Correlations Induced by Quench Protocols in Critical Spin Chains

The dynamics of critical spin systems near quantum phase transitions are governed by universal behavior. Probing non-equilibrium criticality via quench protocols has been the subject of much experimental [1] and theoretical [2] effort, both through the Kibble-Zurek sweep and the abrupt quench. Such endeavors have yielded promising results for particle densities, but the modified behavior of correlations and the conformal field theory at the critical point have yet to be fully explored. We study these properties analytically (using the Landau-Zener evolution) and numerically (using MPS), starting with the simplest integrable case, the quantum Ising model in 1+1 dimensions. We present results of one- and two-point correlations after a sweep to the critical point and analysis of the universal behavior. We compare results for Kibble-Zurek sweeps and sequences of abrupt quenches to explore the feasibility of Trotter discretizations for such processes in quantum computers.