Results 31 to 40 of about 467 (173)
Isotropic loop quantum cosmology [PDF]
Classical and Quantum Gravity, 2002 Isotropic models in loop quantum cosmology allow explicit calculations, thanks largely to a completely known volume spectrum, which is exploited in order to write down the evolution equation in a discrete internal time. Because of genuinely quantum geometrical effects the classical singularity is absent in those models in the sense that the evolution ...
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INFLATIONARY COSMOLOGY AND OSCILLATING UNIVERSES IN LOOP QUANTUM COSMOLOGY [PDF]
International Journal of Modern Physics A, 2005 We study oscillatory universes within the context of Loop Quantum Cosmology. We make a comparative study of flat and positively curved universes sourced by scalar fields with either positive or negative potentials. We investigate how oscillating universes can set the initial conditions for successful slow-roll inflation, while ensuring that the semi ...
Mulryne, David J. +3 more
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Noncommutativity in Effective Loop Quantum Cosmology
Advances in High Energy Physics, 2019 We construct a noncommutative extension of the Loop Quantum Cosmology effective scheme for the flat FLRW model with a free scalar field via a theta deformation.
Abraham Espinoza-García +3 more
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Loop quantum gravity and cosmological constant
Physics Letters B, 2021 A one-parameter regularization freedom of the Hamiltonian constraint for loop quantum gravity is analyzed. The corresponding spatially flat, homogenous and isotropic model includes the two well-known models of loop quantum cosmology as special cases. The
Xiangdong Zhang, Gaoping Long, Yongge Ma
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ON THE SEMICLASSICAL LIMIT OF LOOP QUANTUM COSMOLOGY
International Journal of Modern Physics D, 2012 We consider a k = 0 Friedman–Robertson–Walker (FRW) model within loop quantum cosmology (LQC) and explore the issue of its semiclassical limit. The model is exactly solvable and allows us to construct analytical (Gaussian) coherent-state solutions for each point on the space of classical states.
Corichi, Alejandro, Montoya, Edison
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Quantum reduced loop gravity and the foundation of loop quantum cosmology [PDF]
International Journal of Modern Physics D, 2016 Quantum reduced loop gravity is a promising framework for linking loop quantum gravity and the effective semiclassical dynamics of loop quantum cosmology. We review its basic achievements and its main perspectives, outlining how it provides a quantum description of the Universe in terms of a cuboidal graph which constitutes the proper framework for ...
Emanuele Alesci, Francesco Cianfrani
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European Physical Journal C: Particles and Fields, 2019 Mimetic gravity can be described as a formulation capable of mimicking different evolutionary scenarios regarding the universe dynamics. Notwithstanding its initial aim of producing a similar evolution to the one expected from the dark components of the ...
Eunice Bezerra, Oswaldo D. Miranda
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Observational Constraints on Loop Quantum Cosmology
Physical Review Letters, 2011 In the inflationary scenario of loop quantum cosmology in the presence of inverse-volume corrections, we give analytic formulas for the power spectra of scalar and tensor perturbations convenient to compare with observations. Since inverse-volume corrections can provide strong contributions to the running spectral indices, inclusion of terms higher ...
Bojowald, M. +2 more
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Effective Field Theory of Loop Quantum Cosmology
Universe, 2019 Quantum cosmology is traditionally formulated in a minisuperspace setting, implicitly averaging fields over space to obtain homogeneous models. For universal reasons related to the uncertainty principle, quantum corrections then depend on the size of the
Martin Bojowald
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Absence of a Singularity in Loop Quantum Cosmology [PDF]
Physical Review Letters, 2001 It is shown that the cosmological singularity in isotropic minisuperspaces is naturally removed by quantum geometry. Already at the kinematical level, this is indicated by the fact that the inverse scale factor is represented by a bounded operator even though the classical quantity diverges at the initial singularity.
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