Restoring ergodicity in a strongly disordered interacting chain

Abstract

We consider a chain of interacting fermions with random disorder that was intensively studied in the context of many-body localization. We show that only a small fraction of the two-body interaction represents a true local perturbation to the Anderson insulator. While this true perturbation is nonzero at any finite disorder strength W, it decreases with increasing W. This establishes a view that the strongly disordered system should be viewed as a weakly perturbed integrable model, i.e., a weakly perturbed Anderson insulator. As a consequence, the latter can hardly be distinguished from a strictly integrable system in finite-size calculations at large W. We then introduce a rescaled model in which the true perturbation is of the same order of magnitude as the other terms of the Hamiltonian, and show that the system remains ergodic at arbitrary large disorder.

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• Strongly disordered Anderson insulator chains with generic two-body interaction
• Fermionic Magic Resources of Quantum Many-Body Systems
• Localization and integrability breaking in weakly interacting Floquet circuits
• Phenomenology of many-body localization in bond-disordered spin chains
• Key Observable for Linear Thermalization
• Finding local integrals of motion in quantum lattice models in the thermodynamic limit
• Spin and energy diffusion vs. subdiffusion in disordered spin chains
• Quasiconservation Laws and Suppressed Transport in Weakly Interacting Localized Models