Type of Publication:  Journal article 
Publication status:  Published 
URI (citable link):  http://nbnresolving.de/urn:nbn:de:bsz:3520424244 
Author:  Russ, Maximilian; Burkard, Guido 
Year of publication:  2017 
Published in:  Journal of Physics: Condensed Matter ; 29 (2017), 39.  393001.  ISSN 09538984.  eISSN 1361648X 
Pubmed ID:  28562367 
DOI (citable link):  https://dx.doi.org/10.1088/1361648X/aa761f 
Summary: 
The goal of this article is to review the progress of threeelectron spin qubits from their inception to the state of the art. We direct the main focus towards the exchangeonly qubit (Bacon et al 2000 Phys. Rev. Lett. 85 175861, DiVincenzo et al 2000 Nature 408 339) and its derived versions, e.g. the resonant exchange (RX) qubit, but we also discuss other qubit implementations using three electron spins. For each threespin qubit we describe the qubit model, the envisioned physical realization, the implementations of singlequbit operations, as well as the readout and initialization schemes. Twoqubit gates and decoherence properties are discussed for the RX qubit and the exchangeonly qubit, thereby completing the list of requirements for quantum computation for a viable candidate qubit implementation. We start by describing the full system of three electrons in a triple quantum dot, then discuss the chargestability diagram, restricting ourselves to the relevant subsystem, introduce the qubit states, and discuss important transitions to other charge states (Russ et al 2016 Phys. Rev. B 94 165411). Introducing the various qubit implementations, we begin with the exchangeonly qubit (DiVincenzo et al 2000 Nature 408 339, Laird et al 2010 Phys. Rev. B 82 075403), followed by the RX qubit (Medford et al 2013 Phys. Rev. Lett. 111 050501, Taylor et al 2013 Phys. Rev. Lett. 111 050502), the spincharge qubit (Kyriakidis and Burkard 2007 Phys. Rev. B 75 115324), and the hybrid qubit (Shi et al 2012 Phys. Rev. Lett. 108 140503, Koh et al 2012 Phys. Rev. Lett. 109 250503, Cao et al 2016 Phys. Rev. Lett. 116 086801, Thorgrimsson et al 2016 arXiv:1611.04945). The main focus will be on the exchangeonly qubit and its modification, the RX qubit, whose singlequbit operations are realized by driving the qubit at its resonant frequency in the microwave range similar to electron spin resonance. Two different types of twoqubit operations are presented for the exchangeonly qubits which can be divided into shortranged and longranged interactions. Both of these interaction types are expected to be necessary in a largescale quantum computer. The shortranged interactions use the exchange coupling by placing qubits next to each other and applying exchangepulses (DiVincenzo et al 2000 Nature 408 339, Fong and Wandzura 2011 Quantum Inf. Comput. 11 1003, Setiawan et al 2014 Phys. Rev. B 89 085314, Zeuch et al 2014 Phys. Rev. B 90 045306, Doherty and Wardrop 2013 Phys. Rev. Lett. 111 050503, Shim and Tahan 2016 Phys. Rev. B 93 121410), while the longranged interactions use the photons of a superconducting microwave cavity as a mediator in order to couple two qubits over long distances (Russ and Burkard 2015 Phys. Rev. B 92 205412, Srinivasa et al 2016 Phys. Rev. B 94 205421). The nature of the threeelectron qubit states each having the same total spin and total spin in zdirection (same Zeeman energy) provides a natural protection against several sources of noise (DiVincenzo et al 2000 Nature 408 339, Taylor et al 2013 Phys. Rev. Lett. 111 050502, Kempe et al 2001 Phys. Rev. A 63 042307, Russ and Burkard 2015 Phys. Rev. B 91 235411). The price to pay for this advantage is an increase in gate complexity. We also take into account the decoherence of the qubit through the influence of magnetic noise (Ladd 2012 Phys. Rev. B 86 125408, Mehl and DiVincenzo 2013 Phys. Rev. B 87 195309, Hung et al 2014 Phys. Rev. B 90 045308), in particular dephasing due to the presence of nuclear spins, as well as dephasing due to charge noise (Medford et al 2013 Phys. Rev. Lett. 111 050501, Taylor et al 2013 Phys. Rev. Lett. 111 050502, Shim and Tahan 2016 Phys. Rev. B 93 121410, Russ and Burkard 2015 Phys. Rev. B 91 235411, Fei et al 2015 Phys. Rev. B 91 205434), fluctuations of the energy levels on each dot due to noisy gate voltages or the environment. Several techniques are discussed which partly decouple the qubit from magnetic noise (Setiawan et al 2014 Phys. Rev. B 89 085314, West and Fong 2012 New J. Phys. 14 083002, Rohling and Burkard 2016 Phys. Rev. B 93 205434) while for charge noise it is shown that it is favorable to operate the qubit on the socalled '(double) sweet spots' (Taylor et al 2013 Phys. Rev. Lett. 111 050502, Shim and Tahan 2016 Phys. Rev. B 93 121410, Russ and Burkard 2015 Phys. Rev. B 91 235411, Fei et al 2015 Phys. Rev. B 91 205434, Malinowski et al 2017 arXiv: 1704.01298), which are least susceptible to noise, thus providing a longer lifetime of the qubit.

