Regensburg 2019 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 7: Dynamics in many-body systems: Equilibration and localization I (joint session DY/TT)
TT 7.4: Vortrag
Montag, 1. April 2019, 10:45–11:00, H19
Thermalization and eigenstate thermalization hypothesis in the Holstein polaron model — David Jansen1, •Jan Stolpp2, Lev Vidmar3, and Fabian Heidrich-Meisner2 — 1Arnold-Sommerfeld-Center for Theoretical Physics, LMU Munich — 2Institute for Theoretical Physics, University of Göttingen — 3Jozef Stefan Institute, Ljubljana
The 1d Holstein model is a paradigmatic system to study polaron physics and the nonequilibrium dynamics of charge carriers coupled to phonons. While the electronic relaxation dynamics of a single charge carrier is a much studied topic (see, e.g. [1]), here, we systematically investigate whether the 1d Holstein model in the single-polaron limit is ergodic by checking the criteria of the eigenstate thermalization hypothesis and by testing for established quantum chaos indicators. Using exact diagonalization techniques we find that the level spacing distribution is Wigner-Dyson, which is characteristic for a quantum chaotic system. Remarkably, both the diagonal and offdiagonal matrix elements of typical observables obey properties predicted by the eigenstate thermalization hypothesis. Thus, we found an example in which the coupling term between the electronic and phononic subspaces leads to ergodic behavior, even though the phonon system itself consists of uncoupled, local harmonic oscillators.
[1] Phys. Rev. B 91, 104302 (2015)