title: Fluctuations in the level density of a fermi gas.
abstract: We present a theory that accurately describes the counting of excited states of a noninteracting fermionic gas. At high excitation energies the results reproduce Bethe's theory. At low energies oscillatory corrections to the many-body density of states, related to shell effects, are obtained. The fluctuations depend nontrivially on energy and particle number. Universality and connections with Poisson statistics and random matrix theory are established for regular and chaotic single-particle motion.
authors.affiliation: Laboratoire de Physique Théorique et Modèles Statistiques, Bâtiment 100, Université de Paris-Sud, 91405 Orsay CEDEX, France.
authors.forename: P
authors.initials: P
authors.lastname: Leboeuf
authors.forename: A G
authors.initials: AG
authors.lastname: Monastra
authors.forename: A
authors.initials: A
authors.lastname: Relaño