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We discuss the concept of measurement in cosmology from the relativistic and quantum mechanical points of view. The uncertainty principle within the particle horizon, excludes the momentum of particles to be less than $\pi\hbar H/c$. This…

Astrophysics · Physics 2007-05-23 S. Rahvar , M. Sadegh Movahed , M Saadat

A unified description of early-time inflation with the current cosmic acceleration is achieved by means of a new theory that uses a quadratic model of gravity, with the inclusion of an exponential $F(R)$-gravity contribution for dark…

General Relativity and Quantum Cosmology · Physics 2017-06-28 E. Elizalde , S. D. Odintsov , L. Sebastiani , R. Myrzakulov

We study the generation of primordial perturbations in a (single-field) slow-roll inflationary universe. In momentum space, these (Gaussian) perturbations are characterized by a zero mean and a non-zero variance $\Delta^2(k, t)$. However,…

High Energy Physics - Theory · Physics 2010-04-06 Ivan Agullo , Jose Navarro-Salas , Gonzalo J. Olmo , Leonard Parker

The Renyi entropy coprises a group of data estimates that sums up the well-known Shannon entropy, acquiring a considerable lot of its properties. It appears as unqualified and restrictive entropy, relative entropy, or common data, and has…

General Relativity and Quantum Cosmology · Physics 2023-02-01 H. R. Fazlollahi

We study the Friedmann inflation in general covariant Horava-Lifshitz (HL) gravity without the projectability conditions and with detailed and non-detailed balance conditions. Accordingly, we derive modifications in the Friedmann equations…

General Relativity and Quantum Cosmology · Physics 2017-12-04 A. Tawfik , A. Diab , E. Abou El Dahab

The thermodynamics-gravity conjecture reveals that one can derive the gravitational field equations by using the first law of thermodynamics and vice versa. Considering the entropy associated with the horizon in the form of non-extensive…

General Relativity and Quantum Cosmology · Physics 2021-11-04 Mahnaz Asghari , Ahmad Sheykhi

We consider observational limits on a proposed model of the string landscape in inflation. In this scenario, effects from the decoherence of entangled quantum states in long-wavelength modes in the universe result in modifications to the…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-08 William H. Kinney

As part of our program to develop a general theory of relativity for open systems, we introduce a covariant theory that incorporates the effects of classical and quantum spacetime alterations in a new metric tensor that effectively includes…

General Relativity and Quantum Cosmology · Physics 2025-09-25 Alan Sebastián Morales , Mauricio Bellini , Juan Ignacio Musmarra

We investigate the inflationary realization in the context of unimodular $F(T)$ gravity, which is based on the $F(T)$ modification of teleparallel gravity, in which one imposes the unimodular condition through the use of Lagrange…

General Relativity and Quantum Cosmology · Physics 2017-06-29 Kazuharu Bamba , Sergei D. Odintsov , Emmanuel N. Saridakis

This paper discusses the problem of inflation in the context of Friedmann-Robertson-Walker Cosmology. We show how, after a simple change of variables, one can quantize the problem in a way which parallels the classical discussion. The…

High Energy Physics - Theory · Physics 2007-05-23 Marvin Weinstein , Ratin Akhoury

We study inflation driven by a slow-rolling inflaton field, characterised by a quadratic potential, and incorporating radiative corrections within the context of supergravity. In this model the energy scale of inflation is not overly…

High Energy Physics - Phenomenology · Physics 2011-02-16 Gabriel German , Graham Ross , Subir Sarkar

Thermal inflation, a brief low energy inflation after the primordial inflation, resolves the moduli problem in the context of supersymmetric cosmology. In the thermal inflation scenario, the primordial power spectrum is modestly redshifted…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-14 Heeseung Zoe

We investigate the possibility that nonlinear gravitational effects influence the preheating era after inflation. Our work is based on numerical solutions of the inhomogeneous Einstein field equations, and is free of perturbative…

High Energy Physics - Phenomenology · Physics 2009-10-31 Richard Easther , Matthew Parry

In this paper we will analyze generic predictions of an inflection-point model of inflation with Hubble-induced corrections and study them in light of the Planck data. Typically inflection-point models of inflation can be embedded within…

High Energy Physics - Phenomenology · Physics 2013-07-29 Sayantan Choudhury , Anupam Mazumdar , Supratik Pal

In this study, we investigate the consequence of the constant-roll condition and examine the role of $f(Q,T)$ gravity in the cosmological inflation process. We analyze the inflationary scenario by calculating modified Friedmann equations,…

General Relativity and Quantum Cosmology · Physics 2023-01-11 K. El Bourakadi , M. Koussour , G. Otalora , M. Bennai , T. Ouali

In this work, two originally separate adjustments for the Friedmann equations are concurrently considered. Firstly, the fractal structure of the black hole horizon region is imposed by the Barrow entropy. The second adjustment is the…

General Relativity and Quantum Cosmology · Physics 2024-06-13 Tuhina Ghorui , Prabir Rudra , Farook Rahaman

We study the implications of the recently proposed Trans-Planckian Censorship Conjecture (TCC) for early universe cosmology and in particular inflationary cosmology. The TCC leads to the conclusion that if we want inflationary cosmology to…

High Energy Physics - Theory · Physics 2020-05-06 Alek Bedroya , Robert Brandenberger , Marilena Loverde , Cumrun Vafa

Alan Guth introduced cosmologists to inflation at the 1980 Texas Symposium. Since, inflation has had almost as much impact on cosmology as the big-bang model itself. However, unlike the big-bang model, it has little observational support.…

Astrophysics · Physics 2014-10-13 Michael S. Turner

Decoupling of heavy modes in effective low energy theory is one of the most fundamental concepts in physics. It tells us that modes must have a negligible effect on the physics of gravitational backgrounds with curvature radius larger than…

High Energy Physics - Theory · Physics 2020-05-12 Gia Dvali , Alex Kehagias , Antonio Riotto

We shall investigate the inflation for the D-brane model, motivated by the modified gravity $F(\phi,T)$. This gravity has been recently introduced in the literature. The feasibility of the D-brane inflation theory in the $F(\phi,T)$-gravity…

General Relativity and Quantum Cosmology · Physics 2025-08-04 Feyzollah Younesizadeh , Davoud Kamani