Quantum scaling of the spin lattice relaxation rate in the checkerboard-model.

Motivated by recent progress on the experimental realization of proximate deconfined quantum critical point in a frustrated quantum magnet, we study the low-energy spin dynamics of a related checkerboard-model by using quantum Monte Carlo simulations. The ground state of this model undergoes a weakly first-order quantum phase transition with an emergent(4) symmetry between an antiferromagnetic state and a plaquette valence bond solid. The calculated spin lattice relaxation rate of nuclear magnetic resonance,1/T1, exhibits distinct low-temperature behaviors depending on the ground states.

Proximate deconfined quantum critical point in SrCuBO.

The deconfined quantum critical point (DQCP) represents a paradigm shift in quantum matter studies, presenting a "beyond Landau" scenario for order-order transitions. Its experimental realization, however, has remained elusive. Using high-pressure B nuclear magnetic resonance measurements on the quantum magnet SrCu(BO), we here demonstrate a magnetic field-induced plaquette singlet to antiferromagnetic transition above 1.