Dynamics after a sweep through a quantum critical point

ORAL

Abstract

The coherent quantum evolution of a one-dimensional many-particle system after slowly sweeping the Hamiltonian through a critical point is studied using a generalized quantum Ising model containing both integrable and non-integrable regimes. It is known from previous work that universal power laws of the sweep rate appear in such quantities as the mean number of excitations created by the sweep. Several other phenomena are found that are not reflected by such averages: there are two scaling regimes of the entanglement entropy and a relaxation that is power-law in time rather than exponential. The final state of evolution after the quench is not characterized by any effective temperature, and the Loschmidt echo converges algebraically for long times, with cusplike singularities in the integrable case that are dynamically broadened by nonintegrable perturbations.

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Authors

  • Joel Moore

    University of California, Berkeley, U.C. Berkeley, University of California, Berkeley, and Lawrence Berkeley National Laboratory, University of California, Berkeley and Lawrence Berkeley National Laboratory

  • Frank Pollmann

    UC-Berkeley, Department of Physics, University of California, Berkeley CA 94720, USA, University of California, Berkeley

  • Subroto Mukerjee

    Indian Institute of Science, Bangalore

  • Andrew Green

    University of St Andrews