Fermionic quantum critical point of spinless fermions on a honeycomb lattice

Spinless fermions on a honeycomb lattice provide a minimal realization of lattice Dirac fermions. Repulsive interactions between nearest neighbors drive a quantum phase transition from a Dirac semimetal to a charge-density-wave state through a fermionic quantum critical point, where the coupling of the Ising order parameter to the Dirac fermions at low energy drastically affects the quantum critical behavior. Encouraged by a recent discovery (Huffman and Chandrasekharan 2014 Phys. Rev. B 89 111101) of the absence of the fermion sign problem in this model, we study the fermionic quantum critical point using the continuous-time quantum Monte Carlo method with a worm-sampling technique. We estimate the transition point V / t = 1.356 ( 1 ) ?> with the critical exponents &ngr; = 0.80 ( 3 ) ?> and &eegr; = 0.302 ( 7 ) ?> . Compatible results for the transition point are also obtained with infinite projected entangled-pair states.