Inflationary universe in deformed phase space scenario

Journal Article · Fri Jun 15 04:00:00 EDT 2018 · Annals of Physics

DOI:https://doi.org/10.1016/J.AOP.2018.04.014· OSTI ID:22852250

Rasouli, S. M.M., ^[1]; Saba, Nasim; Farhoudi, Mehrdad ^[2]; Marto, João; Moniz, P. V. ^[1]

---

1. Departamento de Física, Universidade da Beira Interior, Rua Marquês d’Avila e Bolama, 6200-001 Covilhã (Portugal)
2. Department of Physics, Shahid Beheshti University, G.C. Evin, Tehran, 19839 (Iran, Islamic Republic of)

We consider a noncommutative (NC) inflationary model with a homogeneous scalar field minimally coupled to gravity. The particular NC inflationary setting herein proposed, produces entirely new consequences as summarized in what follows. We first analyze the free field case and subsequently examine the situation where the scalar field is subjected to a polynomial and exponential potentials. We propose to use a canonical deformation between momenta, in a spatially flat Friedmann–Lemaî tre–Robertson–Walker (FLRW) universe, and while the Friedmann equation (Hamiltonian constraint) remains unaffected the Friedmann acceleration equation (and thus the Klein–Gordon equation) is modified by an extra term linear in the NC parameter. This concrete noncommutativity on the momenta allows interesting dynamics that other NC models seem not to allow. Let us be more precise. This extra term behaves as the sole explicit pressure that under the right circumstances implies a period of accelerated expansion of the universe. We find that in the absence of the scalar field potential, and in contrast with the commutative case, in which the scale factor always decelerates, we obtain an inflationary phase for small negative values of the NC parameter. Subsequently, the period of accelerated expansion is smoothly replaced by an appropriate deceleration phase providing an interesting model regarding the graceful exit problem in inflationary models. This last property is present either in the free field case or under the influence of the scalar field potentials considered here. Moreover, in the case of the free scalar field, we show that not only the horizon problem is solved but also there is some resemblance between the evolution equation of the scale factor associated to our model and that for the R{sup 2} (Starobinsky) inflationary model. Therefore, our herein NC model not only can be taken as an appropriate scenario to get a successful kinetic inflation, but also is a convenient setting to obtain inflationary universe possessing the graceful exit when scalar field potentials are present.

• OSTI ID: 22852250
• Journal Information: Annals of Physics, Journal Name: Annals of Physics Vol. 393; ISSN 0003-4916; ISSN APNYA6
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
79 ASTRONOMY AND ASTROPHYSICS
COMMUTATION RELATIONS
EVOLUTION EQUATIONS
GRAVITATION
HAMILTONIANS
INFLATIONARY UNIVERSE
LIMITING VALUES
PHASE SPACE
POLYNOMIALS
SCALAR FIELDS
UNIVERSE