This study presents a high-fidelity optical readout of a nuclear spin qubit in Silicon Carbide (SiC). The researchers demonstrate a method for reading the quantum state of a nuclear spin based on a repetitive readout technique, achieving up to 99.5% readout fidelity and 99% state preparation fidelity. The nuclear spin is used as a long-lived memory for quantum sensing applications, particularly for detecting weakly coupled nuclear spin baths. The work focuses on the V2 center in 4H-SiC, a promising solid-state platform for quantum information processing due to its excellent optical and material properties. The electron spin state of the V2 center is probed using resonant optical excitation, while the nuclear spin state is coupled to the electron spin through hyperfine interactions. The researchers utilize a two-point measurement scheme with a charge resonance check to filter out unwanted events and improve readout fidelity. The study shows that the nuclear spin can be initialized and read out with high fidelity, and that the nuclear spin state can be manipulated coherently. The team demonstrates Rabi oscillations and Ramsey free precession of the nuclear spin, indicating the ability to control and measure the spin state with high precision. They also show that the nuclear spin can be used as a memory for quantum sensing, with applications in probing the coherence properties of nuclear spin memories and detecting weakly coupled nuclear spin baths. The results highlight the potential of the V2 center in SiC as a qubit platform, with high-fidelity optical readout enabling quantum information processing, error correction, and quantum sensing. The study also shows that the nuclear spin can be used as a long-lived memory, which is essential for quantum sensing applications. The researchers conclude that their work represents a key step forward in the development of the V2 center as a qubit platform, bringing it closer to a fully functional quantum computing system.This study presents a high-fidelity optical readout of a nuclear spin qubit in Silicon Carbide (SiC). The researchers demonstrate a method for reading the quantum state of a nuclear spin based on a repetitive readout technique, achieving up to 99.5% readout fidelity and 99% state preparation fidelity. The nuclear spin is used as a long-lived memory for quantum sensing applications, particularly for detecting weakly coupled nuclear spin baths. The work focuses on the V2 center in 4H-SiC, a promising solid-state platform for quantum information processing due to its excellent optical and material properties. The electron spin state of the V2 center is probed using resonant optical excitation, while the nuclear spin state is coupled to the electron spin through hyperfine interactions. The researchers utilize a two-point measurement scheme with a charge resonance check to filter out unwanted events and improve readout fidelity. The study shows that the nuclear spin can be initialized and read out with high fidelity, and that the nuclear spin state can be manipulated coherently. The team demonstrates Rabi oscillations and Ramsey free precession of the nuclear spin, indicating the ability to control and measure the spin state with high precision. They also show that the nuclear spin can be used as a memory for quantum sensing, with applications in probing the coherence properties of nuclear spin memories and detecting weakly coupled nuclear spin baths. The results highlight the potential of the V2 center in SiC as a qubit platform, with high-fidelity optical readout enabling quantum information processing, error correction, and quantum sensing. The study also shows that the nuclear spin can be used as a long-lived memory, which is essential for quantum sensing applications. The researchers conclude that their work represents a key step forward in the development of the V2 center as a qubit platform, bringing it closer to a fully functional quantum computing system.