Bound states in gauge theory

Paul Hoyer, University of Helsinki

The aim of understanding hadrons as bound states of QCD motivates a study of how atoms emerge in QED perturbation theory. The properties of atoms in motion illuminate relativistic effects on bound states, such as Lorentz contraction in quantum physics. The Dirac equation results from summing a certain subset of Feynman diagrams. The Dirac spectrum reflects the degrees of freedom of a single electron even though the Fock states have any number of electron-positron pairs. The solutions of the Dirac equation for a confining (linear) potential are qualitatively different from those obtained with a 1/r potential. The QED experience suggests an approach to hadrons which is consistent with the field theory rules of QCD.

Approx 6 hours lecture (tba).