Laser Light Re-creates 'Black Holes' in the Lab

yodasz writes "The New Scientist reports that a team of researchers from the UK were able to recreate a black hole's event horizon in the lab by firing a laser pulse down an optical fibre. The team's observations confirm predictions made by cosmologists and now they are trying to prove Hawking's hypothesis of escaping particles, dubbed Hawking radiation. 'The first pulse distorts the optical properties of the fibre simply by traveling through it. This distortion forces the speedy probe wave to slow down dramatically when it catches up with the slower pulse and tries to move through it. In fact, the probe wave becomes trapped and can never overtake the pulse's leading edge, which effectively becomes a black hole event horizon, beyond which light cannot escape.'"

Re:Am I slow?

[KublaiKhan]

As far as I can tell, they're using this technique to develop a technique to measure hawking radiation--which, you're correct, involves gravitational forces et al.

However, up until now, we had no real way to measure it unless we happened to see a small black hole blow up, something that we haven't figured out how to find.

Re:Am I slow?

[xanthines-R-yummy]

I was under the impression it was due to quantum particle pairs forming spontaneously. Under "normal" conditions we don't see these things because the pairs collide and sort of evaporate back to wherever the hell those things come from. However, in a black hole one of the particles escapes leaving the energy balance, well, in balance. The only reason that radiation escapes is that its partner went into the black hole absorbing some of its energy. Apparently, this phenomenon will cause all black holes to shrink to nothing over a long enough period of time.

I read about it in "The Physics of Star Trek", but Wikipedia has something on it too:

http://en.wikipedia.org/wiki/Hawking_radiation [wikipedia.org]

Re:Sounds safe

[orclevegam]

That sounds safe, to reproduce the effects of the point at which all matter collapses into a virtual singularity. Where were they testing this again? Somewhere on Earth? Alrighty then... Taxi!

They aren't simulating a black hole, the title is misleading. They're simulating the optical properties of a black holes event horizon. Subtle but very important difference.

Re:Black Hole

[explosivejared]

Given that this experiment seems to back up hawking radiation, it's fairly reasonable to say that creating a black hole this small would not suck, but instead be pretty cool. Evaporation [wikipedia.org] would take care of the black hole before it became a problem. Remember, that these experiments are still low energy, and low mass (very much so) when compared to natural occurences of black holes.

black hole analogy is a stretch

[xPsi]

The experiment is cool, but as far as I can tell, this is nothing like a black hole in the cosmological sense. Simply reproducing one superficial property of black hole ("light cannot escape") does not make it a gravitational singularity with an event horizon and its associated properties. For example, I seriously doubt electron-positron conversions in their light cavity would behave at all like said conversions at a real event horizon since the charged particles would be subject to very different kinds of forces from those near a real black hole. Also, Hawking radiation is related to black hole evaporation. This would not occur with the lasers in an analogous way because the mechanics of this light bubble "evaporation" is totally different. It sounds to me like a case of one subfield (photonics) sexing up their lingo by adopting the lingo of another subfield (general relativity) to get press. IAAP, but not a cosmologists/GR expert, so I'm willing to stand corrected.

Please enough already...

[mahlerfan999]

Please, New Scientist is not a credible source for news on physical science. I wish people would stop posting New Scientist articles. If you want to find out what's hot in physics the Physical Review Focus is a great accessible source of real science stories that are important, and unlike the PRL they are free to read. http://focus.aps.org/ [aps.org]

Re:Black Hole

[spidercoz]

ugh, dude, did you RTFA? this experiment had nothing to do with black holes, singularities, Hawking radiation, or any kind of mass. It was a trick of optics to produce an ANALOGUE of an event horizon

it is currently IMPOSSIBLE to produce any kind of singularity. The LHC has a chance, infinitesimal, to do so, but that's still quite a ways off.

Re:black hole analogy is a stretch

[Biff Stu]

I am also perplexed. I to am not an expert on relativity & cosmology, but I know a thing or two about nonlinear optics. An intense light field can modify the index of refraction of the medium through which it's propagating. This is known as the AC or optical Kerr effect. http://en.wikipedia.org/wiki/Kerr_effect/ [wikipedia.org] The second light pulse will gradually encounter a higher index as it approaches the first pulse and therefore slow down. While I know nothing about Hawking radiation, it seems like gravity must be somehow involved, and this experiment is all about electromagnetic forces.

Re:Old SF

[jbeaupre]

Earth http://www.amazon.com/Earth-David-Brin/dp/055329024X [amazon.com]

Re:I don't get sending a "slow" and then "fast" wa

[spidercoz]

Properties of the medium. C is only in a vacuum, light has variable speeds all the way down to stop depending on what it's traveling through.

Re:black hole analogy is a stretch

[mattxb]

As a follow up to my own comment, arXiv has what looks like the (a?) preprint for this current optical-fibre work arXiv:0711.4796v2 [gr-qc] [arxiv.org]?

Re:HEAT!

[orclevegam]

Someone may have already asked this, but what about the heat generated as the wave approaches C?

These waves wouldn't approach C. C is the speed of light in a vacuum, not in a fiber optic cable. In fact this experiment wouldn't work in a vacuum because it relies on the second wave traveling faster than the first wave.

Re:Am I slow?

[click2005]

Hawking radiation is to do with Heisenberg's Uncertainty Principle and the creation of virtual particles (pairs like Quarks/Antiquarks, Electrons/Positrons, Neutrino/Antineutrino, Proton/Antiproton etc) that only exist for a negligible amount of time and they're impossible to detect directly. Usually they annihilate each other but if a pair is created near the event horizon, its possible that one part of the pair gets swallowed by the black hole and the other escapes. As multiple particles do this, they interact creating energy, photons & annihilate each other to create a thermal distribution of energies known as Hawking Radiation.

I saw part of The Teaching Company course covering this yesterday on Understanding The Universe.

Re:Am I slow?

[Jerf]

The bit that's missing from this article, and that completes the explanation of why this is interesting, is the question of information.

One of the open questions facing physics is whether the event horizon of a black hole destroys information. It's not just the event horizon itself that is interesting, the destruction of information is by itself a legitimately interesting question by itself.

If we can create an optical event horizon that also seems to destroy information, this may allow us to witness how the Universe responds to such information destruction. This is radically easier than creating a large enough black hole to observe these effects. Black hole horizons are interesting in many ways; this may allow us to extract and experiment on one aspect of them.

I've seen a few proposals for the creation of an optical black hole, this is the first claim I've seen that someone may have actually created one.

Calcium carbonate crystals

[Kupfernigk]

You can do something like this without a laser using calcium carbonate (calcite) crystals. In these, the speed of light varies according to the angle of polarisation (I kid you not) so that when you look through the crystal you see things double (the refractive index, of course, depends on the speed of light in the medium versus that in air. The different speed rays are called the ordinary and the extraordinary ray.)

It was learning about this at Cambridge that made me decide that crystallographers had to be much cleverer than I was ever going to be, so I decided to do something easier instead. Many years later I got promoted because we encountered an engineering problem nobody else in the company could solve. I did not know the answer, but I retained enough knowledge to know that I needed a metallurgist with a specific area of expertise, found one and got the problem fixed. Learning apparently irrelevant stuff may one day be a job saver.

Re:How the universe works

[deblau]

A cosmic Jewish Zombie who was his own father can make you live forever if you symbolically eat his flesh and telepathically tell him you accept him as your master. He will do it by removing an evil force from your soul that is there because a rib-woman was convinced by a talking snake to eat from a magical tree.

That's how the universe works.