title: Stability of Dirac Liquids with Strong Coulomb Interaction.
abstract: We develop and apply the diagrammatic Monte Carlo technique to address the problem of the stability of the Dirac liquid state (in a graphene-type system) against the strong long-range part of the Coulomb interaction. So far, all attempts to deal with this problem in the field-theoretical framework were limited either to perturbative or random phase approximation and functional renormalization group treatments, with diametrically opposite conclusions. Our calculations aim at the approximation-free solution with controlled accuracy by computing vertex corrections from higher-order skeleton diagrams and establishing the renormalization group flow of the effective Coulomb coupling constant. We unambiguously show that with increasing the system size L (up to ln(L)∼40), the coupling constant always flows towards zero; i.e., the two-dimensional Dirac liquid is an asymptotically free T=0 state with divergent Fermi velocity.
authors.affiliation: Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA.|National Research Center "Kurchatov Institute", 123182 Moscow, Russia.
authors.forename: Igor S
authors.initials: IS
authors.lastname: Tupitsyn
authors.affiliation: Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA.|National Research Center "Kurchatov Institute", 123182 Moscow, Russia.|Department of Theoretical Physics, The Royal Institute of Technology, Stockholm SE-10691, Sweden.
authors.forename: Nikolay V
authors.initials: NV
authors.lastname: Prokof'ev