## “Physics is like sex: sure, it may give some practical results, but that’s not why we do it”*…

Beloved late physicist Richard P. Feynman (1918–1988) first met his hero Paul Dirac (1902–1984) during Princeton University’s Bicentennial Celebration in 1946 and then again at least twice, in 1948 and 1962. Most notably, the two came to heads during the so-called Pocono Conference when Feynman gave a lecture on a nascent “Alternative Formulation of Quantum Electrodynamics”

,reformulating the theory which had earned Dirac the Nobel Prize in Physics in 1933. A star-studded audience of 28 of the world’s leading physicists attended the conference, including J. Robert Oppenheimer, Niels Bohr, Eugene Wigner, John von Neumann, Enrico Fermi, Hans Bethe and of course, the inventor of the theory himself, Paul Dirac.Feynman’s reformulation of Dirac’s theory was not well received at Pocono, as Bohr, Teller and Dirac all raised objections. Feynman’s disappointment from the audience’s reaction motivated him to write up his work for publication instead. He did so, and in the next three years went on to publish four major papers describing his now well-developed theory and its implications…

Feynman and Dirac [met for the last] time, at the International Conference on Relativistic Theories of Gravitation in Warsaw, Poland in 1962… Their conversation, as overheard by a nearby physicist, was so remarkable that he jotted it down:

F: I am Feynman.

D: I am Dirac.(Silence)

F: It must be wonderful to be the discoverer of that equation.

D: That was a long time ago.(Pause)

D: What are you working on?

F: Mesons.

D: Are you trying to discover an equation for them?

F: It is very hard.

D: One must try.

Feynman’s work earned him a share of the Nobel Prize in Physics in 1965.

Paul Dirac died in 1984 at the age of 82 years old. Two years later, Feynman was invited to give one of three Dirac Memorial Lectures. He did so, with a lecture entitled “Elementary Particles and the Laws of Physics”, which he opened as follows:

When I was a young man, Dirac was my hero. He made a new breakthrough, a new method of doing physics. He had the courage to simply guess at the form of an equation, the equation we now call the Dirac equation, and to try to interpret it afterwards.

How Paul Dirac, Richard Feynman’s hero-turned-opponent, motivated a life’s work which not only altered the trajectory of modern physics, but also erected Feynman’s legend as one history’s finest scientist: “When Feynman met Dirac.”

* Richard Feynman

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**As we chase after clarity,** we might send very tiny birthday greetings to Wolfgang Paul; he was born on this date in 1913. A physicist, he developed the non-magnetic quadrupole mass filter which laid the foundation for what is now called an ion trap— a device (also known as a Paul trap) that captures ions and holds them long enough for study and precise measurement of their properties. During the 1950s he developed the so-called Paul trap as a means of confining and studying electrons. He shared the Nobel Prize in Physics in 1989 for his work.

He humorously referred to Wolfgang Pauli as his imaginary part.