▎ 摘　　要

We compute the two-loop interaction correction to the minimal conductivity of disorder-free intrinsic graphene with the help of dimensional regularization. The calculation is done in two different ways: via density-density and via current-current correlation functions. Upon properly renormalizing the perturbation theory, in both cases, we find that sigma = sigma(0) ( 1 + alpha ( 19 - 6 Pi)/ 12) approximate to sigma(0) ( 1 + 0.01 alpha), where alpha = e(2) /( 4 Pi hv) is the renormalized fine structure constant and sigma(0) = e(2) /( 4 h). Our results are consistent with experimental uncertainties and resolve a theoretical dispute. editor's choice Copyright (C) EPLA, 2014