Paradigm shift in the field of optically active quantum dots: improved qubit and the nuclear interface

ORAL · Invited

Abstract

Epitaxial Quantum Dots (QDs) are world-leading single-photon sources owing to their efficient light-matter coupling [1]. Despite that, they have underperformed as spin-photon interfaces due to a short spin coherence time of a few microseconds. This cap, inherent to self-assembled QDs, originates from substantial strain inhomogeneity affecting the mesoscopic nuclear environment of the qubit. This talk will focus on the solution to this long-standing problem offered by lattice-matched QDs, in which significantly reduced strain inhomogeneity leads to a hundred-fold extension of coherence time [2]. Together with progress in photon collection, these experimental advances promote QDs to robust quantum nodes and allow for generating multi-photon entangled states. Beyond, the improved homogeneity of the collective qubit-nuclear coupling enables the exploration of many-body phenomena relying on feedback [3] and coherent exchange [4,5]. In the second part of the talk, I will review the recent experimental achievements and emerging proposals in this field.

[1] N. Tomm, …, R. J. Warburton, Nature Nanotechnology 16, pages 399–403 (2021)

[2] L. Zaporski, …, C. Le Gall, Nature Nanotechnology 18, 257–263 (2023)

[3] D. M. Jackson, ..., D. A. Gangloff, PRX 12, 031014 (2022)

[4] D. A. Gangloff, ..., M. Atature, Science 364, 62-66 (2019)

[5] L. Zaporski, …, D. A. Gangloff, arXiv:2301.10258 (2023)

* We acknowledge support from the Royal Society (EA/181068), the US Ofice of Naval Research Global (N62909-19-1-2115), the EU Horizon 2020 FET Open project QLUSTER (862035), the EU Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant QUDOT-TECH (861097), Qurope (899814), ASCENT+ (871130.), Engineering and Physical Sciences Research Council (grant EP/V048333/1), the Austrian Science Fund (FWF; FG 5, P 30459, I 4380, I 4320 and I 3762), the state of Upper Austria, the EPSRC DTP, the St. John's College Fellowship, the Royal Society University Research Fellowship, the Dorothy Hodgkin Royal Society Fellowship and the Royal Society University Research Fellowship.

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Publication: L. Zaporski, …, C. Le Gall, Nature Nanotechnology 18, 257–263 (2023),
D. M. Jackson, ..., D. A. Gangloff, PRX 12, 031014 (2022)
D. A. Gangloff, ..., M. Atature, Science 364, 62-66 (2019)
L. Zaporski, …, D. A. Gangloff, arXiv:2301.10258 (2023) - under review in PRX Quantum

Presenters

  • Leon Zaporski

    Cambridge

Authors

  • Leon Zaporski

    Cambridge

  • Noah Shofer

    Univ. of Cambridge

  • Jonathan H Bodey

    Univ of Cambridge

  • Santanu Manna

    JKU Linz

  • George Gillard

    Univ. of Sheffield

  • Martin Hayhurst Appel

    University of Cambridge, Univ. of Cambridge

  • Christian Schimpf

    Univ. of Oxford

  • Saimon F Covre da Silva

    JKU Linz

  • John Jarman

    Univ. of Cambridge

  • Geoffroy Delamare

    Univ. of Cambridge

  • Gunhee Park

    California Institute of Technology

  • Urs Haeusler

    Univ. of Cambridge

  • Stijn R de Wit

    Univ. of Twente

  • Takuya Isogawa

    MIT

  • Evgeny A Chekhovich

    Univ. of Sheffield

  • Armando Rastelli

    JKU Linz

  • Dorian Gangloff

    Univ. of Oxford

  • Mete Atatüre

    Univ of Cambridge, University of Cambridge

  • Claire Le Gall

    Nu Quantum