MG13 - Talk detail |
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Participant |
Clifton, Timothy | |||||||
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Institution |
Queen Mary, University of London - Mile End Road - London - London - United Kingdom | |||||||
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Session |
TC3 |
Accepted |
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Order |
Time |
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Talk |
Oral abstract |
Title |
Backreaction in relativistic cosmology | |||||
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Abstract |
We consider a range of exact n-body solutions of Einstein's constraint equations, restricting our attention to regularly arranged distributions of masses in topological 3-spheres. We find that when all the mass in the universe is condensed into a small number of objects (<10) then the amount of backreaction in dust models can be large, with O(1) deviations from the predictions of the corresponding FLRW solutions. When the number of masses is large (>100), however, then our measures of backreaction become small (<1%). This result does not rely on any averaging procedures, which are notoriously hard to define uniquely in general relativity, and so provides (to the best of our knowledge) the first exact and unambiguous demonstration of backreaction in general relativistic cosmological modelling. |
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