The scattering length effect on properties of cold interacting Fermion systems in LOCV framework

The properties of cold interacting Fermi gases in terms of scattering length are investigated. The scattering length is calculated by exact solution of Schrödinger equation. A Cosine hyperbolic potential with variable strength is employed in this study. The different interaction regimes are provided by choosing different strength of potential, which are characterized by an inverse of S-wave scattering length and Fermi wave number. The energy per particle for 3He system is calculated within the lowest order constrained variational (LOCV) method. It is found that the bound bosonic pairs as well as bound molecules are formed at positive scattering length, only by considering two-body interactions.

A NUMERICAL STUDY OF THE QUANTUM OSCILLATIONS IN MULTIPLE DANGLING RINGS

We present the quantum mechanical calculations on the conductance of the quantum waveguide topology containing multiply connected dangling mesoscopic rings with the transfer matrix approach. The profiles of the conductance as functions of the Fermi wave number of electrons depend on the number of rings and also on the geometric configuration of the system. The conductance spectrum of this system for disordered lengths in the ring circumferences, dangling links, ballistic leads connecting consecutive dangling rings is examined in detail. We find that there exist two kinds of mini-bands, one originating from the eigenstates of the rings, i.e. the intrinsic mini-bands, and the extra mini-bands. Some of these extra minibands are associated with the dangling links connecting the rings to the main quantum wire, while others are from the standing wave modes associated with the ballistic leads connecting adjacent dangling rings. These different kinds of mini-bands have completely different properties and respond differently to the geometric parameter fluctuations. Unlike the system of potential scatterers, this system of geometric scatterers shows complete band formations at all energies even for finite number of scatterers present. There is a preferential decay of the energy states, depending upon the type of disorder introduced. By controling the geometric parameters, the conductance band structure of such a model can be artificially tailored.

Density Dependent Potentials in Simple Liquids

The density dependence of effective pair potentials may be studied through the density dependence of the liquid structure factor. For a liquid alkali metal (Rb) it is suggested that the ρ1/3 behavior of the Fermi wave-number of the electron gas explains the ρ1/3 behavior of the liquid structure factor recently discovered by Egelstaff et al. For the Lennard-Jones fluid and for liquid neon it is suggested that a near ρ-independent potential gives rise to ρ-dependent changes in the liquid structure factor corresponding to changes in the number of nearest neighbors in real space. This suggestion is tested by comparison with experiment.