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Bouncing cosmologies, suggested by String/M-theory, may provide an alternative to standard inflation to account for the origin of inhomogeneities in our universe. The fundamental question regards the correct way to evolve the scalar…

High Energy Physics - Theory · Physics 2009-11-11 V. Bozza

We consider certain aspects of cosmological dynamics of a spatially curved Universe in $f(T)$ gravity. Local analysis allows us to find conditions for bounces and for static solutions; these conditions appear to be in general less…

General Relativity and Quantum Cosmology · Physics 2021-06-10 Maria A. Skugoreva , Alexey V. Toporensky

Scenario of a bouncing universe is one of the most active area of research to arrive at singularity free cosmological models. Different proposals have been suggested to avoid the so called 'big bang' singularity through the quantum aspect…

General Relativity and Quantum Cosmology · Physics 2022-10-26 Indrani Banerjee , Tanmoy Paul , Soumitra SenGupta

Bouncing cosmologies are often proposed as alternatives to standard inflation for the explanation of the homogeneity and flatness of the universe. In such scenarios, the present cosmological expansion is preceded by a contraction phase.…

High Energy Physics - Theory · Physics 2010-04-30 V. Bozza , M. Bruni

We investigate a bounce realization in the framework of higher order curvature in $ f(R,T) $ modified theory of gravity. We perform a detailed analysis of the cosmological parameters to explain the contraction phase, the bounce phase, and…

General Relativity and Quantum Cosmology · Physics 2023-07-19 J. K. Singh , Shaily , Akanksha Singh , Aroonkumar Beesham , Hamid Shabani

Some bouncing models are investigated in the framework of an extended theory of gravity. The extended gravity model is a simple extension of the General Relativity where an additional matter geometry coupling is introduced to account for…

General Relativity and Quantum Cosmology · Physics 2021-06-10 S K Tripathy , B Mishra , Saibal Ray , Rikpratik Sengupta

Modeling of matter bounce in $f(R,T)$ gravity has been presented with no violation of the null energy condition. Only a closed universe with negative pressure is allowed in good agreement with some recent observations which favor a universe…

General Relativity and Quantum Cosmology · Physics 2022-06-22 Vinod Kumar Bhardwaj , Anirudh Pradhan , Nasr Ahmed , A. A. Shaker

We outline a global approach to scattering theory in one dimension that allows for the description of a large class of scattering systems and their $\mathcal{P}$-, $\mathcal{T}$-, and $\mathcal{P}\mathcal{T}$-symmetries. In particular, we…

Quantum Physics · Physics 2019-01-25 Ali Mostafazadeh

In this paper, we have presented a bouncing cosmological model of the Universe in an extended theory of gravity. The dynamical behaviour of the model obtained from the flat FLRW space-time along with the violation of null energy condition…

General Relativity and Quantum Cosmology · Physics 2022-04-22 A. S. Agrawal , Francisco Tello-Ortiz , B. Mishra , S. K. Tripathy

We consider the introduction of anisotropy in a class of bouncing models of cosmology. The presence of anisotropy often spells doom on bouncing models, since the energy density due to the anisotropic stress outweighs that of other matter…

General Relativity and Quantum Cosmology · Physics 2022-01-27 Karthik Rajeev , Vikramaditya Mondal , Sumanta Chakraborty

We offer a new proposal for cosmic singularity resolution based upon a quantum cosmology with a unitary bounce. This proposal is illustrated via a novel quantization of a mini-superspace model in which there can be superpositions of the…

General Relativity and Quantum Cosmology · Physics 2018-12-17 Sean Gryb , Karim P. Y. Thébault

We describe an exact solution representing a bouncing cosmology in the Minimal Exponential Measure (MEMe) model. Such a solution, obtained by means of the linearization around small values of the characteristic energy scale q of the theory,…

General Relativity and Quantum Cosmology · Physics 2025-04-23 Antonio Troisi , Sante Carloni

We present a simple picture that provides the energy and scattering length dependence for all inelastic three-body collision rates in the ultracold regime for three-body systems with short range two-body interactions. In particular, we…

Other Condensed Matter · Physics 2007-05-23 J. P. D'Incao , B. D. Esry

The main objective of this manuscript is to investigate the bouncing cosmology in the background of $f(\mathcal{Q})$ gravity, where $\mathcal{Q}$ defines the non-metricity. For this purpose, we use the reconstruction approach and consider a…

General Relativity and Quantum Cosmology · Physics 2024-04-02 M. Sharif , M. Zeeshan Gul , Nusrat Fatima

We study the expansion of the universe at late times in the case that the cosmological constant obeys certain scaling laws motivated by renormalisation group running in quantum theories. The renormalisation scale is identified with the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Florian Bauer

We present a bounce universe in modified $f(Q,C)$ gravity considering linear as well as exponential form of gravity. Bounce cosmological models are introduced to remove the singularity problem of the early universe. A new quadratic boundary…

General Relativity and Quantum Cosmology · Physics 2025-08-07 Bhaswati Mandal , B. C. Paul

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

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

In the matter bounce scenario, a dust-dominated contracting space-time generates scale-invariant perturbations that, assuming a nonsingular bouncing cosmology, propagate to the expanding branch and set appropriate initial conditions for the…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Edward Wilson-Ewing

Using the simplest model for a bouncing universe, namely that for which gravity is described by pure general relativity, the spatial sections are positively curved and the matter content is a single scalar field, we obtain the transition…

High Energy Physics - Theory · Physics 2016-11-09 Patrick Peter , Jerome Martin