Academic interests
My interests are gleaning insight into how the universe works at a fundamental level. I use theoretical tools, particularly gravity, to understand different aspect of cosmological and gravitational physics. The hope is to develop possible tests to better understand fundamental physics.
My PhD is roughly split into three projects:
Particle production from gravitational waves and alternative to black holes. The fact that black holes emit radiation, Hawking radiation, raises questions about the nature of horizon. One possible solution is that the horizon isn't there at all, but that black holes are actually exotic compact objects (ECO). ECOs possess many of the characteristics as black holes except the horizon is a reflective surface. I am exploring a way to test this idea through gravitational waves' production of particles. For gravitational waves to produce particles, they must be trapped between the surface and the gravitational potential. A normal black hole can't do this but an ECO would trap the gravitational wave. This would be a possible signature for modifications to the standard black hole picture.
Modified gravity with disformally coupled scalars. The discovery of dark energy has spawned a panoply of alternatives to general relativity (GR), normally by adding a scalar field to standard GR. The most general relation a scalar field can have while still working in the typical geometry of GR is that of a disformal coupling. Here we're trying to analyse the cosmology of such a theory and see how deviations from the regular results can be looked for in future surveys. In collaboration with people at Imperial College London.
Three-forms in higher dimensions. Changing track somewhat, this project aims to do a dynamical analysis on a three-form in a 5-dimensional spacetime. Three-forms are interesting as modifications to gravity since their dynamics are unique as an alternative to standard inflationary mechanisms. Vectors have issues during inflation, as do two-forms, and four-forms or higher resemble scalar dynamics, no different to the regular inflaton field. Motivation for their existence is from string theory. We work in a 5-dimensional spacetime where the three-form supports the bulk, with the idea that there may be consequences in our own 4-dimensional brane. In collaboration with people at the University of Lisbon and the University of Cape Town. Paper out on three-forms in thick branes here.
In the past I worked on variations on cosmic string models, and how they may be linked to fast radio bursts - enigmatic astrophysical objects with no known progenitor mechanism. I argued that cosmic string perturbations prohibits their being the source of fast radio bursts. Papers are here and here.
Background
MSc. in Astrophysics, University of Cape Town, South Africa.
BSc. (Hons) in Astrophysics and Physics, University of Cape Town, South Africa.