J. Phys. I France
Volume 7, Numéro 7, July 1997
Page(s) 827 - 832
DOI: 10.1051/jp1:1997204
J. Phys. I France 7 (1997) 827-832

Energy-Energy Correlations in Square and Cubic Ising Models

Roland R. Netz1, 2 and Ingo H. Gersonde2

1  Department of Physics, Box 351560, University of Washington, Seattle, WA 98195-1560, USA
2  Service de Physique Théorique, CEA-Saclay, 91191 Gif sur Yvette, France

(Received 9 September 1996, revised 4 February 1997, accepted 6 May 1997)

Cluster-Monte-Carlo simulations are used to calculate the structure factors associated with order-parameter and energy correlations for square and cubic Ising models, from which the corresponding correlation lengths $\xi$ and $\xi_{\rm E}$, respectively, are determined. The amplitude ratio $X_{\rm E}\equiv \xi_{\rm E}^2 /\xi^2$ is asymptotically universal but strongly influenced by the crossover from mean-field behavior. The numerically determined $X_{\rm E}$ therefore does not reach its universal asymptotic value but agrees well with $\varepsilon$-expansion predictions including corrections to scaling. The consequences for experiments on near-critical fluids and colloidal systems are briefly discussed.

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