John Preskill

There's a wiggly line and then another wiggly line.

And that's another Feynman diagram.

The electron and the positron can collide with one another, and that can give rise to particles of light, photons, but then those photons convert to other particles like quarks and anti-quarks, and those interact with other particles.

like gluons and so on.

And to keep track of all those things that can happen and how to quantitatively evaluate how all those different processes contribute to the total rate, that's a pretty complicated problem.

Feynman diagrams can help you organize that type of computation.

These are incredibly difficult and unwieldy for 99.999% of the human race.

And that 0.001% that could work with them was Julian Schwinger.

Schwinger was an extraordinarily brilliant guy, but brilliant in a different way.

People always talked about them as being competitive.

It was clear when we spoke to Schwinger that he had that kind of barbed respect that you have for a worthy adversary.

He clearly wasn't all that fond of Feynman.

Feynman also spoke about it, and he said that he thought that people like us made a bit too much of their rivalry.

And he said it was more like two people running a race.

But it's, you know, fundamentally a friendly competition because they're both pushing each other.

I'd asked him to explain what he'd done to win the Nobel Prize, and he started talking about quantum electrodynamics, and of course I really couldn't understand this.

I'm Christopher Sykes.

I was a documentary filmmaker for many years for the BBC and Channel 4.

I found myself at some point saying, was it worth the Nobel Prize?

Which did produce, I have to say, a really classic response.