Freiburg 2019 – wissenschaftliches Programm
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FM: Fall Meeting
FM 20: Entanglement: Many-Body States II
FM 20.4: Talk
Montag, 23. September 2019, 17:15–17:30, 2004
Many-body localization in the two-dimensional Bose-Hubbard-model — •Andreas Geißler1,2 and Guido Pupillo1,3 — 1ISIS, University of Strasbourg, Strasbourg, France — 2Institut für Theoretische Physik, Goethe-Universität, Frankfurt am Main, Germany — 3IPCMS, University of Strasbourg, Strasbourg, France
Some experiments [1,2] already have shown signatures of many-body localization (MBL) for the bosonic Hubbard model in one and two dimensional ultracold atomic gases in optical lattices. A proper theoretical understanding of the MBL phenomenon depends on knowledge about the full eigenstate spectrum. Therefore, commonly used exact numerical studies have been limited to small system sizes. Applying a recently extended beyond-Bogoliubov quasiparticle expansion [3] I have performed a detailed finite size scaling analysis of the quasiparticle eigenstate fractal dimension and gap ratio showing Berezinskii-Kosterlitz-Thouless (BKT) scaling consistent with recent predictions [4]. The low energy mobility edge terminates at the MBL transition. Furthermore, I present theoretical results for a recent experiment [2] showing comparable signatures of localization while suggesting that the observed localization also strongly depends on the confining potential.
[1] C. D'Errico et al., PRL 113, 095301 (2014)
[2] J.-y. Choi et al., Science 352, 1547 (2016)
[3] A. Geissler et al., PRA 98, 063635 (2018)
[4] A. Goremykian et al., PRL 122 040601 (2019); P. Dumitrescu et al., PRB 99 094205 (2019); A. Morningstar et al., arXiv:1903.02001