In:
Classical and Quantum Gravity, IOP Publishing, Vol. 38, No. 11 ( 2021-06-03), p. 115003-
Abstract:
We study a metric-affine gravitational theory given by the Einstein–Hilbert (EH) action plus a parity violating contribution (which we will refer to as the Hojman term, also known as Holst term) in vacuum. We find out that for a certain value of the Barbero–Immirzi (BI) parameter the total action possesses a remarkable invariance under particular transformations of the affine connection. We prove that in all cases, with appropriate gauge choices, the connection reduces to the Levi-Civita one and that the theory turns out to be equivalent to general relativity (GR) in vacuum. Subsequently, we generalize our discussion and analyze the case of metric-affine f ( R ) gravity plus the Hojman term. In particular, we show that for f ′( R ) ≠ constant the theory results to be on-shell equivalent to a metric-compatible torsionless scalar–tensor model with a propagating pseudo-scalar. Matter coupling of the aforementioned models is also discussed, together with explicit examples and applications.
Type of Medium:
Online Resource
ISSN:
0264-9381
,
1361-6382
DOI:
10.1088/1361-6382/abde1a
Language:
Unknown
Publisher:
IOP Publishing
Publication Date:
2021
detail.hit.zdb_id:
1473117-4
SSG:
16,12
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