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arXiv · 1611.05038

Caustics for Spherical Waves

Claudia de Rham·Hayato Motohashi
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Abstract

We study the development of caustics in shift-symmetric scalar field theories by focusing on simple waves with an $SO(p)$-symmetry in an arbitrary number of space dimensions. We show that the pure Galileon, the DBI-Galileon, and the extreme-relativistic Galileon naturally emerge as the unique set of caustic-free theories, highlighting a link between the caustic-free condition for simple $SO(p)$-waves and the existence of either a global Galilean symmetry or a global (extreme-)relativistic Galilean symmetry.

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Claudia de Rham, Hayato Motohashi. 2016-11-15. Caustics for Spherical Waves. https://doi.org/10.1103/physrevd.95.064008

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