Subject (DDC):  530 Physics 
Link to License:  Terms of use 
Bibliography of Konstanz:  Yes 
RUSS, Maximilian, Guido BURKARD, 2017. Threeelectron spin qubits. In: Journal of Physics: Condensed Matter. 29(39), 393001. ISSN 09538984. eISSN 1361648X. Available under: doi: 10.1088/1361648X/aa761f
@article{Russ20171004Three40135, title={Threeelectron spin qubits}, year={2017}, doi={10.1088/1361648X/aa761f}, number={39}, volume={29}, issn={09538984}, journal={Journal of Physics: Condensed Matter}, author={Russ, Maximilian and Burkard, Guido}, note={Article Number: 393001} }
<rdf:RDF xmlns:dcterms="http://purl.org/dc/terms/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:rdf="http://www.w3.org/1999/02/22rdfsyntaxns#" xmlns:bibo="http://purl.org/ontology/bibo/" xmlns:dspace="http://digitalrepositories.org/ontologies/dspace/0.1.0#" xmlns:foaf="http://xmlns.com/foaf/0.1/" xmlns:void="http://rdfs.org/ns/void#" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" > <rdf:Description rdf:about="https://kops.unikonstanz.de/rdf/resource/123456789/40135"> <dc:creator>Russ, Maximilian</dc:creator> <dcterms:isPartOf rdf:resource="https://kops.unikonstanz.de/rdf/resource/123456789/41"/> <dcterms:title>Threeelectron spin qubits</dcterms:title> <dcterms:issued>20171004</dcterms:issued> <dc:creator>Burkard, Guido</dc:creator> <dspace:hasBitstream rdf:resource="https://kops.unikonstanz.de/bitstream/123456789/40135/1/Russ_0424244.pdf"/> <dc:contributor>Burkard, Guido</dc:contributor> <dc:date rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">20170921T07:53:38Z</dc:date> <dcterms:rights rdf:resource="https://kops.unikonstanz.de/page/termsofuse"/> <dcterms:abstract xml:lang="eng">The goal of this article is to review the progress of threeelectron spin qubits from their inception to the state of the art. We direct the main focus towards the exchangeonly qubit (Bacon et al 2000 Phys. Rev. Lett. 85 175861, DiVincenzo et al 2000 Nature 408 339) and its derived versions, e.g. the resonant exchange (RX) qubit, but we also discuss other qubit implementations using three electron spins. For each threespin qubit we describe the qubit model, the envisioned physical realization, the implementations of singlequbit operations, as well as the readout and initialization schemes. Twoqubit gates and decoherence properties are discussed for the RX qubit and the exchangeonly qubit, thereby completing the list of requirements for quantum computation for a viable candidate qubit implementation. We start by describing the full system of three electrons in a triple quantum dot, then discuss the chargestability diagram, restricting ourselves to the relevant subsystem, introduce the qubit states, and discuss important transitions to other charge states (Russ et al 2016 Phys. Rev. B 94 165411). Introducing the various qubit implementations, we begin with the exchangeonly qubit (DiVincenzo et al 2000 Nature 408 339, Laird et al 2010 Phys. Rev. B 82 075403), followed by the RX qubit (Medford et al 2013 Phys. Rev. Lett. 111 050501, Taylor et al 2013 Phys. Rev. Lett. 111 050502), the spincharge qubit (Kyriakidis and Burkard 2007 Phys. Rev. B 75 115324), and the hybrid qubit (Shi et al 2012 Phys. Rev. Lett. 108 140503, Koh et al 2012 Phys. Rev. Lett. 109 250503, Cao et al 2016 Phys. Rev. Lett. 116 086801, Thorgrimsson et al 2016 arXiv:1611.04945). The main focus will be on the exchangeonly qubit and its modification, the RX qubit, whose singlequbit operations