TY  - JOUR
A1  - Assaad, Fakher F.
A1  - Herbut, Igor F.
T1  - Pinning the Order: The Nature of Quantum Criticality in the Hubbard Model on Honeycomb Lattice
T2  - Physical Review X
N2  - In numerical simulations, spontaneously broken symmetry is often detected by computing two-point correlation functions of the appropriate local order parameter. This approach, however, computes the square of the local order parameter, and so when it is small, very large system sizes at high precisions are required to obtain reliable results. Alternatively, one can pin the order by introducing a local symmetrybreaking field and then measure the induced local order parameter infinitely far from the pinning center. The method is tested here at length for the Hubbard model on honeycomb lattice, within the realm of the projective auxiliary-field quantum Monte Carlo algorithm. With our enhanced resolution, we find a direct and continuous quantum phase transition between the semimetallic and the insulating antiferromagnetic states with increase of the interaction. The single-particle gap, measured in units of Hubbard U, tracks the staggered magnetization. An excellent data collapse is obtained by finite-size scaling, with the values of the critical exponents in accord with the Gross-Neveu universality class of the transition.
KW  - strongly correlated materials
KW  - mesoscopics
KW  - computational physics
Y1  - 2013
UR  - https://opus.bibliothek.uni-wuerzburg.de/frontdoor/index/index/docId/12982
UR  - https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-129829
VL  - 3
IS  - 031010
ER  -