Toward a measurement of the effective gauge field and the Born-Huang   potential with atoms in chip traps
  We study magnetic traps with very high trap frequencies where the spin is coupled to the motion of the atom. This allows us to investigate how the Born-Oppenheimer approximation fails and how effective magnetic and electric fields appear as the consequence of the non-adiabatic dynamics. The results are based on exact numerical diagonalization of the full Hamiltonian describing the coupling between the internal and external degrees of freedom. The position in energy and the decay rate of the trapping states correspond to the imaginary part of the resonances of this Hamiltonian and are computed using the complex rotation method. 
Zeynep Nilhan G\"urkan, Erik Sj\"oqvist, Bj\"orn Hessmo, Beno\^it   Gr\'emaud
quant-ph