Noise-resistant off-resonance {\pi}-rotation realized in an NMR system

Abstract:Precise manipulation of qubits (spins) requires strong suppression of noise arising from couplings between qubits and their environment, as well as from driving field fluctuations. We propose a double-pulse sequence and an eighteen-pulse sequence to realize a single spin pi-rotation under off-resonance conditions (instead of conventional on-resonance or near-resonance conditions). It is proved that the latter sequence performs much better than the former in simultaneously suppressing both dephasing and driving field noise. As a proof of principle, we experimentally demonstrate, by implementing both sequences in an NMR spin system with a polarized initial spin state, that the off-resonance pi-rotation fidelity reaches as high as 0.9992 +/- 0.0008 for the double-pulse sequence and 0.9997 +/- 0.0006 for the eighteen-pulse sequence. In addition, the noise-tolerance range of the eighteen-pulse sequence is about 20 percent of the driving field strength, approximately three times wider than that of the double-pulse sequence. Besides its potential application in the NMR community, our proposal provides an alternative practical way to accurately control qubits by suppressing the coexisting transversal and longitudinal noises.

arXiv:2610.16098 [quant-ph]

(or arXiv:2610.16098v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2610.16098 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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