Ergodic inclusions in many-body localized systems

Physical review. B./Physical review. B, vol. 109

Abstract

We investigate the effect of ergodic inclusions in putative many-body localized systems. We consider the random field Heisenberg chain, which is many-body localized at strong disorder and we couple it to an ergodic bubble, modeled by a random matrix Hamiltonian. Recent theoretical work suggests that localized systems are unstable to ergodic bubbles, driving the delocalization transition. We tentatively confirm this by numerically analyzing the response of the on-site purities to the insertion of the bubble. For a range of intermediate disorder strengths, this response decays very slowly, or not at all, with increasing distance to the bubble. This suggests that at those disorder strengths, the system is actually delocalized in the thermodynamic limit. However, the signal is quite weak and artefacts in the numerics cannot be ruled out conclusively. Published by the American Physical Society 2024

Authors 3

1. Luis Colmenárez Aachen Institute for Quantum Information

   RWTH Aachen University · Forschungszentrum Jülich · Max Planck Institute for the Physics of Complex Systems

   Affiliation as printed

   Institute for Quantum Information, RWTH Aachen University, 52056 Aachen, Germany

   Institute for Theoretical Nanoelectronics (PGI-2), Forschungszentrum Jülich, 52428 Jülich, Germany

   Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187-Dresden, Germany

2. David J. Luitz

   University of Bonn

   Affiliation as printed

   Institute of Physics, University of Bonn, Nußallee 12, 53115 Bonn, Germany

3. Wojciech De Roeck

   KU Leuven

   Affiliation as printed

   KU Leuven, 3001 Leuven, Belgium