Capone M, Castellani C, Grilli M
Dipartimento di Fisica, Università di Roma La Sapienza, and INFM Center for Statistical Mechanics and Complexity, Piazzale Aldo Moro 2, I-00185 Roma, Italy.
Phys Rev Lett. 2002 Mar 25;88(12):126403. doi: 10.1103/PhysRevLett.88.126403. Epub 2002 Mar 11.
A dynamical mean-field theory analysis of the attractive Hubbard model in the normal phase is carried out upon restricting to solutions where superconducting order is not allowed. A clear first-order pairing transition as a function of the coupling takes place at all the electron densities out of half filling between a Fermi liquid, stable for U<U(c), and an insulating bound pairs phase for U>U(c), and it is accompanied by phase separation. The spectral function in the metallic phase is constituted by a low-energy structure around the Fermi level, which disappears discontinuously at U = U(c), and two high-energy features (Hubbard bands), which persist in the insulating phase.
在不考虑超导序的情况下，对正常相中吸引性哈伯德模型进行了动态平均场理论分析。作为耦合函数的清晰一阶配对转变发生在所有非半填充电子密度下，在费米液体（对于U < U(c)稳定）和U > U(c)时的绝缘束缚对相之间，并且伴随着相分离。金属相中的谱函数由费米能级附近的低能结构构成，该结构在U = U(c)时不连续消失，以及两个高能特征（哈伯德带），它们在绝缘相中持续存在。
