## Abstract

We generalize the SU(N=2) S=1/2 square-lattice quantum magnet with nearest-neighbor antiferromagnetic coupling (J _{1}) and next-nearest-neighbor ferromagnetic coupling (J _{2}) to arbitrary N. For all N>4, the ground state has valence-bond-solid order for J _{2}=0 and Néel order for J _{2}/J _{1}1, allowing us access to the transition between these types of states for large N. Using quantum MonteCarlo simulations, we show that both order parameters vanish at a single quantum-critical point, whose universal exponents for large enough N (here up to N=12) approach the values obtained in a 1/N expansion of the noncompact CPN ^{-}1 field theory. These results lend strong support to the deconfined quantum-criticality theory of the Néel-valence-bond-solid transition.

Original language | English |
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Article number | 137201 |

Journal | Physical Review Letters |

Volume | 108 |

Issue number | 13 |

DOIs | |

State | Published - Mar 28 2012 |

## ASJC Scopus subject areas

- Physics and Astronomy (all)