My research centres on modified theories of gravity and their phenomenological implications for particle physics and cosmology. Recent focus has been on quantum corrected metric solutions with a minimum length, i.e. the existence of a characteristic scale at which classical physics transitions to a quantum regime. The latest observational data -- most importantly those forthcoming from the Event Horizon Telescope -- present new insight into what could be our first glimpse of quantum gravity effects. Identifying such signatures of current models that can subsequently be constrained by this data is an immediate and compelling task.
Current areas of focus include:
Quantum Gravity Corrected Black Holes
There exists a threshold scale at which quantum gravity effects become important. Such a minimal length emerges naturally in a number of areas, including string theory, loop quantum gravity, noncommutative geometries, and generalized uncertainty principles (GUP). I have shown that such black holes allow for dimensional reduction at the Planck scale, an intriguining new window on quantum gravity phenomenology. GUP black holes may also be suitable candidates for dark matter.
Lower Dimensional Gravity
A variety of approaches to quantum gravity predict that the effective dimension of spacetime reduces at high energies. Several viable string-inspired methods have recently been proposed to model such dimensional transitions. The unconventional nature of gravity in lower dimensions points to novel -- and moreover experimentally-testable -- consequences for both high energy physics and early-universe cosmology, thus making this an intriguing area of exploration.
My most significant work in this area explored the impact of generic dimensional reduction on black hole thermodynamics and their potential phenomenological signatures. I proposed that such a signature could manifest itself as a fundamental gravitational wave cut-off frequency marking the effective dimension drops below (3+1)-D, a threshold which is in principle detectable by future space-based gravity wave observatories.
Black hole physics is entering a golden age. A century after Einstein proposed his celebrated theory of General Relativity, two key experiments are providing new data that promise to revolutionize the field: the Laser Interferrometer Gravitational Wave Observatory (LIGO), and the Event Horizon Telescope (EHT). LIGO has already ushered in the era gravitational wave astronomy, allowing us for the first time to probe the Universe beyond the electromagnetic spectrum. Through this window, we will be able to test black hole mergers, coalescence, and ringdowns with high precision. Conversely, the EHT is expected to reveal such novel characteristics as "black hole shadows" -- i.e. regions surrounding black holes from which no light escapes -- which will provide unprecedented tests of gravitational physics at the event horizon.
I am interested in exploring potential macroscopic signatures of quantum gravity in such supermassive black holes. These include aspects of the information paradox and Hawking radiation as they relate to near-horizon physics. The prospective imaging of the black hole shadow by the EHT and related experiments could reveal hints of related quantum effects on scales of the horizon. These could be within the sensitivity of the experiments, and thus experimentally testable.