Black Hole Firewalls

audioloop

Hence the term....


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Guest Post: Joe Polchinski on Black Holes, Complementarity, and Firewalls
http://blogs.discovermagazine.com/co...and-firewalls/
...The idea is that an observer falling into a black hole, contrary to everything you would read in a general relativity textbook, really would notice something when they crossed the event horizon. In fact, they would notice that they are being incinerated by a blast of Hawking radiation: the firewall....



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.....or the information is lost
(or the unitarity is lost, option gaining attention now)





right

Almheiri, Marolf, Polchinski, Sully, arXiv:1207.3123: You hit
a firewall at the horizon if t > O(R log R) (scrambling time)

PAllen

Note, this observation is related to 'old' being the Page time. This is what is most strongly argued in the Polchinski et.al. paper. However, they argue that very likely the criterion is the scrambling time. The above observation does not apply if this is true.

sshai45

So does this mean that any black hole existing now would have a firewall? I find this intriguing, since it seems to be suggesting that general relativity starts to fail even sooner than one may think, in that it starts to fail right at the event horizon, well before the singularity.

PAllen

Yes, that would be the consequence if Polchinski et.al. are right about firewalls forming in scramble time.

S.Daedalus

Continuing what is apparently en vogue for this topic, Bousso has 'completely rewritten' his paper, from "Observer Complementarity Upholds the Equivalence Principle" to now "Complementarity Is Not Enough", apparently now considering his earlier argument 'naive'.

S.Daedalus

Hm, there's a new paper by Andrew Hamilton -- "Illusory horizons, thermodynamics, and holography inside black holes" -- which does not address the firewall issue directly, but might nevertheless be relevant: he argues for an 'illusory horizon', which is the horizon an infalling observer continues to see 'below' himself, even after crossing the 'true' horizon. This horizon is the one where the infalling observer sees the Hawking radiation being emitted. He only 'reaches' this horizon upon reaching the singularity. This seems to suggest that either there is no necessity for a firewall, or, if there still is, the infalling observer only encounters it at the singularity. But I haven't really thought about this much (and it's not my field at any rate).

Sourabh N

It seems a popular assumption -- "Consider a black hole that forms from collapse of some pure state" (quoted from the AMPS paper). I don't see an obvious reason for this though. Can someone explain this or direct me to one?

audioloop

http://www.nature.com/news/astrophys...e-hole-1.12726

"Polchinski admits that he thought they could have made a silly mistake. So he turned to Susskind, one of the fathers of holography, to find it. “My first reaction was that they were wrong,” says Susskind. He posted a paper stating as much8, before quickly retracting it, after further thought. “My second reaction was that they were right, my third was that they were wrong again, my fourth was that they were right,” he laughs. “It’s earned me the nickname, ‘the yo-yo,’ but my reaction is pretty much the same as most physicists’.”

Since then, more than 40 papers have been posted on the topic in arXiv, but as yet, nobody has found a flaw in the team’s logic. “It’s a really beautiful argument proving that there’s something inconsistent in our thinking about black holes,” says Don Page, a collaborator of Hawking’s during the 1970s who is now at the University of Alberta in Edmonton, Canada."

"here is another option that would save the equivalence principle, but it is so controversial that few dare to champion it: maybe Hawking was right all those years ago and information is lost in black holes. Ironically, it is Preskill, the man who bet against Hawking’s claim, who raised this alternative, at a workshop on firewalls at Stanford at the end of last year. “It’s surprising that people are not seriously thinking about this possibility because it doesn’t seem any crazier than firewalls,” he says"

Ben Niehoff

As someone who works on fuzzballs, I have to point out that being incinerated at the horizon does NOT necessarily violate unitarity. It just means that one's degrees of freedom are being violently reorganized.

audioloop

Black hole horizons and Quantum information
21-29 March 2013. CERN.
http://indico.cern.ch/conferenceOthe...&confId=222307

An Apology for Firewalls
Speaker: Joseph Polchinski (KITP)
http://indico.cern.ch/getFile.py/acc...&confId=222307

Comments on black hole interiors
Speaker: Juan Maldacena (IAS Princeton)
http://indico.cern.ch/getFile.py/acc...&confId=222307

Quantum Mechanics vs. the Equivalence Principle
Speaker: Raphael Bousso (LBL Berkeley)

.........

jacophile

Hi, can someone help me understand the firewall idea?

I have a heuristic understanding that the firewall is created due to breaking entanglement between particles (virtual particles?) inside the EH and old Hawking radiation that emanated from the BH previously.

I don't understand how the entanglement problem arises. They seem to be saying that all particles "in" the BH are entangled with previous Hawking radiation. They then say that a recent Hawking radiated particle must be entangled with its anti-pair that falls inside the EH.

So far so good...

The problem seems to be that the new particle is also entangled with previous radiation. Why?

The new particle is generated outside the EH not inside it where the previously entangled particles are.

So why is the newly created particle entangled with old radiation?

I know that the particle pair explanation is a heuristic analogy but whatever is going on, it's outside the EH and therefore not associated with previous radiation surely?

Judging from the previous post this is a very trivial and huristic view of the postulated system but can someone explain it to me in these terms?

tade

I believe the answer lies in entanglement.

jacophile

Care to elaborate?
My question is about entanglement so yep, I'm sure the answer is too...

tade

At first I thought the photons due to Hawking radiation were entangling with one another through some kind of holographic manifestation. Though now that I think about it, it sounds highly unlikely.