5月20日凝聚态物理Colloquium《Repulsive pairing in many-body interacting system and the extended Hubbard model》 [2010-05-16]

　　Prof. Dr. Jiu-Qing Liang fron Shanxi Univ. will be visiting USTC from May 19 to 22 and will give a colloquium on May 20 at 4:00 pm in National Lab Building Rm. 9004.

　　The title of his talk is "Repulsive pairing in many-body interacting ystem and the extended Hubbard model".

Abstract:

　　We propose a Hamiltonian of ultracold atoms in optical lattices including the two-body interaction of nearest neighbors, which reduces to the Bose-Hubbard model in weak-interaction limit. An atom-pair hopping term appearing in the Hamiltonian explains naturally the recent experimental observation of correlated tunneling in a double-well trap with strong atom-atom interactions and moreover leads to a dynamic process of atom-pair tunneling where strongly interacting atoms can tunnel back and forth as a fragmented pair. A new dynamic state of oscillations induced by the atom-pair tunneling is found in the strong interaction regime, where the Bose-Hubbard model gives rise to the insulator state with fixed time-averaged value of atom-occupation number only. Quantum phase transitions between two quantum phases characterized by degenerate and nondegenerate ground states are shown to be coinciding with the Landau second-order phase-transition theory. New repulsive bound-state solutions of atom-pair in a one-dimension optical lattice are found explicitly. We also show the rich phase diagrams of supersolid and pair-superfluid phases.

　　All Welcome!