Infrared finite bremsstrahlung and compact time in conformal QED

We argue that the scalea of the compact evolution time\(|\bar t| \leqslant \pi a\) allowed by conformal invariance can be used as infrared regulator of Abelian gauge theories. By quantizing scalar conformal QED in the compact basisO(4)×O(2), and by classifying the photon states accordingly, we show that the charged-particle bremsstrahlung and the corresponding coherent states are both infrared and collinear finite.