Optimal Two-Qubit Gates for Group-IV Color-Centers in Diamond

TL;DR

This paper develops a numerical framework using quantum optimal control to implement fast, robust two-qubit gates with high fidelity in group-IV diamond color centers, advancing quantum computing and communication.

Contribution

It introduces a scalable optimal control strategy for high-fidelity two-qubit gates in group-IV diamond color centers, applicable to quantum networks.

Findings

Achieved two-qubit gate fidelities exceeding 99.9%.

Demonstrated robustness of gates under realistic noise conditions.

Provided a scalable approach adaptable to related quantum architectures.

Abstract

Color centers associated with group-IV dopants in diamond with long-lived nuclear spins have emerged as major candidates for distributed quantum computing nodes and quantum repeaters. Several proof-of-principle experiments have already been demonstrated. A key operation for long-distance entanglement-distribution protocols are fast and robust gates between the electron spin and a nuclear spin. Here, we investigate numerically for an existing experimental platform of a Germanium-vacancy (GeV) center with a strongly-coupled ${}^{13}$C spin, how such gates can be implemented via quantum optimal control. In the presence of realistic noise we investigate different parameter regimes and gate operations and obtain robust two-qubit gates with fidelities exceeding $99.9 \%$. The framework provides a scalable strategy for group-IV quantum nodes and can be adapted to related architectures.