▎ 摘　　要

We reexamine the effect of long-range Coulomb interactions on the quasiparticle velocity in graphene. Using a nonperturbative functional renormalization group approach with partial bosonization in the forward scattering channel and momentum transfer cutoff scheme, we calculate the quasiparticle velocity, v(k), and the quasiparticle residue, Z, with frequency-dependent polarization. One of our most striking results is that v(k) alpha ln[C-k(alpha)/k] where the momentum-and interaction-dependent cutoff scale C-k(alpha) vanishes logarithmically for k -> 0. Here k is measured with respect to one of the charge neutrality (Dirac) points and alpha = 2.2 is the strength of dimensionless bare interaction. Moreover, we also demonstrate that the so-obtained multilogarithmic singularity is reconcilable with the perturbative expansion of v(k) in powers of the bare interaction.