An Accelerating Universe without Lambda: Delta Gravity Using Monte Carlo
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Date
2019
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Abstract
A gravitational field model based on two symmetric tensors, gμν and g˜μν , is studied, using a Markov Chain Monte Carlo (MCMC) analysis with the most updated catalog of SN-Ia. In this model, new matter fields are added to the original matter fields, motivated by an additional symmetry ( δ˜ symmetry). We call them δ˜ matter fields. This theory predicts an accelerating Universe without the need to introduce a cosmological constant Λ by hand in the equations. We obtained a very good fit to the SN-Ia Data, and with this, we found the two free parameters of the theory called C and L2 . With these values, we have fixed all the degrees of freedom in the model. The last H0 local value measurement is in tension with the CMB Data from Planck. Based on an absolute magnitude MV=−19.23 for the SN, Delta Gravity finds H0 to be 74.47±1.63 km/(s Mpc). This value is in concordance with the last measurement of the H0 local value, 73.83±1.48 km/(s Mpc).
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Keywords
Accelerated expansion, Cosmological constant, Cosmology, Dark energy, Delta Gravity, Modified gravity, Phantom energy, Supernovae