Simulating optically-active spin defects with a quantum computer

TL;DR

This paper develops fault-tolerant quantum algorithms to simulate optically active defect states in materials, aiming to improve the accuracy of quantum sensing applications.

Contribution

It introduces a quantum defect embedding theory combined with block-encoding and phase estimation for simulating defect states on quantum computers.

Findings

Quantum algorithms for defect state simulation are feasible with estimated resources.

The approach accurately models dielectric screening effects in defect Hamiltonians.

Potential for quantum computers to outperform classical methods in defect simulations.

Abstract

There is a pressing need for more accurate computational simulations of the opto-electronic properties of defects in materials to aid in the development of quantum sensing platforms. In this work, we explore how quantum computers could be effectively utilized for this purpose. Specifically, we develop fault-tolerant quantum algorithms to simulate optically active defect states and their radiative emission rates. We employ quantum defect embedding theory to translate the Hamiltonian of a defect-containing supercell into a smaller, effective Hamiltonian that accounts for dielectric screening effects. Our approach integrates block-encoding of the dipole operator with quantum phase estimation to selectively sample the optically active excited states that exhibit the largest dipole transition amplitudes. We also provide estimates of the quantum resources required to simulate a negatively-charged boron vacancy in a hexagonal boron nitride cluster. We conclude by offering a forward-looking perspective on the potential of quantum computers to enhance quantum sensor capabilities and identify specific scenarios where quantum computing can resolve problems traditionally challenging for classical computers.