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The cosmological singularities of the Bianchi I universe are analyzed in the setting of loop geometry underlying the loop quantum cosmology. We solve the Hamiltonian constraint of the theory and find the Lie algebra of elementary…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Piotr Dzierzak , Wlodzimierz Piechocki

We describe the quantum evolution of the vacuum Bianchi II universe in terms of the transition amplitude between two asymptotic quantum Kasner-like states. For large values of the momentum variable the classical and quantum calculations…

General Relativity and Quantum Cosmology · Physics 2015-06-19 Hervé Bergeron , Orest Hrycyna , Przemysław Małkiewicz , Włodzimierz Piechocki

A non-singular bouncing cosmology is generically obtained in loop quantum cosmology due to non-perturbative quantum gravity effects. A similar picture can be achieved in standard general relativity in the presence of a scalar field with a…

General Relativity and Quantum Cosmology · Physics 2014-03-17 Yi-Fu Cai , Edward Wilson-Ewing

In this paper we study the dynamics of {\it orthogonal spatially homogeneous} Bianchi cosmologies in $R^n$-gravity. We construct a compact state space by dividing the state space into different sectors. We perform a detailed analysis of the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Naureen Goheer , Jannie A. Leach , Peter K. S. Dunsby

We analyse a n-dimensional Generalized Uncertainty Principle (GUP) quantization framework, characterized by a non-commutative nature of the configurational variables. First, we identify a set of states which are maximally localized only…

General Relativity and Quantum Cosmology · Physics 2025-04-02 Sebastiano Segreto , Giovanni Montani

In loop quantum cosmology, non-perturbative quantum gravity effects lead to the resolution of the big bang singularity by a quantum bounce without introducing any new degrees of freedom. Though fundamentally discrete, the theory admits a…

General Relativity and Quantum Cosmology · Physics 2010-05-12 Gonzalo J. Olmo , Parampreet Singh

Coherent state functional integral for the minisuperspace model of loop quantum cosmology is studied. By the well-established canonical theory, the transition amplitude in the path integral representation of loop quantum cosmology with…

General Relativity and Quantum Cosmology · Physics 2012-06-07 Li Qin , Yongge Ma

The detailed formulation for loop quantum cosmology (LQC) in the Bianchi I model with a scalar massless field has been constructed. In this paper, its effective dynamics is studied in two improved strategies for implementing the LQC…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Dah-Wei Chiou

In this paper we study the evolution of spatially homogeneous and anisotropic Bianchi type-I Universe models with the cosmological constant, \Lambda, and filled with nonlinear viscous fluid. The dynamical equations for these models are…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Nouraddin Mostafapoor , Oyvind Gron

We have recently introduced an approach for studying perturbatively classical and quantum canonical general relativity. The perturbative technique appears to preserve many of the attractive features of the non-perturbative quantization…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Rodolfo Gambini , Jorge Pullin

This paper has a dual purpose. One aim is to study the evolution of coherent states in ordinary quantum mechanics. This is done by means of a Hamiltonian approach to the evolution of the parameters that define the state. The stability of…

General Relativity and Quantum Cosmology · Physics 2012-08-27 A. A. Minzoni , Marcos Rosenbaum , Michael P. Ryan,

Coherent states consist of superposition of infinite number of particles and do not have a classical analogue. We study their evolution in a FLRW cosmology and show that only when full quantum corrections are considered, they may survive…

High Energy Physics - Phenomenology · Physics 2015-08-26 Houri Ziaeepour

Using squeezed vacuum state formalism of quantum optics, an approximate solution to the semiclassical Einstein equation is obtained in Bianchi type-I universe. The phenomena of nonclassical particle creation is also examined in the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 P. K. Suresh

We study a spatial-temporal structure of quantum fluctuations in the stress-energy tensor of zero-point modes for a scalar field in order to formulate a covariant model. The model describes an invariant vacuum contribution to the…

High Energy Physics - Theory · Physics 2025-05-06 A. Aynbund , V. V. Kiselev

We discuss the time-continuous path integration in the coherent states basis in a way that is free from inconsistencies. Employing this notion we reproduce known and exact results working directly in the continuum. Such a formalism can set…

Quantum Physics · Physics 2016-05-24 G. Kordas , S. I. Mistakidis , A. I. Karanikas

We provide an explicit construction of entangled states in a noncommutative space with nonclassical states, particularly with the squeezed states. Noncommutative systems are found to be more entangled than the usual quantum mechanical…

Quantum Physics · Physics 2015-06-18 Sanjib Dey , Véronique Hussin

Anisotropies generically dominate the earliest stages of expansion of a homogeneous universe. They are particularly relevant in bouncing models, since shears grow in the contracting phase of the cosmos, making the isotropic situation…

General Relativity and Quantum Cosmology · Physics 2020-09-04 Ivan Agullo , Javier Olmedo , V. Sreenath

The effective quantum dynamics of Bianchi I spacetime is addressed within the statistical regularization scheme in Quantum Reduced Loop Gravity. The case of a minimally coupled massless scalar field is studied and compared with the…

General Relativity and Quantum Cosmology · Physics 2019-05-29 Emanuele Alesci , Gioele Botta , Giovanni Luzi , Gabriele V. Stagno

The effects of noncommutativity in the phase-space of the classical and quantum cosmology of Bianchi models are investigated. Exact solutions in both commutative and noncommutative cases are presented and compared. Further, the Noether…

General Relativity and Quantum Cosmology · Physics 2008-11-26 B. Vakili , N. Khosravi , H. R. Sepangi

The "improved dynamics" of loop quantum cosmology is extended to include anisotropies of the Bianchi I model. As in the isotropic case, a massless scalar field serves as a relational time parameter. However, the extension is non-trivial…

General Relativity and Quantum Cosmology · Physics 2010-04-14 Abhay Ashtekar , Edward Wilson-Ewing
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