Multipartite entanglement at dynamical quantum phase transitions with nonuniformly spaced criticalities

We report a dynamical quantum phase transition portrait in the alternating field transverse XY spin chain with Dzyaloshinskii-Moriya interaction by investigating singularities in the Loschmidt echo and the corresponding rate function after a sudden quench of system parameters. Unlike the Ising model, the analysis of the Loschmidt echo yields nonuniformly spaced transition times in this model. Comparative study between the equilibrium and the dynamical quantum phase transitions in this case reveals that there are quenches where one occurs without the other and reveals the regimes where they coexist. However, such transitions happen only when quenching is performed across at least a single gapless or critical line. Contrary to equilibrium phase transitions, bipartite entanglement measures do not turn out to be useful for the detection, while multipartite entanglement emerges as a good identifier of this transition when the quench is done from a disordered phase of this model.