https://doi.org/10.1140/epjc/s10052-024-12454-w
Regular Article - Theoretical Physics
Super-extremal black holes in the quasitopological electromagnetic field theory
1
The Ruppin Academic Center, 40250, Emeq Hefer, Israel
2
The Hadassah Academic College, 91010, Jerusalem, Israel
Received:
15
November
2023
Accepted:
16
January
2024
Published online:
2
February
2024
It has recently been proved that a simple generalization of electromagnetism, referred to as quasitopological electromagnetic field theory, is characterized by the presence of dyonic black-hole solutions of the Einstein field equations that, in certain parameter regions, are characterized by four horizons. In the present compact paper we reveal the existence, in this non-linear electrodynamic field theory, of super-extremal black-hole spacetimes that are characterized by the four degenerate functional relations ![$$[g_{00}(r)]_{r=r_{\text {H}}}=[dg_{00}(r)/dr]_{r=r_{\text {H}}}=[d^2g_{00}(r)/dr^2]_ {r=r_{\text {H}}}=[d^3g_{00}(r)/dr^3]_{r=r_{\text {H}}}=0$$](/articles/epjc/abs/2024/02/10052_2024_Article_12454/10052_2024_Article_12454_tex_eq1.png)
, where 
is the tt-component of the curved line element and 
is the black-hole horizon radius. In particular, using analytical techniques we prove that the quartically degenerate super-extremal black holes are characterized by the universal (parameter-independent) dimensionless compactness parameter 
, where 
.
© The Author(s) 2024
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