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The Black Hole information loss problem is unsolvable

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Re: The Black Hole information loss problem is unsolvable

#61

Post by seppel »

gizmo686 wrote: post #41
xevrem wrote: post #38

I still don't understand what they mean by "loss". Why is this even a problem? The information isn't gone, its right -there- in the black hole, which until proven otherwise, is part of the universe. Until someone can prove the universe cares whether the info is in a black hole or not, its not really a problem is it? If anything the universe usually shows it doesn't care what we humans think, its going to do its own t…

The black hole is not eternal. Once it is fully evaporated, you still need to account for the information that was contained within (or accept information loss).

> Once it is fully evaporated, you still need to account for the information that was contained within (or accept information loss).

One way to escape this is:

* You accept that the Hawkin radiation contains the original information.

* But it is scrambled in a reversible way, but so hard that you cannot reverse it with the energie available in the universe.

There are nice talk by Scott Aaronson about this, e.g.: https://simons.berkeley.edu/events/theoretically-speaking-se...

Re: The Black Hole information loss problem is unsolvable

#62

Post by abdullahkhalids »

andrewflnr wrote: post #36

Hawking radiation itself is not observed, but she seems willing to take that for granted on the basis of pure math. I don't see a notable difference between that and the theoretical work she's dismissing here.

Yes, one resolution of the paradox is that there is no Hawking radiation, which is what the author almost said

> Another option is that the black holes do not entirely evaporate and the information is kept in what’s left, usually called a black hole remnant.

Re: The Black Hole information loss problem is unsolvable

#63

Post by c1ccccc1 »

Kranar wrote: post #54
c1ccccc1 wrote: post #27

So this new result is derived semiclassically, right? Which means it was derived using more or less the same assumptions Hawking used to derive Hawking radiation. So couldn't the same objection be made about the claim that black holes evaporate at all? After all, we also have no empirical data about that, and likely won't have such data for a long long time.

Of course the criticism can also apply to Hawking radiation but it wouldn't be a particularly strong or even novel critique. Scientists already understand that an experimentally unverified prediction in theoretical physics could end up being wrong. If Hawking radiation does end up being wrong, however, it would most definitely result in some groundbreaking insights because Hawking radiation is itself built upon a set…

> It's a theory that is almost uniquely derived from a pre-existing set of assumptions that do have a large body of empirical support.

What additional assumptions (on top of the ones Hawking made) does the new calculation use that don't have a large body of empirical support?

Re: The Black Hole information loss problem is unsolvable

#64

Post by rightbyte »

AnimalMuppet wrote: post #5

For me, this was the money quote: > The black hole information loss problem is not a math problem. It’s not like trying to prove the Riemann hypothesis. You cannot solve the black hole information loss problem with math alone. You need data, there is no data, and there won’t be any data. Which is why the black hole information loss problem is for all practical purposes unsolvable. We lack experimental data. We lack a…

> We lack experimental data. We lack a way to get experimental data

Sounds like pseudoscience to me.

I wonder what happens if a particle is in early orbit in a black hole and another black hole gets close by and changes the net force. Is that impossible somehow? Can't you grab that particle with a spoon and bail if you are quick?

Re: The Black Hole information loss problem is unsolvable

#65

Post by effie »

sterlind wrote: post #28

Not a physicist, but Hossenfelder didn't clarify well that, unlike previous proposed solutions, this one only relies on standard quantum mechanics and general relativity, not strings or LQG. Similar in spirit to Hawking's original approach, which she did mention. She seems to have a beef with extrapolating (even well-accepted) math, rather than doing experiments. But this kind of work clarifies where the theories cla…

Casimir effect prediction had a good theoretical grounding and testable prediction (force between parallel conducting planes). It was clear the effect (not the theory behind it) was is in principle testable in a lab.

