Frustrated antiferromagnets with entanglement renormalization: ground state of the spin-1/2 Heisenberg model on a kagome lattice

TL;DR

This paper uses entanglement renormalization to numerically study the ground state of the spin-1/2 Heisenberg model on a kagome lattice, finding a valence bond crystal with lower energy than previous spin liquid candidates.

Contribution

It introduces a novel application of entanglement renormalization to determine the ground state of the kagome lattice Heisenberg model, identifying a valence bond crystal as the optimal state.

Findings

Ground state is a valence bond crystal with a 36-site unit cell.

Energy per site is -0.43221, lower than previous spin liquid states.

Provides an upper bound on the ground state energy.

Abstract

Entanglement renormalization techniques are applied to numerically investigate the ground state of the spin-1/2 Heisenberg model on a kagome lattice. Lattices of N={36,144,inf} sites with periodic boundary conditions are considered. For the infinite lattice, the best approximation to the ground state is found to be a valence bond crystal (VBC) with a 36-site unit cell, compatible with a previous proposal. Its energy per site, E=-0.43221, is an exact upper bound and is lower than the energy of any previous (gapped or algebraic) spin liquid candidate for the ground state.