Testing quantum adiabaticity with quench echo

Abstract

Adiabaticity of quantum evolution is important in many settings; one example is adiabatic quantum computation (AQC). Nevertheless, to date, there is no effective method available for testing the adiabaticity of the evolution for the case where the eigenenergies of the driven Hamiltonian are not known. We propose a simple method for checking the adiabaticity of a quantum process for an arbitrary quantum system. We further propose an operational method for finding more efficient protocols that approximate adiabaticity, and suggest a 'uniformly adiabatic' quench scheme based on the Kibble-Zurek mechanism for the case where the initial and final Hamiltonians are given. This method should help in implementing AQC and other tasks where preserving the system in the ground state of a time-dependent Hamiltonian is desired. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.