Variational Quantum Simulation for Periodic Materials

TL;DR

This paper introduces a hybrid quantum-classical algorithm for simulating electronic structures of periodic materials, demonstrating its effectiveness on hydrogen chains and extending to quasiparticle band structures.

Contribution

It extends the UCC theory to periodic systems and combines it with quantum subspace expansion to compute band structures, bridging quantum computing and material science.

Findings

Successful optimization of UCC ansatz on quantum circuits for hydrogen chains

Accurate computation of quasiparticle band structures using the proposed method

Establishment of a new interface between quantum technology and material science

Abstract

We present a quantum-classical hybrid algorithm that simulates electronic structures of periodic systems such as ground states and quasiparticle band structures. By extending the unitary coupled cluster (UCC) theory to describe crystals in arbitrary dimensions, for a hydrogen chain, we numerically demonstrate that the UCC ansatz implemented on a quantum circuit can be successfully optimized with a small deviation from the exact diagonalization over the entire range of the potential energy curves. Furthermore, by using the quantum subspace expansion method, in which we truncate the Hilbert space within the linear response regime from the ground state, the quasiparticle band structure is computed as charged excited states. Our work establishes a powerful interface between the rapidly developing quantum technology and modern material science.