Thursday, July 4, 2013

1307.0501 (Kenji Harada et al.)

Possibility of Deconfined Criticality in SU(N) Heisenberg Models at
Small N

Kenji Harada, Takafumi Suzuki, Tsuyoshi Okubo, Haruhiko Matsuo, Jie Lou, Hiroshi Watanabe, Synge Todo, Naoki Kawashima
To examine the validity of the scenario of the deconfined critical phenomena, we carry out quantum Monte Carlo simulation for the SU(N) generalization of the Heisenberg model with four-body and six-body interactions. The quantum phase transition between the SU(N) N\'eel and valence-bond solid phases is characterized for N=2,3, and 4 on the square and honeycomb lattices. While finite-size scaling analysis works well up to the maximum lattice size (L=256) and indicates the continuous nature of the phase transition, a clear systematic change is observed in the estimates of the critical exponent $y \equiv 1/\nu$ as the system size increases. The scaling-dimension of the squared valence-bond solid field $\Psi^2$ is also estimated for the SU(3) model with the assumption of the criticality. It suggests the relevance of $\Psi^2$ at the deconfined-critical fixed point.
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