Speaker
Description
The contrast between (asymptotic) freedom and confinement was a source of great unease and some confusion in the early days of QCD. Some people still obsess over it. The degrees of freedom in which the theory is most naturally formulated, and that in a real sense become manifest at high energies or short distances – that is, quarks and gluons - are completely different from the degrees of freedom – that is, hadrons - that appear in the spectrum and the S matrix. How can such different descriptions coexist? In what sense can virtual particles be real physical entities?
I will discuss how similar behavior arises in much simpler models than QCD – specifically, QED in 1 + 1 dimensions – where we can understand how it works in detail, both intuitively and mathematically. Along the way I will give a precise discussion of time-energy uncertainty, which is central to resolving the tension. I will also discuss some recent work using related ideas to suggest new observable phenomena in condensed matter physics.
Following that (not very!) technical part of the presentation I will reminiscence briefly about my own experiences in the early days, and add some brief remarks about the status of QCD today and going forward.
