SKM 2021 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 15: Many-Body Quantum Dynamics II (joint session DY/TT)
TT 15.3: Vortrag
Donnerstag, 30. September 2021, 10:30–10:45, H2
Disorder-Free Localization in an Interacting 2D Lattice Gauge Theory — •Peter Karpov1,2, Roberto Verdel1, Yi-Ping Huang3, Markus Schmitt4, and Markus Heyl1 — 1Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — 2National Univesity of Science and Technology “MISiS”, Moscow, Russia — 3National Tsing Hua University, Hsinchu, Taiwan — 4University of Cologne, Cologne, Germany
Disorder-free localization has been recently introduced as a mechanism for ergodicity breaking in low-dimensional homogeneous lattice gauge theories caused by local constraints. We show that also genuinely interacting systems in two spatial dimensions can become nonergodic due to this mechanism. This is all the more surprising since the conventional many-body localization is conjectured to be unstable in two dimensions; hence the gauge constraints represent an alternative robust localization mechanism for interacting models in higher dimensions.
Specifically, we demonstrate nonergodic behavior in the quantum link model by obtaining a bound on the localization-delocalization transition through a unconventional percolation problem implying a fragmentation of Hilbert space. We study the quantum dynamics in this system by introducing the method of “variational classical networks”, an efficient representation of the wave function in terms of a network of classical spins. We show that propagation of line defects has different light cone structures in the localized and ergodic phases.
[1] P. Karpov et al, Phys. Rev. Lett. 126, 130401 (2021).
[2] R. Verdel et al, Phys. Rev. B 103, 165103 (2021).