Ground-state energies of Ising models calculated using the samples from a quantum computer that simulates short-time evolution

TL;DR

This paper demonstrates calculating the ground-state energy of the Ising model using a quantum computer with the CVQE algorithm and GSA, analyzing error thresholds and quantum performance.

Contribution

It introduces the use of CVQE with GSA on a quantum computer for large Ising models, providing insights into quantum error tolerance and model suitability.

Findings

Successfully computed energies for up to 63 qubits.

Identified quantum error boundary as a function of qubit number and coupling.

Revealed Ising models are well-suited for near-term quantum devices.

Abstract

We find the ground-state energy of the Ising model using the Cascaded Variational Quantum Eigensolver (CVQE) algorithm with the Guided-Sampling Ansatz (GSA) using up to 63 qubits on a quantum computer. We study a heavy-hex lattice to match the qubit architecture, allowing us to perform calculations in the quantum utility regime. We study both a homogeneous and random-coupling model. We locate the boundary of acceptable quantum errors as a function of the number of qubits and coupling strength. An entropic analysis is performed giving insights into the quantum computing performance. A subspace analysis is performed that suggests that the Ising model is especially suited for near-term quantum computing.