4 papers
Scattered wave functions and worldline instantons for particle production in curved spacetime
Philip Semrén, Greger Torgrimsson
We study the production of spin- particle-antiparticle pairs in curved spacetimes with nontrivial dependence on more than one coordinate. To this end, we develop two complemen…
The near equilibrium Einstein-Boltzmann system with a simplified collision term
Philip Semrén, Michael Bradley, João M. S. Oliveira +1
A simplified relativistic kinetic theory for gases with internal degrees of freedom, based on a BGK-type collision term, is considered. First the Boltzmann equation is rewritten in…
Modified vacuum polarization in the presence of a plasma
Sebastian Lundström, Philip Semrén, Haidar Al-Naseri +1
We study vacuum polarization due to strong fields, in the presence of an electron-positron plasma. For this purpose, we expand quantum kinetic equations using weak fields and slow…
Worldline instantons for nonperturbative particle production by space and time dependent gravitational fields
Philip Semrén, Greger Torgrimsson
We develop a worldline-instanton approach for calculating the momentum spectrum of particles produced by gravitational fields which depend on both space and time. The instantons ar…