Are loop quantum cosmos never singular?

By Parampreet Singh. 2009

225 citations recorded by the source corpus.

A unified treatment of all known types of singularities for flat, isotropic and homogeneous spacetimes in the framework of loop quantum cosmology (LQC) is presented. These include bangs, crunches and all future singularities. Using effective spacetime description we perform a model-independent general analysis of the properties of curvature, behavior of geodesics and strength of singularities. For illustration purposes a phenomenological model based analysis is also performed. We show that all values of the scale factor at which a strong singularity may occur are excluded from the effective loop quantum spacetime. Further, if the evolution leads to either a vanishing or divergent scale factor then the loop quantum universe is asymptotically deSitter in that regime. We also show that there exists a class of sudden extremal events, which includes a recently discussed possibility, for which the curvature or its derivatives will always diverge. Such events however turn out to be harmless weak curvature singularities beyond which geodesics can be extended. Our results point toward a generic resolution of physical singularities in LQC.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/9ef6284727bd451177318462717d410276cc68ca

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Citations in the corpus

Loop quantum cosmology: an overview (2008, background): “els, partial results have been obtained also in more complicated models indicating that the singularity resolution may be robust [44] (in the sense of geodesic completeness [ 59 ]).”
Inflationary Cosmology in Modified Gravity Theories (2015, methodology): “In this case, the relation {β̂LQC, V̂volume} = γBI/2 is satisfied [91].”
Loop Quantum Gravity (2003, background): “The same technique that leads to the resolution of the initial cosmological singularity has also been shown to lead to the resolution to all other (‘strong’) cosmological singularities [130, 131], and even to the singularities inside black holes [132–134].”
Loop quantization of the Schwarzschild interior revisited (2015, background): “It was cured by the introduction of the ‘improved’ (µ̄) dynamics of LQC which resulted in change of the uniform discreteness variable from triad to volume [3].”