Back to Search
Start Over
New scaling solutions in cubic Horndeski theories
- Source :
- Physical Review D. 98
- Publication Year :
- 2018
- Publisher :
- American Physical Society (APS), 2018.
-
Abstract
- We propose a viable dark energy scenario in the presence of cubic Horndeski interactions and a standard scalar-field kinetic term with two exponential potentials. We show the existence of new scaling solutions along which the cubic coupling $G_3$ provides an important contribution to the field density that scales in the same way as the background fluid density. The solutions finally exit to the epoch of cosmic acceleration driven by a scalar-field dominated fixed point arising from the second exponential potential. We clarify the viable parameter space in which all the theoretically consistent conditions including those for the absence of ghost and Laplacian instabilities are satisfied on scaling and scalar-field dominated critical points. In comparison to Quintessence with the same scalar potential, we find that the cubic coupling gives rise to some novel features: (i) the allowed model parameter space is wider in that a steeper potential can drive the cosmic acceleration; (ii) the dark energy equation of state $w_{\phi}$ today can be closer to $-1$ relative to Quintessence; (iii) even if the density associated with the cubic coupling dominates over the standard field density in the scaling era, the former contribution tends to be suppressed at low redshifts. We also compute quantities associated with the growth of matter perturbations and weak lensing potentials under the quasi-static approximation in the sub-horizon limit and show that the cubic coupling leads to the modified evolution of perturbations which can be distinguished from Quintessence.<br />Comment: 15 pages, 7 figures, accepted version by PRD
- Subjects :
- Physics
Cosmology and Nongalactic Astrophysics (astro-ph.CO)
010308 nuclear & particles physics
Equation of state (cosmology)
FOS: Physical sciences
Scalar potential
General Relativity and Quantum Cosmology (gr-qc)
Astrophysics::Cosmology and Extragalactic Astrophysics
Kinetic term
Parameter space
01 natural sciences
General Relativity and Quantum Cosmology
0103 physical sciences
Dark energy
010306 general physics
Scaling
Weak gravitational lensing
Astrophysics - Cosmology and Nongalactic Astrophysics
Quintessence
Mathematical physics
Subjects
Details
- ISSN :
- 24700029 and 24700010
- Volume :
- 98
- Database :
- OpenAIRE
- Journal :
- Physical Review D
- Accession number :
- edsair.doi.dedup.....92988cf5af9b2c9619bea71d58d96e0d