Archive for Mateja Gosenca

Cosmology Talks: Mateja Gosença & Bodo Schwabe on Simulating Mixed Fuzzy and Cold Dark Matter

Posted in The Universe and Stuff with tags , , , , , , on November 11, 2020 by telescoper

It’s been too long since I shared one of those interesting cosmology talks on the Youtube channel curated by Shaun Hotchkiss. This channel features technical talks rather than popular expositions so it won’t be everyone’s cup of tea but for those seriously interested in cosmology at a research level they should prove interesting.

Anyway, although I’ve been too busy to check out the talks much recently I couldn’t resist sharing this one not only because it’s on a topic I find interesting (and have worked on) but also because one of the presenters (Mateja Gosença) is a former PhD student of mine from Sussex! So before I go fully into proud supervisor mode, I’ll just say that the talk is about AxioNyx, which is a new public code for simulating both ultralight (or “Fuzzy”, so called because its Compton de Broglie wavelength is large enough to be astrophysically relevant) dark matter (FDM) and Cold dark matter (CDM) simultaneously. The code simulates the FDM using adaptive mesh refinement and the CDM using N-body particles.

P. S. The paper that accompanies this talk can be found on the arXiv here.

A First Author Paper

Posted in The Universe and Stuff with tags , , , , , on February 16, 2015 by telescoper

I thought I’d take a few minutes to celebrate the fact that the first first-author paper by my PhD student here at the University of Sussex, Mateja Gosenca, has just hit the arXiv. The abstract reads:

We explore the dynamical behaviour of cosmological models involving a scalar field (with an exponential potential and a canonical kinetic term) and a matter fluid with spatial curvature included in the equations of motion. Using appropriately defined parameters to describe the evolution of the scalar field energy in this situation, we find that there are two extra fixed points that are not present in the case without curvature. We also analyse the evolution of the effective equation-of-state parameter for different initial values of the curvature.

There has been a lot of interest recently in treating cosmological models as dynamical systems, and the class of models we studied has been analysed before (see the references in the paper) but this paper addresses them in a different (and perhaps slightly more elegant) way and in the context of quintessence models for dark energy. It also contains some very pretty multi-dimensional phase portraits, like this:

Mateja

Of course these figures are self-explanatory, so I’ll say no more about them…