Giant Lamb shift in a Kerr nonlinear blackbody

Abstract

The Lamb shift in a Kerr nonlinear blackbody (KNB) is studied in the framework of nonrelativistic quantum electrodynamics theory. It is found that the Lamb shift in a KNB depends on the absolute temperature and the Kerr nonlinear coefficient. Below a transition temperature ${T}_{c}$, the Lamb shift is larger than that in a nonabsorbing linear medium. Under some conditions, the Lamb shift in a KNB can become much larger than that in a nonabsorbing linear medium or in free space. Above ${T}_{c}$, the Lamb shift equals that in a nonabsorbing linear medium. The application of our theory is also discussed.