Fundamental measure theory for predicting many-body correlation functions

Ilian Pihlajamaa; Teunike A. van de Pol; Liesbeth M. C. Janssen

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arXiv · 2508.14642

Fundamental measure theory for predicting many-body correlation functions

Ilian Pihlajamaa·Teunike A. van de Pol·Liesbeth M. C. Janssen

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Abstract

We study many-body correlation functions within various Fundamental Measure Theory (FMT) formulations and compare their predictions to Monte Carlo simulations of hard-sphere fluids. FMT accurately captures the qualitative behavior of three- and four-body structure, particularly at low and intermediate wavevectors. At higher wavevectors, the predictions of FMT vary in quantitative accuracy. We show that the dominant contributions to the four-point structure factor arise from direct triplet correlations, allowing the evaluation of four-point correlations to be greatly simplified. In glass-forming liquids at high volume fractions, FMT correctly reproduces deviations from the convolution approximation, highlighting FMT's ability to capture growing structural multipoint correlations upon supercooling.

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Ilian Pihlajamaa, Teunike A. van de Pol, Liesbeth M. C. Janssen. 2025-08-20. Fundamental measure theory for predicting many-body correlation functions. https://arxiv.org/abs/2508.14642

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