Talk by Manasse Mbonye

Speaker:   Manasse Mbonye, ICTP-East African Institute for Fundamental Research, University of Rwanda, Kigali, Rwanda

Place: The Cloud

Date: Tuesday April 25th

Time: 9am Central.

Recording

Bio

AriXiv paper

Title:   Is cosmic dynamics self-regulating?

Abstract: 

We discuss a cosmological model for a universe with self-regulating features. We set up the theoretical framework for the model and determine the time evolution of the scale-factor a(t). It is shown that such a universe repeatedly goes through alternate periods of matter and dark energy domination. The resulting dynamics oscillates about the would-be ideal time-linear or coasting path, with monotonic expansion. When compared to dynamics of the observed physical Universe, the model recovers the observationally-established evolutionary features of the latter, from the big bang to the current acceleration, and farther. It suggests a universe that initially emerges from a non-singular state, associated with a non-inflationary acceleration, and which acceleration it exits naturally with matter-energy generation. The model does not have a horizon problem or a flatness problem. It reproduces the observed current values of standard cosmic parameters, including the age t0, the current Hubble parameter H0 and dark energy Ωde and matter Ωm density parameters. We find the dark matter density-profile generated by the model naturally leads to flat rotation curves in galaxy halos. The model is falsifiable. It makes predictions that can be tested, as suggested. Finally, we discuss the dimensionless age (H0t0 ' 1) paradox as an example of the model´s ability to address standing puzzles. The findings suggest dynamics of the physical Universe may be self-regulating and predictable.