Operator product expansion for radial lattice quantization of 3D φ4 theory

At its critical point, the three-dimensional lattice Ising model is described by a conformal feld theory (CFT), the 3d Ising CFT. Instead of carrying out simulations on Euclidean lattices, we use the Quantum Finite Elements method to implement radially quantized critical φ4 theory on simplicial lattices approaching R×S2. Computing the four-point function of identical scalars, we demonstrate the power of radial quantization by the accurate determination of the scaling dimensions Δϵ and ΔT as well as ratios of the operator product expansion (OPE) coefficients fσσϵ and fσσT of the first spin-0 and spin-2 primary operators ϵ and T of the 3d Ising CFT.