Strong-field physics as a new probe of early-time dynamics in heavy-ion collisions

Abstract

In high-energy heavy-ion collisions, there appear two kinds of extremely strong fields: Ordinary electromagnetic fields and non-Abelian color Yang-Mills fields called a glasma. I explain how they are created in collisions, how strong they are, and how important they are in understanding early-time "pre-equilibrium" evolution of collision events. As one of the typical strong-field "nonlinear QED" phenomena, I discuss possible relevance of the "vacuum birefringence" of a photon in probing the very early-time dynamics of heavy-ion collisions.