Speaker
Yin-Chen He
Description
In my talk I will introduce the spin liquid phases that occur in
kagome antiferromagnets, and discuss their physical origin
that are closely related with the newly discovered symmetry
protected topological phase (SPT). I will first present our
numerical (DMRG) study on the kagome XXZ spin model that
exhibits two distinct spin liquid phases, namely the chiral spin
liquid and the kagome spin liquid (the groundstate of the
nearest neighbor kagome Heisenberg model). Both phases
extend from the extreme easy-axis limit, through SU(2)
symmetric point, to the pure easy-plane limit. The two
phases are separated by a continuous phase transition.
Motivated by these numerical results, I will then focus on the
easy-axis kagome spin system, and reformulate it as a lattice
gauge model. Such formulation enables us to achieve a
controlled theoretical description for the spin liquid phases.
We then show that the chiral spin liquid is indeed a gauged
U(1) SPT phase. On the other hand, we also propose that the
kagome spin liquid is a critical spin liquid phase, which can be
considered as a gauged deconfined critical point between a
SPT and a superfluid phase.