Musings

Weekend in Jersey

So I find myself in Central New Jersey again, for Curt Callan’s 60^th birthday Festschrift. The weather sucks, but the talks have been great.

One of the striking things is just how far we have come since the dark days of the late 1960s, when quantum field theory was in disrepute, and no one had the slightest idea how to understand the strong interactions.

Equally striking was how quickly things fell into place, once people started looking at them the right way. Bjorken Scaling (confirmed, in short order, in deep-inelastic scattering experiments at SLAC), Wilson, Callan and Symanzik’s work on the Renormalization Group, asymptotic freedom and QCD all followed quickly.

String theory also had its roots in the late 60s, precisely as a non-field theoretic attempt to understand the strong interactions. It’s evolved considerably, but in many ways, we are faced with the same problem facing the high energy theorists of the 1960s. We appear to lack the intellectual tools to do the sort of computations we need to be able to do.

Of course, they had experiments to fall back on. In the case at hand, scaling in deep-inelastic scattering was the crucial clue. It meant that, at short distances, weakly-coupled field theory was relevant. Making sense of that remark was the key that unlocked all (or at least most of) the doors.

We, of course, don’t seem to be getting much help from experiment these days. That’s a pity, but what was really crucial then was this theoretical insight which picked up on the result of one experiment out of the myriad of data that was available.

The difficulty in finding a more fundamental formulation of string theory is imagining something that might reproduce the rich variety of phenomena we have found in string theory’s various limits. We need a similar “simplifying insight” today.

Gee, that’s far more philosophical than I intended to be in this post. Perhaps next time I’ll get back to discussing some actual physics.