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.
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