Can we observe firewalls or fuzzballs? Shaun Hampton The Physics - - PowerPoint PPT Presentation

Can we observe firewalls or fuzzballs?

Shaun Hampton The Physics Department at the The Ohio State University Great Lakes Strings Conference at the University of Chicago

Bin, Hampton, Mathur arxiv:1711.01617

Firewall Argument

— Hawking Radiation – monotonic increase in

Entropy (Hawking)

— Proposed by Almheiri, Marolf, Polchinski,

Sully in 2013

• (1) The information of the hole is radiated away

the same way as any other black body (no monotonic increase in entropy)

• (II) Consider a surface located at 𝑠

" (stretched

horizon) which is 1 𝑚& outside of horizon (𝑠' = 2𝐻𝑁) then for 𝑠 > 𝑠

" physics is described by

Effective Field Theory

Issue with Firewall construction

— (I) and (II) are in conflict with each other

• (I) standard radiation, (II) 𝑠 > 𝑠

" EFT

— Why? Well consider a black hole of mass 𝑁. Using

(II) anything at 𝑠 > 𝑠

" should behave according to

‘normal physics’

— Consider collapsing shell of massless particles of

mass ∆𝑁. The shell will collapse all the way down to 𝑠 = 𝑠

" uhindered

— Horizon at 𝑠

' . = 2𝐻(𝑁 + ∆𝑁) but by (II) it must

past ‘without problem’ through this region

Issue with Firewall construction

— Information gets trapped inside it’s own horizon — Violates postulate (II): 𝑠 > 𝑠

" have EFT because

we need nonlocal effects to recover information

— Energy can’t radiate from the surface violating (I)

𝑠

'

E .

𝑠

'

.

𝑡343356 𝑡343356 = 𝐹 𝑈

9/;

𝑚& 𝑈 = 1 4𝜌𝑠

'

‘Modified firewall conjecture’

— Consider particle of energy 𝐹 falling towards

black hole of mass 𝑁

— At a certain distance 𝑡343356 from the horizon,

𝑠', the particle should be swallowed up by a new horizon

— Quantum gravitational effects must arise at or

before 𝑡343356

• Fuzzball construction (tunneling into new fuzzball

states as particle approaches 𝑡343356 ) (Mathur, Lunin, et al)

• Fuzzball radiates from its surface: consider interactions
• f in-falling particle with radiation at 𝑡 > 𝑡343356
• If 𝑄?@A~1 ⇒ firewall, if 𝑄?@A ≪ 1 ⇒ NO firewall

Fuzzball Geometry

— Assume we have a fuzzball (long vibrating closed

string) with no charge or rotation, roughly spherical in shape; outside of the fuzzball surface we have the metric

— Fuzzball boundary at 𝑠3 = 2𝐻𝑁 + 𝜗 where

𝜗~

5F

G

HI (tight fuzzball)

— Giving proper distance s~𝑚&

𝑒𝑡; = − 1 − 2𝐻𝑁 𝑠 𝑒𝑢; + 𝑒𝑠; 1 − 2𝐻𝑁 𝑠 𝑒𝑠; + 𝑠;𝑒Ω;

;

𝑠

3

𝑠

' = 2𝐻𝑁

Near horizon scattering

— Perform particle scattering in near horizon region

• In this region we assume radiation is isotropic

— Corresponds to a proper distance

𝑡~𝑠

' 9/; 𝑠 − 𝑠' 9/;

— Consider local orthonormal frame (Schwarzschild

frame) so that metric is locally flat 𝑠 − 𝑠' ≪ 𝑠'

𝑠

3

.

𝑠 − 𝑠

' ≪ 𝑠 '

Electron-Photon scattering

— Electron-photon scattering

𝑠

3

Electron of energy 𝐹, 𝑀 = 0

𝑠

3

Thermal distribution of photons in near horizon region with local temperature 𝑈 Q~ 9

"

Local Electron of energy 𝐹 Q~

I " 𝐹

Near horizon region 𝑠 − 𝑠

' ≪ 𝑠 ' ⟹ 𝑡 ≪ 𝑠 '

e- e-

𝑡343356 = 𝐹 𝑈

9/;

𝑚& 𝐹 > 𝑈 ⟹ 𝑡343356 > 𝑚&

Interaction Probability for electron- photon scattering

Sbubble 10 10 1012 1016 1020

(l )

• 5. × 10-20
• 1. × 10-

1.5 × 10-

• 2. × 10-

Pinteract

eγ

Probability never reaches ~1 There is NO FIREWALL! 𝐹 = 𝑛 𝑁 = 1 𝑁⨀ Bin et. al.

Consider Scattering of low energy photon off of positron/electron gas

𝑠

3

Photon energy 𝐹~𝑈 𝑡343356 ≲ 𝑚& (inside of fuzzball surface)

𝑠

3

Local photon energy 𝐹 Q~𝑈 Q

Near horizon region

found that 𝑄

?@A~𝛽; where 𝛽 = 9 9WX

and 𝑄

6Y6Z[6@\6~ 9 (YZ])

⟹ 𝑄

3^\_"\^AA6Z = 𝑄 ?@A𝑄 6Y6Z[6@\6 ≪ 1 𝑔𝑝𝑠 𝑁 = 𝑁⨀; 𝑄 Z6b56\A?c@ ≪ 1

Local electron/positron gas at threshold 𝑈 Q~𝑛 at s~

9 Y

s~ 1 𝑛

e- e+ e+ e-

Acknowledgements

— I would like to thank Samir Mathur, Bin

Guo for their work on the paper

— I would also like to thank Hong Zhang,

Stuart Raby, Naiyesh Afshordi, and Vitor Cardoso

— I would like to thank the organizers for

allowing me to talk at this great conference