting Brownian particles. To facilitate derivation of the diagrammatic expansion we introduce a basis that…

Soft Condensed Matter · Physics 2009-11-13 Grzegorz Szamel

The time-dependent variational principle proposed by Balian and Veneroni is used to provide the best approximation to the generating functional for multi-time Green's functions of a set of (bosonic) observables $Q_{\mu)$. By suitably…

High Energy Physics - Theory · Physics 2016-09-06 Mohamed Benarous