Ergodicity of a thermostat family of the Nosé-Hoover type.
One-variable thermostats are studied as a generalization of the Nosé-Hoover method, which is aimed at achieving Gibbs' canonical distribution while conserving the time reversibility. A condition for equations of motion for the system with the thermostats is derived in the form of a partial differential equation. Solutions of this equation constitute a family of thermostats including the Nosé-Hoover method as the minimal solution. It is shown that the one-variable thermostat coupled with the one-dimensional harmonic oscillator loses its ergodicity with large enough relaxation time. The present result suggests that multivariable thermostats are required to assure the ergodicity and to work as a heat bath.
Watanabe
Hiroshi
H
Department of Complex Systems Science, Graduate School of Information Science, Nagoya University, Furouchou, Chikusa-ku, Nagoya 464-8601, Japan. hwatanabe@is.nagoya-u.ac.jp
Kobayashi
Hiroto
H