Z4-U(1) crossover of the order parameter symmetry in a two-dimensional valence-bond-solid

Abstract

We discuss ground-state projector simulations of a modified two-dimensional S=1/2 Heisenberg model in the valence bonds basis. Tuning matrix elements corresponding to the diagonal and off-diagonal terms in the quantum dimer model, we show that there is a quantum phase transition from the antiferromagnet into a columnar valence-bond-solid (VBS). There are no signs of discontinuities, suggesting a continuous or very weakly first-order transition. The Z4-symmetric VBS order parameter exhibits an emergent U(1) symmetry as the phase transition is approached. We extract the associated length-scale governing the U(1)-Z4 cross-over inside the VBS phase.

4 pages, 5 figures. v2: minor corrections/additions

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Cited by in corpus (6)

• Plaquette Ordered Phase and Quantum Phase Diagram in the Spin-1/2 J1-J2 Square Heisenberg Model
• Loop updates for variational and projector quantum Monte Carlo simulations in the valence-bond basis
• Néel to valence-bond solid transition on the honeycomb lattice: Evidence for deconfined criticality
• Magnetization plateaus of an easy-axis Kagomé antiferromagnet with extended interactions
• Dual dynamic scaling in deconfined quantum criticality
• Deconfined-critical behavior of the VBS- and nematic-order parameters for the spatially anisotropic S=1-spin model