title: Thermalization of oscillator chains with onsite anharmonicity and comparison with kinetic theory.
abstract: 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.
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory and Stanford University, Menlo Park, California 94025, USA.
authors.forename: Christian B
authors.initials: CB
authors.lastname: Mendl
authors.affiliation: Department of Mathematics, Department of Physics and Department of Chemistry, Duke University, Box 90320, Durham, North Carolina 27708, USA.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Lu
authors.affiliation: University of Helsinki, Department of Mathematics and Statistics, P.O. Box 68, FI-00014 Helsingin yliopisto, Finland.
authors.forename: Jani
authors.initials: J
authors.lastname: Lukkarinen