A puncture in the Euclidean black hole

Ram Brustein, Amit Giveon, Nissan Itzhaki*, Yoav Zigdon

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


We consider the backreaction of the winding condensate on the cigar background. We focus on the case of the SL(2, ℝ)k/U(1) cigar associated with, e.g., the near-horizon limit of k NS5 black-branes. We solve the equations of motion numerically in the large k limit as a function of the amplitude, A, of the winding mode at infinity. We find that there is a critical amplitude, Ac = exp(−γ/2), that admits a critical solution. In string theory, the exact SL(2, ℝ)k/U(1) cigar CFT fixes completely the winding amplitude, As, at infinity. We find that in the large k limit there is an exact agreement, Ac = As. The critical solution is a cigar with a puncture at its tip; consequently, the black-hole entropy is carried entirely by the winding condensate. We argue that, in the Lorentzian case, the information escapes the black hole through this puncture.

Original languageAmerican English
Article number21
JournalJournal of High Energy Physics
Issue number4
StatePublished - Apr 2022

Bibliographical note

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  • Black Holes in String Theory
  • Conformal Field Models in String Theory


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