Infrared Finite Scattering Theory in Quantum Field Theory and Quantum Gravity

Understand

Infrared (IR) divergences arise in scattering theory with massless fields and are manifestations of the memory effect.

• There is nothing singular about states with memory, but they do not lie in the standard Fock space.
• IR divergences are artifacts of trying to represent states with memory in the standard Fock space.
• For collider physics, one can impose an IR cutoff and calculate inclusive quantities.