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How To Build a Quantum Telescope
KentuckyFC (1144503) writes "The resolving power of telescopes is limited by the diffraction limit, a natural bound on resolution caused by the way light diffracts as it passes through a lens. But in recent years, physicists have worked out how to use quantum techniques to beat the diffraction limit. The trick is to create a pair of entangled photons, use one to illuminate the target and the other to increase the information you have about the first. All this is possible in the lab because physicists can use their own sources of light. Indeed, last month, physicists unveiled the first entanglement-enhanced microscope that beats the diffraction limit. But what about astronomy where the light comes from distant astrophysical sources? Now one physicist has worked out how to use quantum techniques to beat the diffraction limit in telescopes too. Her idea is to insert a crystalline sheet of excited atoms into the aperture of the telescope. When astrophysical photons hit this sheet, they generate an entangled pair of photons. One of these photons then passes through the telescope to create an image while the other is used to improve the information known about the first and so beat the diffraction limit. Of course, all this depends on improved techniques for increasing the efficiency of the process and removing noise that might otherwise swamp the astrophysical signal. But it's still the early days in the world of quantum imaging, and at least astronomers now know they're not going to be excluded from the fun."
> excluded form the fun
from* the fun.
- Zav - Imagine a Beowulf cluster of insensitive clods...
Would this technology also enable us to get higher definition satellite images of earth? Or is that a different refraction which makes max resolution about half a meter/pixel ?
Satellite imagery on wikipedia
I already had my mind blown when active mirrors managed to get rid of turbulence. But this is another thing entirely, getting rid of diffraction !?!
Non-Linux Penguins ?
Please Please, call the control system "ziggy".
Do not look at laser with remaining good eye.
All photons are thin at one end, much, much thicker in the middle, and then thin again at the far end.
The field being produced by the telescope optics is still the same, as the same primary mirror, secondary, etc. is being used to form the image. Yes, you can use multiphoton processes, even ones that are promoted by entangled photons, to produce apparently narrowed two-photon wavefunctions. However, this two-photon wavefunction is still derived from the ordinary resolution field created by the telescope optics. Therefore it seems to me that little is to be gained by using photon entangled detection to augment a process of image formation that is still fundamentally limited by the telescope aperture size.
Similar arguments have been used for other forms of imaging (e.g. microscopy and optical coherence tomography) and they all have this issue as the image formation process is still essentially a linear scattering process. There was some excitement around quantum lithography, however, even that has the problem that the probability of two-photon processes can be quite small even with entangled photons. For inherently multiphoton processes, such as two-photon absorption, stimulated Raman scattering, etc. there may be an advantage of increasing resolution and lowering dose, but I don't see much of a benefit to improving an instrument where the image formation process is a linear imaging process.
Its simply somehow 2 'quantum' objects are generated the same way (that gfilter turns 1 photon into 2 with the same quantum properties and they can go down different paths and hold that quantum 'value' to be used in parallel fo different things.
There is no OH we change this one over here and THAT one changes too.
Of course a typical problem is what states you can have for a 'photon' (like energy level) - Im not so sure how many others their coul be. Setting it (or a pair of them) to that state (with any accuracy) is often a seperat problem. Co-emitting pairs of photons of the same energy state is what they are doing.
Another issueis that 'Reading' one of these split 'photons' is destructive, so if you can generate that 'copy' you have a spare taht once one is used up you still have the other to do something else with (a 'copy' that you can reference (once))
Redirecting a photon to stear it a different direction --- shouldnt that change the 'state' of one photon versus another ???
"to increase the information you have about the first" weird phrase meaning 'read its value so you know what the other one was BUT NOT what changes the other subsequently goes independantly thru.
Seriously this quantum stuff is becoming the same old HYPED BS like so many things weve had in the past.
"Her idea is to insert a crystalline sheet of excited atoms into the aperture of the telescope."
I wonder who is going to excite the atoms and up to what point they should be excited. We know there is a point when they don't take any more excitement and go to sleep.
Can they excite each other?
So many details to figure out...
Just wait until we deal with the giant starfish, sentient lobsters and mirror girls.
I remember reading somewhere (and I've spent nearly two minutes searching on Google, so you know it's somewhat obscure) that some people were concerned that our images of distant galaxies were TOO CLEAR. Their reasoning was that any given photon will take a (likely highly biased) random walk through quantum foam, or that the clarity actually helps disprove quantum foam theories (some information here: http://www.scientificamerican.com/article/is-space-digital/).
