Hawking Radiation Claimed Created In a Lab 129
eldavojohn writes "In 1974, a young newcomer to the Royal Society named Stephen Hawking predicted that black holes emit Hawking Radiation. Researchers have been looking for it in space ever since. A new paper up for publication claims to have beaten searchers by observing it in a lab. Doing it wasn't easy. They say they brought light to a standstill by drastically increasing the refractive index of the material it was being fired at, creating a 'white hole.' This horizon, beyond which light cannot penetrate (event horizon), is the same between white and black holes, which caused the team to suspect they observed Hawking Radiation when light of a different uniform wavelength than the input laser was emitted. But, before you rejoice, the Tech Review article notes, 'Of course, the big question is whether the emitted light is generated by some other mechanism such as Cerenkov radiation, scattering or, in particular, fluorescence which is the hardest to rule out.'"
LHC will not kill us all! Future research... (Score:3, Interesting)
Yay, the LHC will not kill us all!
What I want to know is if this could be used to create a cool sort of battery or capacitor. I'm imagining layers of metamaterials to store the photons with only a certain amount of predictable Hawking radiation emitted. I doubt if it'd be better than chemical batteries but the geek cred would be way up there.
-l
Double emission? (Score:4, Interesting)
In this experiment obviously the event horizon doesn't persist indefinitely, so when the horizon collapses, do the 'trapped' photons escape? and hence is there a time delayed double emission of the hawking radiation? Would this provide a testable signature?
Any physicists know?
Interesting related first observation (Score:3, Interesting)
For those who did not RTFA or article comments, more interesting fiber optic black holes (and pictures!) : http://www.st-andrews.ac.uk/~ulf/fibre.html [st-andrews.ac.uk]
Re:what bs are you posting (Score:5, Interesting)
By the way, even if this experiment and their conclusions hold water, it is not a proof of black hole evaporation or Hawking radiation. It would be more like a proof of concept.
In the experiment, they've created a pseudo-event-horizon from which light can't escape. It's only a light event horizon though. Shoot a bullet through their material and you will definately see it go through the event horizon without any problems.
The similarities to a real black hole is that photon pairs created on the pseudo-event-horizon should create radiation if Hawkings reasoning about real black holes is correct. So, it would show that Hawkings thought experiment had some merit but not that black holes necessarily radiate.
Re:what bs are you posting (Score:4, Interesting)
Graviton Diode? (Score:3, Interesting)
We also now create black holes in labs. Could we create pairs of white holes and black holes together in a lab, and study the gradient between them for gravitons? Would we be able to pair them into gravity diodes? If so, could a gravity laser be made from them?
Could we use a gravity laser to focus Hawking radiation onto "blank" quanta to reconstitute the entropic hologram of the complex structure that a black hole reduces to those "blank" quanta when it emits the Hawking radiation?
If so, could we entangle pairs photons, send each member of each pair across space in opposite directions, then work one of the pair against the Hawking radiation to encode it across to the other of the photon pair, which in turn modulates "blank" Hawking radiation at the far end through a gravity laser, reconstituting the quantum entropic state of remote blanks? If so, we'd have teleportation that could run at least double the speed of light on demand (entangled photons rushing at c to opposite points = 2c), and if prepared in advance simply instantaneous teleportation.
Will Hawking finally deserve the "greatest brain of our time" reputation that TV acts like he does?
Re:I don't understand... (Score:3, Interesting)
Now, its creation is a quantum state transition which has a "magical" quality in the same way that, say, a photon escaping an atom's electron shell does. There is no extended energy transport process at all. The electron makes a quantum jump simultaneously with the photon field of the world gaining a new photon traveling away. Indeed, with visible light, the wavelength of the photon -- hundreds of nanometers -- can easily exceed the spatial scale of the atoms electron shell, usually a few nm. So, the photon kind of just "appears".
Re:what bs are you posting (Score:4, Interesting)
Not quite, i was referring to this [wikipedia.org]. i couldn't look that up earlier because i was on a really bad connection that was dropping packets left right and center.
Re:what bs are you posting (Score:4, Interesting)
Why would the black hole diminish? Shouldn't the same amount of virtual particles and virtual anti-particles cross the event horizon?
Re:what bs are you posting (Score:4, Interesting)
Re:what bs are you posting (Score:3, Interesting)
Sean M Carroll has a good book about what that means for time if you are interested...
Re:I don't understand... (Score:1, Interesting)
The explanation I've often seen is that in the virtual pair, one particle has negative mass. If the negative mass particle is captured by the black hole and the positive mass escapes, then the mass of the black hole is reduced. There are two things about this I have never understood:
1) Is the negative mass concept just a convenient analogy to explain Hawking radiation to laymen, and not a real explanation of the underlying physics?
2) Isn't it equally probable that the positive mass particle is captured and the negative mass particle escapes, resulting in no net change of mass in the black hole over time?
Re:what bs are you posting (Score:4, Interesting)
An electron's classical radius isn't zero, but more to the point, you can't use just classical physics at that scale.
Re:what bs are you posting (Score:2, Interesting)
I *guess* (see:not researched) that because space-time really doesn't like very low energy states that it somehow sucks energy from surroundings, ie slowly pumping energy to the event horizon from a little bit inside, and that concentric zone dips in energy and sucks some more from the space inside that, etc until you get to the singularity. But that seems to contradict the whole "point-of-no-return", so I really don't know how it works.
Black holes are fucking weird.
Re:Double emission? (Score:3, Interesting)
So by your explanation, I give off Hawking radiation just by walking across the room? My understanding of Hawking radiation had to do with more of a shearing effect caused by extreme gravitational conditions parting two virtual particles to result in a single real particle. I'm not sure my ass qualifies as a sufficiently large gravitational well, nor can I picture a pseudo event horizon forming at any distance behind it while I walk.
Re:what bs are you posting (Score:3, Interesting)
But what about the normal particles falling into the black hole? Why don't the cancel out the antiparticles, on average? (I'm not a physicist, I never understood Hawking radiation)
Re:Probably not hawking radiation. (Score:3, Interesting)
I love that this is a site where I can tell, and people can get, jokes that require you to see the analogy between quoting an EM frequency as a wavelength, and quoting a mass as an energy. Makes my day :-)
Re:what bs are you posting (Score:3, Interesting)
Re:Double emission? (Score:3, Interesting)
I had the mental image of myself walking, shedding heat particles, generated by my internal processes cracking apart ATP, and using the gained energy inside (in order to walk). It was pretty cool, "self as event horizon", with particles splitting (if you allow the definition somewhat loosely, with "energy" and "heat" being what's split). Also appreciated Unruh being explained so well.