Abstract

  We develop a new model-independent method to probe the constancy of the speed of light c. In our method, the degeneracy between the cosmic curvature and the speed of light can be eliminated, which makes the test more natural and general. Combining the independent observations of Hubble paramete H(z) and luminosity distanc dL(z),  we use the model-independent smoothing technique, Gaussian processes, to reconstruct them and then detect variation of the speed of light. We find no signal of deviation from the present value of the speed of light  c0. Moreover, to demonstrate the improvement in probing the constancy of the speed of light from future experiments, we produce a series of simulated data. The Dark Energy Survey will be able to detect Δc/c0~1% at  ~1.5σ confidence level and  Δc/c0~2% at  ~3σ confidence level. If the errors are reduced to one-tenth of the expected DES ones, it can detect a  Δc/c0~0.1% variation at ~2σ confidence level.

DOI:10.1088/1475-7516/2016/08/016

https://arxiv.org/pdf/1601.05497.pdf