Tunneling theory of two interacting atoms in a trap

A theory for the tunneling of one atom out of a trap containing two interacting cold atoms is developed. The quasiparticle wave function, dressed by the interaction with the companion atom in the trap, replaces the non-interacting orbital at resonance in the tunneling matrix element. The computed tunneling time for two 6Li atoms agrees with recent experimental results [G. Zuern, F. Serwane, T. Lompe, A. N. Wenz, M. G. Ries, J. E. Bohn, and S. Jochim, arXiv:1111.2727], unveiling the `fermionization' of the wave function and a novel two-body effect.