Improving a Solid-State Qubit through an Engineered Mesoscopic Environment

G. Éthier-Majcher, D. Gangloff, R. Stockill, E. Clarke, M. Hugues, C. Le Gall, and M. Atatüre
Phys. Rev. Lett. 119, 130503 – Published 28 September 2017
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Abstract

A controlled quantum system can alter its environment by feedback, leading to reduced-entropy states of the environment and to improved system coherence. Here, using a quantum-dot electron spin as a control and probe, we prepare the quantum-dot nuclei under the feedback of coherent population trapping and observe their evolution from a thermal to a reduced-entropy state, with the immediate consequence of extended qubit coherence. Via Ramsey interferometry on the electron spin, we directly access the nuclear distribution following its preparation and measure the emergence and decay of correlations within the nuclear ensemble. Under optimal feedback, the inhomogeneous dephasing time of the electron, T2*, is extended by an order of magnitude to 39 ns. Our results can be readily exploited in quantum information protocols utilizing spin-photon entanglement and represent a step towards creating quantum many-body states in a mesoscopic nuclear-spin ensemble.

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  • Received 23 June 2017

DOI:https://doi.org/10.1103/PhysRevLett.119.130503

© 2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied PhysicsGeneral PhysicsAtomic, Molecular & OpticalQuantum Information, Science & Technology

Authors & Affiliations

G. Éthier-Majcher1, D. Gangloff1, R. Stockill1, E. Clarke2, M. Hugues3, C. Le Gall1, and M. Atatüre1,*

  • 1Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
  • 2EPSRC National Centre for III-V Technologies, University of Sheffield, Sheffield S1 3JD, United Kingdom
  • 3Université Côte d’Azur, CNRS, CRHEA, rue Bernard Gregory, 06560 Valbonne, France

  • *ma424@cam.ac.uk

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Issue

Vol. 119, Iss. 13 — 29 September 2017

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