infrared catastrophe [¦in·frǝ¦red kǝ`tȧs·trǝ·fē] QUANTUM MECHANICS The logarithmic divergence in the cross section (which one would expect to be finite) for the emission of low- energy photons in bremsstrahlung and in the double Compton effect, according to quantum electrodynamics; the difficulty is resolved by taking radiative corrections to elastic scattering into account. Also known as infrared problem. |