title: On the Lindemann criterion for quantum clusters at very low temperature.
abstract: The Lindemann criterion to discern the solid-like or liquid-like nature of a quantum cluster at T = 0 is discussed. A critical analysis of current Lindemann parameters is presented and a new parameter is proposed that is appropriate to study quantum clusters made of identical particles. A simple model wave function is introduced to fix the range of variation of these parameters. The model presents two extreme limits that correspond to either a liquid-like or a solid-like system; besides, it fulfills the Bose symmetry and also permits evaluations without symmetrization. Variational and diffusion Monte Carlo calculations are also performed for clusters of spinless bosons interacting through Lennard-Jones potentials. It is shown that the liquid-like or solid-like character of quantum clusters at zero temperature cannot be simply established in terms of a single parameter.
authors.affiliation: IFIC (CSIC-Universidad de Valencia), Edificio Institutos de Paterna, Apartado Postal 22085, 46071 Valencia, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Guardiola
authors.forename: J
authors.initials: J
authors.lastname: Navarro