Work from recent years has demonstrated that the eigenstate thermalization hypothesis (ETH) could be violated in a generic class of interacting systems with strong disorder. This phenomenon, called many-body localization (MBL) is characterized by slow spreading of entanglement and absence of transport. Potter and Vasseur  recently investigated the compatibility of MBL with various global symmetries. They conjecture that MBL is incompatible with non-abelian symmetries unless they are spontaneously broken to an abelian subgroup. I will present results from our work  where we explicitly test their conjectures. We build a local spin Hamiltonian invariant under the simplest non-abelian group, S_3 and numerically investigate its properties. Using full entanglement distributions and level statistics, we observe a thermal phase and an MBL phase, where S_3 is spontaneously broken down to Z_3, consistent with their conjectures. We also observe a third region where S_3 is unbroken and whose signatures are inconsistent with both MBL and thermal phases. I speculate about the identity of this region and mention some ongoing work to ascertain it.
Abhishodh Prakash (Stony Brook University, USA)
Date & Time
Tue, 12 December 2017, 10:00 to 11:00
Amal Raychaudhuri Meeting Room, ICTS Campus, Bangalore