Emergence of non-equilibrium superconductivity originated from repulsive interaction; Demonstration using optical lattices and implication to solid-state matter system

Yamamoto, Atsushi; Yamada, Susumu  ; Machida, Masahiko  

We study the dynamical properties of ultracold fermions in one-dimensional optical superlattices by using the adaptive time-dependent density matrix renormalization group method. The system is repulsive Hubbard model with an two-site periodic superlattice potential. Owing to superlattice structure, the ground-state states become the Mott-type insulating state at quarter filling and band-type insulating state at half filling, respectively. We clarify the dynamical properties of time evolution when the system is non-adiabatically changed to another lattice structure. The strongly-correlated interaction an unusual pairing of fermions induced the pair hopping process. We further address the robustness of pair hopping process and possibility of superconductivity by using sudden change of the external potential.