Transmission phases in time-dependent transport

Recent pioneering measurements by a group headed by M. Heiblum have shown that it is possible to directly probe the quantum mechanical phase of a quantum dot. Surprisingly, the experiments show that in the vicinity of a Coulomb oscillation peak a single-particle description is possible, even though the quantum dot has strong interparticle correlations. We point out that a time-dependent gate voltage, applied on the plunger gate controlling the occupation in the quantum dot, should yield a wealth of new information on the phase-relaxation mechanisms within a strongly interacting quantum system. We are in the process of extending our qualitative considerations to realistic experimental systems: the full two-dimensional potential landscape will be discretized and solved on a computer.