Parametrization of Nambu Vertex in a Singlet Superconductor
Abstract
We analyze general properties of the effective Nambu twoparticle vertex and its renormalization group flow in a spinsinglet superconductor. In a fully spinrotation invariant form the Nambu vertex can be expressed by only three distinct components. Solving exactly the flow of a meanfield model with reduced BCS and forward scattering interactions, we gain insight into the singularities in the momentum and energy dependences of the vertex at and below the critical energy scale for superconductivity. Using a decomposition of the vertex in various interaction channels, we manage to isolate singular momentum and energy dependences in only one momentum and energy variable for each term, such that the singularities can be efficiently parametrized.
 Publication:

Progress of Theoretical Physics
 Pub Date:
 September 2010
 DOI:
 10.1143/PTP.124.471
 arXiv:
 arXiv:1005.3521
 Bibcode:
 2010PThPh.124..471E
 Keywords:

 Condensed Matter  Superconductivity;
 Condensed Matter  Strongly Correlated Electrons
 EPrint:
 21 pages, 5 figures