Affiliations 

  • 1 The Rockefeller University, New York 10065, USA
  • 2 The Rockefeller University, New York 10065, USA and Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242, USA
  • 3 Dipartimento di Scienze Matematiche, Graphene@Polito Laboratory, Politecnico di Torino-Corso Duca degli Abruzzi 24, 10125, Torino, Italy; INFN, Sezione di Torino, Via P. Giuria 1, 10125, Torino, Italy; Kavli Institute for Theoretical Physics China, Chinese Academy of Sciences, Beijing 100190, China; and Malaysia Italy Centre of Excellence for Mathematical Sciences, University Putra Malaysia, 43400 Serdang, Selangor, Malaysia
Phys Rev E, 2017 Aug;96(2-1):022125.
PMID: 28950465 DOI: 10.1103/PhysRevE.96.022125

Abstract

The present paper is based on a recent success of the second-order stochastic fluctuation theory in describing time autocorrelations of equilibrium and nonequilibrium physical systems. In particular, it was shown to yield values of the related deterministic parameters of the Langevin equation for a Couette flow in a microscopic molecular dynamics model of a simple fluid. In this paper we find all the remaining constants of the stochastic dynamics, which then is simulated numerically and compared directly with the original physical system. By using these data, we study in detail the accuracy and precision of a second-order Langevin model for nonequilibrium physical systems theoretically and computationally. We find an intriguing relation between an applied external force and cumulants of the resulting flow fluctuations. This is characterized by a linear dependence of an athermal cumulant ratio, an apposite quantity introduced here. In addition, we discuss how the order of a given Langevin dynamics can be raised systematically by introducing colored noise.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.