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arXiv · 0705.1191

Improved Quantum Hard-Sphere Ground-State Equations of State

M. A. Solís·M. de Llano·J. W. Clark·George A. Baker Jr
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Abstract

The London ground-state energy formula as a function of number density for a system of identical boson hard spheres, corrected for the reduced mass of a pair of particles in a sphere-of-influence picture, and generalized to fermion hard-sphere systems with two and four intrinsic degrees of freedom, has a double-pole at the ultimate \textit{regular} (or periodic, e.g., face-centered-cubic) close-packing density usually associated with a crystalline branch. Improved fluid branches are contructed based upon exact, field-theoretic perturbation-theory low-density expansions for many-boson and many-fermion systems, appropriately extrapolated to intermediate densities, but whose ultimate density is irregular or \textit{random} closest close-packing as suggested in studies of a classical system of hard spheres. Results show substantially improved agreement with the best available Green-function Monte Carlo and diffusion Monte Carlo simulations for bosons, as well as with ladder, variational Fermi hypernetted chain, and so-called L-expansion data for two-component fermions.

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M. A. Solís, M. de Llano, J. W. Clark, George A. Baker Jr. 2007-10-26. Improved Quantum Hard-Sphere Ground-State Equations of State. https://doi.org/10.1103/physreve.76.031125

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