# Our lab and experiments

## Resonantly enhanced tunneling

Resonantly enhanced tunneling of a Bose-Einstein condensate inside an accelerated optical lattice. Whenever the energy levels of adjacent lattice wells are shifted into resonance by the resulting force, the tunneling probability is enhanced over the Landau-Zener prediction (dashed line).

When particles tunnel quantum-mechanically between two potential wells, the tunneling probability can be greatly enhanced when the energy of the quantized state in the original well coincides with that of the target well. In the solid state, such resonantly enhanced tunneling can be brought about by applying an electric field and thus shifting the electronic energies into resonance. In our experiment, we used Bose-Einstein condensates inside optical lattices to study this effect. The role of the electric field was played by an acceleration of the lattice which, in its rest frame, corresponds to a force on the condensate atoms. By scanning this force, we clearly observed the expected tunneling resonances. We also added a nonlinearity to our system and study its effects on the resonant tunneling.

C. Sias, A. Zenesini, H. Lignier, S. Wimberger, D. Ciampini, O. Morsch, and E. Arimondo, "*Resonantly Enhanced Tunneling of Bose-Einstein Condensates in Periodic Potentials*", Phys. Rev. Lett. 98, 120403 (2007)