THEORY OF ANDREEV RESONANCES IN QUANTUM DOTS

We present theoretical results for the electrical conductance G of a q uantum dot in the presence of superconductivity. After deriving a gene ralization of the well-known Breit-Wigner formula, valid in the presen ce of superconducting leads, results for the distribution of conductan ce resonances are derived, For a normal (N) contact-normal dot (NDOT)- superconducting (S) contact, as the order parameter Delta of the S con tact tends to zero, recent predictions for the resonant structure of a normal chaotic dot are reproduced. When Delta increases from zero, fo r finite applied voltage, resonances are destroyed.