Research

My research mainly focuses on investigating the effects of modified gravity and massive neutrinos on large-scale structure formation, as well as finding ways to break the degeneracy between the two effects.

One approach to studying structure formation is the use of N-body simulations. With collborators at ICG Portsmouth I helped implement modified gravity in a fast, approximate simulation method called COLA (COmoving Lagrangian Acceleration). This work resulted in arXiv:1703.00879, as well as a code called MG-PICOLA developed by Hans Winther (who is now at Oslo).

Typically, modified gravity enhances structure formation, and this enhancement is a great signal for current and upcoming surveys to look out for. However, massive neutrinos suppress structure formation via their free-streaming effect, with heavier neutrinos causing greater suppression. Thus we can have a degeneracy where the large-scale structure in a universe with modified gravity and heavy neutrinos is difficult to distinguish from that of a universe with GR and light neutrinos. To investigate this degeneracy further, we implemented massive neutrinos in MG-PICOLA, resulting in arXiv:1705.08165.

One way to break this degeneracy is to use redshift-space distortions; we investigated this possibility in arXiv:1902.10692.

The above research makes up the bulk of my PhD thesis, which can be found here.

I have also studied the effects of a time-varying strength of gravity on the ability of Type Ia supernovae to act as standard candles in arXiv:1710.07018; we found that the standardisability could be comprimised in such a scenario. In a follow up paper (arXiv:1804.03066), we flipped this idea around to use gravitational wave standard sirens to constrain the time-variation of the strength of gravity.

Collaboration Memberships

I'm an active member of the Theory and Simulation Working Groups of the Euclid Consortium, and the Theory & Joint Probes Working Group of LSST-DESC.

Publications

Full lists of my publications can be found on Inspire and arXiv.