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Title: Modified Eddington-inspired-Born-Infeld gravity with a trace term

In this study, a modified Eddington-inspired-Born-Infeld (EiBI) theory with a pure trace term g μνR being added to the determinantal action is analysed from a cosmological point of view. It corresponds to the most general action constructed from a rank two tensor that contains up to first order terms in curvature. This term can equally be seen as a conformal factor multiplying the metric g μν . This very interesting type of amendment has not been considered within the Palatini formalism despite the large amount of works on the Born-Infeld-inspired theory of gravity. This model can provide smooth bouncing solutions which were not allowed in the EiBI model for the same EiBI coupling. Most interestingly, for a radiation filled universe there are some regions of the parameter space that can naturally lead to a de Sitter inflationary stage without the need of any exotic matter field. Finally, in this model we discover a new type of cosmic “quasi-sudden” singularity, where the cosmic time derivative of the Hubble rate becomes very large but finite at a finite cosmic time.
 [1] ;  [2] ;  [3]
  1. National Taiwan Univ., Taipei (Taiwan)
  2. Univ. da Beira Interior, Covilha (Portugal); Centro de Matematica e Aplicacoes da Univ. da Beira Interior (CMA-UBI), Covilha (Portugal); Univ. of the Basque Country UPV/EHU, Bilbao (Spain); Basque Foundation for Science, Bilbao (Spain)
  3. National Taiwan Univ., Taipei (Taiwan); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 1434-6044; PII: 3879
Grant/Contract Number:
Accepted Manuscript
Journal Name:
European Physical Journal. C, Particles and Fields
Additional Journal Information:
Journal Volume: 76; Journal Issue: 1; Journal ID: ISSN 1434-6044
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; modified theories of gravity; early time universe; Eddington-inspired-Born-Infeld theories; cosmic singularities
OSTI Identifier: