Physical review. B, Condensed matter
Nonlinear-renormalization-group study of a measurable quantity in a large range of temperature above Tc for Ising-like systems
C. Bagnuls, Claude Bervillier
Abstract
We perform a numerical study, in the framework of the massive ${\ensuremath{\varphi}}^{4}$ field theory in dimension $d=3$ (${\ensuremath{\varphi}}_{3}^{4}$) for Ising-like systems above ${T}_{c}$, of the variation in $t$ of the dimensionless combination $R(t)={{\ensuremath{-}{t}^{3}[\frac{\ensuremath{\partial}C(t)}{\ensuremath{\partial}t}]{\ensuremath{\xi}}^{3}(t)}}^{\frac{1}{3}}$; $C$ being the specific heat, $\ensuremath{\xi}$ the correlation length, and $t$ a critical variable which vanishes at ${T}_{c}$. $R(0)$ is the universal combination of critical amplitudes ${R}_{\ensuremath{\xi}}^{+}$. The range in $t$ studied goes from the classical region to the true critical region. Together with estimations of $R(t)$ for discrete values of $t$, we provide an analytical form of fit for the central values. This will allow experimentalists to improve the analysis of confluent corrections to scaling.