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Title: Thermalization of oscillator chains with onsite anharmonicity and comparison with kinetic theory

We perform microscopic molecular dynamics simulations of particle chains with an onsite anharmonicity to study relaxation of spatially homogeneous states to equilibrium, and directly compare the simulations with the corresponding Boltzmann-Peierls kinetic theory. The Wigner function serves as a common interface between the microscopic and kinetic level. We demonstrate quantitative agreement after an initial transient time interval. In particular, besides energy conservation, we observe the additional quasiconservation of the phonon density, defined via an ensemble average of the related microscopic field variables and exactly conserved by the kinetic equations. On superkinetic time scales, density quasiconservation is lost while energy remains conserved, and we find evidence for eventual relaxation of the density to its canonical ensemble value. Furthermore, the precise mechanism remains unknown and is not captured by the Boltzmann-Peierls equations.
Authors:
 [1] ;  [2] ;  [3]
  1. SLAC National Accelerator Lab., Menlo Park, CA (United States)
  2. Duke Univ., Durham, NC (United States)
  3. Univ. of Helsinki, Helsingin yliopisto (Finland)
Publication Date:
Grant/Contract Number:
DMS-1454939; AC02-76SF00515
Type:
Accepted Manuscript
Journal Name:
Physical Review E
Additional Journal Information:
Journal Volume: 94; Journal Issue: 6; Journal ID: ISSN 2470-0045
Publisher:
American Physical Society (APS)
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
OSTI Identifier:
1361160

Mendl, Christian B., Lu, Jianfeng, and Lukkarinen, Jani. Thermalization of oscillator chains with onsite anharmonicity and comparison with kinetic theory. United States: N. p., Web. doi:10.1103/PhysRevE.94.062104.
Mendl, Christian B., Lu, Jianfeng, & Lukkarinen, Jani. Thermalization of oscillator chains with onsite anharmonicity and comparison with kinetic theory. United States. doi:10.1103/PhysRevE.94.062104.
Mendl, Christian B., Lu, Jianfeng, and Lukkarinen, Jani. 2016. "Thermalization of oscillator chains with onsite anharmonicity and comparison with kinetic theory". United States. doi:10.1103/PhysRevE.94.062104. https://www.osti.gov/servlets/purl/1361160.
@article{osti_1361160,
title = {Thermalization of oscillator chains with onsite anharmonicity and comparison with kinetic theory},
author = {Mendl, Christian B. and Lu, Jianfeng and Lukkarinen, Jani},
abstractNote = {We perform microscopic molecular dynamics simulations of particle chains with an onsite anharmonicity to study relaxation of spatially homogeneous states to equilibrium, and directly compare the simulations with the corresponding Boltzmann-Peierls kinetic theory. The Wigner function serves as a common interface between the microscopic and kinetic level. We demonstrate quantitative agreement after an initial transient time interval. In particular, besides energy conservation, we observe the additional quasiconservation of the phonon density, defined via an ensemble average of the related microscopic field variables and exactly conserved by the kinetic equations. On superkinetic time scales, density quasiconservation is lost while energy remains conserved, and we find evidence for eventual relaxation of the density to its canonical ensemble value. Furthermore, the precise mechanism remains unknown and is not captured by the Boltzmann-Peierls equations.},
doi = {10.1103/PhysRevE.94.062104},
journal = {Physical Review E},
number = 6,
volume = 94,
place = {United States},
year = {2016},
month = {12}
}