Date:10:00am, July 1, 2010

Venue：Conference Hall 322，Science Building

Title: Bilayer quantum Hall phase transitions and non-Abelian fractional quantum Hall states

Speaker: Dr. Maissam Barkeshli (MIT)

Abstract:Topological phases of matter cannot be characterized by any pattern of symmetry-breaking, so describing phase transitions between

them is a significant theoretical challenge. In the case of non-Abelian phases, there are only a few examples of phase transitions

that are theoretically understood. In this talk I will describe a series of phase transitions between well-known bilayer Abelian

fractional quantum Hall (FQH) states -- the (ppq) states -- and a series of non-Abelian FQH states. An example of this transition is

between the (330) state and the non-Abelian Z4 parafermion state, driven by increasing interlayer tunneling and/or interlayer repulsion.

Previously used methods have failed because the transition from these states appears to be driven by the condensation of anyons. After

presenting a recently developed effective field theory for the non-Abelian states, I will explain how it can be used, along with other

methods, to shed light on the nature of these transitions.