Regensburg 2019 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 6: Dynamics in many-body systems: Equilibration and localization I (joint session DY/TT)
DY 6.8: Vortrag
Montag, 1. April 2019, 12:00–12:15, H19
Many-body localization and delocalization in large quantum chains — •Elmer V. H. Doggen1, Frank Schindler2, Konstantin S. Tikhonov1,3, Alexander D. Mirlin1,3,4,5, Titus Neupert2, Dmitry G. Polyakov1, and Igor V. Gornyi1,3,4,6 — 1Institut für Nanotechnologie, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany — 2Department of Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland — 3L. D. Landau Institute for Theoretical Physics RAS, 119334 Moscow, Russia — 4Institut für Theorie der Kondensierten Materie, Karlsruhe Institute of Technology, 76128 Karlsruhe, Germany — 5Petersburg Nuclear Physics Institute, 188300 St. Petersburg, Russia — 6A. F. Ioffe Physico-Technical Institute, 194021 St. Petersburg, Russia
We theoretically study the quench dynamics for an isolated Heisenberg spin chain with a random on-site magnetic field, which is one of the paradigmatic models of a many-body localization transition. We use the time-dependent variational principle as applied to matrix product states, which allows us to controllably study chains of a length up to L=100 spins. We find that the consideration of the larger system sizes substantially increases the estimate for the critical disorder that separates the ergodic and many-body localized regimes, compared to the values in the literature. From a technical perspective, we develop an adaptation of the ``learning by confusion'' machine-learning approach that can determine the critical disorder.