2001/04/30 by Sang Pyo Kim
Physics and Astronomy · #hep-ph #cond-mat.stat-mech #quant-ph
published as J.Korean Phys.Soc. 41 (2003) 643-648 · LaTex 11 pages, no figure; qualitative argument is added for the temperature relation of thermal equilibrium at high temperature and references are added
arxiv created 2001/06/22 · arxiv updated 2009/11/30
The effective theory of an open boson or fermion system is studied, which evolves out of equilibrium with time-dependent Hamiltonian H(t). A measure of nonequilibrium temperature for the open system evolving from an equilibrium is proposed as the time-averaged energy expectation value T(t) = Ti(< H (t) >Ψ/ < I (t) >Ψ), where I (t), the action operator, satisfies the quantum Liouville-von Neumann equation and determines the true density operator. It recovers the result for the adiabatic (quasi-equilibrium) and nonadiabatic (out of equilibrium) evolution from one static Hamiltonian to another and takes into account the particle production due to the intermediate processes.