1211.2956 (Quntao Zhuang et al.)

Equilibration of an isolated quantum system and thermalization of its
subsystem    [PDF]

Quntao Zhuang, Biao Wu

An isolated quantum chaotic system in a pure state in general can equilibrate and serve as a heat bath. We show that once the equilibrium is reached, any of its subsystems that is much smaller than the isolated system is thermalized such that the subsystem is governed by the Gibbs distribution. Within this theoretical framework, the celebrated superposition principle of quantum mechanics should lead to a prediction that the thermalized subsystem can have multiple temperatures if the isolated system is in a superposition state of energy eigenstates which concentrate around multi- ple distinct energy scales. This thermalized state with different temperatures is at equilibrium, completely different from a non-equilibrium state that has multiple temperatures at different parts. Possible experimental schemes to verify this prediction are discussed.

View original: http://arxiv.org/abs/1211.2956