Modifications of Einstein's theory of gravitation have been extensively considered in the past years, in connection to both cosmology and quantum gravity. Higher-curvature and higher-derivative gravity theories constitute the main examples of such modifications. These theories exhibit, in general, more degrees of freedom than those found in standard general relativity; counting, identifying, and retrieving the description/representation of such dynamical variables is currently an open problem, and a decidedly nontrivial one. In this work we review, via both formal arguments and custom-made examples, the most relevant methods to unveil the gravitational degrees of freedom of a given model, discussing the merits, subtleties and pitfalls of the various approaches.

Higher-order theories of gravity: diagnosis, extraction and reformulation via non-metric extra degrees of freedom-a review / Alessio, Belenchia; Letizia, Marco; Liberati, Stefano; Di Casola, Eolo. - In: REPORTS ON PROGRESS IN PHYSICS. - ISSN 0034-4885. - 81:3(2018), pp. 1-34. [10.1088/1361-6633/aaa4ab]

Higher-order theories of gravity: diagnosis, extraction and reformulation via non-metric extra degrees of freedom-a review

Letizia, Marco
Membro del Collaboration group
;
Stefano Liberati
Membro del Collaboration group
;
Eolo Di Casola
Membro del Collaboration group
2018

Abstract

Modifications of Einstein's theory of gravitation have been extensively considered in the past years, in connection to both cosmology and quantum gravity. Higher-curvature and higher-derivative gravity theories constitute the main examples of such modifications. These theories exhibit, in general, more degrees of freedom than those found in standard general relativity; counting, identifying, and retrieving the description/representation of such dynamical variables is currently an open problem, and a decidedly nontrivial one. In this work we review, via both formal arguments and custom-made examples, the most relevant methods to unveil the gravitational degrees of freedom of a given model, discussing the merits, subtleties and pitfalls of the various approaches.
https://arxiv.org/abs/1612.07749
Alessio, Belenchia; Letizia, Marco; Liberati, Stefano; Di Casola, Eolo
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11767/68098
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