Role of hyperfine interaction for cavity-mediated coupling between spin qubits

TL;DR

This paper investigates how hyperfine interactions, specifically the Overhauser field, affect cavity-mediated two-qubit gates in quantum dot spin qubits, revealing their influence on gate fidelity.

Contribution

It provides a perturbative and numerical analysis of hyperfine effects on two-qubit gate fidelities in quantum dot systems mediated by optical cavities.

Findings

Hyperfine interactions influence two-qubit gate fidelities.

Overhauser field impacts the interaction between spin qubits.

Analytical and numerical methods quantify hyperfine effects.

Abstract

We consider two qubits interacting by means of an optical cavity, where each qubit is represented by a single electron spin confined to a quantum dot. It is known that electron spins in III-V semiconductor quantum dots are affected by the decoherence due to the hyperfine interaction with nuclear spins. Here we show that the interaction between two qubits is influenced by the Overhauser field as well. Starting from an unpolarizied nuclear ensemble, we investigate the dependance of the fidelities for two-qubit gates on the Overhauser field. We include the hyperfine interaction perturbatively to second order in our analytical results, and to arbitrary precision numerically.