Genius_ The Life and Science of Richard Feynman - James Gleick [70]
When Richard returned to the fraternity house that evening he found her in the living room. He was ebullient; he grabbed her and swung her around, dancing. “He certainly believes in physical society,” one of the fraternity boys said. At Wheeler’s prodding Feynman had presented their space-time electrodynamics a second time, to a broader audience. The talk went well. After having faced a public of Einstein, Pauli, von Neumann, and Wigner, he had little to fear from the American Physical Society rank and file. Still, he worried that he might have bored his listeners by sticking nervously to his prepared text. There were a few polite questions, and Wheeler helped answer them.
Feynman had enunciated a set of principles for a theory of interacting particles. He wrote them out as follows:
1 The acceleration of a point charge is due only to the sum of its interactions with other charged particles… . A charge does not act on itself.
2 The force of interaction which one charge exerts on a second is calculated by means of the Lorentz force formula, in which the fields are the fields generated by the first charge according to Maxwell’s equations.
Phrasing the third principle was more difficult. He tried:
3 The fundamental equations are invariant with respect to a change of the sign of the time …
Then, more directly:
3 The fundamental (microscopic) phenomena in nature are symmetrical with respect to interchange of past and future.
Pauli, despite his skepticism, understood the power of the last principle. He pointed out to Feynman and Wheeler that Einstein himself had argued for an underlying symmetry of past and future in a little-known 1909 paper. Wheeler needed little encouragement; he made an appointment to call at the white clapboard house at 112 Mercer Street.
Einstein received this pair of ambitious young physicists sympathetically, as he did most scientists who visited in his last years. They were led into his study. He sat facing them behind his desk. Feynman was struck by how well the reality matched the legend: a soft, nice man wearing shoes without socks and a sweater without a shirt. Einstein was well known to be unhappy with the acausal paradoxes of quantum mechanics. He now spent much of his time writing screeds on world government which, from a less revered figure, would have been thought crackpot. His distaste for the new physics was turning him into, as he would have it, “an obstinate heretic” and “a sort of petrified object, rendered blind and deaf by the years.” But the theory Wheeler and Feynman described was not yet a quantum theory—so far, it used only classical field equations, with none of the quantum-mechanical amendments that they knew would ultimately be necessary—and Einstein saw no paradox. He, too, he told them, had considered the problem of retarded and advanced waves. He reminisced about the strange little paper he had published in 1909, a manifesto of disagreement with a Swiss colleague, Walter Ritz. Ritz had declared that a proper field theory should include only retarded solutions, that the time-backward advanced solutions should simply be declared impermissible, innocent though the equations looked. Einstein, however, could see no reason to rule out advanced waves. He argued that the explanation for the arrow of time could not be found in the basic equations, which truly were reversible.
On his bicycle in Far Rockaway.
Melville, Lucille, Richard, and Joan at the house they shared with Lucille's sister's family, at 14 New Broadway.
Richard and Arline : left , at Presbyterian Sanatorium.
At Los Alamos: “I opened the safes which contained behind them the entire secret of the atomic bomb…