▎ 摘　　要

We compute the Coulomb correction C to the ac conductivity of interacting massless Dirac particles in graphene in the collisionless limit using the polarization tensor approach in a regularization-independent framework. Arbitrary parameters stemming from differences between logarithmically divergent integrals are fixed on physical grounds exploiting only the spatial O(2) rotational invariance of the model which amounts to the transversality of the polarization tensor. Consequently C is unequivocally determined to be (19 - 6 pi)/12 within this effective model. We compare our result with explicit regularizations and discuss the origin of other results for C found in the literature. Copyright (C) EPLA, 2013