content_image/419747.jpg content_image/419748.jpg content_image/419749.jpg content_image/419750.jpg content_image/419752.jpg content_image/419754.jpg content_image/419753.jpg content_image/419755.jpg content_image/419757.jpg content_image/419756.jpg content_image/419758.jpg
## Appendix A: Gor’kov-Nambu representation 

We consider equation (11) in Fourier representation. By inserting specific values of charge quantum number 

λ = ± 1 we obtain ( k = ( − → k , iω$_{n}$ )): 

<img src='content_image/419747.jpg'>

<img src='content_image/419748.jpg'>

<img src='content_image/419749.jpg'>

<img src='content_image/419750.jpg'>

Here 

<img src='content_image/419752.jpg'>

Assuming that the system is in a paramagnetic state, that superconductivity has a singlet character and using the definitions (8) together with the additional ones: 

<img src='content_image/419754.jpg'>

we obtain the following results: 

<img src='content_image/419753.jpg'>

<img src='content_image/419755.jpg'>

which coincide with those found in the papers [9 , $^{10]}$. 

In spinor representation the system of equations (A1-A7) has the form 

were 

<img src='content_image/419757.jpg'>

<img src='content_image/419756.jpg'>

By using equation (9) we can obtain 

<img src='content_image/419758.jpg'>

