Thermalization of oscillator chains with onsite anharmonicity and comparison with kinetic theory.
Journal Article (Journal Article)
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. However, the precise mechanism remains unknown and is not captured by the Boltzmann-Peierls equations.
Full Text
Duke Authors
Cited Authors
- Mendl, CB; Lu, J; Lukkarinen, J
Published Date
- December 2, 2016
Published In
Volume / Issue
- 94 / 6-1
Start / End Page
- 062104 -
PubMed ID
- 28085301
Electronic International Standard Serial Number (EISSN)
- 2470-0053
International Standard Serial Number (ISSN)
- 2470-0045
Digital Object Identifier (DOI)
- 10.1103/physreve.94.062104
Language
- eng