Cosmology seminar: Alex Leithes

Alex Leithes is a PhD student at Queen Mary, University of London, working on modified gravity


Linear Density Perturbations in Assisted Coupled Quintessence


In our research we study the behaviour of linear perturbations in assisted coupled quintessence models. We constructed fully general perturbed equations for this class of models including pressures. We then fix the gauge of these perturbed equations in order to write a stable numerical Python code - Pyessence. For a specific model within assisted coupled quintessence, namely a sum of exponentials potential with two fluids and two scalar fields giving transient matter domination, we use this code to generate growth functions and compare these with the standard ΛCDM results, and also with current observational bounds. We also repeat this analysis for two other models from the literature. Finally, we discuss further investigations in this class of models, and also $\Lambda$CDM, using the Pyessence code including examining the validity of the small scale approximation, and also future comparison with upcoming observations such as SKA and Euclid.


Signe Riemer-Sørensen / Benjamin Racine
Published Sep. 15, 2015 10:37 AM - Last modified Nov. 4, 2015 3:15 PM