Spectral-density polynomial expansion for two-particle Green's function in BdG framework

Nagai, Yuki   ; Ota, Yukihiro*; Machida, Masahiko  

We develop an efficient numerical method on the basis of the spectral-density polynomial expansion to calculate two-particle Green's function in Bogoliubov-de Gennes (BdG) framework for inhomogeneous superconducting systems. With use of this method, one can systematically and effectively evaluate various physical quantities such as spin or charge susceptibility, nuclear magnetic relaxation rate, optical or thermal conductivity even in magnetic fields. We demonstrate its remarkable feature, i.e. high efficiency with large-scale parallel computing techniques.