# Covariant Canonical Gauge Gravitation and Cosmology

## TL;DR

This paper develops a novel gauge field theory of gravitation incorporating a quadratic Riemann term, leading to dynamic space-time responses and a variable cosmological function, offering insights into dark energy and early universe inflation.

## Contribution

It introduces a first-order gauge field theory of gravity with a quadratic Riemann term, extending Einstein's equations and linking the deformation parameter to observable cosmological parameters.

## Key findings

- Quadratic Riemann term modifies Einstein's equations.
- The cosmological function Λ(a) explains late-time acceleration.
- Normalized models reproduce current Hubble and deceleration parameters.

## Abstract

The covariant canonical transformation theory applied to the relativistic Hamiltonian theory of classical matter fields in dynamical space-time yields a novel (first order) gauge field theory of gravitation. The emerging field equations necessarily embrace a quadratic Riemann term added to Einstein's linear equation. The quadratic term endows space-time with inertia generating a dynamic response of the space-time geometry to deformations relative to (Anti) de Sitter geometry. A "deformation parameter" is identified, the inverse dimensionless coupling constant governing the relative strength of the quadratic invariant in the Hamiltonian, and directly observable via the deceleration parameter $q_0$. The quadratic invariant makes the system inconsistent with Einstein's constant cosmological term, $\Lambda = \mathrm{const}$. In the Friedman model this inconsistency is resolved with the scaling ansatz of a "cosmological function", $\Lambda(a)$, where $a$ is the scale parameter of the FLRW metric. %Moreover, the strain generated by the quadratic term turns out to act as a geometrical stress. The cosmological function can be normalized such that with the $\Lambda$ CDM parameter set the present-day observables, the Hubble constant and the deceleration parameter, can be reproduced. %We analyze the asymptotics of the such normalized Friedman equations with respect to both, the fundamental parameters (coupling constants) and the scale $a$. With this parameter set we recover the dark energy scenario in the late epoch. The proof that inflation in the early phase is caused by the "geometrical fluid" representing the inertia of space-time is yet pending, though.