Journal of the Physical Society of Japan
Direct Calculation of Dynamical Susceptibility in Strongly Fluctuating Quantum Spin Systems
Seiji Miyashita, Taro Yoshino, Akira Ogasahara
Abstract
We propose a direct numerical method to calculate the dynamical susceptibility, χ''(ω), in strongly fluctuating quantum systems, where the system is nonmagnetic but the exchange effect is very strong. We demonstrate this method by calculating ESR line shape χ''(ω) of the one dimensional antiferromagnetic Heisenberg model ( S =1/2) and comparing the results with those obtained by other methods and experiments.