eprintid: 1410660 rev_number: 30 eprint_status: archive userid: 608 dir: disk0/01/41/06/60 datestamp: 2013-10-21 19:22:16 lastmod: 2021-09-22 22:04:35 status_changed: 2013-10-21 19:22:16 type: article metadata_visibility: show item_issues_count: 0 creators_name: Weiss, KM creators_name: Miguel-Sanchez, J creators_name: Elzerman, JM title: Magnetically tunable singlet-triplet spin qubit in a four-electron InGaAs coupled quantum dot ispublished: pub divisions: UCL divisions: B04 divisions: C06 keywords: Qubits; Quantum information note: © 2013 Macmillan Publishers Limited. This work is licensed under a Creative Commons Attribution 3.0 Unported license. To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0 PubMed ID: 24177037 abstract: A pair of self-assembled InGaAs quantum dots filled with two electrons can act as a singlet-triplet spin qubit that is robust against nuclear spin fluctuations as well as charge noise. This results in a T2* coherence time two orders of magnitude longer than that of a single electron, provided the qubit is operated at a particular ‘‘sweet spot’’ in gate voltage. However, at this fixed operating point the ground-state splitting can no longer be tuned into resonance with e.g. another qubit, limiting the options for coupling multiple qubits. Here, we propose using a four-electron coupled quantum dot to implement a singlet-triplet qubit that features a magnetically tunable level splitting. As a first step towards full experimental realization of this qubit design, we use optical spectroscopy to demonstrate the tunability of the four-electron singlet-triplet splitting in a moderate magnetic field. date: 2013-11-01 official_url: http://dx.doi.org/10.1038/srep03121 vfaculties: VMPS oa_status: green full_text_type: pub primo: open primo_central: open_green verified: verified_manual elements_source: WoS-Lite elements_id: 911431 doi: 10.1038/srep03121 lyricists_name: Elzerman, Jeroen lyricists_id: JELZE94 full_text_status: public publication: SCIENTIFIC REPORTS volume: 3 article_number: ARTN 3121 issn: 2045-2322 citation: Weiss, KM; Miguel-Sanchez, J; Elzerman, JM; (2013) Magnetically tunable singlet-triplet spin qubit in a four-electron InGaAs coupled quantum dot. SCIENTIFIC REPORTS , 3 , Article ARTN 3121. 10.1038/srep03121 <https://doi.org/10.1038/srep03121>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/1410660/1/srep03121.pdf