Investigating dynamical tunnelling in open quantum dots by means of a soft-walled microwave-cavity analogue

We investigate the signatures of dynamical tunnelling in open quantum dots, by implementing a soft-walled microwave cavity as a novel analogue system. We explore the evidence for dynamical tunnelling by studying the evolution of the wavefunction phase as a function of frequency and show evidence for evanescent coupling to isolated orbits, including the existence of 'dirty' states in the wavefunction that are generated from a degenerate pair of 'clean' states when they are degraded by their tunnelling interaction. Our investigations provide a useful analogue of quantum transport in open quantum dots, and demonstrate the importance of dynamical tunnelling that arises from the mixed classical dynamics that is inherent to these structures.