kosmosgenesis

Quantum Electro- and Chromo- Dynamics

Quantum electrodynamics, or QED, is a quantum theory of the interactions of charged particles with the electromagnetic field. It describes mathematically not only all interactions of light with matter but also those of charged particles with one another. QED is a relativistic theory in that Albert Einstein's theory of special relativity is built into each of its equations. Because the behaviour of atoms and molecules is primarily electromagnetic in nature, all of atomic physics can be considered a test laboratory for the theory. Agreement of such high accuracy makes QED one of the most successful physical theories so far devised.

Quantum Chromodynamics (QCD) is the fundamental theory of strong interactions. We are mainly interested to study QCD in its nonperturbative domain. A variety of approaches which respect the fundamental symmetries of QCD have been constructed and applied to the study of the phase transition which restores chiral symmetry in hot matter. These studies, which include effective Lagrangians and random matrix theory, permit detailed comparison with and interpretations of the results of lattice gauge simulations. QCD sum rule techniques permit the extension of results from the perturbative to the non-perturbative sector of QCD and lead to predictions for the modification of hadronic properties at high temperature and density.