As an electrical analog of the optical Hanbury Brown Twiss effect, we study
current cross-correlations in a chaotic quantum dot-superconductor junction.
One superconducting and two normal reservoirs are connected via point contacts
to a chaotic quantum dot. For a wide range of contact widths and
transparencies, we find large positive current correlations. The positive
correlations are generally enhanced by normal backscattering in the contacts.
Moreover, for normal backscattering in the contacts, the positive correlations
survive when suppressing the proximity effect in the dot with a weak magnetic
field.Comment: 4 pages, 3 figure