Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 56: Correlated Electrons: Quantum-Critical Phenomena – Theory

TT 56.9: Talk

Wednesday, March 18, 2015, 11:45–12:00, A 053

Fermionic quantum criticality in honeycomb and π-flux Hubbard models — •Francesco Parisen Toldin¹, Martin Hohenadler¹, Fakher F. Assaad¹, and Igor F. Herbut² — ¹Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Germany — ²Department of Physics, Simon Fraser University, Burnaby, Canada

We numerically investigate the critical behavior of the Hubbard model on the honeycomb and the π-flux lattice, which exhibits a direct transition from a Dirac semimetal to an antiferromagnetically ordered Mott insulator. We use projective auxiliary-field quantum Monte Carlo simulations and a careful finite-size scaling analysis that exploits improved renormalization-group invariant observables. This approach, which is successfully verified for the 3D XY transition of the Kane-Mele-Hubbard model, allows us to extract estimates for the critical couplings and the critical exponents. The results confirm that the critical behavior for the semimetal to Mott insulator transition in the Hubbard model belongs to the Gross-Neveu-Heisenberg universality class on both lattices.

[1] F. P. Toldin, M. Hohenadler, F. F. Assaad, I. F. Herbut,

arXiv:1411.2502