SO(4) symmetry and off-diagonal long-range order in the Hubbard bilayer

作者：Shi Y

来源：Communications in Theoretical Physics, 1997, 28(1): 23-28.

Yang';s eta pairing operator is generalized to explore off-diagonal long-range order in the Hubbard bilayer with an arbitrary chemical potential. With this operator and a constraint condition on annihilation and creation operators, we construct explicitly eigenstates which possess simultaneously three kinds of off-diagonal long-range order, i.e., the intralayer one and the interlayer one for on-site pairing, and that for interlayer nearest-neighbor pairing. As in the simple Hubbard model there is also an SO(4) symmetry, with the generators properly defined. A sufficient condition leads to at least one of the above three kinds of off-diagonal long-range order. A constraint relation among different kinds of off-diagonal long-range order is also given. There exists a triplet of collective modes if the U(1) symmetry pf a subgroup is spontaneously broken.

• 出版日期1997-7-30
• 单位复旦大学