On-site pairing interaction and quantum coherence in strongly correlated systems

Yamada, Susumu  ; Machida, Masahiko  ; Kano, Takuma; Imamura, Toshiyuki*; Koyama, Tomio*

We numerically investigate a dependence of pairing interaction strength on quantum coherence and related tunneling dynamics in order to clarify whether the strong pairing interaction suppresses quantum coherent characters. The simulation is performed by using the attractive Hubbard model with double well potential. The simulation result reveals that the tunneling dynamics between the separated wells is dramatically suppressed with increasing the pairing interaction. This fact implies that the pair coherence is easily lost under randomness when the pairing interaction becomes very strong. We claim that such an issue is related to the loss of the pair coherence in under-doped High- superconductors. In addition, we note that the tunneling dynamics can be directly confirmed by using the crossover from BCS to BEC in atomic Fermi gases.