Сибирский федеральный университет

Тип публикации: статья из журнала

Год издания: 2002

Идентификатор DOI: 10.1023/A:1015935809388

Ключевые слова: spin dynamics; correlation functions; power series in time; frequency moments; singular points; generated functions; lattice trees; multidimensional expansion

Аннотация: Using the d(-1) expansion method (d is the space dimension), we estimate the coordinate of the time-dependent autocorrelation function singular point on the imaginary time axis for the spin 1/2 Heisenberg model on a simple hypercubic lattice at high temperatures. We represent the coefficients of the time expansion (the spectral moments) for the autocorrelation function as the sums of the weighted lattice figures in which the trees constructed from the double bonds give the leading contributions with respect to d(-1) and the same trees with the built-in squares from six bonds or diagrams with the fourfold bonds give the contribution of the next-to-leading order. We find the corrections to the coordinate of the autocorrelation function singular point that are due to the latter contributions.

Журнал: THEORETICAL AND MATHEMATICAL PHYSICS

Выпуск журнала: Vol. 131, Is. 3

Номера страниц: 862-872

ISSN журнала: 00405779

Место издания: NEW YORK

Издатель: CONSULTANTS BUREAU

• Zobov V.E. (KRASNOYARSK STATE UNIV)
• Popov M.A. (KRASNOYARSK STATE UNIV)

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