Speaker: Yoshihito Kuno (University of Tsukuba)

Date & Time: 3pm, Jul. 29, 2021.

Title: Many-body localization and quantum scar in flat-band systems

Abstract:

Flat-band system exhibits rich physical phenomena. Recent experimental systems such as cold atoms and photonic crystals give a platform to simulate flat-band physics. In this seminar, we shall present two topics about flat-band physics. As the first topic, we present localization phenomena in flat-band systems and especially discuss its many-body localization phenomena. The origin of the localization in the flat-band system is the presence of compact localized states (CLS). We numerically confirm that many-body localization like phenomena occur in the flat-band system with interactions. As the second topic, we shall discuss the presence of quantum many-body scar states in a flat-band system. By making use of the CLS, we can construct some special states embedded in the energy band and the special states show sub-volume law of entanglement entropy, which indicates breaking of strong eigenstate-thermalization hypothesis. We also numerically demonstrate slow-thermalization for a specific initial state in the flat-band system.