COM framework for d-wave superconductivity in the 2D Hubbard model

✍ Scribed by Adolfo Avella; Ferdinando Mancini; Evgeny Plekhanov

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 256 KB
• Volume: 470
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2010.02.087

✦ Synopsis

The two-dimensional Hubbard model has been studied within the Composite Operator Method (COM) [1] starting from a basis made of the two Hubbard composite fields in the Nambu representation and computing the residual self-energy in the non-crossing approximation (NCA) [2]. The charge-charge, spinspin and pair-pair susceptibilities, involved in the calculation of the self-energy within NCA in the paramagnetic phase, has been computed in the two-pole approximation [1]. The analysis of the d-wave superconducting solution additionally requires the calculation of the charge-pair susceptibility. Therefore, we decided to enlarge the bosonic basis and consider a four-component composite bosonic field to be studied within a four-pole approximation. We here report, in some detail, the quite complex calculation framework and the charge-pair susceptibility in the one-loop approximation.