Deconfined quantum criticality in the spin-1/2 Shastry-Sutherland model in two dimension

Ling Wang
Zhejiang University

Two dimensional Shastry-Sutherland model is a candidate for a deconfined quantum critical phase (DQCP) transition between a plaquette valence bond solid (pVBS) and an Antiferromagnetic (AFM) phase. We systematically study low-lying singlet and triplet excitations in addition to ground state on cylinders with even (4n) and odd (4n+1) lengths, and understand the quantum criticality based on the gapless behavior of pVBS-domain-walls and Y excitations at the DQCP transition. Both the Y-gapless point and the singlet-triplet level crossings, expected to signal the phase transition, follow the empirical 1/L2 behavior and give consistently a transition point at gc = 0.8. We also provide evidences using fidelity susceptibility, ground state order parameters and the finite size scaling of staggered magnetization, all of which support deconfined nature of the phase transition.

Presentation (PDF File)

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