Condensed-Matter Physics Seminar: "A bosonic topological phase in a paired superfluid"

Date: 
Thu, 24/12/201512:00-13:30
Location: 
Danciger B building, Seminar room
Lecturer: Dr. Snir Gazit
Affiliation: Technion - Israel Institute of Technology
Abstract:
We study an effective model of two
interacting species of bosons in two
dimensions, which is amenable to sign
problem free Monte Carlo simulations.
In addition to conventional ground
states, we access a paired superfluid
which is also a topological phase,
protected by the remaining unbroken
symmetry. This phase arises from the
condensation of a composite object, the
bound state of vortices and anti-
vortices of one species, to a boson of
the second species. We introduce a
bulk response function, the Ising analog
of the quantized Hall Effect, to
diagnose the topological phase. The
interplay of broken symmetry and
topology leads to interesting effects
such as fractionally charged vortices in
the paired superfluid. Possible
extensions towards realistic models of
cold atomic bosons will be discussed.