TY - JOUR
T1 - Large-scale (in) stability analysis of an exactly solved coupled dark-energy model
AU - Yang, Weiqiang
AU - Pan, Supriya
AU - Herrera, Ramón
AU - Chakraborty, Subenoy
N1 - Funding Information:
The authors thank the referee for his/her constructive and illuminating comments that improved the work considerably. W. Y. is supported by the National Natural Science Foundation of China under Grants No. 11705079 and No. 11647153. R. H. was supported by Proyecto VRIEA-PUCV No. 039.309/2018. S. C. acknowledges the financial support from the Mathematical Research Impact Centric Support (MATRICS), Project Reference No. MTR/2017/000407, by the Science and Engineering Research Board, Government of India. S. P. thanks Rafael C. Nunes, Burin Gumjudpai, and J. A. S. Lima for useful discussions and comments while working on the draft.
Publisher Copyright:
© 2018 American Physical Society.
PY - 2018/8/15
Y1 - 2018/8/15
N2 - Assuming a nongravitational interaction among the dark fluids of our Universe - namely, dark matter and dark energy - we study a specific interaction model in the background of a spatially flat Friedmann-Lemaître-Robertson-Walker geometry. We find that the interaction model solves the background evolution in an analytic way when the dark energy takes a constant barotropic equation of state, wx. In particular, we analyze two separate interaction scenarios, namely, when the dark energy is a fluid other than the vacuum energy (i.e., wx≠-1) and when it is vacuum energy itself (i.e., wx=-1). We find that the interacting model with wx≠-1 produces stable perturbations at large scales for wx<-1 with the coupling strength ξ<0. Both scenarios are constrained by the latest astronomical data. The analyses show that a very small interaction with the coupling strength is allowed, and within the 68.3% confidence region ξ=0 is recovered. The analyses further show that a large coupling strength significantly affects the large-scale dynamics of the Universe, while according to the observational data the interaction models are very well consistent with Λ cosmology. Furthermore, we observe that for the vacuum interaction scenario, the tension on H0 is not released while for the interacting dark energy scenario with wx<-1, the tension on H0 seems to be released partially because of the high error bars in H0. Finally, we conclude the work by calculating the Bayesian evidence, which shows that ΛCDM cosmology is favored over the two interacting scenarios.
AB - Assuming a nongravitational interaction among the dark fluids of our Universe - namely, dark matter and dark energy - we study a specific interaction model in the background of a spatially flat Friedmann-Lemaître-Robertson-Walker geometry. We find that the interaction model solves the background evolution in an analytic way when the dark energy takes a constant barotropic equation of state, wx. In particular, we analyze two separate interaction scenarios, namely, when the dark energy is a fluid other than the vacuum energy (i.e., wx≠-1) and when it is vacuum energy itself (i.e., wx=-1). We find that the interacting model with wx≠-1 produces stable perturbations at large scales for wx<-1 with the coupling strength ξ<0. Both scenarios are constrained by the latest astronomical data. The analyses show that a very small interaction with the coupling strength is allowed, and within the 68.3% confidence region ξ=0 is recovered. The analyses further show that a large coupling strength significantly affects the large-scale dynamics of the Universe, while according to the observational data the interaction models are very well consistent with Λ cosmology. Furthermore, we observe that for the vacuum interaction scenario, the tension on H0 is not released while for the interacting dark energy scenario with wx<-1, the tension on H0 seems to be released partially because of the high error bars in H0. Finally, we conclude the work by calculating the Bayesian evidence, which shows that ΛCDM cosmology is favored over the two interacting scenarios.
UR - http://www.scopus.com/inward/record.url?scp=85052661582&partnerID=8YFLogxK
U2 - 10.1103/PhysRevD.98.043517
DO - 10.1103/PhysRevD.98.043517
M3 - Article
AN - SCOPUS:85052661582
VL - 98
JO - Physical Review D
JF - Physical Review D
SN - 2470-0010
IS - 4
M1 - 043517
ER -