Re: The Black Hole information loss problem is unsolvable

#66

Post by effie »

pdonis wrote: post #59
xevrem wrote: post #38

I still don't understand what they mean by "loss". Why is this even a problem? The information isn't gone, its right -there- in the black hole, which until proven otherwise, is part of the universe. Until someone can prove the universe cares whether the info is in a black hole or not, its not really a problem is it? If anything the universe usually shows it doesn't care what we humans think, its going to do its own t…

> The information isn't gone, its right -there- in the black hole No, it isn't; it hits the singularity inside of the hole and gets destroyed. At least, that's what Hawking's original model, the one he used to predict that black holes evaporate, says. One way of seeing why Hawking's model had to say this is to combine the following facts about the evaporating black hole and the Hawking radiation in Hawking's model: (…

> The hole itself cannot contain any information other than its mass, charge, and spin... which is far too little information

Maybe the information gets encoded in digits of value of mass expressed in some unit. There is enough digits to store any finite number of bits.

Re: The Black Hole information loss problem is unsolvable

#67

Post by Kranar »

c1ccccc1 wrote: post #63
Kranar wrote: post #54

Earlier quoted context omitted.

Of course the criticism can also apply to Hawking radiation but it wouldn't be a particularly strong or even novel critique. Scientists already understand that an experimentally unverified prediction in theoretical physics could end up being wrong. If Hawking radiation does end up being wrong, however, it would most definitely result in some groundbreaking insights because Hawking radiation is itself built upon a set…

> It's a theory that is almost uniquely derived from a pre-existing set of assumptions that do have a large body of empirical support. What additional assumptions (on top of the ones Hawking made) does the new calculation use that don't have a large body of empirical support?

The most plausible solutions can be read on Wikipedia along with the assumptions they either make, or violate:

https://en.wikipedia.org/wiki/Black_hole_information_paradox...

Re: The Black Hole information loss problem is unsolvable

#68

Post by pa7x1 »

xevrem wrote: post #38

I still don't understand what they mean by "loss". Why is this even a problem? The information isn't gone, its right -there- in the black hole, which until proven otherwise, is part of the universe. Until someone can prove the universe cares whether the info is in a black hole or not, its not really a problem is it? If anything the universe usually shows it doesn't care what we humans think, its going to do its own t…

All of Quantum Mechanics respect unitary evolution, unitary evolution can be rewinded back. Black hole evaporation breaks unitary evolution, at least in the semi-classical approximation of Hawking. If you prepare a pure quantum state it will come out as mangled thermal radiation. You cannot return to the pure quantum state from the thermal radiation (i.e. we have lost information about it).

This transition is impossible in Quantum Mechanics and it would suppose a killing blow to Quantum Mechanics if true. So a better way to rephrase our worries is that if Black Holes do not respect unitary evolution then our most precise physical theory is fundamentally wrong.

Re: The Black Hole information loss problem is unsolvable

#69

Post by effie »

Causality1 wrote: post #55

I don't fully understand the claim that all quantum processes are time-reversible. Aren't there a lot of spontaneous quantum phenomena that aren't?

There are "pure quantum evolution" processes (those described by unitary evolution of ket vector), such as atom sitting forever in its ground state or being in a superposition of different Hamiltonian eigenstates. Those are time-reversible.

There are other processes which are not of such kind. Some people don't want to call those quantum processes, but they sure do have a prominent place in QM textbooks. For example spontaneous emission of light from an excited atom or radioactive decay of uranium atomic nucleus. Description of these processes isn't reducible to unitary evolution, instead irreversibility is assumed by employing the golden rule.

Re: The Black Hole information loss problem is unsolvable

#70

Post by SmooL »

effie wrote: post #66
pdonis wrote: post #59

Earlier quoted context omitted.

> The information isn't gone, its right -there- in the black hole No, it isn't; it hits the singularity inside of the hole and gets destroyed. At least, that's what Hawking's original model, the one he used to predict that black holes evaporate, says. One way of seeing why Hawking's model had to say this is to combine the following facts about the evaporating black hole and the Hawking radiation in Hawking's model: (…

> The hole itself cannot contain any information other than its mass, charge, and spin... which is far too little information Maybe the information gets encoded in digits of value of mass expressed in some unit. There is enough digits to store any finite number of bits.

Sure, and the point of this video is that while that may be _mathematically and theoretically_ sound, there's no way you can realistically make any measurements or any observations to confirm or deny your particular idea. What we have a lot of these ideas, with no way to discern between theories which accurately represent nature and theories which are merely mathematically correct.
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