Decoherence-protected entangling gates in a silicon carbide quantum node

TL;DR

This paper demonstrates a silicon carbide quantum node with high-fidelity, decoherence-protected entangling gates between electron and nuclear spins, advancing scalable quantum network components.

Contribution

It introduces a pulse sequence combining dynamical decoupling and hyperfine interactions for universal gate operations in silicon carbide quantum nodes.

Findings

Achieved 90% fidelity in entangled state preparation.

Demonstrated decoherence-protected universal gates.

Enabled scalable quantum node architecture.

Abstract

Solid-state color centers are promising candidates for nodes in quantum network architectures. However, realizing scalable and fully functional quantum nodes, comprising both processor and memory qubits with high-fidelity universal gate operations, remains a central challenge in this field. Here, we demonstrate a fully functional quantum node in silicon carbide, where electron spins act as quantum processors and nuclear spins serve as quantum memory. Specifically, we design a pulse sequence that combines dynamical decoupling with hyperfine interactions to realize decoherence-protected universal gate operations between the processor and memory qubits. Leveraging this gate, we deterministically prepare entangled states within the quantum node, achieving a fidelity of 90%, which exceeds the fault-tolerance threshold of certain quantum network architectures. These results open a pathway toward scalable and fully functional quantum nodes based on silicon carbide.