title: Semiclassical approach to survival probability at quantum phase transitions.
abstract: We study the decay of survival probability at quantum phase transitions with infinitely degenerate ground levels at critical points. For relatively long times, the semiclassical theory predicts power-law decay of the survival probability in systems with d=1 and exponential decay in systems with sufficiently large d, where d is the degrees of freedom of the classical counterpart of the system. The predictions are checked numerically in four models.
authors.affiliation: Department of Modern Physics, University of Science and Technology of China, Hefei, China. wgwang@ustc.edu.cn
authors.forename: Wen-ge
authors.initials: WG
authors.lastname: Wang
authors.forename: Pinquan
authors.initials: P
authors.lastname: Qin
authors.forename: Lewei
authors.initials: L
authors.lastname: He
authors.forename: Ping
authors.initials: P
authors.lastname: Wang