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arXiv · 2012.09125

Emmy's letter to Santa Claus (and a reply): Vaidya geometries and scalar fields with null gradients

Valerio Faraoni·Andrea Giusti·Bardia H. Fahim
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Abstract

Emmy, a child prodigy, writes a letter to Santa Claus asking for a Vaidya solution sourced by a massless scalar field with null gradient for Christmas. Santa writes back explaining why such a toy cannot be built and offers an exact plane wave sourced by a scalar field with lightlike gradient as a replacement.

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Valerio Faraoni, Andrea Giusti, Bardia H. Fahim. 2020-12-16. Emmy's letter to Santa Claus (and a reply): Vaidya geometries and scalar fields with null gradients. https://arxiv.org/abs/2012.09125

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