Multicanonical Monte Carlo simulations of anisotropic SU(3) and SU(4) Heisenberg models

We present the results of multicanonical Monte Carlo simulations on two-dimensional anisotropic SU(3) and SU(4) Heisenberg models. In our previous study [K.~Harada, et al., J.~Phys.~Soc.~Jpn. \textbf{76}, 013703 (2007)], we found evidence for a direct quantum phase transition from the valence-bond-solid(VBS) phase to the SU(3) symmetry breaking phase on the SU(3) model and we proposed the possibility of deconfined critical phenomena (DCP) [T.~Senthil, et al., Science \textbf{303}, 1490 (2004); T.~Grover and T.~Senthil, Phys. Rev. Lett. \textbf{98}, 247202 (2007)]. Here we will present new results with an improved algorithm, using a multicanonical Monte Carlo algorithm. Using a flow method-like technique [A.B.~Kuklov, et al., Annals of Physics \textbf{321}, 1602 (2006)], we discuss the possibility of DCP in both models.