Valence Bond Solids and Their Quantum Melting in Hard-Core Bosons on the Kagome Lattice

TL;DR

This study uses quantum Monte Carlo simulations and dual vortex theory to explore the phase diagram of hard-core bosons on the kagome lattice, revealing novel solid phases and phase transitions without supersolid formation.

Contribution

It introduces the first detailed analysis of valence bond solids and their quantum melting in hard-core bosons on the kagome lattice, highlighting unique partial ordering phenomena.

Findings

No supersolid phase at strong interactions unlike triangular lattice.

Emergence of two novel solid phases at 1/3 and 2/3 filling.

Weakly first-order transition between solids and superfluid.

Abstract

Using large scale quantum Monte Carlo simulations and dual vortex theory we analyze the ground state phase diagram of hard-core bosons on the kagome lattice with nearest neighbor repulsion. In contrast to the case of a triangular lattice, no supersolid emerges for strong interactions. While a uniform superfluid prevails at half-filling, two novel solid phases emerge at densities $\rho=1/3$ and $\rho=2/3$. These solids exhibit an only partial ordering of the bosonic density, allowing for local resonances on a subset of hexagons of the kagome lattice. We provide evidence for a weakly first-order phase transition at the quantum melting point between these solid phases and the superfluid.