Cold atoms in an amplitude modulated optical lattice - dynamical tunneling.

We give an overview of our experiments on the quantum and classical dynamics of atoms in an amplitude modulated standing wave - the quantum driven pendulum. Atoms are prepared in a magneto-optic trap or as a dilute Bose-Einstein condensate and subjected to a far detuned optical standing wave. We observe the occurrence of a bifurcation sequence in the parameter space of the quantum driven pendulum. We also observe dynamical tunnelling between two classically isolated states of motion. The tunnelling process is coherent and we see more than eight tunnelling periods.