title: Dynamical Quantum Phase Transitions: Role of Topological Nodes in Wave Function Overlaps.
abstract: A sudden quantum quench of a Bloch band from one topological phase toward another has been shown to exhibit an intimate connection with the notion of a dynamical quantum phase transition (DQPT), where the returning probability of the quenched state to the initial state-i.e., the Loschmidt echo-vanishes at critical times {t^{*}}. Analytical results to date are limited to two-band models, leaving the exact relation between topology and DQPT unclear. In this Letter, we show that, for a general multiband system, a robust DQPT relies on the existence of nodes (i.e., zeros) in the wave function overlap between the initial band and the postquench energy eigenstates. These nodes are topologically protected if the two participating wave functions have distinctive topological indices. We demonstrate these ideas in detail for both one and two spatial dimensions using a three-band generalized Hofstadter model. We also discuss possible experimental observations.
authors: Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors: Zhoushen
authors: Z
authors: Huang
authors: Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.|NORDITA, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden.
authors: Alexander V
authors: AV
authors: Balatsky