Signatures of a Discrete Level Spectrum and Dynamical Tunneling in the Conductance of a Large Open Quantum Dot

We simulate transport in large, strongly-open, quantum dots, which typically would be viewed as lying well within the semiclassical regime for which all energy levels can be assumed to be broadened. Contrary to this assumption, we find that resonances, which can be associated with individual eigenstates, can persist even under these conditions. Their presence yields regular fluctuations in the low temperature conductance which persist in the presence of a moderately-disordered dot potential and can be observed experimentally. Examining the resonant wave functions, we typically find them to be scarred by regular periodic orbits which are classically inaccessible from the leads. As such, our results suggest that dynamical phase-space tunneling may play a more generic role in transport through mesoscopic structures than has thus far been appreciated.