Berlin 2024 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 25: Nonequilibrium Quantum Systems I (joint session TT/DY)
TT 25.7: Talk
Tuesday, March 19, 2024, 11:00–11:15, H 3005
Hilbert space fragmentation and slow dynamics in particle-conserving quantum East models — •Pietro Brighi1, Marko Ljubotina2, and Maksym Serbyn2 — 1University of Vienna, Boltzmanngasse 5, 1090 Vienna Austria — 2ISTA, am Campus 1, 3400 Klosterneuburg Austria
Quantum kinetically constrained models have recently attracted significant attention due to their anomalous dynamics and thermalization. In this work, we introduce a hitherto unexplored family of kinetically constrained models featuring conserved particle number and strong inversion-symmetry breaking due to facilitated hopping. We demonstrate that these models provide a generic example of so-called quantum Hilbert space fragmentation, that is manifested in disconnected sectors in the Hilbert space that are not apparent in the computational basis. Quantum Hilbert space fragmentation leads to an exponential in system size number of eigenstates with exactly zero entanglement entropy across several bipartite cuts. These eigenstates can be probed dynamically using quenches from simple initial product states. In addition, we study the particle spreading under unitary dynamics, and find faster than diffusive dynamics at high particle densities, crossing over into logarithmically slow relaxation at smaller densities. Our work suggests that particle conserving constrained models with inversion symmetry breaking realize so far unexplored dynamical behavior and invite their further theoretical and experimental studies.
Keywords: Quantum dynamics; Kinetically constrained models; Hilbert space fragmentation; Cellular Automata