Functional renormalisation group for Brownian motion I: The effective equations of motion

Wilkins, Ashley, Rigopoulos, Gerasimos and Masoero, Enrico 2021. Functional renormalisation group for Brownian motion I: The effective equations of motion. [Online]. Cornell University. Available at: https://doi.org/10.48550/arXiv.2008.00472

PDF - Submitted Pre-Print Version Download (538kB)

Abstract

We use the functional Renormalisation Group (fRG) to describe the in and out of equilibrium dynamics of stochastic processes, governed by an overdamped Langevin equation. Exploiting the connection between Langevin dynamics and supersymmetric quantum mechanics in imaginary time, we write down renormalisation flow equations for the effective action, approximated in terms of the Local Potential Approximation and Wavefunction Renormalisation. We derive effective equations of motion (EEOM) from the effective action (EA) Γ for the average position hxi, variance h(x − hxi) 2 i and covariance. The fRG flow equations outlined here provide a concrete way to compute the EA and thus solve the derived EEOM. The obtained effective potential should determine directly the exact equilibrium statistics, name the position, the variance, as well as all higher order cumulants of the equilibrium Boltzmann distribution. This first paper of a two part series is mostly concerned with setting up the necessary formalism while in part two we will numerically solve the equations derived her and assess their validity both in and out of equilibrium.

Item Type:	Website Content
Date Type:	Published Online
Status:	Published
Schools:	Engineering
Publisher:	Cornell University
ISSN:	2331-8422
Last Modified:	06 Jan 2024 02:11
URI:	https://orca.cardiff.ac.uk/id/eprint/148069

Actions (repository staff only)

Edit Item