Non-singular rotating black hole with a time delay in the center

  • Tommaso De Lorenzo
  • Andrea Giusti
  • Simone SpezialeEmail author
Research Article


As proposed by Bambi and Modesto, rotating non-singular black holes can be constructed via the Newman–Janis algorithm. Here we show that if one starts with a modified Hayward black hole with a time delay in the centre, the algorithm succeeds in producing a rotating metric, but curvature divergences reappear. To preserve finiteness, the time delay must be introduced directly at the level of the non-singular rotating metric. This is possible thanks to the deformation of the inner stationarity limit surface caused by the regularisation, and in more than one way. We outline three different possibilities, distinguished by the angular velocity of the event horizon. Along the way, we provide additional results on the Bambi–Modesto rotating Hayward metric, such as the structure of the regularisation occurring at the centre, the behaviour of the quantum gravity scale alike an electric charge in decreasing the angular momentum of the extremal black hole configuration, or details on the deformation of the ergosphere.


Non-singular black holes Newman–Janis algorithm Violations of weak energy condition 



We thank Pietro Donà, Thibaut Josset and Carlo Rovelli for useful discussions.


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Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  • Tommaso De Lorenzo
    • 1
  • Andrea Giusti
    • 1
    • 2
  • Simone Speziale
    • 1
    Email author
  1. 1.Centre de Physique Theorique, CNRS-UMR 7332Aix-Marseille Université & Université de ToulonMarseilleFrance
  2. 2.Dip. di Fisica e AstronomiaUniversità di BolognaBolognaItaly

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