Freiburg 2019 – wissenschaftliches Programm

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FM: Fall Meeting

FM 56: Entanglement: Many-Body Dynamics II

FM 56.1: Invited Talk

Mittwoch, 25. September 2019, 14:00–14:30, 2004

New quantum many-body phases enabled by ergodicity breakdown — •Dmitry Abanin — University of Geneva, Geneve, Switzerland

The experimental advances in synthetic quantum systems, such as ultracold atoms, have enabled researchers to probe quantum thermalization and its breakdown. Thermalization occurs in ergodic systems and erases quantum information contained in the initial many-body states. Therefore, to create long-lived quantum states, it is of particular interest to find mechanisms of thermalization breakdown. One way of suppressing thermalization is by introducing strong quenched disorder, which induces many-body localization (MBL). MBL systems exhibit a new kind of emergent robust integrability and a wealth of novel dynamical phenomena. Surprisingly, MBL systems may also avoid heating under periodic driving, which opens up the possibility of having stable, Floquet-MBL phases with unusual properties. I will discuss one example of such a phase: a two-dimensional Anomalous Floquet Insulator, characterized by fully localized bulk states and chiral, thermalizing edge states.

Further, I will argue that MBL may not be the only way to break ergodicity. I will propose another mechanism, quantum many-body scarring, which bears a similarity to the well-known phenomenon of quantum scars in few-body chaos, and leads to a weaker form of ergodicity breaking that was recently observed in a many-body system of Rydberg atoms.