Quantum Monte Carlo study of electrostatic potential in graphene

In this paper the interaction potential between static charges in suspended graphene is studied within the quantum Monte Carlo approach. We calculated the dielectric permittivity of suspended graphene for a set of temperatures and extrapolated our results to zero temperature. The dielectric permittivity at zero temperature is found to have the following properties. At zero distance ε=2.24±0.02. Then it rises and at a large distance the dielectric permittivity reaches the plateau ε≃4.20±0.66. The results obtained in this paper allow us to draw a conclusion that full account of many-body effects in the dielectric permittivity of suspended graphene gives ε very close to the one-loop results. Contrary to the one-loop result, the two-loop prediction for the dielectric permittivity deviates from our result. So one can expect large higher order corrections to the two-loop prediction for the dielectric permittivity of suspended graphene.