Nonperturbative theoretical description of two atoms in an optical lattice with time-dependent perturbations

A theoretical approach for a nonperturbative dynamical description of two interacting atoms in an optical lattice potential is introduced. The approach builds upon the stationary eigenstates found by a procedure described by Grishkevich [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.84.062710 84, 062710 (2011)]. It allows us presently to treat any time-dependent external perturbation of the lattice potential up to quadratic order. Example calculations of the experimentally relevant cases of an acceleration of the lattice and the turning-on of an additional harmonic confinement are presented.