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GR: Fachverband Gravitation und Relativitätstheorie
GR 2: Cosmology I
GR 2.5: Vortrag
Montag, 20. März 2023, 17:50–18:10, ZEU/0255
Torsional dark energy in quadratic gauge gravity — •Armin van de Venn1, David Vasak2, Johannes Kirsch3, and Jürgen Struckmeier4 — 1Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany — 2Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany — 3Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany — 4Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany
The Covariant Canonical Gauge theory of Gravity (CCGG) is a gauge field formulation of gravity which a priori includes non-metricity and torsion. It extends the Lagrangian of Einstein’s theory of general relativity by terms at least quadratic in the Riemann-Cartan tensor. This work investigates the implications of metric compatible CCGG on cosmological scales. For a totally anti-symmetric torsion tensor we derive the resulting equations of motion in a Friedmann-Lemaître-Robertson-Walker (FLRW) Universe. In the limit of a vanishing quadratic Riemann-Cartan term, the arising modifications of the Friedmann equations are shown to be equivalent to spatial curvature. Furthermore, the modified Friedmann equations are investigated in detail in the early and late times of the Universe’s history. It is demonstrated that in addition to the standard ΛCDM behaviour of the scale factor, there exist novel time dependencies, emerging due to the presence of torsion and the quadratic Riemann-Cartan term. Finally, at late times, we present how the accelerated expansion of the Universe can be understood as a geometric effect of spacetime through torsion.