Universal short-time dynamics: boundary functional renormalization group for a temperature quench

TL;DR

This paper introduces a functional renormalization-group method to compute universal short-time exponents in non-equilibrium dynamics, demonstrated on classical critical dynamics after a temperature quench, aligning with existing theoretical and simulation results.

Contribution

It develops a novel boundary functional renormalization-group approach for calculating short-time universal exponents in non-equilibrium systems.

Findings

Calculated initial slip exponent consistent with perturbative and Monte Carlo results.

Validated the method on classical critical dynamics after a temperature quench.

Provided a new tool for analyzing short-time universal behaviour in non-equilibrium systems.

Abstract

We present a method to calculate short-time non-equilibrium universal exponents within the functional renormalization-group scheme. As an example, we consider the classical critical dynamics of the relaxational model A after a quench of the temperature of the system and calculate the initial slip exponent which characterizes the non-equilibrium universal short-time behaviour of both the order parameter and correlation functions. The value of this exponent is found to be consistent with the result of a perturbative dimensional expansion and of Monte Carlo simulations in three spatial dimensions.