Year: 2014
Type: article
Abstract: Motivated by the properties of matter quantum fields in curved space-times, we work out a gravity theory that combines the Born-Infeld gravity Lagrangian with an $f(R)$ piece. To avoid ghostlike instabilities, the theory is formulated within the Palatini approach. This construction provides more freedom to address a number of important questions, such as the dynamics of the early Universe and the cosmic accelerated expansion, among others. In particular, we consider the effect that adding an $f(R)=a{R}^{2}$ term has on the early-time cosmology. We find that bouncing solutions are robust against these modifications of the Lagrangian whereas the solutions with loitering behavior of the original Born-Infeld theory are very sensitive to the ${R}^{2}$ term. In fact, these solutions are modified in such a way that a plateau in the ${H}^{2}$ function may arise, yielding a period of (approximately) de Sitter inflationary expansion. This inflationary behavior may be found even in a radiation-dominated universe.
Institutions: Tomsk State Pedagogical University, National Research Tomsk State University, Institució Catalana de Recerca i Estudis Avançats, Institute of Space Sciences, Consejo Superior de Investigaciones Científicas, King Abdulaziz University, Universitat de València, Universidade Federal da Paraíba
Language: Latvian
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1977071844