Decoherence-protected entangling gates in a silicon carbide quantum node

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 (SiC), 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 protocol, we deterministically prepare an electron–nuclear Bell state with an end-to-end state fidelity of 90 ± 3% at room temperature. This result establishes a protected control strategy for SiC spin registers and provides a step toward scalable solid-state quantum-network nodes.