Variational simulation of the Lipkin-Meshkov-Glick model on a neutral atom quantum computer

TL;DR

This paper demonstrates the simulation of the Lipkin-Meshkov-Glick model using a variational quantum algorithm on a neutral atom quantum computer, achieving improved fidelity with efficient encoding and noise mitigation.

Contribution

It introduces an efficient Gray code encoding scheme for simulating large spin systems on neutral atom quantum computers.

Findings

Successfully simulated up to 15 spins.

Gray code encoding reduces qubit requirements.

Zero noise extrapolation improves energy fidelity.

Abstract

We simulate the Lipkin-Meshkov-Glick (LMG) model using the Variational-Quantum-Eigensolver (VQE) algorithm on a neutral atom quantum computer. We test the ground-state energy of spin systems with up to 15 spins. Two different encoding schemes are used: an individual spin encoding where each spin is represented by one qubit, and an efficient Gray code encoding scheme which only requires a number of qubits that scales with the logarithm of the number of spins. This more efficient encoding, together with zero noise extrapolation techniques, is shown to improve the fidelity of the simulated energies with respect to exact solutions.