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arXiv · 1701.07771

Consistent Cosmic Bubble Embeddings

S. Shajidul Haque·Bret Underwood
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Abstract

The Raychaudhuri equation for null rays is a powerful tool for finding consistent embeddings of cosmological bubbles into a background spacetime in a way that is largely independent of the matter content. We find that spatially flat or positively curved thin wall bubbles surrounded by a cosmological background must have a Hubble expansion that is either contracting or expanding slower than the background, which are more stringent constraints than those obtained by the usual Israel thin-wall formalism. Similarly, a cosmological bubble surrounded by Schwarzschild space, occasionally used as a simple "swiss cheese" model of inhomogenities in an expanding universe, must be contracting (for spatially flat and positively curved bubbles) and bounded in size by the apparent horizon.

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S. Shajidul Haque, Bret Underwood. 2017-01-26. Consistent Cosmic Bubble Embeddings. https://doi.org/10.1103/physrevd.95.103513

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