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arXiv · 2607.14620

Scalarization of Charged Black Hole in Gauss-Bonnet Extended Starobinsky-Maxwell Gravity

Rui-Xi Zhu·Hai-Shan Liu
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Abstract

We re-examine spontaneous scalarization of black holes within Starobinsky gravity supplemented by the Gauss-Bonnet invariant. A novel feature is uncovered: scalarized solutions split into two smooth branches that connect at a common minimal horizon radius, a multi-branch structure previously unreported for static, spherically symmetric scalarization. Extending the theory with a Maxwell field, we find that this multi-branch structure persists, while a new additional disconnected branch emerges within certain parameter ranges. We thoroughly analyse the transition from a single smooth branch to two disconnected branches. Lastly, we verify, employing the standard Maxwell thermodynamic relations, that all charged hairy solutions obey the first law exactly.

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Rui-Xi Zhu, Hai-Shan Liu. 2026-07-16. Scalarization of Charged Black Hole in Gauss-Bonnet Extended Starobinsky-Maxwell Gravity. https://arxiv.org/abs/2607.14620

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