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arXiv · 2508.12760

Infinite-dimensional symmetries in plane wave spacetimes

Emilie Despontin·Stéphane Detournay·Dima Fontaine
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Abstract

We study the asymptotic symmetries of the Nappi-Witten spacetime in four dimensions, a plane wave arising as the Penrose limit of AdS$_2\times S^2$. Imposing suitable boundary conditions at large transverse distance, we uncover a new infinite-dimensional symmetry algebra allowing for non-trivial central extensions. The corresponding phase space encompasses the most general four-dimensional pp-wave metric, including in particular the Penrose limit of Kerr black holes.

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Emilie Despontin, Stéphane Detournay, Dima Fontaine. 2025-08-18. Infinite-dimensional symmetries in plane wave spacetimes. https://doi.org/10.1103/2q94-5crl

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