by David Vasak
The cosmological implications of the Covariant Canonical Gauge Theory of Gravity (CCGG) developed at FIAS are investigated. We deduce that, in a metric compatible geometry, the requirement of covariant conservation of matter inevitably invokes torsion of space-time. In the Friedman model this transforms the cosmological constant to a time-dependent function. Moreover, the quadratic, scale invariant Riemann-Cartan term in the CCGG Lagrangian endows space-time with kinetic energy and inertia, and in the field equations adds a geometrical curvature correction to Einstein gravity.
In the Friedman model with the standard ΛCDM parameter set, CCGG thus supplies an additional, dimensionless “deformation” parameter that determines the strength of the quadratic term, viz. the deviation from the Einstein-Hilbert ansatz. The apparent curvature of the universe then differs from the curvature parameter K of the metric.
The numerical analysis yields three cosmology types:
(I) A bounce universe starting off from a finite scale followed by a steady inflation,
(II) a singular Big Bang universe undergoing a secondary inflation-deceleration phase, and
(III) a solution similar to standard cosmology but with a different temporal profile.
The common feature of all scenarios is the graceful exit to the current dark energy era. The value of the deformation parameter can be deduced by comparing theoretical calculations with observations, namely with the SNeIa Hubble diagram and the deceleration parameter. That comparison implies a considerable admixture of quadratic to Einstein gravity. This theory also sheds new light on the resolution of the cosmological constant and the coincidence problems, and of the Hubble tension.