Dynamical quantum phase transitions in a system of interacting bosons

One way to generalize the concept of quantum criticality to non-equilibrium situations is to define dynamical quantum phase transitions as zeros of the Loschmidt echo, which serves as a dynamical analog of the partition function [Rep. Prog. Phys. 81, 054001 (2018)]. Here, we study quench dynamics in the one-dimensional extended Bose-Hubbard model using the time-dependent variational principle with matrix product states. The model offers a rich phase diagram, including the gapped Mott insulator (MI), Haldane insulator (HI) and charge density wave (CDW) phases. After initializing the system in generic ground states corresponding to these phases and a sudden quench of the on-site and nearest-neighbor interactions, we analyze how the occurrence of dynamical quantum phase transitions relates to the equilibrium phase transitions. A particular emphasis is placed on the topological MI-HI and HI-CDW transitions, as well as the dynamics of various non-local string order parameters that characterize the ground states.