BLACK-HOLE MICROSTRUCTURE

Contribution List

1. How to Spot Microstructure in the Wild

Daniel Mayerson

6/7/21, 11:30 AM

The advent of gravitational waves and black hole imaging has opened a new window into probing the horizon scale of black holes. An important question is whether string theory results for black hole physics can predict interesting and observable features that current and future experiments can probe. I will give a brief overview of the relevant observational experiments, before reviewing this...

2. Black Holes, Unscripted

Niayesh Afshordi

6/7/21, 2:00 PM

Black Holes occupy a special place in the fascination of astronomers and physicists. From the most speculative mathematical physicist, to the most sensible radio astronomer, everyone has their own narrative of what lies within a black hole, based on their own preconceptions. As an alternative, I will outline an empirical and agnostic roadmap for probing black hole physics, by combining...

3. How does a black-hole microstate ringdown?

Paolo Pani

6/7/21, 3:30 PM

The quasinormal-mode spectrum of a horizonless compact object can differ significantly from that of the corresponding classical black hole. However, the time response can be initially very similar if the object is sufficiently compact. A generic smoking gun of the absence of a classical horizon is the presence of echoes in the late-time ringdown. The echo delay time and morphology depend...

4. Panel: Distinguishing Microstructure from Black Holes

Iosif Bena (Moderator), Geoff Penington, Massimo Bianchi, Daniel Mayerson

6/7/21, 5:15 PM

Iosif Bena (moderator), Massimo Bianchi, Daniel Mayerson, Geoff Penington

https://www.youtube.com/watch?v=0BO-p58Pypc

5. Black Hole Microstates in Holography and Worldsheet CFT

David Turton

6/8/21, 11:30 AM

In this talk I will review recent progress on two topics. The first topic is the holographic description of heavy configurations in supergravity, in which holography can provide a microscopic interpretation of a supergravity solution as describing a particular pure black hole microstate. Recent results have enabled holographic studies with improved precision for supergravity solutions such as...

6. The CFT Dual of a Tidal Force

Shaun Hampton

6/8/21, 2:00 PM

It was demonstrated that a string probe falling radially within a superstrata geometry would experience tidal forces. These tidal forces were shown to excite the string by converting its kinetic energy into motion along the transverse directions. Using the AdS/CFT correspondence we seek to understand this behavior from the perspective of the dual D1D5 CFT. To study this process we turn on an...

7. Black hole microstates vs the additivity conjectures

Geoff Penington

6/8/21, 3:30 PM

I will argue that at least one of the following statements must be true: either (a) extensive violations of quantum information theory's “additivity conjectures” exist or (b) there exists a set of “disentangled” black hole microstates that can account for the entire Bekenstein-Hawking entropy (up to at most a subleading O(1) correction). Possibility (a) would be a significant result in quantum...

8. An overview of Jackiw-Teitelboim gravity and applications

Joaquin Turiaci

6/8/21, 5:15 PM

We will give an overview of recent developments in two dimensional Jackiw-Teitelboim (JT) gravity in asymptotically AdS, and applications. The talk will be separated into two parts. First we will review perturbative quantum effects in JT gravity, which are a good approximation of low energy physics for a variety of systems including near-extremal black holes in higher dimensions and SYK-like...

9. Interpolating between multi-center solutions

Masaki Shigemori

6/9/21, 11:30 AM

We study interpolation between two multi-center microstate geometries in 4d/5d that represent Lunin-Mathur geometries with circular profiles. The interpolating solution is a Lunin-Mathur geometry with a helical profile, and is represented by a 2-center solution with a codimension-2 source. The interpolating 2-center solution exhibits interesting features such as some of the charges being...

10. Comments on the Page curve for Hawking radiation

Juan Maldacena

6/9/21, 3:00 PM

We will review the ideas that lead to the computation of the Page curve for Hawking radiation. We will discuss what aspects of the black hole information problem this addresses and which ones remain to be understood.

http://www.youtube.com/watch?v=-vHrjKGgtMk

11. Contrasting the fuzzball and wormhole paradigms for resolving the black hole information paradox

Samir Mathur

6/9/21, 4:00 PM

We summarize the information paradox and how the fuzzball paradigm resolves the paradox. We note that the small corrections theorem implies that any alternative to fuzzballs must involve long-distance nonlocality. We comment on some aspects of the wormhole paradigm, trying to pinpoint the kind of nonlocalities implied by such an approach.

https://www.youtube.com/watch?v=-vHrjKGgtMk&t=4215s

20. Maldacena Response

Juan Maldacena

6/9/21, 5:00 PM

21. Mathur Response

Samir Mathur

6/9/21, 5:15 PM

12. Panel: Islands

Emil Martinec (Moderator), Douglas Stanford, Juan Maldacena, Samir Mathur

6/9/21, 6:15 PM

Moderator: Emil Martinec

http://www.youtube.com/watch?v=m_1mzZ9tlvc

14. Superstrata and Microstrata

Nicholas Warner

6/10/21, 2:30 PM

I will review that current status of superstrata as a description of BPS microstructure and summarize some of the open problems. I will also describe some new progress in the construction of "microstrata:" non-extremal analogues of superstrata.

https://youtu.be/nvPqTqNs00U

13. Bubble Bag End: a Non-BPS Floating Brane’s Tale

Pierre Heidmann

6/10/21, 4:30 PM

Using the Weyl formalism, we will describe a new mechanism for constructing smooth bubbling geometries in the non-BPS regime. The solutions require at least 6 dimensions, they are static, axially symmetric and asymptotic to four-dimensional Minkowski flat dimensions plus extra compact dimensions. They are generated by a set of harmonic functions like their BPS cousins but are sourced by rods....

16. Wormholes and microstructure

Steve Shenker

6/10/21, 6:00 PM

https://youtu.be/yQ0Q58FvsHM

18. Scrambling in rotating BTZ from CFT

Ben Craps

6/11/21, 2:00 PM

Slow scrambling has recently been discussed in the context of extremal BTZ black holes and associated microstate geometries. This talk addresses the CFT origin of this phenomenon and of related results for more general rotating BTZ black holes.

https://youtu.be/qo8c3xXOvyE

19. AdS3/(worldsheet)CFT2

Emil Martinec

6/11/21, 3:30 PM

Perturbative string methods provide a wealth of insights into AdS3/CFT2 duality, and its generalization to little string theory. An overview of these methods will be given as well as a survey of results obtained to date.

http://www.youtube.com/watch?v=lHjQdvGu-mc

23. AdS3 with no BTZs

Bruno Balthazar

6/11/21, 4:45 PM

I will describe AdS3 string theory with NS fluxes in a regime where the AdS3 radius of curvature is smaller than the string scale. The asymptotic density of states consists of highly excited fundamental strings rather than BTZ black holes. I will present evidence that the CFT dual to this string theory is a symmetric product orbifold with a linear dilaton "block" CFT, with a deformation that...

22. Panel: Scrambling and Tidal Disruption

Nicholas Warner (Moderator), Ben Craps, Julian Sonner, Shaun Hampton

6/11/21, 6:00 PM

https://youtu.be/jHp1WVBdYww