Continuously varying critical exponents in an exactly solvable long-range cluster XY model

We investigate a generalized antiferromagnetic cluster XY model in a transverse magnetic field, where longrange interactions decay algebraically with distance. This model can be exactly solvable within a free fermion framework. By analyzing the gap, we explicitly derive the critical exponents nu and z, finding that the relationship nu z = 1 still holds. However, the values of nu and z depend on the decaying exponent alpha, in contrast to those for the quantum long-range antiferromagnetic Ising chain. To optimize scaling behavior, we verify these critical exponents using correlation functions and fidelity susceptibility, achieving excellent data collapse across various system sizes by adjusting fitting parameters. Finally, we compute the entanglement entropy at the critical point to determine the central charge c, and find it also varies with alpha. This study provides insights into the unique effect of long-range cluster interactions on the critical properties of quantum spin systems.