Title: Probing Many Body Localization Speaker: Rajdeep Sensarma (TIFR, India)
Abstract: The phenomenon of many body localization (MBL) in interacting strongly disordered systems have been studied in complimentary ways in theory and experiments. Theoretical studies have focussed on the properties of many body eigenstates, including their entanglement properties, while experimental tests have looked at how memories of initial states are retained in non equilibrium dynamics. In this talk I will first discuss how distributions of entanglement spectra can be used to study the MBL to ergodic transition in disordered spin chains and try to identify an "order parameter" for this transition. Expetimentally, disordered cold atom systems are initialized to Fock states with density imbalance between alternate sites and allowed to evolve. A finite long time imbalance is then taken as an indicator of MBL. Using a recent extension of Keldysh field theory, I will analyze these experiments and relate the long time imbalance in non interacting systems to the localization length using an exact analytic result. I will then present numerical results about long time imbalance in interacting disordered systems.