Improved mean-field dynamical equations are able to detect the two-steps relaxation in glassy dynamics at low temperatures

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Main Authors: Machado, David, Mulet, Roberto, Ricci-Tersenghi, Federico
Format: Preprint
Published: 2023
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author Machado, David
Mulet, Roberto
Ricci-Tersenghi, Federico
author_facet Machado, David
Mulet, Roberto
Ricci-Tersenghi, Federico
contents We study the stochastic relaxation dynamics of the Ising p-spin model on a random graph, a well-known model with glassy dynamics at low temperatures. We introduce and discuss a new closure scheme for the master equation governing the continuous-time relaxation of the system, that translates into a set of differential equations for the evolution of local probabilities. The solution to these dynamical mean-field equations describes very well the out-of-equilibrium dynamics at high temperatures, notwithstanding the key observation that the off-equilibrium probability measure contains higher-order interaction terms, not present in the equilibrium measure. In the low-temperature regime, the solution to the dynamical mean-field equations shows the correct two-step relaxation (a typical feature of the glassy dynamics), but with a relaxation timescale too short. We propose a solution to this problem by identifying the range of energies where entropic barriers play a key role and defining a renormalized microscopic timescale for the dynamical mean-field solution. The final result perfectly matches the complex out-of-equilibrium dynamics computed through extensive Monte Carlo simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2307_00882
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Improved mean-field dynamical equations are able to detect the two-steps relaxation in glassy dynamics at low temperatures
Machado, David
Mulet, Roberto
Ricci-Tersenghi, Federico
Statistical Mechanics
We study the stochastic relaxation dynamics of the Ising p-spin model on a random graph, a well-known model with glassy dynamics at low temperatures. We introduce and discuss a new closure scheme for the master equation governing the continuous-time relaxation of the system, that translates into a set of differential equations for the evolution of local probabilities. The solution to these dynamical mean-field equations describes very well the out-of-equilibrium dynamics at high temperatures, notwithstanding the key observation that the off-equilibrium probability measure contains higher-order interaction terms, not present in the equilibrium measure. In the low-temperature regime, the solution to the dynamical mean-field equations shows the correct two-step relaxation (a typical feature of the glassy dynamics), but with a relaxation timescale too short. We propose a solution to this problem by identifying the range of energies where entropic barriers play a key role and defining a renormalized microscopic timescale for the dynamical mean-field solution. The final result perfectly matches the complex out-of-equilibrium dynamics computed through extensive Monte Carlo simulations.
title Improved mean-field dynamical equations are able to detect the two-steps relaxation in glassy dynamics at low temperatures
topic Statistical Mechanics
url https://arxiv.org/abs/2307.00882