Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 56: Correlated Electrons: Quantum-Critical Phenomena – Theory
TT 56.6: Talk
Wednesday, March 18, 2015, 10:45–11:00, A 053
Deconfined quantum criticality beyond designer Hamiltonians — •Ribhu K. Kaul1 and Thomas C. Lang2 — 1University of Kentucky, Lexington, USA — 2Boston University, Boston, USA
The SU(6) symmetric generalization of the Hubbard model on the square lattice constitutes a candidate for a direct, continuous quantum phase transition from Néel to valence bond solid (VBS) order. By constructing dimensionless quantities such as ratios of the magnetic structure factor and valence bond correlations we are able to unambiguously determine the existence of weak, but robust antiferromagnetic order in the weak coupling regime and a plaquette VBS in the strong coupling limit. Furthermore these ratios provide a tool to accurately determine the (critical) point from both sides of the phase transition separating the two limits. Preliminary results suggest a direct continuous transition for which we extract basic estimates for the critical exponents and compare the scaling function with results from designer SU(6) spin models to investigate whether this quantum phase transition is compatible with the scenario of deconfined quantum criticality.