Extreme black hole anabasis

Shahar Hadar, Alexandru Lupsasca, Achilleas P. Porfyriadis

Research output: Contribution to journalArticlepeer-review


We study the SL(2) transformation properties of spherically symmetric perturbations of the Bertotti-Robinson universe and identify an invariant μ that characterizes the backreaction of these linear solutions. The only backreaction allowed by Birkhoff’s theorem is one that destroys the AdS2× S2 boundary and builds the exterior of an asymptotically flat Reissner-Nordström black hole with Q=M1−μ/4. We call such backreaction with boundary condition change an anabasis. We show that the addition of linear anabasis perturbations to Bertotti-Robinson may be thought of as a boundary condition that defines a connected AdS2×S2. The connected AdS2 is a nearly-AdS2 with its SL(2) broken appropriately for it to maintain connection to the asymptotically flat region of Reissner-Nordström. We perform a backreaction calculation with matter in the connected AdS2× S2 and show that it correctly captures the dynamics of the asymptotically flat black hole.

Original languageEnglish
Article number223
JournalJournal of High Energy Physics
Issue number3
StatePublished - Mar 2021
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2021, The Author(s).


  • Black Holes
  • Space-Time Symmetries

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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