当前位置： 文档下载 > 所有分类 > Exact and numerical results for the dimerized spin-orbital modelWe establish exact results for the one-dimensional spin-orbital model for special values of the four-spin interaction $V$ and dimerization parameter $\delta$. The first exact result is at $\delta=1/2$ and $V=-2$. Because we find a very small but finite gap
IASSNS-HEP-00/31
arXiv:cond-mat/0004238v1 [cond-mat.stat-mech] 14 Apr 2000Exactandnumericalresultsforthedimerizedspin-orbitalchainM.J.Martins1,2andB.Nienhuis31SchoolofNaturalSciences,InstituteforAdvancedStudyOldenLane,Princeton,NJ08540,USA2DepartamentodeF´isica,UniversidadeFederaldeS aoCarlosCaixaPostal676,13565-905,S aoCarlos,Brazil3InstituutvoorTheoretischeFysica,UniversiteitvanAmsterdamValckenierstraat65,1018XE,Amsterdam,TheNetherlandsAbstractWeestablishexactresultsfortheone-dimensionalspin-orbitalmodelforspecialvaluesofthefour-spininteractionVanddimerizationparameterδ.The rstexactresultisatδ=1/2andV= 2.Becausewe ndaverysmallbut nitegapinthisdimerizedchain,thiscanserveasaverystrongtestcasefornumericalandapproximateanalyticaltechniques.ThesecondresultisforthehomogeneouschainwithV= 4andgivesevidencethatthesystemhasaspontaneouslydimerizedgroundstate.Numericalresultsindicatethattheinterplaybetweendimerizationandinteractioncouldresultingapless
phasesintheregime0≤V< 2.
PACSnumbers:05.50+q,75.10.Jm
March2000
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