Speaker
Description
I will first discuss how one can understand and define quantum chaos through sensitivity of eigenstates encoded in the fidelity susceptibility and more generally in a quantum geometric tensor. I will argue that transition to chaos to integrability is highly nonperturbative characterized by emergence of exponentially long in the system size time scales. Then I will consider a specific setup of a strong impurity coupled to a bath and show how one can find approximate local integral of motion (LIOM) using Birkhoff construction and how this construction diverges leading to eventual decay of this LIOM. I will comment how these results imply that many body localization (MBL) is unstable and instead there is a slow transient glassy phase. At the end I will comment on the issues in both analytical and numerical analysis of the disordered systems, which previously lead to erroneous conclusions about stability of the localized phase in the thermodynamic limit.
