title: Well-defined quasiparticles in interacting metallic grains.
abstract: We analyze spectral functions of mesoscopic systems with large dimensionless conductance, which can be described by a universal Hamiltonian. We show that an important class of spectral functions are dominated by one single state only, which implies the existence of well-defined (i.e., infinite-lifetime) quasiparticles. Furthermore, the dominance of a single state enables us to calculate zero-temperature spectral functions with high accuracy using the density-matrix renormalization group. We illustrate the use of this method by calculating the tunneling density of states of metallic grains, of which we discuss the crossover from the few-electron to the bulk regime.
authors.affiliation: Physics Department and CeNS, LMU München, Theresienstrasse 37, 80333 Münich, Germany. gobert@lmu.de
authors.forename: Dominique
authors.initials: D
authors.lastname: Gobert
authors.forename: Moshe
authors.initials: M
authors.lastname: Schechter
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schollwöck
authors.forename: Jan
authors.initials: J
authors.lastname: von Delft