Scientists have discovered a new mechanism involved in the creation of paired light particles, which could have significant impact on the study of quantum physics.
Researchers at the University of East Anglia (UEA) have shown that when photons - the fundamental particles of light - are created in pairs, they can emerge from different, rather than the same, location.
The ground-breaking research could have significant implications for quantum physics, the theoretical basis of modern physics. Until now, the general assumption was that such photon pairs necessarily originate from single points in space.
Quantum entanglement - when particles are linked so closely that what affects one directly affects the other - is widely used in labs in numerous processes from quantum cryptography to quantum teleportation.
The UEA team were studying a process called spontaneous parametric down-conversion (SPDC), in which photon beams are passed through a crystal to generate entangled pairs of photons.
Prof David Andrews in UEA's School of Chemistry said: "When the emergent pairs equally share the energy of the input, this is known as degenerate down-conversion, or DDC.
"Until now, it has been assumed that such paired photons come from the same location. Now, the identification of a new delocalized mechanism shows that each photon pair can be emitted from spatially separated points, introducing a new positional uncertainty of a fundamental quantum origin."
An abstract is available; full article is paywalled. (DOI: https://doi.org/10.1103/PhysRevLett.118.133602)
(Score: 1) by khallow on Friday March 31 2017, @11:41AM (1 child)
Researchers at the University of East Anglia (UEA) have shown that when photons - the fundamental particles of light - are created in pairs, they can emerge from different, rather than the same, location.
You'd think that if that were so, the particle accelerators would have seen that a half century ago. They generate a vast number of collisions and sprays of particle pair creation. I can't tell from the abstract [aps.org] of the paper what the energy of the photons is. Perhaps low energy pair creation is weird?
(Score: 1, Interesting) by Anonymous Coward on Friday March 31 2017, @11:48AM
If the photon is temporaly coherent, its position along the propagation direction is very indistinct, due to time-energy uncertainty.
(Score: 1, Informative) by Anonymous Coward on Friday March 31 2017, @11:42AM (7 children)
The article is paywalled. Why does this stuff show up on SN? Is it a site for science PR flaks to dump their product? The over-hype makes me want to puke. And people wonder why "science" is questioned.
(Score: 0) by Anonymous Coward on Friday March 31 2017, @01:54PM (5 children)
Maybe some of us CAN access the paywalled stuff and find it interesting, Skippy. Why hamstring ourselves by ignoring interesting stories?
(Score: 0) by Anonymous Coward on Friday March 31 2017, @04:50PM (4 children)
Yes, I can access the paywalled stuff too during my work hours, when I don't browse SN much. But I hate it, and call it out for that reason. Paywalling is the opposite of what scientific authors should do, as is widely recognized. The authors don't even care enough about openness to post an arXiv version, and the phys.org writeup certainly over-hypes the paper. The actual article seems to say nothing about "challenging our understanding of quantum mechanics."
(Score: 0) by Anonymous Coward on Friday March 31 2017, @05:00PM (3 children)
Scientist dudes gotta like eat, bro.
(Score: 0) by Anonymous Coward on Friday March 31 2017, @05:18PM
True, true, but they get none of the pay-wall money directly. For PRL, the money probably funds other American Physical Society activities. That's not a good enough reason to lock up the world's knowledge.
(Score: 1) by Scruffy Beard 2 on Saturday April 01 2017, @05:18AM
I was under the impression that scientist get none of the money from journal subscriptions. They don't even get paid for the work of submitting or reviewing submissions.
(Score: 2) by kaszz on Saturday April 01 2017, @02:19PM
Taxpayers in most cases has already paid for this. So evilvier and other paywall journals profit from systematic theft.
(Score: 2) by kaszz on Saturday April 01 2017, @02:29PM
Tip....
https://sci-hub.ac/ [sci-hub.ac] + "https://doi.org/10.1103/PhysRevLett.118.133602"
(Score: 4, Informative) by opinionated_science on Friday March 31 2017, @12:09PM (1 child)
journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.133602
here's the real citation...
phys.org "feels" like some sort of middle-man ad-collector and yet, cannot seem to find the original citation.
Every technical word is hyperlinked to their own site...
(Score: 2) by martyb on Friday March 31 2017, @01:43PM
Hey, thanks for that! Yes, phys.org is kind of a strange beast. At least with ScienceDaily.com (in the vast majority of cases) they provide a link to the source. I searched for the journal info for this story but came up empty.
I've updated the story with your link. Thanks again!
Wit is intellect, dancing.
(Score: 2) by inertnet on Friday March 31 2017, @12:44PM (1 child)
There's no information on how far these points of creation can be apart, nor if these spacial locations can be controlled. If there are no limitations, this could lead to instant communication between any two points in space.
(Score: 2) by Scruffy Beard 2 on Friday March 31 2017, @04:58PM
Photons travel at relativistic speeds, so time passes lower for them. Not sure if that is enough to resolve quantum weirdness, but we know that at relativistic speeds: different observers can not always agree if one event proceeded another or not.
(Score: 0) by Anonymous Coward on Saturday April 01 2017, @05:03AM
This wouldn't happen if they had a series of intricate contracts between the scientist and the particles.