I realize I'm light on details, and that's due to my memory and weak goggle-fu (I'm on a lot of [legal] drugs today) so go gently on ripping the science apart, but if anyone had actual references to the real theory, I'd be interested in its current efficacy, and how it relates to the /. article.
You mean 'bated breath'. Baited breath is what you get from eating fish.
I must have been actually working last month because I haven't heard about the entanglement-enhanced microscope. Does it do fluorescence microscopy? The was no mention of fluorescence in the article. It sounds like this is just better DIC imaging, which is of limited use in biology. Electron microscopy has (literally) been around since before the internet and has better resolution than anything you're going to get with light. Light microscopy seems to be primarily important today for basic stuff like whole tissue imaging (generally not requiring the resolution described here) or fluorescence microscopy, which it doesn't sound like this microscope can do. Fluorescence is useful because with most applications, you're trying to visualize a small thing in a much much much bigger volume of stuff. Like you're trying to see a protein within a cell within a tissue. Looking at cells with light for a small thing doesn't tell you much, you just see a blur. When the small thing is basically emitting it's own light, as happens sorta with fluorescence, you can see it.
There are also already fluorescence based microscopy techniques which surpass the diffraction limit.
I'm not going to say it doesn't sound useful, since most of the time, you only realize how useful a thing is once you already have it. I'll just say that if the microscope mentioned here doesn't do fluorescence, I can't think of anything one would use it for that they wouldn't be able to do better with EM or fluorescence microscopy.
Taken at face value, that would be sending photons to nebulas millions of light-years away, and then waiting another million+ years for them to bounce off the target and arrive back here.
At least the cockroaches will have these great space-themed calenders.
Table-ized A.I.
You describe the Hidden Variables description of Quantum Mechanics, which was wiped by Bell's Inequality...
Sorry...
There are government limits on the quality of satellite images that can be made available.
http://en.wikipedia.org/wiki/GeoEye-2
This commercial bird would of had a resolution for .34 meters per pixel.
but it sounds pretty cool! yea quantum physics bitch!
No.
First off entangled particles aren't "copies", they're linked complements. I.e. in an entangled electron pair one will have an up spin, and one a down spin. And there very defintiely *is* an "Oh, we change this one over here and THAT one changes too", or at least that's the conclusion of every experiment thus far constructed to try to prove or disprove your proposition, that there are "hidden variables" set at the moment of entanglement. As best we can tell the entangled particles become a single interlinked wavefunction and doing something to particle 1's quantum state *will* change particle 2's state instantaneously, regardless of the intervening distance. And yes, at first glance this does appear to violate special relativity, but doesn't actually do so for two reasons: 1 - it appears to be impossible to meaningfully transmit information in this way, and 2 - particles don't actually possess locality. The wavefunction of every "particle" in the universe exists simultaneously at all points in the universe, even if it's almost entirely focussed within a single small volume. Yes, it's brain-bending stuff, but all the experiments and math so far point strongly to the fact that it's the truth.
Secondly you only destroy the entanglement if you do something to one "particle" that depends on the quantum state. A lens that treats every photon the same will not disrupt the quantum state, and thus entanglement will be preserved.
And finally there's nothing weird about "to increase the information you have about the first" - so long as entanglement is maintained the particles quantum state *cannot* change independently. You need to make the measurements pretty much simultaneously (i.e. "second" refers to "the particle labeled as 2", not "the particle we measured later"), but when you do so you know that particle 1's detection will have a certain amount of quantum distortion to it, while particle 2 will have a complementary quantum distortion. By comparing the two you can then determine the nature of the distortion (to within certain limits) and computationally remove it from your measurements.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
..... it was called Tom Swift and His Megascope Space Projector --- never thought it would actually work, though?
I promise that How to Build a Quantum Telescope will go on my bookshelf right next to How to Stuff a Wild Bikini 'cause I'm soooo serious......
I thought most modern telescopes used mirrors instead of lenses to avoid diffraction. Well, maybe there are still some lenses left in the system, or maybe we can switch back to lenses if this works. Also, the research is interesting anyway.
Tom Swift and His Megascope Space PROBER. How could you mess that up?
... a crystalline sheet of excited atoms? Do the electrons dance for them? Dance of the Seven Wave functions perhaps?
Physicists are already working on meta-materials with a negative diffraction index and work without the need for glass at all.