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Related papers: Fuzzy Bounces

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We explore simple but novel bouncing solutions of general relativity that avoid singularities. These solutions require curvature k=+1, and are supported by a negative cosmological term and matter with -1 < w < -1/3. In the case of moderate…

High Energy Physics - Theory · Physics 2014-01-16 Peter W. Graham , Bart Horn , Shamit Kachru , Surjeet Rajendran , Gonzalo Torroba

A bouncing scenario of a flat homogeneous and isotropic universe is explored by using the reconstruction technique for the power-law parametrization of the Hubble parameter in a modified gravity theory with higher-order curvature and trace…

General Relativity and Quantum Cosmology · Physics 2023-04-03 J. K. Singh , Harshna Balhara , Kazuharu Bamba , J. Jena

Matter bounces are bouncing scenarios wherein the universe contracts as in a matter dominated phase at early times. Such scenarios are known to lead to a scale invariant spectrum of tensor perturbations just as de Sitter inflation does. In…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-11 Debika Chowdhury , V. Sreenath , L. Sriramkumar

We explore a dual scenario of generalized inflation and bounce cosmologies, producing a scale-invariant curvature perturbation spectrum. Bayesian analysis with pulsar timing array data identifies, for the first time, viable regions from…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-07 Changhong Li , Junrong Lai , Jinjie Xiang , Chaofan Wu

Problem of cosmological singularity of general relativity theory is discussed. The possible resolution of this problem in the framework of inflationary cosmology is proposed. Physical conditions leading to bouncing inflationary solutions in…

General Relativity and Quantum Cosmology · Physics 2007-05-23 A. V. Minkevich

The present work analyzes the various conditions in which there can be a bouncing universe solution in f(R) gravity. In the article an interesting method, to analyze the bouncing FRW solutions in a spatially flat universe using f(R) gravity…

General Relativity and Quantum Cosmology · Physics 2014-12-09 Niladri Paul , Saikat Nil Chakrabarty , Kaushik Bhattacharya

According to classical GR, negative-energy (AdS) bubbles in the multiverse terminate in big crunch singularities. It has been conjectured, however, that the fundamental theory may resolve these singularities and replace them by non-singular…

High Energy Physics - Theory · Physics 2015-06-17 Jaume Garriga , Alexander Vilenkin , Jun Zhang

If the spatial curvature of the universe is positive, then the curvature term will always dominate at early enough times in a slow-rolling inflationary epoch. This enhances inflationary effects and hence puts limits on the possible number…

General Relativity and Quantum Cosmology · Physics 2015-06-25 G. F. R. Ellis , W. Stoeger , P. McEwan , P. Dunsby

We introduce the "wedge diagram," an intuitive way to illustrate how cosmological models with a classical (non-singular) bounce generically resolve fundamental problems in cosmology. These include the well-known horizon, flatness, and…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-27 Anna Ijjas , Paul J. Steinhardt

Inflationary and bouncing scenarios are two frameworks that provide the mechanism to overcome the horizon problem as well as generate the primordial perturbations. In this work, we investigate the conservation of perturbations in…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-07 Rathul Nath Raveendran

We show that it is possible to realize a cosmological bouncing solution in an anisotropic but homogeneous Bianchi-I background in a class of non-local, infinite derivative theories of gravity. We show that the anisotropic shear grows slower…

General Relativity and Quantum Cosmology · Physics 2021-07-20 K. Sravan Kumar , Shubham Maheshwari , Anupam Mazumdar , Jun Peng

Assuming the existence of a scalar field which undergoes "ghost condensation" and which has a suitably chosen potential, it is possible to obtain a non-singular bouncing cosmology in the presence of regular matter and radiation. The…

High Energy Physics - Theory · Physics 2011-04-20 Chunshan Lin , Robert H. Brandenberger , Laurence Perreault Levasseur

In this paper, we model the bounce phase, stability, and the reconstruction of the universe by non-minimal kinetic coupling. In the process, we obtained importance information about the energy density and the matter pressure of the universe…

General Relativity and Quantum Cosmology · Physics 2026-02-10 Alireza Amani , A. S. Kubeka , E. Mahichi

We propose a new cosmological paradigm in which our observed expanding phase is originated from an initially large contracting Universe that subsequently experienced a bounce. This category of models, being geodesically complete, is…

General Relativity and Quantum Cosmology · Physics 2008-11-07 Patrick Peter , Nelson Pinto-Neto

Bounce-averaged theories provide a framework for simulating relatively slow processes, such as collisional transport and quasilinear diffusion, by averaging these processes over the fast periodic motions of a particle on a closed orbit.…

Plasma Physics · Physics 2025-07-02 I. E. Ochs

We study the stability of cosmological scaling solutions within the class of spatially homogeneous cosmological models with a perfect fluid subject to the equation of state p_gamma=(gamma-1) rho_gamma (where gamma is a constant satisfying 0…

General Relativity and Quantum Cosmology · Physics 2009-10-31 A. P. Billyard , A. A. Coley , R. J. van den Hoogen

The present manuscript presents modeling of matter bounce in the framework of $f(R,T)$ gravity where $f(R,T) = R + 2 \lambda T$. We start by defining a parametrization of scale factor which is non-vanishing. The geometrical parameters such…

General Relativity and Quantum Cosmology · Physics 2020-02-04 Parbati Sahoo , S. Bhattacharjee , S. K. Tripathy , P. K. Sahoo

We re-examine the non-singular Matter Bounce scenario first developed in [arXiv:1206.2382], which starts with a matter-dominated period of contraction and transitions into an Ekpyrotic phase of contraction. We consider both matter fields,…

High Energy Physics - Theory · Physics 2014-03-04 Yi-Fu Cai , Evan McDonough , Francis Duplessis , Robert Brandenberger

The main objective of this study is to investigate the phenomenon of the bouncing scenario of the universe. The most widely recognized cosmological framework is the standard cosmological model, sometimes referred to as the Big Bang model.…

General Relativity and Quantum Cosmology · Physics 2024-02-13 A. S. Agrawal

We present a full investigation of scalar perturbations in a rather generic model for a regular bouncing universe, where the bounce is triggered by an effective perfect fluid with negative energy density. Long before and after the bounce…

General Relativity and Quantum Cosmology · Physics 2009-07-09 V. Bozza , G. Veneziano