arXiv:cond-mat/0502569 · Journal of Physics A Mathematical and General
High temperature expansion of the emptiness formation probability for the isotropic Heisenberg chain
Zengo Tsuboi, Masahiro Shiroishi
Abstract
Recently, Göhmann, Klümper and Seel have derived novel integral formulae for the correlation functions of the spin-1/2 Heisenberg chain at finite temperature. We have found that the high temperature expansion (HTE) technique can be effectively applied to evaluate these integral formulae. Actually, as for the emptiness formation probability P ( n ) of the isotropic Heisenberg chain, we have found a general formula of the HTE for P ( n ) with arbitrary up to O (( J / T ) 4 ). If we fix a magnetic field to a certain value, we can calculate the HTE to much higher order. For example, the order up to O (( J / T ) 42 ) has been achieved in the case of P (3) when h = 0. We have compared these HTE results with the data by quantum Monte Carlo simulations. They exhibit excellent agreement.