Queensland researchers prove Albert Einstein wrong
Source: The Australian
Scientists have achieved the rare distinction of proving Albert Einstein wrong, in a demonstration of the now widely accepted theory of quantum mechanics.
Researchers from Queensland and Japan have resolved a longstanding hurdle to the 91-year-old theory Einsteins 1927 thought experiment that disparaged quantum mechanics as spooky action at a distance.
The new study, published overnight in the journal Nature Communications, could also help researchers develop ultra-secure means of communicating.
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Five years ago, the Griffith team conceived a way to rigorously test Einsteins objection splitting a single photon between two laboratories, and experimentally testing whether measurement in one laboratory caused a change in the photons quantum state in the other laboratory.
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Read more: http://www.theaustralian.com.au/news/health-science/queensland-researchers-prove-albert-einstein-wrong/story-e6frg8y6-1227276909773
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bananas
(27,509 posts)Experimental proof of nonlocal wavefunction collapse for a single particle using homodyne measurements
Maria Fuwa, Shuntaro Takeda, Marcin Zwierz, Howard M. Wiseman, Akira Furusawa
Nature Communications 6,
Article number: 6665
doi:10.1038/ncomms7665
Received 02 October 2014
Accepted 18 February 2015
Published 24 March 2015
Abstract
A single quantum particle can be described by a wavefunction that spreads over arbitrarily large distances; however, it is never detected in two (or more) places. This strange phenomenon is explained in the quantum theory by what Einstein repudiated as spooky action at a distance: the instantaneous nonlocal collapse of the wavefunction to wherever the particle is detected. Here we demonstrate this single-particle spooky action, with no efficiency loophole, by splitting a single photon between two laboratories and experimentally testing whether the choice of measurement in one laboratory really causes a change in the local quantum state in the other laboratory. To this end, we use homodyne measurements with six different measurement settings and quantitatively verify Einsteins spooky action by violating an EinsteinPodolskyRosen-steering inequality by 0.042±0.006. Our experiment also verifies the entanglement of the split single photon even when one side is untrusted.
postulater
(5,075 posts)He has been quite nonlocal lately, out of state 'not-running' for president while Wisconsin collapses into Mississippi.
dreamnightwind
(4,775 posts)it says they have verified entanglement, which was required by quantum theory but which Einstein was always skeptical of. I thought this had already been proven and demonstrated.
There was a DU OP on this last year, interesting to read this. I am way over my head on this issue, but like to try to understand as much as I can about the context we live in. When I first read up on entanglement it absolutely blew my mind, amazing if true.
Is Quantum Entanglement Real?
http://www.democraticunderground.com/1016106939
CaptainTruth
(6,602 posts)Which has been demonstrated at least dozens of times, even in labs several km apart.
dreamnightwind
(4,775 posts)Using Google I see there have been other demonstrations of it too.
DCBob
(24,689 posts)So distance and time wouldn't matter. The states of associated particles would be tracked and maintained in the "database" no matter how far apart they are. I think God is a DBA in addition to being a programmer. IMHO.
IsItJustMe
(7,012 posts)He was one heck of a philosopher. One famous phrase of his was (paraphrasing) I know of two things which are infinite. The universe and mans stupidity.
I think of that quote often when I read the news.
loudsue
(14,087 posts)I wish I could read more, but they all cost $$.
Half-Century Man
(5,279 posts)Last edited Wed Mar 25, 2015, 06:30 PM - Edit history (1)
This is an "regardless of the distance of the separation" sort of thing. If that is so,we could have real time communications with probes sent into space. No time lag of signals. I see that as the most profound aspect of this.
CaptainTruth
(6,602 posts)So, the entangled particles could be on opposite sides of the universe & a change in one particle is instantly reflected in the other. No speed-of-light delay, it's as if the space between the particles doesn't exist.
Last year China announced plans to build a QE communications network, two base stations hundreds of km apart (or more) & a satellite.
The military implications are interesting because according to the laws of physics a QE communications network is unhackable. Observing the signal in any way changes the signal.
dixiegrrrrl
(60,010 posts)Both is practical concepts and ideas for further studies.
erronis
(15,355 posts)I'm guessing that this cosmic entanglement comes with some costs that will make the spooky effect at a distance difficult/expensive if the distance is substantial. Perhaps even expending this cost becomes part of the overall equation of how this effect works.
