Dark Energy From Dynamical Projective Connections
| Autor: | Catherine A. Whiting, Samuel Brensinger, Vincent G. J. Rodgers, Kenneth Heitritter, Kory Stiffler |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Physics
High Energy Physics - Theory Angular momentum Physics and Astronomy (miscellaneous) 010308 nuclear & particles physics Scalar (mathematics) Dark matter FOS: Physical sciences Observable universe General Relativity and Quantum Cosmology (gr-qc) Cosmological constant 01 natural sciences General Relativity and Quantum Cosmology Gravitation High Energy Physics - Theory (hep-th) 0103 physical sciences Dark energy Projective connection 010306 general physics Mathematical physics |
| Popis: | We further develop the gravitational model, Thomas-Whitehead Gravity (TW Gravity), that arises when projective connections become dynamical fields. TW Gravity has its origins in geometric actions from string theory where the TW projective connection appears as a rank two tensor, $\mathcal{D}_{ab}$, on the spacetime manifold. Using a Gauss-Bonnet (GB) action built from the $(\mathrm{d}+1)$-dimensional TW connection, and applying the tensor decomposition $\mathcal{D}_{ab} = D_{ab} + 4\Lambda /(\mathrm{d}(\mathrm{d}-1)) g_{ab}$, we arrive at a gravitational model made up of a $\mathrm{d}$-dimensional Einstein-Hilbert + GB action sourced by $D_{ab}$ and with cosmological constant $\Lambda$. The $\mathrm{d}=4$ action is studied and we find that $\Lambda \propto 1/J_0$, with $J_0$ the coupling constant for $D_{ab}$. For $\Lambda$ equal to the current measured value, $J_0$ is on the order of the measured angular momentum of the observable Universe. We view this as $\Lambda$ controlling the scale of patches of the Universe that acquire angular momentum, with the net angular momentum of multiple patches vanishing, as required by the cosmological principle. We further find a universal axial scalar coupling to all fermions where the trace, $\mathcal{D} = \mathcal{D}_{ab}g^{ab}$ acts as the scalar. This suggests that $\mathcal{D}$ is also a dark matter portal for non-standard model fermions. Comment: 49 pages. Made revisions required for acceptance to the journal Classical and Quantum Gravity |
| Databáze: | OpenAIRE |
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