text: 1 
  2 
  Σ′(ω) = −  λnωo Re 
  
  Z 
  
  (16) 
  Observe that Σ′′(ω) is no-zero only for ω < −ωo − ∆. 
  Also, although it does not straightforwardly follow from 
  Eq. 16, but real and imaginary parts of the self-energy 
  do satisfy Σ′(ω) = −Σ′(−ω) and Σ′′(ω) = Σ′′(−ω). 
  
  Fig7 shows conductivities σ(ω) and Kubo sums WK 
  as a function of the dimensionless coupling λ. We see 
  that, like in the previous case, the Kubo sum in the NS 
  is larger than that in the SCS. The diﬀerence ∆WK is 
  between 5 and 8 meV. 
  
  Fig 8 shows the evolution of the optical integrals. Here 
  we see the diﬀerence with the BCSI model – only about 
  75% of the optical integral is recovered, both in the NS 
  and SCS, when we integrate up to the bandwidth of 1eV . 
  The rest comes from higher frequencies. 