Cosmology with the Einstein telescope: No Slip Gravity model and redshift specifications

Abstract

The Einstein Telescope and other third generation interferometric detectors of gravitational waves are projected to be operational post 2030. The cosmological signatures of gravitational waves would undoubtedly shed light on any departure from the current gravitational framework. We here confront a specific modified gravity model, the No Slip Gravity model, with forecast observations of gravitational waves. We compare the predicted constraints on the dark energy equation of state parameters $w_0^{}-w_a^{}$, between the modified gravity model and that of Einstein gravity. We show that the No Slip Gravity model mimics closely the constraints from the standard gravitational theory, and that the cosmological constraints are very similar. The use of spectroscopic redshifts, especially in the low–redshift regime, lead to significant improvements in the inferred parameter constraints. We test how well such a prospective gravitational wave dataset would function at testing such models, and find that there are significant degeneracies between the modified gravity model parameters, and the cosmological parameters that determine the distance, due to the gravitational wave dimming effect of the modified theory.

No slip gravity in light of LISA standard sirens

“…We find that the free parameter that quantifies deviation of GR, ξ, can be measured with 33%, 21% and 41% accuracy from the Pop III, Delay and No Delay populations, respectively. As already pointed out in [71], we see a significant degeneracy between the parameters ξ and n, which on the other hand is also very degenerate with the matter density Ω m and the Hubble constant, H 0 . Note that for n = 0, the equations of the model also reduces to GR.…”

“…Therefore, in this case, it will be important to combine the SS sample We have extended the analysis in Ref. [71] considering mock data from the LISA perspective. We see an overall improvement on the precision of the Hubble constant, H 0 , and Ω m by including the CMB information.…”

“…The equation for ξ and n as a function of redshift is given in terms of time-dependent Planck mass in Ref. [71]…”

“…The main characteristics of this model read as the speed of GWs propagation is equal to the speed of light, and equality between the effective gravitational coupling strengths to matter and light, but yet different from Newton's constant, which is capable of generating an effective gravitational coupling. Some observational perspectives of this class were previously investigated in [60,[71][72][73][74]. Our approach is to use the LISA standard sirens to predict the bounds on the No Slip gravity baseline parameters.…”

Constraining the Swiss-Cheese IR-Fixed Point Cosmology with Cosmic Expansion

“…In the future, it will be interesting to apply further constraints from upcoming future survey data [72,73] and other probes, such as clustering, FRB [74], and gravitational waves [75] and to examine the allowed range for the anomalous dimension η, which is related to the free parameter b = 2 − η in the model [7].…”