title: How accurately can the microcanonical ensemble describe small isolated quantum systems?
abstract: We numerically investigate quantum quenches of a nonintegrable hard-core Bose-Hubbard model to test the accuracy of the microcanonical ensemble in small isolated quantum systems. We show that, in a certain range of system size, the accuracy increases with the dimension of the Hilbert space D as 1/D. We ascribe this rapid improvement to the absence of correlations between many-body energy eigenstates. Outside of that range, the accuracy is found to scale either as 1/√D or algebraically with the system size.
authors.affiliation: Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.|Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Tatsuhiko N
authors.initials: TN
authors.lastname: Ikeda
authors.affiliation: Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.|RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Ueda