Fundamental limits of electron and nuclear spin qubit lifetimes in an isolated self-assembled quantum dot

Abstract Combining external control with long spin lifetime and coherence is a key challenge for solid state spin qubits. Tunnel coupling with electron Fermi reservoir provides robust charge state control in semiconductor quantum dots, but results in undesired relaxation of electron and nuclear spin...

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Autores principales:	George Gillard, Ian M. Griffiths, Gautham Ragunathan, Ata Ulhaq, Callum McEwan, Edmund Clarke, Evgeny A. Chekhovich
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Physics QC1-999 Electronic computers. Computer science QA75.5-76.95
Acceso en línea:	https://doaj.org/article/a14ee07b5c1f41418c96d2a4cad0efc1
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spelling	oai:doaj.org-article:a14ee07b5c1f41418c96d2a4cad0efc12021-12-02T13:35:05ZFundamental limits of electron and nuclear spin qubit lifetimes in an isolated self-assembled quantum dot10.1038/s41534-021-00378-22056-6387https://doaj.org/article/a14ee07b5c1f41418c96d2a4cad0efc12021-02-01T00:00:00Zhttps://doi.org/10.1038/s41534-021-00378-2https://doaj.org/toc/2056-6387Abstract Combining external control with long spin lifetime and coherence is a key challenge for solid state spin qubits. Tunnel coupling with electron Fermi reservoir provides robust charge state control in semiconductor quantum dots, but results in undesired relaxation of electron and nuclear spins through mechanisms that lack complete understanding. Here, we unravel the contributions of tunnelling-assisted and phonon-assisted spin relaxation mechanisms by systematically adjusting the tunnelling coupling in a wide range, including the limit of an isolated quantum dot. These experiments reveal fundamental limits and trade-offs of quantum dot spin dynamics: while reduced tunnelling can be used to achieve electron spin qubit lifetimes exceeding 1 s, the optical spin initialisation fidelity is reduced below 80%, limited by Auger recombination. Comprehensive understanding of electron-nuclear spin relaxation attained here provides a roadmap for design of the optimal operating conditions in quantum dot spin qubits.George GillardIan M. GriffithsGautham RagunathanAta UlhaqCallum McEwanEdmund ClarkeEvgeny A. ChekhovichNature PortfolioarticlePhysicsQC1-999Electronic computers. Computer scienceQA75.5-76.95ENnpj Quantum Information, Vol 7, Iss 1, Pp 1-8 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Physics QC1-999 Electronic computers. Computer science QA75.5-76.95
spellingShingle	Physics QC1-999 Electronic computers. Computer science QA75.5-76.95 George Gillard Ian M. Griffiths Gautham Ragunathan Ata Ulhaq Callum McEwan Edmund Clarke Evgeny A. Chekhovich Fundamental limits of electron and nuclear spin qubit lifetimes in an isolated self-assembled quantum dot
description	Abstract Combining external control with long spin lifetime and coherence is a key challenge for solid state spin qubits. Tunnel coupling with electron Fermi reservoir provides robust charge state control in semiconductor quantum dots, but results in undesired relaxation of electron and nuclear spins through mechanisms that lack complete understanding. Here, we unravel the contributions of tunnelling-assisted and phonon-assisted spin relaxation mechanisms by systematically adjusting the tunnelling coupling in a wide range, including the limit of an isolated quantum dot. These experiments reveal fundamental limits and trade-offs of quantum dot spin dynamics: while reduced tunnelling can be used to achieve electron spin qubit lifetimes exceeding 1 s, the optical spin initialisation fidelity is reduced below 80%, limited by Auger recombination. Comprehensive understanding of electron-nuclear spin relaxation attained here provides a roadmap for design of the optimal operating conditions in quantum dot spin qubits.
format	article
author	George Gillard Ian M. Griffiths Gautham Ragunathan Ata Ulhaq Callum McEwan Edmund Clarke Evgeny A. Chekhovich
author_facet	George Gillard Ian M. Griffiths Gautham Ragunathan Ata Ulhaq Callum McEwan Edmund Clarke Evgeny A. Chekhovich
author_sort	George Gillard
title	Fundamental limits of electron and nuclear spin qubit lifetimes in an isolated self-assembled quantum dot
title_short	Fundamental limits of electron and nuclear spin qubit lifetimes in an isolated self-assembled quantum dot
title_full	Fundamental limits of electron and nuclear spin qubit lifetimes in an isolated self-assembled quantum dot
title_fullStr	Fundamental limits of electron and nuclear spin qubit lifetimes in an isolated self-assembled quantum dot
title_full_unstemmed	Fundamental limits of electron and nuclear spin qubit lifetimes in an isolated self-assembled quantum dot
title_sort	fundamental limits of electron and nuclear spin qubit lifetimes in an isolated self-assembled quantum dot
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/a14ee07b5c1f41418c96d2a4cad0efc1
work_keys_str_mv	AT georgegillard fundamentallimitsofelectronandnuclearspinqubitlifetimesinanisolatedselfassembledquantumdot AT ianmgriffiths fundamentallimitsofelectronandnuclearspinqubitlifetimesinanisolatedselfassembledquantumdot AT gauthamragunathan fundamentallimitsofelectronandnuclearspinqubitlifetimesinanisolatedselfassembledquantumdot AT ataulhaq fundamentallimitsofelectronandnuclearspinqubitlifetimesinanisolatedselfassembledquantumdot AT callummcewan fundamentallimitsofelectronandnuclearspinqubitlifetimesinanisolatedselfassembledquantumdot AT edmundclarke fundamentallimitsofelectronandnuclearspinqubitlifetimesinanisolatedselfassembledquantumdot AT evgenyachekhovich fundamentallimitsofelectronandnuclearspinqubitlifetimesinanisolatedselfassembledquantumdot
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Fundamental limits of electron and nuclear spin qubit lifetimes in an isolated self-assembled quantum dot

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