Abstract
AGIn 1999 [1] R. R. Caldwell coined the term phantom energy to describe dark energy components with wde < −1. In universes with a phantom energy component the scale factor will grow to infinity at some finite time in the future, and the time at which the scale factor is singular is known as the Big Rip. Here we want to model a meson in such a universe, with the focus on formulating a convenient model, rather than on developing clever numerical schemes. The strong interaction’s property of color confinement leads to the creation of a new quark/antiquark pair when separating the original meson’s constituent quark/antiquark a sufficient distance, thus resulting in two mesons after the separation. The expansion of the universe will naturally separate the constituent quarks/antiquarks, leading to a production of new mesons.
The central question is how the matter density evolves when including the production of new mesons. Will the dilution caused by the expansion win, or can the production make up for this dilution?
We considered two models for our mesons: an approach based on the Dirac equation with a confining potential, and an approach based on modelling the meson as a relativistic string. The former proved unsuccessful, but the latter allowed us to compute the evolution of the matter density. We found that, under our string-model, the production of new mesons cannot make up for the dilution. But even further, we can say with a high level of confidence that any model for a meson will predict a decreasing matter density - it is a generic consequence of the strong interaction
[1] R.R Caldwell. A phantom menace? cosmological consequences of a dark energy component with super-negative equation of state. Physics Letters B, 545(1-2):23– 29, oct 2002.
Supervisor: Professor Øystein Elgarøy, Institute of Theoretical Astrophysics, UiO
Intern. assessor: Professor Boris V. Gudiksen, Institute of Theoretical Astrophysics, UiO
Extern. assessor: Professor Anders Tranberg, University of Stavanger