Work on Cosmological Particle Production

After completing my theses I felt it was time for a change and started work on quantized field theories in curved space time, particularly external gravitational fields. The main motivation for doing so came from Cosmology: The rapidly changing gravitational field during the very first moments of existence of our universe (10^-30 s) should lead to phenomena such as particle production out of the vacuum. This effect clearly results from the non-existence of energy conservation caused by the rapidly changing external gravitational field (given anyone knows what energy means in this context at all).

Based on my previous experience I was interested in cosmological particle production in non-Abelian gauge fields. This work was partly performed together with B. Kämpfer and some results can be found in Gen. Rel. Grav. 21 (1989), 881-898. Later we turned to the effect of particle creation during inflationary reheating which - given the inflationary model of the universe does apply - leads to much larger particle creation rates than the gravitational effect. Finally, I did some more generally oriented investigations on the definition of the path integral measure in curved space time resulting in the review Fortschr. Phys. 41 (1993), 1-43.