Tunneling of two interacting atoms from excited states

• Published in: Physica. E, Low-dimensional systems & nanostructures Vol. 109; pp. 24 - 29
• Main Authors: Ishmukhamedov, I.S., Ishmukhamedov, A.S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2019
• Subjects: Anharmonic trap; Avoided crossing; Energy spectrum; One-dimensional geometry; Tunneling rate; Ultracold atoms; Energy spectrum; Tunneling rate; One-dimensional geometry; Ultracold atoms; Anharmonic trap; Avoided crossing
• ISSN: 1386-9477; 1873-1759
• DOI: 10.1016/j.physe.2018.12.026

We consider a tunneling problem of two interacting cold atoms, with the even spatial symmetry, subject to an anharmonic optical trap and linear magnetic-field gradient. The atoms are initially, i.e. at t = 0, prepared in the two lowest excited states with respect to relative and center-of-mass motions. We calculate the energy spectrum for a wide range of the interatomic coupling strength g1D. In the limit of g1D → 0, an avoided crossing of the energy levels is revealed. For the dynamics, i.e. for t > 0, we observe monotonic and non-monotonic dependence of a tunneling rate as a function of g1D. We find a condition to observe a transition from uncorrelated to correlated pair tunneling as a function of g1D and a size of the external trap barrier. This system, although for lower energy levels, has been recently investigated in the deterministic Heidelberg experiment using two interacting 6Li atoms. •Two interacting atoms subject to anharmonic laser field are initially prepared in the lowest excited quantum states.•The energy levels become avoided crossings, which is due to rotational symmetry breaking.•Non-monotonic dependence of a tunneling rate as a function of the interatomic coupling constant.•Transition from uncorrelated to correlated pair tunneling can be observed by reducing a size of the trap barrier.