Archive for Quintessence

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…

Cosm(et)ology

Posted in The Universe and Stuff with tags , , , , on January 5, 2012 by telescoper

I’ve mentioned before that in some parts of the world, cosmology is likely to be confused with cosmetology. I now think cosmologists are missing a trick, and should in fact be borrowing terms from the world of cosmetics.

I suggested on Twitter that the Dark Energy responsible for making the Universe expand more rapidly should henceforth be known as Volumiser, a term which could also apply to the scalar field that drives cosmic inflation. I do think, however, that it might be better to think of inflation as an anti-wrinkle agent, as it smooths away any primordial irregularities.

Anyway, esteemed Nobel laureate and even more esteemed wine producer Brian Schmidt offered this contribution to show that someone has already had the idea…

I’m sure Quintessence isn’t the only example of physics that’s entirely made up, and no doubt you’ll be offering your own suggestions through the comments box…