Integral equation generates high-temperature expansion of the Heisenberg chain.
Recently a new integral equation describing the thermodynamics of the 1D Heisenberg model was discovered by Takahashi. Using the integral equation we have succeeded in obtaining the high-temperature expansion of the specific heat and the magnetic susceptibility up to O[(J/T)(100)]. This is much higher than those obtained so far by the standard methods such as the linked-cluster algorithm. Our results will be useful to examine various approximation methods to extrapolate the high-temperature expansion to the low temperature region.
Shiroishi
Masahiro
M
Institute for Solid State Physics, University of Tokyo, Tokyo, Japan.
Takahashi
Minoru
M