Universal coherence protection in a solid-state spin qubit

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Science  18 Sep 2020:
Vol. 369, Issue 6510, pp. 1493-1497
DOI: 10.1126/science.abc5186

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Dressed for coherence

Solid-state qubits based on the electron spin of defects in silicon carbide or diamond provide a robust and versatile architecture for developing quantum technologies. The longer the lifetime of a spin, the more manipulations and quantum calculations can be performed, making for a more powerful quantum computational platform. Miao et al. show that by dressing the spins associated with the divacancy in silicon carbide with microwave photons, the lifetime can be extended by several orders of magnitude into milliseconds (see the Perspective by Hemmer). The technique effectively creates a quiet space for the qubit, thereby protecting it from magnetic, electric, and temperature fluctuations. This approach could be applicable to other architectures and provide a universal route to protecting qubits.

Science, this issue p. 1493; see also p. 1432


Decoherence limits the physical realization of qubits, and its mitigation is critical for the development of quantum science and technology. We construct a robust qubit embedded in a decoherence-protected subspace, obtained by applying microwave dressing to a clock transition of the ground-state electron spin of a silicon carbide divacancy defect. The qubit is universally protected from magnetic, electric, and temperature fluctuations, which account for nearly all relevant decoherence channels in the solid state. This culminates in an increase of the qubit’s inhomogeneous dephasing time by more than four orders of magnitude (to >22 milliseconds), while its Hahn-echo coherence time approaches 64 milliseconds. Requiring few key platform-independent components, this result suggests that substantial coherence improvements can be achieved in a wide selection of quantum architectures.

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