Interference effects in restricted systems

I considered two types of interference problems in restricted systems: the interference between bulk and boundary scattering in metal films and the effect of interference between particle repulsion and the constraining potential in Bose-Einstein Condensation (BEC) in inhomogeneous traps. The quantum mechanical and quasiclassical interference between bulk and boundary scattering in thin metal films with rough surface was first investigated by calculating the effective transport time beyond the Mathiessen’s approximation, which was shown to exhibit a non-analytical dependence on the bulk relaxation time. The interference between the bulk and boundary scattering channels strongly affects the effective transport time and conductivity and is dependent on the temperature and the concentration of the impurities. Simple analytical expressions for the results for large bulk free paths [special characters omitted] and large correlation radii (lateral sizes) R of surface inhomogeneities were found. At R² ∼ [special characters omitted] a crossover was predicted between two asymptotic regimes for interference contributions characterized by a different dependence to temperature and concentration. I also studied the condensation process in a strongly interacting trapped BEC in an optical lattice. The interaction between particles in a BEC within a trap pushes the normal particles to a spherical shell in the periphery reducing the condensation problem to a quasi-two dimensional one. By conducting a study of these two types of interference problems in different restricted systems, I was able to better understand the underlying physics of competing phenomena in these systems