Nonlinear QED Effects in Heavy Ion Collisions

Peripheral collisions of relativistic heavy ions uniquely probe many aspects of QED. Examples include $e^+e^-$ pair production and nuclear excitation in strong fields. After discussing these reactions, I will draw parallels between $\gamma\to e^+e^-$ and $\gamma\to q\bar q$ and consider partly hadronic reactions. The scattered $q\bar q$ pairs are a prolific source of vector mesons, which demonstrate many quantum effects. The two ions are a two-source interferometer, demonstrating interference between meson waves. Multiple vector meson production will demonstrate superradiance, a first step toward a vector meson laser. Finally, I will discuss the experimental program planned at the RHIC and LHC heavy ion colliders.