Sound speed as a source of the gravitational field in modified gravity

• Tipo: Artigo em Revista Científica Internacional
• Data: 2024

Autores

Avelino, PP (Autor) FCUP

Revista

Título: Physical Review D

Vol. 110 Nº 2

ISSN: 2470-0010

Editora: American Physical Society

Indexação

ISI Web of Knowledge - 0 Citações

Scopus - 0 Citações

Outras Informações

ID Authenticus: P-011-6ST

DOI: 10.1103/physrevd.110.024064

Abstract (EN): In the context of f(R, T) gravity and other modified theories of gravity, the knowledge of the first order variation of the trace T of the energy-momentum tensor with respect to the metric is essential for an accurate characterization of the gravitational field. In this paper, by considering a paradigmatic example of a perfect fluid whose dynamics is described by a pure k-essence matter Lagrangian in f(R, T) = R + .T(T) gravity, we show that the first order variation of the trace of the energy-momentum tensor cannot in general be determined from the proper density, proper pressure, and 4-velocity of the fluid alone, and that the sound speed of the fluid can directly influence the dynamics of gravity. We also confirm that the second variation of the matter Lagrangian with respect to the metric should not in general be neglected. These results can be particularly relevant for cosmological studies of f(R, T) gravity in which some of the material content of the Universe is modeled as a perfect fluid.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 4