Hellmann-Feynman theorem and fluctuation-correlation analysis of the Calogero-Sutherland model
Abstract
Exploiting the results of the exact solution for the ground state of the one-dimensional spinless quantum gas of Fermions and impenetrable Bosons with the mu/x_{ij}^2 particle-particle interaction, the Hellmann-Feynman theorem yields mutually compensating divergences of both the kinetic and the interaction energy in the limiting case mu to -1/4. These divergences result from the peculiar behavior of both the momentum distribution (for large momenta) and the pair density (for small inter-particle separation). The available analytical pair densities for mu=-1/4, 0, and 2 allow to analyze particle-number fluctuations. They are suppressed by repulsive interaction (mu>0), enhanced by attraction (mu<0), and may therefore measure the kind and strength of correlation. Other recently proposed purely quantum-kinematical measures of the correlation strength arise from the small-separation behavior of the pair density or - for Fermions - from the non-idempotency of the momentum distribution and its large-momenta behavior. They are compared with each other and with reference-free, short-range correlation-measuring ratios of the kinetic and potential energies.
Cite
@article{arxiv.cond-mat/0005129,
title = {Hellmann-Feynman theorem and fluctuation-correlation analysis of the Calogero-Sutherland model},
author = {Rudolf A. Roemer and Paul Ziesche},
journal= {arXiv preprint arXiv:cond-mat/0005129},
year = {2009}
}
Comments
30 pages, 9 figures, revised version, short version appeared as PRB 62, 15279-15282 (2000)