Simulating excitation spectra with projected entangled-pair states

TL;DR

This paper introduces a new variational method using projected entangled-pair states (PEPS) to accurately simulate excitation spectra in two-dimensional quantum lattice systems, demonstrating high precision in benchmark models.

Contribution

The authors develop a novel PEPS-based variational approach for simulating excitation spectra, improving accuracy in capturing quasiparticle properties in 2D quantum systems.

Findings

Accurately captures quasiparticle dispersion in the transverse-field Ising model.

Reproduces spin-wave velocity and anomaly in the Heisenberg model.

Demonstrates high precision in benchmark simulations.

Abstract

We develop and benchmark a technique for simulating excitation spectra of generic two-dimensional quantum lattice systems using the framework of projected entangled-pair states (PEPS). The technique relies on a variational ansatz for capturing quasiparticle excitations on top of a PEPS ground state. Our method perfectly captures the quasiparticle dispersion relation of the square-lattice transverse-field Ising model, and reproduces the spin-wave velocity and the spin-wave anomaly in the square-lattice Heisenberg model with high precision.