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Describing metric-affine theories anew: alternative frameworks, examples and solutions

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Published 19 May 2023 © 2023 IOP Publishing Ltd and Sissa Medialab
, , Citation Damianos Iosifidis and Konstantinos Pallikaris JCAP05(2023)037 DOI 10.1088/1475-7516/2023/05/037

1475-7516/2023/05/037

Abstract

In this work we describe metric-affine theories anew by making a change of field variables. A series of equivalent frameworks is presented and identifications are worked out in detail. The advantage of applying the new frameworks is that any MAG theory can be handled as a Riemannian theory with additional fields. We study the Hilbert-Palatini action using the new field variables and disclose interesting symmetries under SO transformations in field space. Then, we use solvable and suitable Riemannian theories as seed models for solvable MAG theories, restricting ourselves to three examples. We present a black hole solution with torsion and non-metricity which under a certain tuning acquires a regular core. A de Sitter universe with the expansion powered by 3-form torsion, is also reported.

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