Controlling spin relaxation with a cavity

A. Bienfait, J. J. Pla, Y. Kubo, X. Zhou, M. Stern, C. C. Lo, C. D. Weis, T. Schenkel, D. Vion, D. Esteve, J. J.L. Morton, P. Bertet

Research output: Contribution to journalArticlepeer-review

123 Scopus citations

Abstract

Spontaneous emission of radiation is one of the fundamental mechanisms by which an excited quantum system returns to equilibrium. For spins, however, spontaneous emission is generally negligible compared to other non-radiative relaxation processes because of the weak coupling between the magnetic dipole and the electromagnetic field. In 1946, Purcell realized that the rate of spontaneous emission can be greatly enhanced by placing the quantum system in a resonant cavity. This effect has since been used extensively to control the lifetime of atoms and semiconducting heterostructures coupled to microwave or optical cavities, and is essential for the realization of high-efficiency single-photon sources. Here we report the application of this idea to spins in solids. By coupling donor spins in silicon to a superconducting microwave cavity with a high quality factor and a small mode volume, we reach the regime in which spontaneous emission constitutes the dominant mechanism of spin relaxation. The relaxation rate is increased by three orders of magnitude as the spins are tuned to the cavity resonance, demonstrating that energy relaxation can be controlled on demand. Our results provide a general way to initialize spin systems into their ground state and therefore have applications in magnetic resonance and quantum information processing. They also demonstrate that the coupling between the magnetic dipole of a spin and the electromagnetic field can be enhanced up to the point at which quantum fluctuations have a marked effect on the spin dynamics; as such, they represent an important step towards the coherent magnetic coupling of individual spins to microwave photons.

Original languageEnglish
Pages (from-to)74-77
Number of pages4
JournalNature
Volume531
Issue number7592
DOIs
StatePublished - 3 Mar 2016

Bibliographical note

Publisher Copyright:
© 2016 Macmillan Publishers Limited. All rights reserved.

Funding

Acknowledgements We acknowledge technical support from P. Sénat, D. Duet, J.-C. Tack, P. Pari and P. Forget, as well as discussions within the Quantronics group. We acknowledge support of the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013) through grant agreements No. 615767 (CIRQUSS), 279781 (ASCENT) and 630070 (quRAM), and of the C’Nano IdF project QUANTROCRYO. J.J.L.M. is supported by the Royal Society. C.C.L. is supported by the Royal Commission for the Exhibition of 1851. T.S. and C.D.W. were supported by the US Department of Energy under contract DE-AC02-05CH11231.

FundersFunder number
U.S. Department of EnergyDE-AC02-05CH11231
Seventh Framework Programme279781, 608512, 630070, 615767
Royal Society
Royal Commission for the Exhibition of 1851
European Commission

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