Dimensional crossover of the superfluid state in the attractive Hubbard model

International Conference on Strongly Correlated Electron Systems 2014

Ogawa, Naoki^1 ; Kaneko, Tatsuya^1 ; Ohta, Yukinori^1

Department of Physics, Chiba University, Chiba

263-8522, Japan^1

关键词: Cluster approximation;    Coherence lengths;    Density of state;    Dimensional crossover;    Order parameter;    Quantum fluctuation;    Square lattices;    Superfluid state;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/592/1/012103/pdf
DOI  :  10.1088/1742-6596/592/1/012103

来源: IOP

【 摘 要 】

The superfluid state in the attractive Hubbard is studied for the stacked square lattices to simulate the two- to three-dimensional crossover effects. We use the variation cluster approximation to calculate the order parameter and pair coherence length from the weak-coupling BCS state to the strong-coupling BEC state at T =0 K. We show that in the weak-coupling BCS region the density of states at Fermi level plays an important role in the dimensional crossover of the superfluid state but in the strong-coupling BEC region the quantum fluctuations depending on the dimensionality of the system play an essential role.