title: Level density of a Fermi gas: average growth and fluctuations.
abstract: We compute the level density of a two-component Fermi gas as a function of the number of particles, angular momentum, and excitation energy. The result includes smooth low-energy corrections to the leading Bethe term (connected to a generalization of the partition problem and Hardy-Ramanujan formula) plus oscillatory corrections that describe shell effects. When applied to nuclear level densities, the theory provides a unified formulation valid from low-lying states up to levels entering the continuum. The comparison with experimental data from neutron resonances gives excellent results.
authors.affiliation: Laboratoire de Physique Théorique et Modèles Statistiques, Bâtiment 100, Université de Paris-Sud, 91405 Orsay Cedex, France.
authors.forename: Patricio
authors.initials: P
authors.lastname: Leboeuf
authors.forename: Jérôme
authors.initials: J
authors.lastname: Roccia