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In this work we investigate the impact of two phenomenological Beyond the Standard Model (BSM) scenarios concerning the role of neutrinos in the early universe: non-standard neutrino interactions (NSI) and non-unitary three-neutrino mixing.…

High Energy Physics - Phenomenology · Physics 2025-10-13 Gabriela Barenboim , Stefano Gariazzo , Alberto Sánchez-Vargas

We present modified cosmological scenarios that arise from the application of the "gravity-thermodynamics" conjecture, using the Barrow entropy instead of the usual Bekenstein-Hawking one. The former is a modification of the black hole…

General Relativity and Quantum Cosmology · Physics 2020-07-22 Emmanuel N. Saridakis

Taking into consideration of a fractal structure for the black hole horizon, Barrow argued that the area law of entropy get modified due to quantum-gravitational effects. Accordingly, the corrected entropy takes the form $S\sim…

General Relativity and Quantum Cosmology · Physics 2023-09-28 Amin Salehi

We investigate the sensitivity of a universe's nuclear entropy after Big Bang nucleosynthesis (BBN) to variations in both the baryon-to-photon ratio and the temporal evolution of cosmological expansion. Specifically, we construct…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-22 Charlie F. Sharpe , Luke A. Barnes , Geraint F. Lewis

In conventional general relativity, the expansion rate H of a Robertson-Walker universe is related to the energy density by the Friedmann equation. Aside from the present day, the only epoch at which we can constrain the expansion history…

Astrophysics · Physics 2014-10-13 Sean M. Carroll , Manoj Kaplinghat

Big-bang nucleosynthesis (BBN) is valuable as a means to constrain the physics of the early universe and it is the only probe of the radiation-dominated epoch. A fundamental assumption in BBN is that the nuclear velocity distributions obey…

Nuclear Theory · Physics 2020-06-29 Nishanth Sasankan , Atul Kedia , Motohiko Kusakabe , Grant J Mathews

One of the greatest challenges of theoretical physics today is to unveil the quantum information theory concerning what happens when one bit of information enters the black hole (BH) horizon. The Landauer principle showed that a certain…

General Relativity and Quantum Cosmology · Physics 2024-02-27 Everton M. C. Abreu

Neutrino non-standard interactions (NSI) with electrons, predicted in many extended theoretical models of particle physics, are known to alter the picture of neutrino decoupling from the cosmic plasma. We update previous analyses of…

High Energy Physics - Phenomenology · Physics 2026-03-02 Stefano Gariazzo , Jaume Moncho , Sergio Pastor , Ofelia Pisanti

Both the Barrow and Tsallis $\delta$ entropies are one-parameter generalizations of the black-hole entropy, with the same microcanonical functional form. The ensuing deformation is quantified by a dimensionless parameter $\Delta$, which in…

General Relativity and Quantum Cosmology · Physics 2024-10-28 Petr Jizba , Gaetano Lambiase , Giuseppe Gaetano Luciano , Leonardo Mastrototaro

The term dark radiation is used both to describe a noninteracting neutrino species and as a correction to the Friedmann Equation in the simplest five-dimensional RS-II brane-world cosmology. In this paper we consider the constraints on both…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-04 Nishanth Sasankan , Mayukh. R. Gangopadhyay , Grant. J. Mathews , Motohiko Kusakabe

Big-bang nucleosynthesis (BBN) describes the production of the lightest nuclides via a dynamic interplay among the four fundamental forces during the first seconds of cosmic time. We briefly overview the essentials of this physics, and…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-13 Richard H. Cyburt , Brian D. Fields , Keith A. Olive , Tsung-Han Yeh

We investigate the validity of the generalized second law of thermodynamics, applying Barrow entropy for the horizon entropy. The former arises from the fact that the black-hole surface may be deformed due to quantum-gravitational effects,…

General Relativity and Quantum Cosmology · Physics 2021-09-16 Emmanuel N. Saridakis , Spyros Basilakos

We consider the Big Bang Nucleosynthesis (BBN) bounds on light dark matter whose cross section off nucleons is sufficiently large to enable acceleration by scattering off of cosmic rays in the local galaxy. Such accelerated DM could then…

High Energy Physics - Phenomenology · Physics 2020-07-01 Gordan Krnjaic , Samuel D. McDermott

This paper is superseded by Arxiv:1911.07334. Big-bang nucleosynthesis (BBN) is a valuable tool to constrain the physics of the early universe and is the only probe of the radiation-dominated epoch. A fundamental assumption in BBN is that…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-01 Nishanth Sasankan , Atul Kedia , Motohiko Kusakabe , Grant J Mathews

Big Bang Nucleosynthesis can provide, via constraints on the expansion rate at that time, limits on possible variations in Newton's Constant, $G$. The original analyses were performed before an independent measurement of the…

Astrophysics · Physics 2009-11-10 Craig J. Copi , Adam N. Davis , Lawrence M. Krauss

In this study, we explore temperature-dependent CPT violation during Big Bang Nucleosynthesis (BBN) through electron-positron mass asymmetries parametrized by $b_0(T) = \alpha T^2$. The $T^2$ scaling naturally evades stringent laboratory…

High Energy Physics - Phenomenology · Physics 2026-05-21 Gabriela Barenboim , Anne-Katherine Burns

We investigate whether Big Bang nucleosynthesis (BBN) remains compatible with the Covarying Coupling Constants plus Tired Light (CCC+TL) cosmology. In this framework, only quantities with explicit length dimensionality covary through a…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-27 Rajendra P. Gupta , Nikolaos Samaras

The BBN predictions for the abundances of the light element isotopes is reviewed and compared with recent observational data. The single unknown parameter of standard BBN is the baryon-to-photon ratio, \eta, and can be determined by the…

Astrophysics · Physics 2017-08-23 Keith A. Olive

We construct Barrow holographic dark energy with varying exponent. Such an energy-scale-dependent behavior is typical in quantum field theory and quantum gravity under renormalization group considerations, however in the present scenario it…

General Relativity and Quantum Cosmology · Physics 2025-04-08 Spyros Basilakos , Andreas Lymperis , Maria Petronikolou , Emmanuel N. Saridakis

The Hubble expansion of galaxies, the $2.73\dK$ blackbody radiation background and the cosmic abundances of the light elements argue for a hot, dense origin of the universe --- the standard Big Bang cosmology --- and enable its evolution to…

High Energy Physics - Phenomenology · Physics 2011-02-16 Subir Sarkar