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#Mon Aug 09 12:15:07 CEST 2010
Text__8wG1oKOeEd-WfYQ0GneCwQ_title=Loops and cosmology
Text__8wG1oKOeEd-WfYQ0GneCwQ_text=Loop quantum gravity has led to interesting cosmological results. In classical general relativity (sketched in the upper part of the image on the left), the universe begins with the big bang singularity and just keeps on expanding. At least in simplified loop models, this singularity disappears (sketched in the lower part of the image)\: there, we stat with a collapsing cosmos. It reaches a size where quantum effects become important (symbolized by the looking glass in the image), then undergoes a jumpy quantum evolution, reaches zero size and, afterwards, starts expanding, just as in classical cosmology. In this model, the unphysical singularity is absent.