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A model of chiral spin liquids with tunable chiral edge states

June 20, 2018 - 11:00am
Speaker: 
Christopher Mudry
Institution: 
Paul Scherrer Institute
Abstract: We present a two-dimensional lattice model for quantum spin-1/2 
for which the low-energy limit is governed by four flavors of strongly 
interacting Majorana fermions. We study this low-energy effective theory 
using two alternative approaches. The first consists of a mean-field 
approximation. The second consists of a Random Phase approximation (RPA) 
for the single-particle Green's functions of the Majorana fermions built 
from their exact forms in a certain one-dimensional limit. The resulting 
phase diagram consists of two competing chiral phases, one with Abelian 
and the other with non-Abelian topological order, separated by a 
continuous phase transition. Remarkably, the Majorana fermions propagate 
in the two-dimensional bulk, as in the Kitaev model for a spin liquid on 
the honeycomb lattice. We identify the vison fields, which are mobile 
(they are static in the Kitaev model) domain walls propagating along only 
one of the two space directions.
 
CMTC Conference Room (2205 Physics Toll Building)