Sidney Michael Dancoff (September 27, 1913, Philadelphia – August 15, 1951, Urbana, Illinois) was an American theoretical physicist best known for the Tamm–Dancoff approximation method and for nearly developing a renormalization method for solving quantum electrodynamics (QED).Dancoff was raised in the Squirrel Hill neighborhood of Pittsburgh. He attended Carnegie Tech on a private scholarship and received his B.S.