Feynman’s Path to Quantum Electrodynamics
The end of the Manhattan project marked the beginning of a new phase in Feynman’s life. He followed Hans Bethe to Cornell University and struggled at first to get used to his new life as a university professor – the dramatic experiences of the last few months had been too deep. But he gradually overcame his depression and began to blossom again. He worked tirelessly on the semi-intuitive approach to quantum electrodynamics (QED) that his path integrals had opened up for him. Eventually, this effort was rewarded and Feynman achieved the breakthrough that has shaped our understanding of quantum electrodynamics and other quantum field theories to this day.