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arXiv · 1805.00026

Decreasing entropy of dynamical black holes in critical gravity

Hideki Maeda·Robert Svarc·Jiri Podolsky
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Abstract

Critical gravity is a quadratic curvature gravity in four dimensions which is ghost-free around the AdS background. Constructing a Vaidya-type exact solution, we show that the area of a black hole defined by a future outer trapping horizon can shrink by injecting a charged null fluid with positive energy density, so that a black hole is no more a one-way membrane even under the null energy condition. In addition, the solution shows that the Wald-Kodama dynamical entropy of a black hole is negative and can decrease. These properties expose the pathological aspects of critical gravity at the non-perturbative level.

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Hideki Maeda, Robert Svarc, Jiri Podolsky. 2018-04-30. Decreasing entropy of dynamical black holes in critical gravity. https://doi.org/10.1007/jhep06(2018)118

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