DE1 - Dark Energy and the Accelerating Universe |
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Speaker |
Arai, Shun |
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Coauthors |
Kiyotomo Ichiki, Masahide Yamaguchi |
| Talk Title |
Generalized criterion of thawing and freezing models in Horndeski theory |
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Abstract |
The thawing and freezing criterion is well known as the division of the dark energy models with a quintessence field, depending on the signature of the time derivative of the equation of state of dark energy (EoSofDE). Not only the criterion well traces the shapes of a potential of the field, but also it is able to be investigated by cosmological observations. We generalize the thawing and freezing criterion for the model-classification in Horndeski theory. We consider the cases when matters minimally couple with gravity and the EoSofDE is defined in terms of the Freedman equations previously provided in Bellini and Sawicki 2014. In this set-up, we numerically confirm that the criterion we made significantly partitions the EFT parameters given in Bellini and Sawicki 2014. In particular, the models whose gravitational couplings deviate from the Newton constant, we find there is a tight correlation between the sign of the time derivative of EoSofDE and that of the Planck mass run rate at low redshifts below z=1. In the end, we discuss the consequences of our criterion for the observational constraints on the Horndeski theory. |
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