Absence of diffusion in an interacting system of spinless fermions on a one-dimensional disordered lattice

Understand

We study the infinite temperature dynamics of a prototypical one-dimensional system expected to exhibit many-body localization.

• Using numerically exact methods, we establish the dynamical phase diagram of this system based on the statistics of its eigenvalues and its dynamical behavior.
• We show that the nonergodic phase is reentrant as a function of the interaction strength, illustrating that localization can be reinforced by sufficiently strong interactions even at infinite temperature.
• Surprisingly, within the accessible time range, the ergodic phase shows subdiffusive behavior, suggesting that the diffusion coefficient vanishes throughout much of the phase diagram in the thermodynamic limit.