Exploring frustrated spin-systems using Projected Entangled Pair States (PEPS)

TL;DR

This paper uses PEPS variational algorithms to analyze the ground states of frustrated spin systems, revealing different order regions and comparing with exact methods to identify possible quantum phases.

Contribution

It introduces a PEPS-based variational approach to study frustrated spin systems and characterizes their ground state phases.

Findings

Identification of long-range and short-range order regions.

Good agreement with exact diagonalizations in short-range valence bond subspace.

Discussion of potential spin-liquid and valence bond crystal phases.

Abstract

We study the nature of the ground state of the frustrated J1-J2 model and the J1-J3 model using a variational algorithm based on projected entangled-pair states (PEPS). By investigating spin-spin correlation functions, we observe a separation in regions with long-range and short-range order. A direct comparison with exact diagonalizations in the subspace of short-range valence bond singlets reveals that the system is well described by states within this subset in the short-range order regions. We discuss the question whether the system forms a spin-liquid, a plaquette valence bond crystal or a columnar dimer crystal in these regions.