Functional Dimensional Regularization for the Lee-Yang Model

Abstract

We apply functional dimensional regularization (FDR) to the Lee-Yang universality class, a paradigmatic non-unitary theory, and compute its main critical exponents across the dimension range $3\leq d\leq 6$. By combining a second-order derivative expansion with polynomial field expansions, we obtain results that are compatible with resummed $\varepsilon$-expansion as well as with state-of-the-art estimates from Conformal Bootstrap and Fuzzy Sphere techniques. This demonstrates that, in the context of non-unitary theories, FDR retains the efficiency and rapid convergence to accurate critical exponents already observed in the Ising and O(N) cases.