IAS Quantum Aspects of Black Holes Group Meeting

Continuing Past the Inner Horizon Using WKB

Abstract: Features of the black hole interior can be extracted from the analytic structure of boundary correlation functions. Working in the geodesic approximation, we find analytic continuations that probe the interior of rotating and charged black holes. These generate contributions from timelike geodesics that thread the interior and emerge in a future universe. We implement these continuations on the momentum space two-point function and exemplify this in several black hole backgrounds. We also identify position space analytic continuations achieving the same task that incorporate different continued momentum space correlators. These correspond to non-perturbative corrections to the WKB approximation. We demonstrate this explicitly in the rotating BTZ black hole by showing that the interior geodesics contribute to the continued position space correlator and motivate a picture for how these contributions arise in higher dimensions. For AdS Schwarzschild, we identify the analytically continued solution that captures the bouncing geodesic. We discuss the possibility of using these continuations to probe the instability of inner horizons from the boundary.

Continuing past the inner horizon using WKB

Date & Time

January 29, 2026 | 11:00am – 12:00pm
Add to calendar 01/29/2026 11:00 01/29/2026 12:00 IAS Quantum Aspects of Black Holes Group Meeting use-title Topic: Continuing Past the Inner Horizon Using WKB Speakers: Ahmed Almheiri, IAS & New York University Abu Dhabi More: https://www.ias.edu/sns/events/ias-quantum-aspects-black-holes-group-meeting-58 ABSTRACT: Features of the black hole interior can be extracted from the analytic structure of boundary correlation functions. Working in the geodesic approximation, we find analytic continuations that probe the interior of rotating and charged black holes. These generate contributions from timelike geodesics that thread the interior and emerge in a future universe. We implement these continuations on the momentum space two-point function and exemplify this in several black hole backgrounds. We also identify position space analytic continuations achieving the same task that incorporate different continued momentum space correlators. These correspond to non-perturbative corrections to the WKB approximation. We demonstrate this explicitly in the rotating BTZ black hole by showing that the interior geodesics contribute to the continued position space correlator and motivate a picture for how these contributions arise in higher dimensions. For AdS Schwarzschild, we identify the analytically continued solution that captures the bouncing geodesic. We discuss the possibility of using these continuations to probe the instability of inner horizons from the boundary. Continuing past the inner horizon using WKB [https://urldefense.com/v3/__https://inspirehep.net/literature/3097737__;!!NubF!P1ZwY_qCcFL3G8_CRuAeOUb3awoIY4BjJxQ3a5H3Koayc44Sfh2H1zYp3YPr5XI2RopJZhmblDVpOQ$] Bloomberg Hall Physics Library & Zoom a7a99c3d46944b65a08073518d638c23

Location

Bloomberg Hall Physics Library & Zoom

Speakers

Ahmed Almheiri, IAS & New York University Abu Dhabi

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