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| Main Authors: | , , , |
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| Format: | Preprint |
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2023
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2304.03803 |
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| _version_ | 1866916350003249152 |
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| author | Das, Raj Kumar Mondal, Aurindam Ghosh, Subir Pan, Supriya |
| author_facet | Das, Raj Kumar Mondal, Aurindam Ghosh, Subir Pan, Supriya |
| contents | A well known extension of Einstein General Relativity is the addition of an $R^2$-term, which is free of ghost excitations and in the linearized framework, reduces Einstein General Relativity and an additional higher derivative scalar. According to \cite{Chakraborty:2020ktp}, the above scalar sector can sustain a Time Crystal-like minimum energy state, with non-trivial time dependence. Exploiting previous result that the scalar can sustain modes with periodic time dependence in its lowest energy, we consider this condensate as a source and study the Friedmann-Lemaître-Robertson-Walker (FLRW) cosmology in this background. The effect of the $R^2$-term is interpreted as a back reaction. A remarkable consequence of the condensate is that, irrespective of open or close geometry of the Universe, for an appropriate choice of parameter window, the condensate can induce a decelerating phase before the accelerated expansion starts and again, in some cases, it can help to avoid the singularity in the deceleration parameter (that is present in conventional FLRW Cosmology). |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2304_03803 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Cosmology in $R^2$-gravity: Effects of a Higher Derivative Scalar Condensate Background Das, Raj Kumar Mondal, Aurindam Ghosh, Subir Pan, Supriya General Relativity and Quantum Cosmology High Energy Physics - Theory Quantum Physics A well known extension of Einstein General Relativity is the addition of an $R^2$-term, which is free of ghost excitations and in the linearized framework, reduces Einstein General Relativity and an additional higher derivative scalar. According to \cite{Chakraborty:2020ktp}, the above scalar sector can sustain a Time Crystal-like minimum energy state, with non-trivial time dependence. Exploiting previous result that the scalar can sustain modes with periodic time dependence in its lowest energy, we consider this condensate as a source and study the Friedmann-Lemaître-Robertson-Walker (FLRW) cosmology in this background. The effect of the $R^2$-term is interpreted as a back reaction. A remarkable consequence of the condensate is that, irrespective of open or close geometry of the Universe, for an appropriate choice of parameter window, the condensate can induce a decelerating phase before the accelerated expansion starts and again, in some cases, it can help to avoid the singularity in the deceleration parameter (that is present in conventional FLRW Cosmology). |
| title | Cosmology in $R^2$-gravity: Effects of a Higher Derivative Scalar Condensate Background |
| topic | General Relativity and Quantum Cosmology High Energy Physics - Theory Quantum Physics |
| url | https://arxiv.org/abs/2304.03803 |