Publications
Nonlinear growth in modified gravity theories of dark energy(2007). Istvan Laszlo and Rachel Bean. We carry out N-Body simulations of various modified gravity theories, including theories that modify the Poisson Equation thus altering the relationship of the gravitational potential to the matter distribution and theories that introduce anisotropic shear stress, altering the response of matter to the potential. We then compare the simulations to two main analytical fits for nonlinear power and find that although the fits are developed for standard gravity, they do remarkably well even in the case of the modified theories. Published in Phys. Rev. D 77 024048(Jan 30, 2008).
Constraining Interactions in Cosmology's Dark Sector(2008). Rachel Bean, Eanna Flanagan, Istvan Laszlo, and Mark Trodden. We investigate possible dark sector interactions, in particular interactions between dark matter and dark energy or self interaction of dark matter. Using large scale structure observations, we then constrain their strengths relative to that of gravity. In the case of dark matter-dark energy interactions we find a maximum interaction strength of 7% that of gravity, while in the case of dark matter self interaction (via a Yukawa type coupling) we find that at a scale of 10 Mpc the strength of the interaction must be less than 5% that of gravity. Submitted to Phys. Rev. D.