scholarly journals Late-time cosmological evolution in degenerate higher-order scalar-tensor models

2020 ◽  
Vol 102 (2) ◽  
Author(s):  
Hamza Boumaza ◽  
David Langlois ◽  
Karim Noui
2020 ◽  
Vol 35 (19) ◽  
pp. 2050154
Author(s):  
Jun Wang ◽  
Kang Liu

In this paper, a class of [Formula: see text] gravitational models with coupling between matter and geometry have been studied by a dynamical approach in cosmology. The result shows that both the cosmic radiation dominated era and the late-time cosmic accelerated expansion can be achieved in this class of models. Moreover, the corresponding parameters are constrained as well.


Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 164
Author(s):  
Igor I. Smolyaninov

In this paper, we study the corrections to the Friedmann equations due to fast fluctuations in the universe scale factor. Such fast quantum fluctuations were recently proposed as a potential solution to the cosmological constant problem. They also induce strong changes to the current sign and magnitude of the average cosmological force, thus making them one of the potential probable causes of the modification of Newtonian dynamics in galaxy-scale systems. It appears that quantum fluctuations in the scale factor also modify the Friedmann equations, leading to a considerable modification of cosmological evolution. In particular, they give rise to the late-time accelerated expansion of the universe, and they may also considerably modify the effective universe potential.


2011 ◽  
Vol 235 (8) ◽  
pp. 2412-2422 ◽  
Author(s):  
Fahimeh Biglari ◽  
Malik Abu Hassan ◽  
Wah June Leong

2019 ◽  
Vol 28 (14) ◽  
pp. 1944008 ◽  
Author(s):  
Gustavo Arciniega ◽  
Pablo Bueno ◽  
Pablo A. Cano ◽  
José D. Edelstein ◽  
Robie A. Hennigar ◽  
...  

We propose a novel explanation for universe’s inflationary period. We argue that when the Einstein–Hilbert action is supplemented by an infinite tower of higher-curvature terms — selected order by order by the criterium that they give rise to a well-posed cosmological evolution — the usual Big Bang characteristic of Einstein gravity is replaced by a singularity-free period of exponential growth of the scale factor, which is gracefully connected with standard late-time [Formula: see text]CDM cosmology. No inflaton or any additional fields besides the metric are required.


2015 ◽  
Vol 24 (08) ◽  
pp. 1550068 ◽  
Author(s):  
Vartika Gupta ◽  
Rakesh Kabir ◽  
Amitabha Mukherjee ◽  
Daksh Lohiya

We study the interaction between dark matter and dark energy, with dark energy described by a scalar field having a double exponential effective potential. We discover conditions under which such a scalar field driven solution is a late time attractor. We observe a realistic cosmological evolution which consists of sequential stages of dominance of radiation, matter and dark energy, respectively.


Author(s):  
F. Mavoa ◽  
M. Ganiou ◽  
S. Houndjo ◽  
A. D. Kanfon ◽  
I. Salako

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