Static and dynamic properties of the classicalXYchain

Abstract

We present results for the static and dynamic behavior of a one-dimensional classical $\mathrm{XY}$ chain. Equilibrium configurations are produced by an importance-sampling Monte Carlo method. Static properties are evaluated from these data and a spin-dynamics method is then used to evaluate time-displaced correlation functions and to calculate the scattering function $S(q,\ensuremath{\omega})$. The transverse spin-spin correlation functions decay exponentially for large times. The longitudinal spin-spin correlation functions show oscillatory behavior, especially at low temperatures. The longitudinal-scattering function displays spin-wave peaks, and the transverse-scattering function shows central peaks (relaxational behavior) which change to fluctuation-broadened spin-wave peaks for large values of $\frac{q}{\ensuremath{\kappa}}$. The energy-energy correlation function shows diffusive behavior for high temperatures and non-diffusive behavior for low temperatures.