HEP Theory Journal Club

Supersizing hydrodynamical simulations of reionization using EFT

Katelin Schutz

McGill University

I will show that perturbative techniques inspired by effective field theory (EFT) can be used to “paint on” the 21 cm field during reionization using only the underlying linear density field. This procedure is accurate to within O (10%) on large scales and thus can be used to enlarge or “supersize” hydrodynamical simulations. In particular, the EFT provides a mapping between the linear density field and the nonlinear 21 cm field, which I will review in this talk. I will show how this mapping can be reliably extracted from relatively small simulation volumes using the THESAN suite of simulations as a test case. Specifically, if we fit the EFT coefficients in a small ∼ 5% sub-volume of the simulation, we can accurately predict the 21 cm field in the rest of the simulation given only the linear density field. I will show that our technique is robust to different models of dark matter and differences in the sub-grid implementation of reionization in the simulation.