Relaxation in the isotropic Heisenberg chain at T = ∞: Towards a simple intuitive interpretation

This work reports a significantly improved estimation of the on-site dynamical spin pair correlation function in the isotropic Heisenberg chain at T = ∞ with respect to an earlier study (Phys. Rev. B 46 (1992) 14617) which has received some attention in the literature. The calculations have been performed using a recently developed technique for estimating unsolvable infinite continued fractions which are relevant for calculating the relaxation functions. This improvement became possible due to an important advance in the machine based computation of quantum mechanical commutators by M. Böhm and H. Leschke (Physica A 199 (1993) 116). The work reported here builds on the results of Böhm and Leschke and provides new predictions on the behavior of the on-site dynamical spin pair correlation function. This work also provides insights into possible ways to qualitatively understand the complex relaxation at high temperatures associated with a hermitian operator A(t) in a system described by a hermitian Hamiltonian H = H0 + H1, where none of these three operators commutes with one another.