If your particles are photons (and they will be for such applications), you use an optical fiber (though fibers that maintain polarization states are much more expensive). Or you can send them across free space.
The main problem is just that you can't send a signal that way, as the joint measurement outcomes are random even though the individual results are perfectly correlated. It's like saying I can encode a message using a series of coin flips - yes, those can be rendered as binary 0 and 1 digits, but the sequence is where the message would be and the sequence is random.
erronis
(15,355 posts)And aren't there some perturbations (dust, gravity waves, etc.) wot would make that trip somewhat problematic? And once there, how would we actually measure the "effect at a distance"? Another round trip of information (at what cost)?
Since I never graduated high-school (US) I'm going to give up now but I'm still intrigued by how things that are hard to explain often have another explanation.
caraher
(6,279 posts)With all these experiments, the verification step is just as you picture it - you need to exchange information again. Generally all the experiments to date involve some kind of "classical" channel (which can be as simple as Alice and Bob - the people performing measurements - exchanging physical notebooks, emails, whatever).
I don't think graduating high school is the crucial thing here - you can go pretty far on curiosity! A great, accessible book with a quasi-historical development of these ideas is Louisa Gilder's "Age of Entanglement."
erronis
(15,355 posts)I'm a book gourmand and so it shall join my groaning bedside table.
While I've managed to never finish any prescribed degree programs, I've been able to work quite lucratively in the computer field for 40+ years and actually teach a few university courses. You're right, curiosity is the main ingredient.
Half-Century Man
(5,279 posts)So four years to reach Alpha Centauri. So this becomes a "from here forward" thing.
But, now we know it can happen; the question arises, "Has it already happened"?
Followed by, Does it occur in nature?
How would we detect it?
How do we use it?
Considering the largest quantity of anything in the Universe is Dark Energy, Is there a "dark" equivalent of a photon?
Just the start of the millions of potential questions we might answer.
nomorenomore08
(13,324 posts)mopinko
(70,238 posts)unless you wish to negate the word regardless.
sorry to be a grammer nazi. not something i usually do.
Kelvin Mace
(17,469 posts)http://dictionary.cambridge.org/us/dictionary/american-english/irregardless
http://www.oxforddictionaries.com/us/definition/american_english/irregardless
Technically a word, technically means the same as "regardless", but frowned upon by "careful users of English". Not that I am happy about it...
mopinko
(70,238 posts)it just bugs me. one of my few grammar thingies.
gregcrawford
(2,382 posts)The negative prefix, "IRR-" and the negative suffix, "-LESS" essentially cancel each other out, making the word meaningless.
If someone says they "don't got none," which is a double negative phrase, it is not unreasonable to question their literacy. Using nonsense words like "irregardless" is no less indicative of a limited vocabulary and a tenuous grasp of proper grammar. And don't EVEN get me started on "nuclear/nuke-ular!"
Good grammar matters. Some grammarians make excuses for those who cannot speak their native language properly, which degrades the quality and accuracy of communication. For instance, imply and infer are NOT interchangeable synonyms. To imply is to suggest, to infer is to deduce. Two five-letter, two-syllable words beginning in "I" with no other relationship to one another, and two completely different definitions.
"Less" and "Fewer" are also frequently misused, even by those, like journalists and writers, who should know better. Less refers to volume, fewer refers to quantity or number. "FEWER people drink LESS milk."
"Hone" in is often used when the writer should say, "Home" in. Hone means to sharpen, as in "to hone a knife, or one's skills." The phrase, "home in" is derived from the homing pigeon's ability to find its way HOME over great distances.
Okay, I'm done. But you get my point, right?
So, I'm with you, Mo, though maybe I'm a little less tolerant of "grammar thingies!"
But Einstein, he be cool, don't he?
mopinko
(70,238 posts)i enjoy the evolution of language that is happening these days, and use a lot of abbreviations and slurred words like prolly. but i do it to effect. what i mean is quite clear.
people can infer my meaning easily. yeah, i hate that one, too.
xocet
(3,873 posts)...in use* but have heard and do hear 'pry-ee' quite frequently.
*'Prolly' has never been noticed at least.
rogerashton
(3,920 posts)Disregardless ...
xocet
(3,873 posts)Further, do you really believe that words that contain two negative affixes can possess no meaning?
How about unanesthetized? Does it have a meaning? Yes, it does:
Half-Century Man
(5,279 posts)Upon your observation, I checked Webster's and learned something new.
