%0 Journal Article
%@ 2045-2322
%A Weiss, KM
%A Miguel-Sanchez, J
%A Elzerman, JM
%D 2013
%F discovery:1410660
%J SCIENTIFIC REPORTS
%K Qubits; Quantum information
%T Magnetically tunable singlet-triplet spin qubit in a four-electron InGaAs coupled quantum dot
%U https://discovery.ucl.ac.uk/id/eprint/1410660/
%V 3
%X 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.
%Z © 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