Dephasing in strongly disordered interacting quantum wires

Many-body localization is a fascinating theoretical concept describing the intricate interplay of quantum interference, i.e., localization, with many-body interaction-induced dephasing. Numerous computational tests and also several experiments have been put forward to support the basic concept. Typically, averages of time-dependent global observables have been considered, such as the charge imbalance. We here investigate within the disordered spinless Hubbard (t -V) model how dephasing manifests in time-dependent variances of observables. We find that after quenching a Ned state the local charge density exhibits strong temporal fluctuations with a damping that is sensitive to disorder W: variances decay in a power-law manner t(-zeta), with an exponent zeta(W) strongly varying with W. A heuristic argument suggests the form zeta approximate to alpha(W)xi(sp), where xi(sp)(W) denotes the noninteracting localization length and alpha(W ) characterizes the multifractal structure of the dynamically active volume fraction of the many-body Hilbert space. In order to elucidate correlations underlying the damping mechanism, exact computations are compared with results from the time-dependent Hartree-Fock approximation. Implications for experimentally relevant observables, such as the imbalance, will be discussed.

Automated summary

Many-body localization is a theoretical concept describing the interplay of quantum interference and many-body interaction-induced dephasing. The study investigates how dephasing affects observable variance in the disordered spinless Hubbard model, revealing strong temporal fluctuations in local charge density. Results comparing exact computations with the time-dependent Hartree-Fock approximation shed light on the correlations underlying the damping mechanism and its implications for experimentally relevant observables.