Quintessence and phantom dark energy from ghost<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>D</mml:mi></mml:math>-branes

Saridakis, Emmanuel N.; Ward, John

doi:10.1103/physrevd.80.083003

Cited by 21 publications

(18 citation statements)

References 92 publications

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“…Now, this method for analysing the stability of the solutions has only been applied to the case where the DBI field has a quadratic potential and the associated D-brane is in the anti-de Sitter throat [69]. The late-time attrac-tor structure for the case without a potential, known as tachyon cosmology, has been studied extensively, [70][71][72][73][74][75][76][77][78] and the case with another degree of freedom, has been studied in [79,80].…”

Section: Introductionmentioning

confidence: 99%

Cosmological dynamics of a Dirac-Born-Infeld field

2010

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We analyze the dynamics of a Dirac-Born-Infeld (DBI) field in a cosmological set-up which includes a perfect fluid. Introducing convenient dynamical variables, we show the evolution equations form an autonomous system when the potential and the brane tension of the DBI field are arbitrary power-law or exponential functions of the DBI field. In particular we find scaling solutions can exist when powers of the field in the potential and warp-factor satisfy specific relations. A new class of fixed-point solutions are obtained corresponding to points which initially appear singular in the evolution equations, but on closer inspection are actually well defined. In all cases, we perform a phase-space analysis and obtain the late-time attractor structure of the system. Of particular note when considering cosmological perturbations in DBI inflation is a fixed-point solution where the Lorentz factor is a finite large constant and the equation of state parameter of the DBI field is w = −1. Since in this case the speed of sound cs becomes constant, the solution can be thought to serve as a good background to perturb about.

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Section: Introductionmentioning

confidence: 99%

Cosmological dynamics of a Dirac-Born-Infeld field

2010

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“…In the presence of a non-Bogomolnyi-Prasad-Sommerfield (BPS) brane or multiple D 3 -branes, the DBI action acquires an additional potential U multiplying the DBI term [49,50]. U can arise in different places within the theory.…”

Section: The New General Lagrangian Of Dbi Inflationmentioning

confidence: 99%

“…However, Equation (5) is a toy model which is only expected to qualitatively reproduce some aspects of a more realistic theory. Then we neglect the effects of background flux in the warped geometry as [23,50]. We define the scalar field φ= T P 3 r and the brane tension T P 3 is a function of the string scale m s and the string coupling g s , then we have [29] T Dp = 1…”

Section: The New General Lagrangian Of Dbi Inflationmentioning

confidence: 99%

The Dark Energy Properties of the Dirac–Born–Infeld Action

Zhang

Huang

2012

Entropy

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Introducing a new potential, we deduce a general Lagrangian for Dirac-BornInfeld (DBI) inflation, in which the determinant of the induced metric naturally includes the kinetic energy and the potential energy. In particular, the potential energy and kinetic energy can convert into each other at any same order, which is in agreement with the limit of classical physics. We also present a general sound speed in the evolutions of the universe, and the exact expressions of energy-momentum tensor, pressure and density. Furthermore, from the results we obtain the new equation of states. The analytic form of the action that is consistent with data turns out to be surprisingly simple and easy to categorize. Finally, we examine properties of the dark energy and introduce a novel mechanism for realizing either quintessence or phantom dark energy dominated phases within a string theoretical context.

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“…Such scenarios have been constructed through various approaches to modified gravity [4,5], such as the Pre-Big-Bang [6] and the Ekpyrotic [7,8] models, gravity actions with higher order corrections [9,10], f (R) gravity [11,12], f (T ) gravity [13], braneworld scenarios [14,15], non-relativistic gravity [16,17], massive gravity [18], Lagrange modified gravity [19], loop quantum cosmology [20][21][22] or in the frame of a closed universe [23]. Non-singular bounces may be alternatively investigated using effective field theory techniques, introducing matter fields violating the null energy condition [24][25][26], or introduce non-conventional mixing terms [27,28]. The extension of all the above bouncing scenarios is the (old) paradigm of cyclic cosmology [29], in which the universe experiences the periodic sequence of contractions and expansions, which has been rewaked the last years [30,31] since it brings different insights for the origin of the observable universe [32][33][34] (see [35] for a review).…”

Section: Introductionmentioning

confidence: 99%

Bounce and cyclic cosmology in weakly broken Galileon theories

Banerjee

Saridakis

2017

Phys. Rev. D

Self Cite

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Abstract:We investigate the bounce and cyclicity realization in the framework of weakly broken galileon theories. We study bouncing and cyclic solutions at the background level, reconstructing the potential and the galileon functions that can give rise to a given scale factor, and presenting analytical expressions for the bounce requirements. We proceed to a detailed investigation of the perturbations, which after crossing the bouncing point give rise to various observables, such as the scalar and tensor spectral indices and the tensor-toscalar ratio. Although the scenario at hand shares the disadvantage of all bouncing models, namely that it provides a large tensor-to-scalar ratio, introducing an additional light scalar significantly reduces it through the kinetic amplification of the isocurvature fluctuations.

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Quintessence and phantom dark energy from ghostD-branes

Cited by 21 publications

References 92 publications

Cosmological dynamics of a Dirac-Born-Infeld field

Cosmological dynamics of a Dirac-Born-Infeld field

The Dark Energy Properties of the Dirac–Born–Infeld Action

Bounce and cyclic cosmology in weakly broken Galileon theories

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