920860.fig.003a
(a)
920860.fig.003b
(b)
Figure 3: Effective e-ph vertex in units of the bare e-ph coupling as a function of the Matsubara frequency in the HH model at leading order in . The parameters are the same as in Figure 2. Panel (a) is for a small transferred momentum (in units of inverse lattice spacing ); (b) is for a sizable transferred momentum (after [54]).