Confinement-Induced Resonances in Spherical Shell Traps

The energy spectrum and corresponding wave functions of two bosonic particles confined in a spherically symmetric shell trap and interacting via a three-dimensional zero-range potential are computed. Confinement-induced resonances, originating entirely from the strong coupling of the relative and center-of-mass motions of the two particles, are identified as avoided crossings for certain values of the shell radius. By working close to the found resonances, these results offer a new way to control the atom-atom interaction in an atomic gas by tuning only the geometrical parameters of the shell.