42 research outputs found
Cooper pair dispersion relation in two dimensions
The Cooper pair binding energy {\it vs.} center-of-mass-momentum dispersion
relation for Bose-Einstein condensation studies of superconductivity is found
in two dimensions for a renormalized attractive delta interaction. It crosses
over smoothly from a linear to a quadratic form as coupling varies from weak to
strong.Comment: 2 pages, 1 figure, new version published in Physica
The Isgur-Wise Function to from Sum Rules in the Heavy Quark Effective Theory
Radiative corrections to both perturbative and non-perturbative contributions
are added to existing calculations of the Isgur-Wise function . To
this end, we develop a method for calculating two-loop integrals in the heavy
quark effective theory involving two different scales. The inclusion of
terms causes to decrease as compared to the lowest
order result and shows the importance of quantum effects. The slope parameter
violates the bound given by de Rafael and Taron.Comment: 11 pages, 2 figures (not included), (LaTeX), HD-THEP-92-4
Two-dimensional electron gas in a uniform magnetic field in the presence of a delta-impurity
The density of states and the Hall conductivity of a two-dimensional electron
gas in a uniform magnetic field and in the presence of a delta impurity are
exactly calculated using elementary field theoretic techniques. Although these
results are not new, our treatment is explicitly gauge-invariant, and can be
easily adapted to other problems involving a delta potential.Comment: 12+1 pages, 1 ps figure, REVTEX. Corrigendum adde