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Thermal Decay without Information Loss in Horizonless Microstate Geometries
by Iosif Bena, Pierre Heidmann, Ruben Monten, Nicholas P. Warner
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Submission summary
Authors (as registered SciPost users):  Ruben Monten 
Submission information  

Preprint Link:  https://arxiv.org/abs/1905.05194v2 (pdf) 
Date accepted:  20191105 
Date submitted:  20191025 02:00 
Submitted by:  Monten, Ruben 
Submitted to:  SciPost Physics 
Ontological classification  

Academic field:  Physics 
Specialties: 

Approach:  Theoretical 
Abstract
We develop a new hybrid WKB technique to compute boundarytoboundary scalar Green functions in asymptoticallyAdS backgrounds in which the scalar wave equation is separable and is explicitly solvable in the asymptotic region. We apply this technique to a family of sixdimensional $\frac{1}{8}$BPS asymptotically AdS$_3\,\times\,$S$^3$ horizonless geometries that have the same charges and angular momenta as a D1D5P black hole with a large horizon area. At large and intermediate distances, these geometries very closely approximate the extremalBTZ$\,\times\,$S$^3$ geometry of the black hole, but instead of having an event horizon, these geometries have a smooth highlyredshifted globalAdS$_3\,\times\,$S$^3$ cap in the IR. We show that the response function of a scalar probe, in momentum space, is essentially given by the pole structure of the highlyredshifted globalAdS$_3$ modulated by the BTZ response function. In position space, this translates into a sharp exponential blackholelike decay for times shorter than $N_1 N_5$, followed by the emergence of evenly spaced "echoes from the cap," with period $\sim N_1 N_5$. Our result shows that horizonless microstate geometries can have the same thermal decay as black holes without the associated information loss.
Author comments upon resubmission
List of changes
We have:
 corrected misprints such as SchrÃ¶dinger (p.9 and onward),
 replaced the notation $\Psi_E$ by $\Psi_{ex}$ in order to avoid notational conflict with other conventions (eq(2.12) and onward),
 addressed the confusing statement $x \ll \infty$ (p.11),
 added the definitions of the Airy functions (p.11),
 explained the statement that $J_R = 1/2$ is the minimal value (p.27),
 commented briefly on the difficulty extending our method to flat space superstrata (p.5),
 added references to the Virgo/LIGO and Event Horizon Telescope publications.
Published as SciPost Phys. 7, 063 (2019)