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dc.contributor.authorFowler-Wright, Piper
dc.contributor.authorArnardóttir, Kristín B.
dc.contributor.authorKirton, Peter
dc.contributor.authorLovett, Brendon W.
dc.contributor.authorKeeling, Jonathan
dc.identifier.citationFowler-Wright , P , Arnardóttir , K B , Kirton , P , Lovett , B W & Keeling , J 2023 , ' Determining the validity of cumulant expansions for central spin models ' , Physical Review Research , vol. 5 , no. 3 , 033148 .
dc.identifier.otherPURE: 291716271
dc.identifier.otherPURE UUID: 71650e1e-ee80-42b1-a60e-151d62df2a8a
dc.identifier.otherORCID: /0000-0003-1060-445X/work/141643430
dc.identifier.otherORCID: /0000-0002-4283-552X/work/141644044
dc.identifier.otherORCID: /0000-0002-6624-2307/work/141644052
dc.identifier.otherORCID: /0000-0001-5142-9585/work/141644119
dc.identifier.otherScopus: 85171783626
dc.descriptionFunding: P.F.-W. acknowledges support from EPSRC (EP/T518062/1). K.B.A, B.W.L., and J.K. acknowledge support from EPSRC (EP/T014032/1).en
dc.description.abstractFor a model with many-to-one connectivity it is widely expected that mean-field theory captures the exact many-particle limit, and that higher-order cumulant expansions of the Heisenberg equations converge to this same limit whilst providing improved approximations at finite N. Here we show that this is in fact not always the case. Instead, whether mean-field theory correctly describes the large-N limit depends on how the model parameters scale with N, and the convergence of cumulant expansions may be non-uniform across even and odd orders. Further, even when a higher-order cumulant expansion does recover the correct limit, the error is not monotonic with N and may exceed that of mean-field theory.
dc.relation.ispartofPhysical Review Researchen
dc.rightsCopyright The Authors. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.en
dc.subjectQC Physicsen
dc.subjectTK Electrical engineering. Electronics Nuclear engineeringen
dc.titleDetermining the validity of cumulant expansions for central spin modelsen
dc.typeJournal articleen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. School of Physics and Astronomyen
dc.contributor.institutionUniversity of St Andrews. Centre for Designer Quantum Materialsen
dc.contributor.institutionUniversity of St Andrews. Condensed Matter Physicsen
dc.description.statusPeer revieweden

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