Queensland researchers prove Albert Einstein wrong

[bananas]

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 — Einstein’s 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.

<snip>

Five years ago, the Griffith team conceived a way to “rigorously test” Einstein’s objection — splitting a single photon between two laboratories, and experimentally testing whether measurement in one laboratory caused a change in the photon’s quantum state in the other laboratory.

<snip>

Read more: http://www.theaustralian.com.au/news/health-science/queensland-researchers-prove-albert-einstein-wrong/story-e6frg8y6-1227276909773

---

If the article is paywalled, try the links on their official twitter feed:

https://twitter.com/australian/status/580363754140995584

The AustralianVerified account ?@australian

Queensland researchers prove Albert Einstein wrong http://bit.ly/1Hw9Dub

View on web http://t.co/wmjnHlTac9

[bananas]

1. Experimental proof of nonlocal wavefunction collapse for a single particle using homodyne measuremen

http://www.nature.com/ncomms/2015/150324/ncomms7665/full/ncomms7665.html

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 Einstein’s spooky action by violating an Einstein–Podolsky–Rosen-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]

3. Maybe this will help collapse the Scott Walker wavefunction.

He has been quite nonlocal lately, out of state 'not-running' for president while Wisconsin collapses into Mississippi.

[dreamnightwind]

4. So if I read the abstract right

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]

7. Looks like quantum entanglement

Which has been demonstrated at least dozens of times, even in labs several km apart.

[dreamnightwind]

31. Here's the experiment I was previously aware of

http://www.forbes.com/sites/alexknapp/2012/09/06/physicists-quantum-teleport-photons-over-88-miles/

Using Google I see there have been other demonstrations of it too.

[DCBob]

19. I envision the quantum world controlled by a massive "quantum database" linked to every particle.

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]

26. Whether or not Einstien was right or wrong about this

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]

2. I don't really understand what the results of the experiment showed.

I wish I could read more, but they all cost $$.

[Half-Century Man]

5. If I understand the theory of Quantum Entanglement right.

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]

8. Yes, as far as we know the collapse of the quantum state is "instant."

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]

12. Wow...the implications of that are staggering.

Both is practical concepts and ideas for further studies.

[erronis]

15. But doesn't it require a lot of "work" to get those particles that far apart?

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.

[caraher]

22. Nah

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]

23. And how long would it take to get a photon from one edge of the universe to the other?

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]

24. Spanning the universe - yes, that's a challenge!

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]

25. Thanks for the Age of Entanglement link

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]

35. Photons travel at speed of light.

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]

42. Sorry if this is a stupid question, but how do the particles become "entangled" in the first place?

[mopinko]

11. irregardless is not the word you want.

unless you wish to negate the word regardless.
sorry to be a grammer nazi. not something i usually do.

[Kelvin Mace]

13. Well, actually

http://www.merriam-webster.com/dictionary/irregardless
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]

14. i know.

it just bugs me. one of my few grammar thingies.

[gregcrawford]

17. "Irregardless" is a double negative

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]

18. obviously i am not a stickler.

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]

30. Out of curiosity, do you ever hear 'pry-ee' instead of 'prolly'? I have not heard 'prolly'...

...in use* but have heard and do hear 'pry-ee' quite frequently.


*'Prolly' has never been noticed at least.

[rogerashton]

27. so, similarly, inflammable means not flammable?

Disregardless ...

[xocet]

28. Since when is "IRR-(sic)" a negative prefix?

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:

http://www.merriam-webster.com/medical/unanesthetized

[Half-Century Man]

34. It is a word I have heard and used to use.

Upon your observation, I checked Webster's and learned something new.
Thanks.

[caraher]

20. No, it can't be used for signaling

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]

33. I'm not sure about that.

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]

36. It would have to be based on heretofore unknown physics

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]

38. I started my professional life as a Data Systems Technician in the US Navy.

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]

40. There's a lot of difference between Moore's Law and this

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]

6. Yeah, but Einstein knew he was wrong.

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]

9. given the # of times einstein has been "proven wrong", only to end up right...

Please pardon my skepticism.

[erronis]

16. +1 for your (and my) skepticism. Always a good thing.

[caraher]

21. Einstein was wrong about a lot of things

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]

10. "The universe is not only stranger than we imagine;

but stranger than we can imagine."

[DavidDvorkin]

29. "Queerer" in the original version.

[CK_John]

32. Does this mean a voter in California hits a touch screen for Nader will it cause a vote in Iowa for

say Pataki?

[itsrobert]

37. Has this been independently validated by Dr Sheldon Cooper and his team?

Not buying it.

[anAustralianobserver]

39. Aussies should stick to trying to split the beer atom.

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).

[Kaleva]

41. Looks like witchcraft to me!