Fri - 08/02/24

**Title:

      Recalculating Total Number of e-folds in Loop Quantum Cosmology in View of Generalized Reheating**  - **Authors:** Yogesh, Mayukh R. Gangopadhyay, Anzhong Wang  - **Subjects:** Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)  - **Arxiv link:** [https://arxiv.org/abs/](https://arxiv.org/abs/)  - **Abstract**  In loop quantum cosmology, the slow-roll inflation is generic, and when the kinetic energy of the scalar field dominates at the bounce, the evolution of the Friedmann-Lemaître-Robertson-Walker universe will go through three distinguishable epochs, bouncing, transition, and finally slow-roll inflation, before the reheating commences. The bouncing dynamics are insensitive of the potential and initial conditions, so that the expansion factor and the scalar field can be described uniquely by a universal solution during this epoch. After about $10^5$ Planck time, the epoch of transition starts and the universe rapidly turns over from the kinetic energy dominated state to the potential energy dominated one, whereby the slow-roll inflationary phase begins. In this paper, we consider the power law plateau potential and study the pre-inflationary cosmology for different sets of initial conditions, so that during the slow-roll inflation epoch enough e-folds will be produced. Considering the generalized reheating and comparing with the recent Planck 2018 data, we are able to constrain the total number of e-folds ($N_T$) from the bounce till today to be consistent with the current observable universe. Depending on the matter driving the reheating (subject to the different dominant equations of states), we report the observationally allowed $N_T$ and reheating temperature and find in particular $N_T \simeq 127$, which is significantly different from the one $N_T \gtrsim 141$ obtained previously without considering the reheating phase.

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  1. [] - Title: Shadow of a Renormalization Group Improved Regular Rotating Black Hole - Luis A. Sánchez

Thu - 08/01/24

**Title:

      Non-singular naked solutions in quantum spacetime**  - **Authors:** I. P. R. Baranov, H. A. Borges, F. C. Sobrinho, S. Carneiro  - **Subjects:** Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)  - **Arxiv link:** [https://arxiv.org/abs/](https://arxiv.org/abs/)  - **Abstract**  Polymer models have been used to describe non-singular quantum black holes, where the classical singularity is replaced by a transition from a black hole to a white hole. In a previous letter, in the context of a uni-parametric model with asymptotic flat exterior metric, we fixed the radius of the transition surface through the identification of its area with the area gap of Loop Quantum Gravity. This revealed a dependence of the polymerisation parameter on the black hole mass, where the former increases as the latter decreases, and it also enabled the extension of the model to Planck-scale black holes. We have identified the existence of limiting states with masses $m \geq \sqrt{2}/4$ and zero surface gravity, showing that Hawking evaporation asymptotically leads to remnant black holes of Planck size. In the present paper we consider solutions with $m < \sqrt{2}/4$, observing again the presence of a minimal radius, but without formation of horizons. Diversely from the previous mass range, only charged solutions are allowed in this case.

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Wed - 07/31/24

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  1. [] - Title: A Distance Conjecture for Branes - Muldrow Etheredge, Ben Heidenreich, Tom Rudelius

Tue - 07/30/24

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There is no new related paper today

  1. [] - Title: Generalized Hamilton spaces: new developments and applications - J.J. Relancio, L. Santamaría-Sanz

Mon - 07/29/24

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There is no new related paper today

  1. [] - Title: Generalized Hamilton spaces: new developments and applications - J.J. Relancio, L. Santamaría-Sanz

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