Boundary Operator Product Expansion Coefficients of the Three-dimensional Ising Universality Class

Abstract: Recent advances in field theory and critical phenomena have focused on the characterization of boundary or defects in a conformally-invariant system. In this Letter we study the critical behavior of the three-dimensional Ising universality class in the presence of a surface, realizing the ordinary, the special, and the normal universality classes. By using high-precision Monte Carlo simulations of an improved model, where leading scaling corrections are suppressed, and a finite-size scaling analysis, we determine unbiased, accurate estimates of universal boundary operator product expansion coefficients. Furthermore, we improve the value of the scaling dimension of the surface field at the special transition by the estimate $\hat{\Delta}_\sigma = 0.3531(3)$.