Nonlinearity accelerates the thermalization of the quartic FPUT model with stochastic baths

Schmid, Harald and Succi, Sauro and Ruffo, Stefano (2021) Nonlinearity accelerates the thermalization of the quartic FPUT model with stochastic baths. JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT, 2021 (5): 053205. ISSN 1742-5468

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Abstract

We investigate the equilibration process of the strongly coupled quartic Fermi-Pasta-Ulam-Tsingou model by adding Langevin baths to the ends of the chain. The time evolution of the system is investigated by means of extensive numerical simulations and shown to match the results expected from equilibrium statistical mechanics in the time-asymptotic limit. Upon increasing the nonlinear coupling, the thermalization of the energy spectrum displays an increasing asymmetry in favor of small-scale, high-frequency modes, which relax significantly faster than the large-scale, low-frequency ones. The global equilibration time is found to scale linearly with system size and shown to exhibit a power-law decay with the strength of the nonlinearity and temperature. Nonlinear interaction adds to energy distribution among modes, thus speeding up the thermalization process.

Item Type: Article
Uncontrolled Keywords: HAMILTONIAN-SYSTEMS; FERMI; PASTA; ULAM; DYNAMICS; ROUTE; thermalization; stochastic particle dynamics
Subjects: 500 Science > 510 Mathematics
500 Science > 530 Physics
600 Technology > 600 Technology (Applied sciences)
Divisions: Physics > Institute of Experimental and Applied Physics
Depositing User: Dr. Gernot Deinzer
Date Deposited: 18 Aug 2022 11:12
Last Modified: 18 Aug 2022 11:12
URI: https://pred.uni-regensburg.de/id/eprint/46793

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