are realized by driving the qubit at its resonant frequency in the microwave range similar to electron spin resonance. Two different types of twoqubit operations are presented for the exchangeonly qubits which can be divided into shortranged and longranged interactions. Both of these interaction types are expected to be necessary in a largescale quantum computer. The shortranged interactions use the exchange coupling by placing qubits next to each other and applying exchangepulses (DiVincenzo et al 2000 Nature 408 339, Fong and Wandzura 2011 Quantum Inf. Comput. 11 1003, Setiawan et al 2014 Phys. Rev. B 89 085314, Zeuch et al 2014 Phys. Rev. B 90 045306, Doherty and Wardrop 2013 Phys. Rev. Lett. 111 050503, Shim and Tahan 2016 Phys. Rev. B 93 121410), while the longranged interactions use the photons of a superconducting microwave cavity as a mediator in order to couple two qubits over long distances (Russ and Burkard 2015 Phys. Rev. B 92 205412, Srinivasa et al 2016 Phys. Rev. B 94 205421). The nature of the threeelectron qubit states each having the same total spin and total spin in zdirection (same Zeeman energy) provides a natural protection against several sources of noise (DiVincenzo et al 2000 Nature 408 339, Taylor et al 2013 Phys. Rev. Lett. 111 050502, Kempe et al 2001 Phys. Rev. A 63 042307, Russ and Burkard 2015 Phys. Rev. B 91 235411). The price to pay for this advantage is an increase in gate complexity. We also take into account the decoherence of the qubit through the influence of magnetic noise (Ladd 2012 Phys. Rev. B 86 125408, Mehl and DiVincenzo 2013 Phys. Rev. B 87 195309, Hung et al 2014 Phys. Rev. B 90 045308), in particular dephasing due to the presence of nuclear spins, as well as dephasing due to charge noise (Medford et al 2013 Phys. Rev. Lett. 111 050501, Taylor et al 2013 Phys. Rev. Lett. 111 050502, Shim and Tahan 2016 Phys. Rev. B 93 121410, Russ and Burkard 2015 Phys. Rev. B 91 235411, Fei et al 2015 Phys. Rev. B 91 205434), fluctuations of the energy levels on each dot due to noisy gate voltages or the environment. Several techniques are discussed which partly decouple the qubit from magnetic noise (Setiawan et al 2014 Phys. Rev. B 89 085314, West and Fong 2012 New J. Phys. 14 083002, Rohling and Burkard 2016 Phys. Rev. B 93 205434) while for charge noise it is shown that it is favorable to operate the qubit on the socalled '(double) sweet spots' (Taylor et al 2013 Phys. Rev. Lett. 111 050502, Shim and Tahan 2016 Phys. Rev. B 93 121410, Russ and Burkard 2015 Phys. Rev. B 91 235411, Fei et al 2015 Phys. Rev. B 91 205434, Malinowski et al 2017 arXiv: 1704.01298), which are least susceptible to noise, thus providing a longer lifetime of the qubit.</dcterms:abstract> <dspace:isPartOfCollection rdf:resource="https://kops.unikonstanz.de/rdf/resource/123456789/41"/> <dcterms:hasPart rdf:resource="https://kops.unikonstanz.de/bitstream/123456789/40135/1/Russ_0424244.pdf"/> <dc:language>eng</dc:language> <dc:contributor>Russ, Maximilian</dc:contributor> <void:sparqlEndpoint rdf:resource="http://localhost/fuseki/dspace/sparql"/> <dcterms:available rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">20170921T07:53:38Z</dcterms:available> <dc:rights>termsofuse</dc:rights> <bibo:uri rdf:resource="https://kops.unikonstanz.de/handle/123456789/40135"/> <foaf:homepage rdf:resource="http://localhost:8080/jspui"/> </rdf:Description> </rdf:RDF>
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