Theory Hawking Predicted 30 Years Ago Proved by Simulated Black Hole

Quantum mechanics predicts that entangled pairs made up of a particle and its anti-particle can spontaneously pop out of otherwise empty space, exist for a fleeting moment, and then annihilate each other and disappear. In the 1970s, Hawking predicted that if such a pair were created near a black hole’s event horizon, one of its members might fall into the black hole before it could be annihilated. The partner left stranded outside the event horizon would appear to an observer to have been radiated from the black hole.

The most effective way to mimic a black hole and test Hawking's predictions is to create an artificial event horizon using a supercooled substance known as a Bose-Einstein condensate (BEC). If one region of the BEC is manipulated to move faster than the speed of sound, then sound waves travelling through the rest of the substance would not be able to keep up, effectively becoming trapped behind an event horizon. Hawking radiation should show at this boundary as the production of particle-like packets of vibrational energy called phonons.

Iacopo Carusotto at the University of Trento in Italy and his colleagues claim to have seen just that in a computer simulation of a BEC, which shows that phonons do appear at the event horizon – and that one member of the pair falls into the “black hole” while the other remains outside as predicted. Both phonon partners created identical density patterns in the surrounding BEC, confirming that they were entangled.

Posted by Casey Kazan.

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Source link:
http://www.eurekalert.org/pub_releases/2008-03/ns-aeh031208.php

Comments

[tj]

Well I guess I was wrong when I told my freshman astronomy professor that this theory sounded like Hawking was just grasping at straws. Damn I hate being dumber then Stephen Hawking.

[Matt]

How often does these entangled pairs appear and how often do they appear on event horizons of black holes?

[dr. science]

almost exactly never matt

[mt]

Quite often I think...
I can't remember much of the details of this but iirc it was something to do with people thinking radiation was the only thing that could escape a black hole (back at the time, I think it was described as 'black holes spew radiation and that's how we know they are there').
Hawkins theory was not that stuff was actually escaping black holes at all, but the radiation was being created by this pair that should 'kill' each other getting seperated by 1 half entering the black hole and the other bit not. Or something like that.
If anyone knows the whole background to it, feel free to educate us all properly :)

[chiron_wp]

The radiation that might allow us to "see" black holes is not from the black hole itself but rather from the accretion disk that is formed when the black hole is in a binary with another star.
Hawking radiation as it is so called was originally a solution to Bekenstein's conjecture that black holes are not 0 temperature, 0 entropy objects. An interesting consequence of the radiation is that it would cause the black hole to essential evaporate. This evaporation actually happens quite quickly if the black hole is sufficiently small so if worked out from existing equations any black hole smaller than about 10,000kg would take less than a second to disappear due to the enormous number of quantum fluctuations occurring over the event horizon (quite contrary to dr. science's comment) or probably more correctly, disperse. Another thing to note is that after Hawking's revision of his theory in 2004 it now solves the black hole information paradox.

There are tonnes of resources on this subject if anyone has the interest. Just Google it

[David A. Mills]

Is lebenty-zillion, compared to infinity, frequent, or rare?

[Rick]

Dr Science,

Here's the way my feeble mind understands:
The entangled particles consist of a particle and an anti-particle. The anti-particle's charge is opposite that of the black hole. Ergo, the anti-particle is drawn in (opposites attract and all that) and the "regular" particle is not. Since the anti-particle is an *anti*-particle, it has negative mass, and consequently the black hole shrinks a little bit when it is absorbed. After countless such interactions, the black hole eventually evaporates, decreasing in mass until there is nothing left. The regular particle escaping just beyond the event horizon and giving the appearance of having been radiated from the black hole is called "Hawking Radiation."

[Nick Hall]

Nothing can be 'proved' by a model or simulation as the model is created based only on current best-theory and is self referencial.

This is like saying that God is proven to exist by the bible model.

That's not to say I don't think Stephen Hawkin is correct about Hawking radiation, I do, but this amounts to faith and I don't believe in it.

[Frederik Vanhoutte]

Rick, a common mistake: an anti-particle does not have negative mass. Its quantum properties, the simplest of which is charge, are reversed, but not mass. Anti-matter is just as attracted to matter as any other, uh... matter.
What does happen is that upon creation a particle-anti-particle pair usually flies apart with tremendous velocity (cfr. medical PET scanners). One particle can conceivable end up inside the black hole while the other one doesn't. Since pair-creation happens all the time at the quantum-level (on the Planck timescale), it can be a quite significant loss factor for a black hole.

Nick, fact is that science can never "prove" anything, just make it very, very probable. A model is often needed because you cannot always calculate the consequences of a theory in full. I.e. you don't always get a nice analytical result (in my experience, from nanomagnetism to cancer treatment, almost never).
If a model based on a theory gives correct results, this is not merely self-referential, it is a proof that the theory is self-consistent and doesn't lead to contradicting results. This is an important requirement for any decent theory. (BTW. it is indeed simple to build a model that gives the results that one wants, but the scientific community is very capable of spotting these kind of flaws. Science is peer-reviewed and merciless. Believe me, I know, I've been on both sides of the review process ;-))
Saying that the scientific process amounts to "faith" is a grave misunderstanding. A scientist who says "I believe" does not mean the same thing as a religious person.
The scientist actually says "current theories and their results convince me", the religious person means "I accept, blindly".
A common misunderstanding that opens the way for all kinds of crackpot theories, drawing power from "scientists are not sure themselves" or "it's just another belief".
So, Nick, as as scientist: why don't you believe in Hawking radiation? What aspects of it contradict current knowledge, what observable phenomena could disprove it? I think Stephen Hawking himself would be very happy if somebody found proof that his predictions are wrong.

[Phil E. Drifter]

Yeah, but what does it prove? Now there's an extra 'phonon' in our universe, that they just created matter?

[Mitch]

(A) Hawking had a hypothesis, not a theory - they are quite different.

(B) You cannot prove something - you can provide evidence to support, or you can provide evidence to refute.

(C) Simulations are not the real real system you are interested in - this makes it even more difficult to draw the inference that Hawking's hypothesis is "correct"