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dc.contributor.authorShu, Yu-Rongen_US
dc.contributor.authorDupont, Maximeen_US
dc.contributor.authorYao, Dao-Xinen_US
dc.contributor.authorCapponi, Sylvainen_US
dc.contributor.authorSandvik, Anders W.en_US
dc.date.accessioned2018-12-06T18:26:29Z
dc.date.available2018-12-06T18:26:29Z
dc.date.issued2018-03-28
dc.identifierhttp://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000428500900001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=6e74115fe3da270499c3d65c9b17d654
dc.identifier.citationYu-Rong Shu, Maxime Dupont, Dao-Xin Yao, Sylvain Capponi, Anders W Sandvik. 2018. "Dynamical properties of the S=1/2 random Heisenberg chain." Physical Review B, Volume 97, Issue 10. https://doi.org/10.1103/PhysRevB.97.104424
dc.identifier.issn2469-9950
dc.identifier.issn2469-9969
dc.identifier.urihttps://hdl.handle.net/2144/32893
dc.description.abstractWe study dynamical properties at finite temperature (T) of Heisenberg spin chains with random antiferromagnetic exchange couplings, which realize the random singlet phase in the low-energy limit, using three complementary numerical methods: exact diagonalization, matrix-product-state algorithms, and stochastic analytic continuation of quantum Monte Carlo results in imaginary time. Specifically, we investigate the dynamic spin structure factor S(q,ω) and its ω→0 limit, which are closely related to inelastic neutron scattering and nuclear magnetic resonance (NMR) experiments (through the spin-lattice relaxation rate 1/T1). Our study reveals a continuous narrow band of low-energy excitations in S(q,ω), extending throughout the q space, instead of being restricted to q≈0 and q≈π as found in the uniform system. Close to q=π, the scaling properties of these excitations are well captured by the random-singlet theory, but disagreements also exist with some aspects of the predicted q dependence further away from q=π. Furthermore we also find spin diffusion effects close to q=0 that are not contained within the random-singlet theory but give non-negligible contributions to the mean 1/T1. To compare with NMR experiments, we consider the distribution of the local relaxation rates 1/T1. We show that the local 1/T1 values are broadly distributed, approximately according to a stretched exponential. The mean 1/T1 first decreases with T, but below a crossover temperature it starts to increase and likely diverges in the limit of a small nuclear resonance frequency ω0. Although a similar divergent behavior has been predicted and experimentally observed for the static uniform susceptibility, this divergent behavior of the mean 1/T1 has never been experimentally observed. Indeed, we show that the divergence of the mean 1/T1 is due to rare events in the disordered chains and is concealed in experiments, where the typical 1/T1 value is accessed.en_US
dc.description.sponsorshipThe authors are grateful to Mladen Horvatic and Nicolas Laflorencie for valuable discussions and thoughtful comments. Part of this work was performed using HPC resources from GENCI (Grants No. x2016050225 and No. x2017050225) and CALMIP. Y.R.S. and D.X.Y. are supported by NKRDPC-2017YFA0206203, NSFC-11574404, NSFC-11275279, NSFG-2015A030313176, Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund, and Leading Talent Program of Guangdong Special Projects. M.D. and S.C. acknowledge support of the French ANR program BOLODISS (Grant No. ANR-14-CE32-0018), Region Midi-Pyrenees, the Condensed Matter Theory Visitors Program at Boston University, and "Programme des Investissements d'Avenir" within the ANR-11-IDEX-0002-02 program through the grant NEXT No. ANR-10-LABX-0037. A.W.S. was supported by the NSF under Grant No. DMR-1710170 and by the Simons Foundation. (x2016050225 - GENCI; x2017050225 - GENCI; NKRDPC-2017YFA0206203 - Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund; NSFC-11574404 - Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund; NSFC-11275279 - Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund; NSFG-2015A030313176 - Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund; Leading Talent Program of Guangdong Special Projects; ANR-14-CE32-0018 - French ANR program BOLODISS; Region Midi-Pyrenees; Condensed Matter Theory Visitors Program at Boston University; ANR-11-IDEX-0002-02 - NEXT; ANR-10-LABX-0037 - NEXT; DMR-1710170 - NSF; Simons Foundation)en_US
dc.languageEnglish
dc.publisherAmerican Physical Societyen_US
dc.relation.ispartofPHYSICAL REVIEW B
dc.subjectScience & technologyen_US
dc.subjectTechnologyen_US
dc.subjectPhysical sciencesen_US
dc.subjectPhysics, applieden_US
dc.subjectPhysics, condensed matteren_US
dc.subjectMaterials scienceen_US
dc.subjectPhysicsen_US
dc.subjectHubbard modelen_US
dc.titleDynamical properties of the S=1/2 random Heisenberg chainen_US
dc.typeArticleen_US
dc.description.versionAccepted manuscripten_US
dc.identifier.doi10.1103/PhysRevB.97.104424
pubs.elements-sourceweb-of-scienceen_US
pubs.notesEmbargo: Not knownen_US
pubs.organisational-groupBoston Universityen_US
pubs.organisational-groupBoston University, College of Arts & Sciencesen_US
pubs.organisational-groupBoston University, College of Arts & Sciences, Department of Physicsen_US
pubs.publication-statusPublisheden_US
dc.identifier.orcid0000-0002-5638-4619 (Sandvik, Anders W)


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