Kinetic inflation in deformed phase space Brans–Dicke cosmolog

The Honourable Schoolboy

https://www.sciencedirect.com/science/article/pii/S2212686419300184?dgcid=rss_sd_all

Kinetic inflation in deformed phase space Brans–Dicke cosmology

S.M.M.Rasouli^ab

J.Marto^abP.V.Moniz^abc

^a

Departamento de Física, Universidade da Beira Interior, Rua Marquês d’Avila e Bolama, 6200-001 Covilhã, Portugal

^b

Centro de Matemática e Aplicações (CMA - UBI), Universidade da Beira Interior, Rua Marquês d’Avila e Bolama, 6200-001 Covilhã, Portugal

^c

DAMTP, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK

Received 24 May 2018, Revised 23 December 2018, Accepted 16 January 2019, Available online 5 February 2019.

https://doi.org/10.1016/j.dark.2019.100269Get rights and content

Abstract

In this paper, by establishing a Brans–Dicke (BD) cosmology by means of a deformed phase space, in the absence of any scalar potential, cosmological constant and ordinary matter, we show that it is feasible to overcome obstacles reported in the corresponding commutative (non-deformed) frameworks. More concretely, by applying the Hamiltonian formalism and introducing a dynamical deformation, between the momenta associated to the FLRW scale factor and the BD scalar field, we obtain the modified equations of motion. In particular, these equations reduce to their standard counterparts when the noncommutative (NC) parameter is switched off. By focusing on a specific branch of solutions, in contrast to standard frameworks (even with a varying BD coupling parameter), we show that we can obtain an adequate appropriate inflationary epoch possessing a suitable graceful exit. In other words, in the Jordan frame (JF), such branch of solutions properly satisfy the sufficient condition required for satisfactory inflation, which is equivalent to get an inflationary phase in the conformal Einstein frame (EF) without branch change. Concerning the cosmological dynamics, we further show that our NC framework bears close resemblance to the

(Starobinsky) inflationary model.

Keywords

Inflation

Noncommutativity

Brans–Dicke theory