Physics

Qubit

Single shot

Optics

Metallurgy

Materials science

Silicon carbide

Dynamical decoupling

Coherence (philosophical gambling strategy)

Spin (aerodynamics)

Quantum mechanics

Optoelectronics

Shot noise

Quantum

Detector

Thermodynamics

Science Advances

An outstanding hurdle for defect spin qubits in silicon carbide (SiC) is single-shot readout, a deterministic measurement of the quantum state. Here, we demonstrate single-shot readout of single defects in SiC via spin-to-charge conversion, whereby the defect's spin state is mapped onto a long-lived charge state. With this technique, we achieve over 80% readout fidelity without pre- or postselection, resulting in a high signal-to-noise ratio that enables us to measure long spin coherence times. Combined with pulsed dynamical decoupling sequences in an isotopically purified host material, we report single-spin T2 > 5 seconds, over two orders of magnitude greater than previously reported in this system. The mapping of these coherent spin states onto single charges unlocks both single-shot readout for scalable quantum nodes and opportunities for electrical readout via integration with semiconductor devices.

Five-second coherence of a single spin with single-shot readout in silicon carbide