Historic Delft Experiments tests Einstein's 'God does not play dice' using quantum 'dice'

October 21, 2015
An artistic impression of the entanglement between electrons. Credit: ICFO

Random number generators developed at ICFO - The Institute of Photonic Sciences, by the groups of ICREA Professors Morgan W. Mitchell and Valerio Pruneri, played a critical role in the historic experiment was published online today in Nature by the group of Ronald Hanson at TU Delft. The experiment gives the strongest refutation to date of Albert Einstein's principle of "local realism," which says that the universe obeys laws, not chance, and that there is no communication faster than light.

As described in Hanson's group web the Delft experiment first "entangled" two electrons trapped inside two different diamond crystals, and then measured the electrons' orientations. In quantum theory entanglement is powerful and mysterious: mathematically the two electrons are described by a single "wave-function" that only specifies whether they agree or disagree, not which direction either spin points. In a mathematical sense, they lose their identities. "Local realism" attempts to explain the same phenomena with less mystery, saying that the particles must be pointing somewhere, we just don't know their directions until we measure them.

When measured, the Delft electrons did indeed appear individually random while agreeing very well. So well, in fact, that they cannot have had pre-existing orientations, as realism claims. This behaviour is only possible if the electrons communicate with each other, something that is very surprising for electrons trapped in different crystals. But here's the amazing part: in the Delft experiment, the diamonds were in different buildings, 1.3 km away from each other. Moreover, the measurements were made so quickly that there wasn't time for the electrons to communicate, not even with signals traveling at the speed of light. This puts "local realism" in a very tight spot: if the electron orientations are real, the electrons must have communicated. But if they communicated, they must have done so faster than the speed of light. There's no way out, and is disproven. Either God does play "dice" with the universe, or electron spins can talk to each other faster than the speed of light.

This amazing experiment called for extremely fast, unpredictable decisions about how to measure the electron orientations. If the measurements had been predictable, the electrons could have agreed in advance which way to point, simulating communications where there wasn't really any, a gap in the experimental proof known as a "loophole." To close this loophole, the Delft team turned to ICFO, who hold the record for the fastest quantum random number generators. ICFO designed a pair of "quantum dice" for the experiment: a special version of their patented random number generation technology, including very fast "randomness extraction" electronics. This produced one extremely pure random bit for each measurement made in the Delft experiment. The bits were produced in about 100 ns, the time it takes light to travel just 30 meters, not nearly enough time for the to communicate. "Delft asked us to go beyond the state of the art in . Never before has an experiment required such good random numbers in such a short time." Says Carlos Abellán, a PhD student at ICFO and a co-author of the Delft study.

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This movie explains the concept of locality and quantum entanglement and the current experiment. Credit: Text: Michael van Baal. Graphics: Scixel

For the ICFO team, the participation in the Delft experiment was more than a chance to contribute to fundamental physics. Prof. Morgan Mitchell comments: "Working on this experiment pushed us to develop technologies that we can now apply to improve communications security and high-performance computing, other areas that require high-speed and high-quality random numbers."

With the help of ICFO's quantum generators, the Delft experiment gives a nearly perfect disproof of Einstein's world-view, in which "nothing travels faster than light" and "God does not play dice." At least one of these statements must be wrong. The laws that govern the Universe may indeed be a throw of the dice.

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This movie explains how the Bell test works with a couple in love in the fictitious Bell restaurant (animation). Credit: Text: Michael van Baal. Graphics: Scixel

The fastest quantum random number generator to date. Credit: ICFO
Historic Delft Experiments tests Einstein's 'God does not play dice' using quantum 'dice' made in Barcelona
The fastest quantum random number generator to date. Credit: ICFO

Explore further: 'