In 1952, Ahmad served as a visiting professor of mathematics at the Government College University, before accepting the professorship of mathematics at the University of Paris in 1959. He engaged his research in theoretical physics and obtained a one-year-long research fellowship at the Niels Bohr Institute for Theoretical Physics. In 1962–64, he accepted the professorship in physics at the University of Montreal and the University of Ottawa. In Ottawa, he carried out pioneering research in particle resonance and published important publications in theoretical physics.