Scenario for delocalization in translation-invariant systems

• Published in: Physical review. B, Condensed matter and materials physics Vol. 90; no. 16
• Main Authors: De Roeck, Wojciech, Huveneers, François
• Format: Journal Article
• Language: English
• Published: American Physical Society 28-10-2014
• Subjects: Condensed matter; Disorders; Ergodic processes; Localization; Perturbation theory; Physics; Position (location); Quenching (cooling); Spots
• ISSN: 1098-0121; 1550-235X
• DOI: 10.1103/PhysRevB.90.165137

We investigate the possibility of many-body localization in translation-invariant Hamiltonian systems, which was recently brought up by several authors. A key feature of many-body localized disordered systems is recovered, namely the fact that resonant spots are rare and far-between. However, we point out that resonant spots are mobile, unlike in models with strong quenched disorder, and that these mobile spots constitute a possible mechanism for delocalization, albeit possibly only on very long timescales. In some models, this argument for delocalization can be made very explicit in first order of perturbation theory in the hopping. For models where this does not work, we present instead a nonperturbative argument that relies solely on ergodicity inside the resonant spots.