Superfluids and Supersolids on Frustrated 2D Lattices

by Ganpathy Murthy, Daniel Arovas, Assa Auerbach

Today I hand a nice conversation with Erhai who pointed the interesting subject of supersolids on triangular and kagome lattices. What exactly is a supersolid phase, you may ask? Erhai had a nice answer: a phase in which bosons both crystalize and condense into a superfluid. Unfortunately, simple models that exhibit a supersolid phase on the square lattice are unstable towards phase separating into regions of solid and superfluid order (at least according to direct numerical solution of the models for small systems).

This paper raises the possibility that a supersolid phase can arise out of a frustration, a result that is supported by recent numerical studies on the triangular lattice. This is a remarkable result for it implies a type of "order from disorder" arising from quantum fluctuations in a model that can be understood by both simple mean field methods and powerful numerical techniques.