Dark energy and inflation invoked in CCGG by locally contorted space-time

Abstract

The cosmological implications of the covariant canonical gauge theory of gravity (CCGG) are investigated. We deduce that, in a metric-compatible geometry, the requirement of covariant conservation of matter invokes torsion of space-time. In the Friedman model, this leads to a scalar field built from contortion and the metric with the property of dark energy, which 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 in the field equations adds a geometrical curvature correction to Einstein gravity. Applying in the Friedman model the standard $$\Lambda \hbox {CDM}$$ Λ CDM parameter set, those equations yield a cosmological field depending just on one additional, dimensionless “deformation” parameter of the theory that determines the strength of the quadratic term, viz. the deviation from the Einstein–Hilbert ansatz. Moreover, the apparent curvature of the universe differs from the actual curvature parameter of the metric. The numerical analysis in that parameter space yields three cosmology types: (1) a bounce universe starting off from a finite scale followed by a steady inflation, (2) a singular Big Bang universe undergoing a secondary inflation–deceleration phase and (3) 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 scale-invariant quadratic gravity to Einstein gravity. This theory also sheds new light on the resolution of the cosmological constant problem and of the Hubble tension.

Low-redshift constraints on covariant canonical Gauge theory of gravity

“…Using canonical transformation theory the approach unambiguously fixes how matter fields interact with curved geometry of space-time, and enforces a parameter controlled admixture of a quadratic Riemann-Cartan concomitant to the Einstein-Hilbert linear term. In a preliminary study [37] the cosmological consequence of that quadratic extension were examined in alignment with the CDM model. Here we go a step further and test the CCGG cosmology against a comprehensive database of low-redshift cosmological measurements that include the Pantheon Type Ia supernova, Cosmic Chronometers and Baryon Acoustic Oscillations.…”

“…However, albeit this calculation does not conclusively determine the relative admixture of quadratic gravity to Einsten-Cartan gravity, the data neither excludes a non-zero deformation parameter, nor a deviation from the flat geometry assumed in CDM. This leaves the possibility open that the more complex space-time geometry of CCGG applies, which naturally invokes inflation [94] and substantially alters the Hubble expansion in the early universe [37]. The model's superiority thus might become obvious only when including the early universe data in the analysis.…”

“…As shown in Ref. [37] this leads, in a metric compatible space-time, to the necessity to invoke torsion. For the CCGG version of the Friedman model that promotes the cosmological constant to the time or scale dependent function (a) =: λ 0 + 1 4 P(a) =: f (a).…”

“…Such a "universal" approach must of course be subject to a comprehensive testing against all kinds of experiments, especially as CCGG is its novel application to gravity. In that study [37] CCGG was shown to deliver an explanation of dark energy as a torsion based phenomenon For earlier investigations on the possible cosmological role of torsion see for example [38][39][40][41][42][43][43][44][45]. There a first analysis of the CCGG-Friedman cosmology was limited to varying the only new parameter beyond CDM.…”

Quintessential Inflation with Dynamical Higgs Generation as an Affine Gravity

“…With the discovery of the accelerating expansion of the present universe [27][28][29][30][31][32][33][34][35] it appears plausible that a small vacuum energy density, usually referred in this case as "dark energy", is also present even today. The two vacuum energy densities -the one of inflation and the other of the dark energy dominated universe nowadays, have however a totally different scale which demans a plausible explanation of how cosmological evolution may naturally interpolate between such two apparently quite distinctive physical situations.…”