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 A lmheiri, M arolf, P olchinski, S ully 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 . = 2𝐻(𝑁 + ∆𝑁) but by (II) it must — Horizon at 𝑠 ' 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 ' . 9/; 𝑠 𝑡 343356 = 𝐹 ' 𝑚 & . 𝑈 𝑡 343356 1 𝑈 = 4𝜌𝑠 '

‘Modified firewall conjecture’ — Consider particle of energy 𝐹 falling towards black hole of mass 𝑁 — At a certain distance 𝑡 343356 from the horizon, 𝑠 ' , the particle should be swallowed up by a new horizon — Quantum gravitational effects must arise at or before 𝑡 343356 ◦ Fuzzball construction (tunneling into new fuzzball states as particle approaches 𝑡 343356 ) (Mathur, Lunin, et al) ◦ Fuzzball radiates from its surface: consider interactions of in-falling particle with radiation at 𝑡 > 𝑡 343356 ◦ 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 𝑒𝑠 ; 𝑒𝑡 ; = − 1 − 2𝐻𝑁 𝑒𝑢 ; + 𝑒𝑠 ; + 𝑠 ; 𝑒Ω ; ; 1 − 2𝐻𝑁 𝑠 𝑠 — Fuzzball boundary at 𝑠 3 = 2𝐻𝑁 + 𝜗 where G 5 F 𝑠 𝜗~ HI ( tight fuzzball ) 3 — Giving proper distance s~𝑚 & 𝑠 ' = 2𝐻𝑁

Near horizon scattering — Perform particle scattering in near horizon region 𝑠 − 𝑠 ' ≪ 𝑠 ' ◦ In this region we assume radiation is isotropic — Corresponds to a proper distance 9/; 𝑠 − 𝑠 ' 9/; 𝑡~𝑠 ' — Consider local orthonormal frame (Schwarzschild frame) so that metric is locally flat 𝑠 3 . 𝑠 − 𝑠 ' ≪ 𝑠 '

Electron-Photon scattering 9/; 𝑡 343356 = 𝐹 — Electron-photon scattering 𝑚 & 𝑈 𝐹 > 𝑈 ⟹ 𝑡 343356 > 𝑚 & 𝑠 3 Electron of energy 𝐹 , 𝑀 = 0 e - Near horizon region 𝑠 − 𝑠 ' ≪ 𝑠 ' ⟹ 𝑡 ≪ 𝑠 ' 𝑠 3 Local Electron of e - I Q~ energy 𝐹 " 𝐹 Thermal distribution of photons in near horizon region with local Q~ 9 temperature 𝑈 "

Interaction Probability for electron- photon scattering 𝐹 = 𝑛 𝑁 = 1 𝑁 ⨀ e γ P interact 2. × 10 - S bubble 1.5 × 10 - 1. × 10 - 5. × 10 - 20 ( l ) 10 12 10 16 10 20 10 10 Probability never reaches ~1 There is NO FIREWALL! Bin et. al.

Consider Scattering of low energy photon off of positron/electron gas 𝑡 343356 ≲ 𝑚 & (inside of fuzzball surface) 𝑠 3 Photon energy 𝐹~𝑈 Near horizon region 𝑠 9 Q~𝑛 at s~ Local electron/positron gas at threshold 𝑈 3 Y e - e + Q~𝑈 Q Local photon energy 𝐹 e - e + s~ 1 𝑛 9 9 ?@A ~𝛽 ; where 𝛽 = found that 𝑄 and 𝑄 6Y6Z[6@\6 ~ 9WX (YZ ] ) ⟹ 𝑄 3^\_"\^AA6Z = 𝑄 ?@A 𝑄 6Y6Z[6@\6 ≪ 1 𝑔𝑝𝑠 𝑁 = 𝑁 ⨀ ; 𝑄 Z6b56\A?c@ ≪ 1

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