I obtained my PhD in theoretical physics within the subject of string theory from the University of Groningen in The Netherlands. I then worked as a postdoctoral researcher at the Albert Einstein Center in Bern, the Niels Bohr Institute in Copenhagen, Brussels University (International Solvay Institutes) and at the University of Amsterdam. My research concerns holographic dualities in quantum gravity and string theory. According to the holographic principle, gravity and spacetime originate from the holographic projection of another theory without gravity. I work on constructing and testing realisations of this principle.

Physics is organised in terms of length scales. At small scales quantum mechanics describes the dynamics between small particles, whereas at large scales gravity dominates the interactions between large amounts of matter. There are situations, such as in early universe cosmology and black hole physics in which one needs to have a theory that simultaneously describes gravity and quantum mechanics. Such a theory is called quantum gravity. It has proven rather difficult to construct such a theory. Two successful approaches to quantum gravity are called string theory and holography. They are in fact not fully independent. Both of these approaches replace a theory of gravity with a more fundamental theory and views the gravitational interaction (which is the dynamics of spacetime) as an emergent phenomenon.

My research concerns the study of the holographic principle which states that a theory of quantum gravity can be equivalent to a non-gravitational theory in fewer dimensions. Such holographic dualities are currently only partially understood for string theories on what are known as anti-de Sitter spacetimes. My research focusses on extending the range of spacetimes on which we can study quantum gravity via holography. Furthermore I work on finding simpler theories of gravity than Einstein's theory (and its string theory completion) that still have the property of being holographic because this would allow us to study many of the still unknown properties of holography better.

In relation to this last direction of research I recently constructed a theory of gravity that lies midway between Newtonian gravity and Einstein's theory of general relativity. The theory is called `non-relativistic gravity' and extends Newtonian gravity by including effects of time dilation (the phenomenon that clocks tick slower in strong gravitational fields). The theory of non-relativistic gravity correctly describes many of the gravitational phenomena, such as the perihelion precession of planets and cosmological evolution, that are also described by general relativity. My research aims to show that the new theory of non-relativistic gravity opens up a new route towards understanding (aspects of) quantum gravity.