Well-Defined Quasiparticles in Interacting Metallic Grains

Well-defined quasiparticles in interacting metallic grains.

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-te...

Spectroscopy of Interacting Quasiparticles in Trapped Ions.

The static and dynamic properties of many-body quantum systems are often well described by collective excitations, known as quasiparticles. Engineered quantum systems offer the opportunity to study such emergent phenomena in a precisely controlled and otherwise inaccessible way. We present a spectroscopic technique to study artificial quantum matter and use it for characterizing quasiparticles ...

Anderson localization of Bogolyubov quasiparticles in interacting Bose-Einstein condensates.

We study the Anderson localization of Bogolyubov quasiparticles in an interacting Bose-Einstein condensate (with a healing [corrected] length xi) subjected to a random potential (with a finite correlation length sigma(R)). We derive analytically the Lyapunov exponent as a function of the quasiparticle momentum k, and we study the localization maximum k(max). For 1D speckle potentials, we find t...

Superconducting correlations in ultra-small metallic grains

– To describe the crossover from the bulk BCS superconductivity to a fluctuationdominated regime in ultrasmall metallic grains, new order parameters and correlation functions, such as “parity gap” and “pair-mixing correlation function”, have been recently introduced. In this paper, we discuss the small-grain behaviour of the Penrose-Onsager-Yang off-diagonal long-range order (ODLRO) parameter i...

Mitochondrial Haplogroups and Well Defined Populations