I work on a variety of problems in general relativity, with links to cosmology, astrophysics and AdS/CFT. I am interested in particular in dynamical scenarios with nonlinear effects, which I have studied using both analytical approaches and numerical simulations.
My recent interest has been in understanding dynamics in asymptotically anti--de Sitter (AdS) spacetimes. This is motivated both by the AdS/CFT correspondence, as well as the highly nontrivial dynamics that have been uncovered in these settings. As an example, in 2013 it was shown that the gravitational field could become turbulent---very much like a fluid---in the vicinity of large asymptotically AdS black holes. This can be understood at a broad level as arising because gravitational radiation is confined in such scenarios---it cannot propagate away---and as a result complex nonlinear dynamics can occur.
My main line of work has specifically focused on the stability of AdS spacetime. Whereas flat spacetime has been proven to be stable, small perturbations of AdS have been shown in numerical simulations to often---but not always---collapse to a black hole through a turbulent cascade of energy (again because of the confining behavior of AdS). How and when this occurs is a key question of my research, which I have addressed through a combination of numerical and multiscale perturbative techniques.
For my PhD, I studied general relativistic effects in cosmology. I constrained possible nonlinear backreaction effects that had been suggested by others as an alternative to dark energy, and I demonstrated the effectiveness of Newtonian cosmological simulations as an approximation to general relativity.