Projects per year
Abstract
We compare analytical computations with numerical simulations for darkmatter clustering, in general relativity and in the normal branch of DGP gravity (nDGP). Our analytical frameword is the Effective Field Theory of LargeScale Structure (EFTofLSS), which we use to compute the oneloop darkmatter power spectrum, including the resummation of infrared bulk displacement effects. We compare this to a set of 20 COLA simulations at redshifts z = 0, z = 0.5, and z = 1, and fit the free parameter of the EFTofLSS, called the speed of sound, in both ΛCDM and nDGP at each redshift. At oneloop at z = 0, the reach of the EFTofLSS is k_{reach} ≈ 0.14 Mpc^{−1} for both ΛCDM and nDGP. Along the way, we compare two different infrared resummation schemes and two different treatments of the time dependence of the perturbative expansion, concluding that they agree to approximately 1% over the scales of interest. Finally, we use the ratio of the COLA power spectra to make a precision measurement of the difference between the speeds of sound in ΛCDM and nDGP, and verify that this is proportional to the modification of the linear coupling constant of the Poisson equation.
Original language  English 

Number of pages  33 
Journal  Journal of Cosmology and Astroparticle Physics 
Volume  04 
Issue number  063 
DOIs  
Publication status  Published  27 Apr 2018 
Keywords
 astroph.CO
 dark energy theory
 modified gravity
 power spectrum
 cosmological parameters from LSS
 RCUK
 STFC
 ST/N000668/1
Fingerprint
Dive into the research topics of 'Towards precision constraints on gravity with the effective field theory of largescale structure'. Together they form a unique fingerprint.Datasets

Data availability statement for 'Towards precision constraints on gravity with the effective field theory of largescale structure'.
Bose, B. (Creator), Koyama, K. (Creator), Lewandowski, M. (Creator), Vernizzi, F. (Creator) & Winther, H. A. (Creator), IOP Publishing, 27 Apr 2018
Dataset
Projects
 1 Finished