Thermal conductance of the coupled-rotator chain: Influence of temperature and size

The thermal conductance of a homogeneous 1D nonlinear lattice system with neareast-neighbor interactions has recently been computationally studied in detail by Li et al. (Eur. Phys. J. B, 88 (2015) 182), where its power-law dependence on temperature T for high temperatures is shown. Here, we address its entire temperature dependence, in addition to its dependence on the size N of the system. We obtain a neat data collapse for arbitrary temperatures and system sizes, and numerically show that the thermal conductance curve is quite satisfactorily described by a fat-tailed q-Gaussian dependence on $TN^{1/3}$ with $q \simeq 1.55$ . Consequently, its $T \to\infty$ asymptotic behavior is given by $T^{-\alpha}$ with $\alpha=2/(q-1) \simeq 3.64$