Transmission phase of an isolated Coulomb blockade resonance

In two recent papers, O. Entin-Wohlman et al. [cond-mat/0109328 (unpublished) and (private communication)] studied the question: “Which physical information is carried by the transmission phase through a quantum dot?” In the present paper, this question is answered for an islolated Coulomb blockade resonance and within a theoretical model which is more closely patterned after the geometry of the actual experiment by Schuster et al. [Nature 385, 417 (1997)] than is the model of O. Entin-Wohlman et al. We conclude that whenever the number of leads coupled to the Aharanov-Bohm interferometer is larger than two, and the total number of channels is sufficiently large, the transmission phase does reflect the Breit-Wigner behavior of the resonance phase shift.