Tests of Conformal Field Theory at the Yang-Lee Singularity

This paper studies the Yang‐Lee edge singularity of 2‐dimensional (2D) Ising model based on a quantum spin chain and transfer matrix measurements on the cylinder. Based on finite‐size scaling, the low‐lying excitation spectrum is found at the Yang‐Lee edge singularity. Based on transfer matrix techniques, the single structure constant is evaluated at the Yang‐Lee edge singularity. The results of both types of measurements are found to be fully consistent with the predictions for the (A4, A1) minimal conformal field theory, which was previously identified with this critical point.