title: Noncanonical statistics of a finite quantum system with non-negligible system-bath coupling.
abstract: The canonical statistics describes the statistical properties of an open system by assuming its coupling with the heat bath is infinitesimal in comparison with the total energy in thermodynamic limit. In this paper, we generally derive a noncanonical density matrix for the open system with a finite coupling to the heat bath, which deforms the energy shell to effectively modify the conventional canonical way. The obtained noncanonical distribution reflects the back action of system on the bath and thus depicts the statistical correlations between two subsystems by the mutual information as a result of energy conservation.
authors.affiliation: Beijing Computational Science Research Center, Beijing 100084, China and State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Science, Beijing 100190, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: D Z
authors.initials: DZ
authors.lastname: Xu
authors.affiliation: Beijing Computational Science Research Center, Beijing 100084, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Sheng-Wen
authors.initials: SW
authors.lastname: Li
authors.affiliation: Department of Mathematics, Peking University, Beijing 100871, China.
authors.forename: X F
authors.initials: XF
authors.lastname: Liu
authors.affiliation: Beijing Computational Science Research Center, Beijing 100084, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: C P
authors.initials: CP
authors.lastname: Sun