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| Main Authors: | , , |
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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2509.06148 |
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| _version_ | 1866911689633431552 |
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| author | Frion, Emmanuel Pascual, Mateo Vidotto, Francesca |
| author_facet | Frion, Emmanuel Pascual, Mateo Vidotto, Francesca |
| contents | In the framework of Loop Quantum Cosmology, we study a cosmological bouncing model with two fields that reproduce the desired features of the primordial power spectra. The model combines the matter-bounce mechanism, that generates scale-invariant perturbations, with ekpyrotic contraction, that suppresses anisotropies leading to the bounce. The bounce that replaces the classical initial singularity is achieved thanks to the loop quantisation. The matter-bounce is enacted by a \textit{quasi-dust} scalar field, with a slightly-negative equation of state that accounts for a small positive cosmological constant, that generates a red-tilt in the perturbations' power spectra. A second field, endowed with an ekpyrotic potential, is introduced to tame the growth of anisotropies throughout the bouncing phase. The equations of motion of the scalar perturbations are non-trivially coupled, leading to rich phenomenology that cannot be inferred simply from their single-field counterpart. We study the evolution of scalar and tensor perturbations and compare the results to current observations, showing the viability of this model as a base for further investigations. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_06148 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Quasi-dust ekpyrotic scenario in Loop Quantum Cosmology Frion, Emmanuel Pascual, Mateo Vidotto, Francesca General Relativity and Quantum Cosmology In the framework of Loop Quantum Cosmology, we study a cosmological bouncing model with two fields that reproduce the desired features of the primordial power spectra. The model combines the matter-bounce mechanism, that generates scale-invariant perturbations, with ekpyrotic contraction, that suppresses anisotropies leading to the bounce. The bounce that replaces the classical initial singularity is achieved thanks to the loop quantisation. The matter-bounce is enacted by a \textit{quasi-dust} scalar field, with a slightly-negative equation of state that accounts for a small positive cosmological constant, that generates a red-tilt in the perturbations' power spectra. A second field, endowed with an ekpyrotic potential, is introduced to tame the growth of anisotropies throughout the bouncing phase. The equations of motion of the scalar perturbations are non-trivially coupled, leading to rich phenomenology that cannot be inferred simply from their single-field counterpart. We study the evolution of scalar and tensor perturbations and compare the results to current observations, showing the viability of this model as a base for further investigations. |
| title | Quasi-dust ekpyrotic scenario in Loop Quantum Cosmology |
| topic | General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2509.06148 |