# Radiative correction of 4D spinfoam model with a cosmological constant (Qiaoyin Pan, Florida Atlantic University) FAU^2 Talk

Infrared divergence is a common feature of spinfoam models with a vanishing cosmological constant. The disappearance of divergence at the present of a non-zero cosmological constant was conjectured and then recently proved in a spinfoam model constructed with complex Chern-Simons theory. It has been an active research area to study how such divergence depends on the value of the cosmological constant.

In this talk, I will present our recent results on the first-order divergence, also called the radiative correction, of a 4D spinfoam model with a cosmological constant. It is based on the recently constructed spinfoam model with complex SL(2, C) Chern-Simons theory. Taking the cosmological constant to approach the zero limit, our analysis gives a lower bound on the divergence, which is an inverse power law in (the absolute value of) the cosmological constant.