Dynamical spin pair correlations in s=1/2 Heisenberg chain

Calculations are presented for the on-site dynamical spin pair correlation of the s=1/2 Heisenberg chain at T=∞. The result for the isotropic chain is consistent with short time analysis. The long time behavior may be interpreted as compatible with exponential decay as well as with power law decay interpretations. The chain with small Ising-like anisotropy also exhibits exponential-like long time decay as found in recent Mössbauer effect spectroscopy work. Preliminary calculations are also presented for the mathematically challenging case of extreme Ising-like anisotropy.