High Temperature Expansion for the SU(n) Heisenberg Model in One Dimension(Condensed Matter : Electronic Structure, Electrical, Mgagnetic and Optical Properties)

概要

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Thermodynamic properties of the SU(n) Heisenberg model with the nearest-neighbor interaction in one dimension are studied by means of high-temperature expansion for arbitrary n. The specific heat up to O[(βJ)^<23>] and the correlation function up to O[(βJ)^<19>] are derived with βJ being the antiferromagnetic exchange in units of temperature. The series coefficients are obtained as explicit functions of n. It is found for n > 2 that the specific heat exhibits a shoulder on the high-temperature side of a peak. The origin of this structure is clarified by deriving the temperature dependence of the correlation function. With decreasing temperature, the short-range correlation with two-site periodicity develops first, and then another correlation occurs with n-site periodicity at lower temperature. This behavior is in contrast to that of the 1/r^2-model, where the specific heat shows a single peak according to the exact solution.
社団法人日本物理学会の論文
2002-05-15