Field-assisted doublon manipulation in the Hubbard model: A quantum doublon ratchet
Max Planck Research Department for Structural Dynamics, University of Hamburg-CFEL, Building 99 Luruper Chaussee 149, 22761 Hamburg, Germany
Received: 10 March 2014
Accepted: 22 August 2014
For the fermionic Hubbard model at strong coupling, we demonstrate that directional transport of localized doublons (repulsively bound pairs of two particles occupying the same site of the crystal lattice) can be achieved by applying an unbiased ac field of time-asymmetric (sawtooth-like) shape. The mechanism involves a transition to intermediate states of virtually zero double occupation which are reached by splitting the doublon by fields of the order of the Hubbard interaction. The process is discussed on the basis of numerically exact calculations for small clusters, and we apply it to more complex states to manipulate the charge order pattern of one-dimensional systems.
PACS: 71.10.Fd – Lattice fermion models (Hubbard model, etc.) / 71.70.-d – Level splitting and interactions / 37.10.Jk – Atoms in optical lattices
© EPLA, 2014