Thanks.
caraher
(6,279 posts)The collapse is "instantaneous" but random. You can do things like generate a random encryption key, but you don't get to pick the result of the measurement in your lab that "collapses" the wave function in a distant location.
Half-Century Man
(5,279 posts)I read lot of good work is being done around photons (ie. relationships with massfree electrical charges). We humans are fairly clever. I can envision some aspect of photons being exploited for communications in the future.
The DoD is looking into using this for a hack proof communication network. If they work that out, the experiment is simple.
Synchronize a pair of clocks. Send one into space aimed straight out of the Solar System. Compare the base line clock with the transmitted signal from the other clock.
caraher
(6,279 posts)The way the whole entanglement thing works is largely independent of how you choose to "tickle" the entangled particles. What matters is whether you make a measurement of the relevant properties.
To send a signal, you need a method for imprinting the bits comprising your signal on the signal medium. The enticing prospect is to say that I could create an entangled state in one location and send photons in opposite directions. What is true and weird and amazing is this: measurements at one location and time are not independent of measurements made at a location and time such that they could not be "causally connected" (meaning that no lightspeed signal could connect those events).
BUT... those measurements are, individually, utterly random. So if you're on Earth and I'm out by Alpha Centauri you might read a string of polarizations that you translate into binary digits 100110000111001010... and I can make measurements in my location that read out exactly that same string 100110000111001010... But neither of us gets to choose the value of even a single bit of that string! Sending a signal with some real information content demands a way of ensuring that I measure the value for the bit that you want me to measure.
The trouble is, as soon as you do something that guarantees the outcome of my measurement, that breaks the entanglement. You need something other than the tools of quantum theory.
Now there are lots of protocols for eavesdropper-proofing the generation and exchange of encryption keys. This is the kind of thing DOD is doing, and it works in part because random numbers make wonderful encryption keys. It's a case where the randomness I mention is not a bug, it's a feature!
Half-Century Man
(5,279 posts)The computers I learned and repaired were Sperry Univac 642B's. They were the size of a refrigerator, used as much power as 2 modern 5000btu window air conditioners, and were as smart as my current microwave oven. My first generation smart phone has over 20 times the computing power and memory the entire bank of 642Bs aboard the USS Eisenhower did in 1980.
And yet the physics behind electronics stayed the same. We humans became exponentially better at using it.
Caraher, I swear to you I'm not arguing for arguments sake. I have watched us break impossible barriers time after time. Too many of us look at lines in the sand as challenges.
caraher
(6,279 posts)I guess my main point is this: I happily admit it's possible that there could emerge new physics that supplants what we know about quantum mechanics. But the ideas of harnessing entanglement for communications being batted around in this discussion presume that quantum theory as currently understood might allow for it. That isn't the case. For a clever tinkerer to enable FTL signaling would require a change in our most basic understanding of how the quantum world works.
This is something very different from the Moore's Law explosion in computing power you describe. There is a long history of people predicting various physical limits that would likely halt those advances, and those limits being overcome or evaded in unforeseeable ways. But those were all objections of the "I don't see (today) how one would ever work around (putative limit)" variety. Throughout this entire history of advancement, as you note correctly, every device created operated under the same set of physical principles completed with the development of quantum mechanics in the late 1920s. None of the advances entailed overthrowing a fundamental law of nature. They were rapid, breathtaking advances, but they were also evolutionary changes made atop an essentially unchanged underlying physics paradigm.
FTL signaling pretty much requires something fundamentally new. That could happen, but it's a very different game!
bemildred
(90,061 posts)The real problem is the assumption that a photon must be a particle or a wave, it is both, and it can be both, at the same time.
Colorado Vince
(99 posts)Please pardon my skepticism.
erronis
(15,355 posts)caraher
(6,279 posts)There's the crackpot's version of "I've proven Einstein wrong" (usually on something related to relativity).
But Einstein never did quite accept what became the mainstream physics view of quantum mechanics, so really pretty much every practicing physicist has no trouble coming up with well-accepted things about which Einstein was wrong.
Danascot
(4,694 posts)but stranger than we can imagine."
DavidDvorkin
(19,489 posts)CK_John
(10,005 posts)say Pataki?
itsrobert
(14,157 posts)Not buying it.
anAustralianobserver
(633 posts)I kid my countrymen! Don't know what the experiment showed that is new, but this looks like a typical pop science article about it (in a News Corp paper btw - although one of the better ones, relatively speaking).