Superfluids and Supersolids on Frustrated 2D Lattices

TL;DR

This paper investigates the ground states of hard-core bosons on frustrated 2D lattices, revealing superfluid and supersolid phases, with potential for disordered states due to quantum fluctuations.

Contribution

It provides a comparative analysis of superfluid and supersolid phases on triangular and Kagomé lattices using spin-wave theory.

Findings

Both lattices exhibit superfluid and supersolid orders.

Quantum fluctuations may induce a disordered ground state on Kagomé lattice.

The study maps bosonic systems to spin models for analysis.

Abstract

We study the ground state of hard-core bosons with nearest-neighbor hopping and nearest-neighbor interactions on the triangular and Kagom\'e lattices by mapping to a system of spins ($S={1\over2}$), which we analyze using spin-wave theory. We find that the both lattices display superfluid and supersolid (a coexistence of superfluid and solid) order as the parameters and filling are varied. Quantum fluctuations seem large enough in the Kagom\'e system to raise the interesting possibility of a disordered ground state.