Theory of Strong Coupling Superconductors

高温度超导体中最重要的问题之一是伪现象的不可理解的。我们已经用T矩阵近似法来澄清了伪隙的起源。它的起源是在quasi-two dimensional系统中实现强的吸引力交互的超行为。通过这个研究，我们已经成功地推导出了假间隙和超导体间隙上和下面的T-D2c-D2， respectively。The other important result obtained by our study is the explanation of origin of the superconductivity in strong相关电子系统。By using the perturbation theory we have successfully derived the superconducting state corresponding to each system; the d-wave gap state for the cuprates and the organic superconductor BEDT-TTF and the p-wave gap state for the triplet superconductor Sry D22-D2RuO-D24-D2。These facts show that the origin of superconducity is the momentum dependence of the interaction originated from the Coulomb repulOracle。Especially， theory of superconducity in Sry D22，D2RuO，D24，D2 is very important。系统中超导电性的临界温度为1.5 K。Even for this low T-D2c-D2 we can apply the perturbation theory and predict the appearance of superconductivity including the symmetry。因此，我们有一个强有力的方法来研究在密切相关的系统中的超导电性。这是我们研究中最重要的部分。

One of the most important problems in the high temperature superconductors is the understanding of pseudogap phenomena. We have made clear the origin of the pseudogap by using the T-matrix approximation. The origin is the superconducting fluctuation due to the strong attractive interaction in the quasi-two dimensional system. Through this research we have successfully derived the pseudogap and superconducting gap above and below TィイD2cィエD2, respectively.The other important result obtained by our study is the explanation of origin of the superconductivity in strongly correlated electron systems. By using the perturbation theory we have successfully derived the superconducting state corresponding to each system; the d-wave gap state for the cuprates and the organic superconductor BEDT-TTF and the p-wave gap state for the triplet superconductor SrィイD22ィエD2RuOィイD24ィエD2. These facts show that the origin of superconductivity is the momentum dependence of the interaction originated from the Coulomb repulsion.Especially, theory of superconductivity in SrィイD22ィエD2RuOィイD24ィエD2 is very important. The critical temperature of superconductivity in the system is 1.5K. Even for this low TィイD2cィエD2 we can apply the perturbation theory and predict the appearance of superconductivity including the symmetry. Therefore, we have a powerful method to study the possibility of superconductivity in the strongly correlated systems. This is the most important finding of our study.