title: Nonuniversal behavior of the k-body embedded Gaussian unitary ensemble of random matrices.
abstract: Using a novel approach, we investigate the shape of the average spectrum and the spectral fluctuations of the k-body embedded unitary ensemble in the limit of a large matrix dimension. We identify the transition point between a semicircle and a Gaussian shape. The transition also affects the spectral fluctuations which deviate from the Wigner-Dyson form and become Poissonian in the limit k<<m<<l. Here m is the number of fermions and l the number of degenerate single-particle states.
authors.affiliation: Max-Planck-Institut für Kernphysik, D-69029 Heidelberg, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Benet
authors.forename: T
authors.initials: T
authors.lastname: Rupp
authors.forename: H A
authors.initials: HA
authors.lastname: Weidenmüller