Study of the finite-temperature transverse-autocorrelation function in one-dimensional spin-½ XY models
1980; American Physical Society; Volume: 21; Issue: 3 Linguagem: Inglês
10.1103/physrevb.21.1264
ISSN1095-3795
Autores Tópico(s)Spectroscopy and Quantum Chemical Studies
ResumoThe behavior at finite temperatures of the dynamical transverse autocorrelation of a spin is investigated for two special cases of the one-dimensional $\mathrm{XY}$ model. We find for temperatures restricted by $\frac{J}{\mathrm{kT}}>{e}^{\ensuremath{-}2\mathrm{Jt}}$ that its large-time behavior is given by $〈{S}_{i}^{x}(t){S}_{i}^{x}〉\ensuremath{\sim}C(\mathrm{kT})\mathrm{exp}[\ensuremath{-}\frac{1}{2}{J}^{2}{t}^{2}+\frac{2{J}^{2}{t}^{2}}{\mathrm{ln}(\mathrm{Jt})}]$ for the transverse Ising model with field equal to exchange constant and by its square for the isotropic $\mathrm{XY}$ model without field.
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