IQI Weekly Seminar

Abstract: Classical simulation of quantum systems requires exponential resources with the system size, as local degrees of freedom can scramble with exponentially many nonlocal ones. Many-body localization, a uniquely quantum phenomenon arising from interference, is posed to overcome this obstacle by confining scrambling to within only a logarithmically large subset of qubits. Nevertheless, knowing when a generic quantum many-body system localizes is difficult a priori. We demonstrate a partial solution to this problem in the scenario when the system can be mapped onto the dynamics of a free fermion model, even for instances which are not known to be simulable, by computing the out-of-time-ordered correlation function. We find that interference effects which make direct simulation classically intractable cannot destroy the localized phase. We further demonstrate an application of our method to the case where the model has limited interactions, giving some insight into the computationally universal regime.