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There are many possible gravitational applications of an effective approach to Quantum Field Theory (QFT) in curved space. We present a brief review of effective approach and discuss its impact for such relevant issues as the cosmological…

High Energy Physics - Theory · Physics 2015-06-26 Ilya L. Shapiro

The HMW effect in non-commutative quantum mechanics is studied. By solving the Dirac equations on non-commutative (NC) space and non-commutative phase space, we obtain topological HMW phase on NC space and NC phase space respectively, where…

High Energy Physics - Theory · Physics 2008-11-26 Jianhua Wang , Kang Li

An effective Lagrangian approach based on an extended Einstein-Aether (EA) model is presented and formulated in a generic non flat Fridman-Lemaitre-Robertson-Walker (FLRW) space-time. For a flat FLRW space-time, a Friedmann equation similar…

General Relativity and Quantum Cosmology · Physics 2020-06-10 Alessandro Casalino , Lorenzo Sebastiani , Sergio Zerbini

We propose an inflationary scenario inspired by a recent formulation, in terms of coherent states, of non-commutative quantum field theory. We consider the semiclassical Einstein equations, and we exploit the ultraviolet finiteness of the…

General Relativity and Quantum Cosmology · Physics 2011-04-28 Massimiliano Rinaldi

We study the implications of a noncommutative geometry of the minisuperspace variables for the FRW universe with a conformally coupled scalar field. The investigation is carried out by means of a comparative study of the universe evolution…

High Energy Physics - Theory · Physics 2009-11-10 G. D. Barbosa

We introduce two possible ways of defining effective constraints of quantum systems and applied this effective constraint method to models of WDW Quantum Cosmology and Loop Quantum Cosmology. We analyze effective Hamiltonian constraint on…

General Physics · Physics 2012-12-27 Xinquan Wu , Yongge Ma

We provide an analytical solution to the quantum dynamics of a flat Friedmann-Lema\^itre- Robertson-Walker model with a massless scalar field in the presence of a small and positive cosmological constant, in the context of Loop Quantum…

General Relativity and Quantum Cosmology · Physics 2020-02-06 Mercedes Martín-Benito , Rita B. Neves

$f(R,T)$ gravity was proposed as an extension of the $f(R)$ theories, containing not just geometrical correction terms to the General Relativity equations, but also material correction terms, dependent on the trace of the energy-momentum…

General Relativity and Quantum Cosmology · Physics 2019-05-17 Ronaldo V. Lobato , G. A. Carvalho , A. G. Martins , P. H. R. S. Moraes

The k=0 Friedmann Lemaitre Robertson Walker model with a positive cosmological constant and a massless scalar field is analyzed in detail. If one uses the scalar field as relational time, new features arise already in the Hamiltonian…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Tomasz Pawlowski , Abhay Ashtekar

We develop a novel framework for describing quantum fluctuations in field theory, with a focus on cosmological applications. Our method uniquely circumvents the use of operator/Hilbert-space formalism, instead relying on a systematic…

General Relativity and Quantum Cosmology · Physics 2024-06-25 Ding Ding , Zhao Yu , Yidun Wan

We consider Feynman's path integral approach to quantum mechanics with a noncommutativity in position and momentum sectors of the phase space. We show that a quantum-mechanical system with this kind of noncommutativity is equivalent to the…

High Energy Physics - Theory · Physics 2007-05-23 Branko Dragovich , Zoran Rakic

We consider electrodynamics on a noncommutative spacetime using the enveloping algebra approach and perform a non-relativistic expansion of the effective action. We obtain the Hamiltonian for quantum mechanics formulated on a canonical…

High Energy Physics - Theory · Physics 2009-11-11 Xavier Calmet , Michele Selvaggi

We study the effect of noncommutativity of space on the physics of a quantum interferometer located in a rotating disk in a gauge field background. To this end, we develop a path-integral approach which allows defining an effective action…

High Energy Physics - Theory · Physics 2010-11-19 H. R. Christiansen , F. A. Schaposnik

We present the canonical and quantum cosmological investigation of a four-dimensional, spatially flat, Friedmann-Robertson-Walker (FRW) model that is derived from the bosonic Neveu-Schwarz/Neveu-Schwarz sector of the low-energy M-theory…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Marco Cavaglia , Paulo Vargas Moniz

As is well known, an external magnetic field in configuration space coupled to a quantum dynamics induces noncommutativity in its velocity momentum space. By phase space duality, an external vector potential in the conjugate momentum sector…

Quantum Physics · Physics 2024-01-09 Jan Govaerts

We show that simple scalar field models can give rise to curvature singularities in the effective Friedmann dynamics of Loop Quantum Cosmology (LQC). We find singular solutions for spatially flat Friedmann-Robertson-Walker cosmologies with…

General Relativity and Quantum Cosmology · Physics 2009-01-22 Thomas Cailleteau , Antonio Cardoso , Kevin Vandersloot , David Wands

In this paper, working in a Friedman-Lemaitre-Robertson-Walker (FLRW), first, in the flat case, we recover the generalized Friedman equation of Quantum Loop cosmology, and therefore the cosmological bounce, in the framework of modified…

General Relativity and Quantum Cosmology · Physics 2021-01-20 Alessandro Casalino , Bruno Sanna , Lorenzo Sebastiani , Sergio Zerbini

The loop quantum cosmological model from ADM Hamiltonian is studied in this paper. We consider the spatially flat homogeneous FRW model. It turns out that the modified Friedmann equation keeps the same form as the APS LQC model. However,…

General Relativity and Quantum Cosmology · Physics 2022-12-27 You Ding , Xiangdong Zhang

A new approach for arbitrary dimension to the Friedmann cosmological models is presented. Taking suitable changes of the parameters of the spacetime the harmonic motion equations appear, where the curvature determines the angular frequency.…

General Relativity and Quantum Cosmology · Physics 2014-03-03 Rafael M. Rubio , Juan J. Salamanca

In this paper, we introduce a noncommutative version of the Brans-Dicke (BD) theory and obtain the Hamiltonian equations of motion for a spatially flat Friedmann--Lema\^{\i}tre--Robertson--Walker universe filled with a perfect fluid. We…

General Relativity and Quantum Cosmology · Physics 2014-11-06 S. M. M. Rasouli , Paulo Vargas Moniz
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