Slashdot Mirror
First Acoustic Black Hole Created
KentuckyFC writes "One of the many curious properties of Bose Einstein Condensates (BECs) is that the flow of sound through them is governed by the same equations that describe how light is bent by a gravitational field. Now, a group of Israeli physicists have exploited this idea to create an acoustic black hole in a BEC. The team created a supersonic flow of atoms within the BEC, a flow that prevents any phonon caught in it from making headway. The region where the flow changes from subsonic to supersonic is an event horizon, because any phonon unlucky enough to stray into the supersonic region can never escape. The real prize is not the acoustic black hole itself but what it makes possible: the first observation of Hawking radiation. Quantum mechanics predicts that pairs of phonons with opposite momentum ought to be constantly springing in and out of existence in a BEC. Were one of the pair to stray across the event horizon into the supersonic region, it could never escape. However, the other would be free to go on its way. This stream of phononic radiation away from an acoustic black hole would be the first observation of Hawking radiation. The team hasn't gotten that far yet, but it can't be long now before either they or their numerous competitors make this leap."
I got a shot Bose amp here, and any sound you put in turns into silence. Voila, accustic black hole.
I'd sell this baby for cheap, too!
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
that in space, no one can hear you scre...
If "disco" means "I learn" in Latin, does "discothèque" mean "I learn technology"?
"In one ear and out the other."
That's somewhere in between a metaphor for Hawking Radiation and the real thing. It's not true HR, but it would be a nice demonstration if they were to get it to work, especially if they could show some sort of analog to black hole "evaporation," which is the main implication of HR. I suppose that should naturally happen as the separation of the pairs sucks energy from the BEC and slows the fluid inside, shrinking the event-horizon-analogue.
Also, let's get properly flowing BEC layers in our noise canceling headphones!
"I zero-index my hamsters" - Willtor (147206)
Let's use the cone of silence, chief!
I knew light was quantized, but I had seriously never heard of Phonons, or that sound can be quantized as well.
Well, apparently it can: Phonon
Nah, Bose doesn't suck so much as you can get similar quality gear for a better price. It's swanky audio gear for people who don't know anything about audio gear.
Linux, you magnificent bastard, I read the fucking manual!
There is an analogy there in the macro physics but that doesn't mean the small scale stuff like QM will be mirrored.
You can model gravity in the orbital mechanics sense with a marble and vertical cone that tapers at 1/square(height). That doesn't mean it will do anything relativistic or quantum mechanical.
I would hope we can use it to defend our civilization from both outside and inside attack. Maybe put a few of them in orbit that would suck in the drudgery of the reality shows and entertainment-news talking heads so that no outside civilization will feel the need to demolish the planet to build a hyperspace bypass. Plus, we won't have to listen/watch this crap anymore. A world without Fox/CNN/MSNBC... wow. I can only hope.
-- All this knowledge is giving me a raging brainer.
I need one of these for one of my neighbors. Does it swallow people and dogs, too? Cuz that'd be really good.
Fuck systemd. Fuck Redhat. Fuck Soylent, too. Wait, scratch the last one.
Black holes in a Bathtub by E. Berti (2005):
www.iop.org/EJ/article/1742-6596/8/1/013/jpconf5_8_013.pdf
The argument basically goes that when you unplug your bathtub, there's a certain point at which waves generated past the "event horizon" near the hole never escape the hole. It's an interesting read, but I was under the impression that this is basically the same thing, albeit not an effect that arises from quantum field theory.
You'll create a BLACK HOLE that ENGULFS THE EARTH! Just like the LHC!
It's like Monster Cables for speakers.
now we know how they made the "cone of silence" http://en.wikipedia.org/wiki/Cone_of_Silence
This could be even better than the "bass-seeking missile" that I've wanted to deploy for years.
"Nigel Tufnel: The numbers all go to eleven. Look, right across the board, eleven, eleven, eleven and...
Marty DiBergi: Oh, I see. And most amps go up to ten?
Nigel Tufnel: Exactly.
Marty DiBergi: Does that mean it's louder? Is it any louder?
Nigel Tufnel: Well, it's one louder, isn't it? It's not ten. You see, most blokes, you know, will be playing at ten. You're on ten here, all the way up, all the way up, all the way up, you're on ten on your guitar. Where can you go from there? Where?
Marty DiBergi: I don't know.
Nigel Tufnel: Nowhere. Exactly. What we do is, if we need that extra push over the cliff, you know what we do?
Marty DiBergi: Put it up to eleven.
Nigel Tufnel: Eleven. Exactly. One louder.
Marty DiBergi: Why don't you just make ten louder and make ten be the top number and make that a little louder?
Nigel Tufnel: [pause] These go to eleven."
"Nigel Tufnel: It's like, how much more black could this be? and the answer is none. None more black. "
Sweet, now I just have to trick my wife into standing in it.. ah peace
Here, I'll fix it.
The real prize is not the acoustic black hole itself but what it might makes possible: the first observation of something analogous to Hawking radiation. The Theory of Quantum mechanics predicts that pairs of phonons with opposite momentum ought to be constantly springing in and out of existence in a BEC. Theoretically, were one of the pair to stray across the event horizon into the supersonic region, it could never escape. However, the other would be free to go on its way. This stream of phononic radiation away from an acoustic black hole would be the first observation of anything even vaguely resembling Hawking radiation. The team hasn't actually achieved any of this though. It can't be long now before they or their numerous competitors make this leap. Unless their hypothesis is totally wrong, which is entirely possible. But that doesn't sound particularly impressive, so we'll just forget about that bit...
-1 Uncomfortable Truth
In the same way that finding somebody that judges a person based on what cellphone they use is a nice way to know what type of person they are in advance?
Isn't that the name of the new Britney Spears album?
How do you infer from the effects of phonons, that the same happens to photons? If they had the same effects, this would mean that luminiferous aether would exist. Which as far as we know, is not true, and replaced by the theory of relativity. Or would it be the effect of a quantized space-time? And would those quantums then be some kind of particles?
Or is the analogy just wrong, except for some subsets? ^^
Any sufficiently advanced intelligence is indistinguishable from stupidity.
The first Acoustic Black Hole was actually created back in 1981.
It must have been something you assimilated. . . .
we all know photon pairs are connected. an observation on changes the state of the other. (quantum entanglement) but what happens if one of a pair of photons enters a black hole and the other remains outside?
does quantum entanglement still exist fo these photons? does the photon still exist inside the black hole or does it disintegrate or change state? if so: what would happen to the other photon outside?
i call whatever will happen the Fuzzums effect ;)
Privacy is terrorism.
The reality is, most people don't have super-discriminating ears, and are therefore not really capable of telling much difference between any speakers.
You don't need super-discriminating ears to know that Bose systems sound like shit. It's perfectly obvious. Bose doesn't even do well against inexpensive systems, let alone ones in the Bose price-range.
... and then they built the supercollider.