steven c. frautschi (; born december 6, 1933) is an american theoretical physicist, currently professor of physics emeritus at the california institute of technology (caltech). he is known principally for his contributions to the bootstrap theory of the strong interactions and for his contribution to the resolution of the infrared divergence problem in quantum electrodynamics (qed). he was named a fellow of the american physical society in 2015 for "contributions to the introduction of regge poles into particle physics, elucidation of the role of infrared photons in high energy scattering, and for seminal contributions to undergraduate physics education".