http://arxiv.org/abs/1908.11223
We consider the structure formation in $f(Y)$ model of nonlocal gravity recently proposed by Deser and Woodard, which can not only reproduce the $\Lambda$CDM cosmology without fine-tuning puzzle but also may provide a screening mechanism for free. Via numerical method, we have found that the effective Equation-of-State parameter $w_{de}$ provided by the nonlocal modifications approximates to $0.33$, identical to radiation, in the early era and its late-time value approximates to $-1$ in keeping with the cosmological constant, which provides the accelerated phase in the expansion began in the recent cosmological time. Then we find that this model has the better fit with the redshift-space distortions data than DW model and $\Lambda$CDM model where the background is fixed by $(\Omega_{m0},\Omega_{\Lambda0})\sim (0.3153,0.6847)$. At last, we discuss a possible screening mechanism for free in this model.
J. Ding
Fri, 30 Aug 19
56/58
Comments: 9pages, 4 figures, 1 table