Loops on the Celestial Sphere

Understand

We study the effect of loop corrections to conformal correlators on the celestial sphere at null infinity.

• We first analyze finite one-loop celestial amplitudes in pure Yang-Mills theory and Einstein gravity.
• We then turn to our main focus: infrared divergent loop amplitudes in planar $\mathcal{N}=4$ super Yang-Mills theory.
• We compute the celestial one-loop amplitude in dimensional regularization and show that it can be recast as an operator acting on the celestial tree-level amplitude.