Instant folded strings and black fivebranes

Abstract

We study the recent claim that black NS5-branes are filled with folded strings. We calculate, in the near-extremal case, the number of folded strings at the black fivebranes interior, using different approaches, and get the exact same answer. The backreaction of the folded strings leads us to argue that the interior of the black fivebrane is AdS 2 (times a compact manifold) and that infalling matter cannot reach the interior, due to a shock wave at the horizon. These considerations also suggest a novel insight into the black fivebranes entropy.

$$ T\overline{T} $$ , black holes and negative strings

“…It would be interesting to investigate their role in the present context. In particular, it would be interesting to understand if the p negative strings that form the M − 3 background are related to the order 1/g 2 s instant folded strings in the interior of the two-dimensional black hole discussed in [47][48][49].…”

Explicit microstates at the Schwarzschild horizon

“…where Φ hor is the value of the two-dimensional dilaton on the horizon and N IFS stands for the number of 'instantly created folded strings' (IFSs) of [15,16] at the vicinity of the BH horizon. This assumption has strong support in [12] and below. 8…”

“…which has remarkable consequences, following [4][5][6][7][8][9][10][11][12][13], both technical and conceptual. Concretely, for large BHs, the winding condensate profile near the horizon is sufficient to obtain the entire BH entropy.…”

“…6 2. The number N of "string bits" which amounts to the condensate 7 F ∼ W + W − in the 2d SL(2) k /U(1) BH is (see [12] for details)…”

“…where S and N are those in ( 8), ( 10) and (12), respectively; a.k.a, the microstates which give rise to the BH entropy correspond to the long strings modes at the (stringy) vicinity of its horizon.…”