Speaker: Jad Halimeh  (Garching)

Title of Talk: Quasiparticle origin of dynamical quantum phase transitions

Abstract: We consider one- and two-dimensional Ising models with varying interaction ranges. Using matrixproduct state techniques, we study the dynamics of these systems and show a direct connectionbetween the type of lowest-energy quasiparticles in the spectrum of the quench Hamiltonian andthe type of nonanalyticities occuring in the Loschmidt return rate, a dynamical analog of the freeenergy. Our results also show a clear connection between the type of nonanalyticities and the phaseof the long-time steady state in addition to how the order parameter decays at intermediate times.In particular, we discuss anomalous nonanalyticities that occur with no underlying local signature inthe order parameter dynamics, unlike the traditional regular nonanalyticities that always correspondto a zero crossing of the order parameter. We demonstrate how dynamical quantum phase transitionscan be used to extract the equilibrium physics of the model from short-time dynamics.