Abstract

We introduce a model-independent approach to the null test of the cosmic curvature which is geometrically related to the Hubble parameter H(z) and luminosity distance d_L(z). Combining the independent observations of H(z) and d_L(z), we use the model-independent smoothing technique, Gaussian processes, to reconstruct them and determine the cosmic curvature Ω_K⁽⁰⁾ in the null test relation. The null test is totally geometrical and does not assume any cosmological model. We show that the cosmic curvature Ω_K⁽⁰⁾=0 is consistent with current observational data sets, falling within the 1σ limit. To demonstrate the effect on the precision of the null test, we produce a series of simulated data of the models with different Ω_K⁽⁰⁾. Future observations in better quality can provide a greater improvement to constrain or refute the flat universe with Ω_K⁽⁰⁾=0.

DOI:10.1103/PhysRevD.93.043517

https://arxiv.org/pdf/1509.06283.pdf