‘Master of the path integral’ speaks in London

Edward Witten at the Institute of Physics

By Hamish Johnston

On Friday I took the train up to London to learn about “the theory that nobody wanted”.

That’s how Cambridge University’s Michael Green described string theory in his introduction to a lecture of the subject by Edward Witten.

And how did he describe Witten?

“Master of the path integral”.

Witten was in town to accept the 2010 Isaac Newton Medal from the Institute of Physics – and to give the 2010 Newton Lecture.

Witten is Charles Simonyi Professor of Mathematical Physics at the Institute for Advanced Study in Princeton, New Jersey and a pioneer in what must be the most controversial theory of modern physics.

Instead of plunging the audience into all 10 – or is that 11? – dimensions of the theory, Witten took a very gentle and historical approach to its development.

I entered the lecture hall knowing very little about string theory, so do I feel enlightened?

Well I suppose I have a better understanding of how and why the theory emerged and the various twists and turns it has taken. But I was continually frustrated by a lack of connection to measurements that can be made in the lab or with a telescope. I suppose this could be just a cultural issue – my background is in experimental condensed-matter physics.

The dearth of experimental evidence could soon be over with the emergence of “precision cosmology” – the latest example being the Planck mission’s unprecedented measurements of the cosmic microwave background, which could help to refine string theory.

Witten’s lecture was filmed and this, along with an interview, will soon be released by the IOP. Stay tuned for more.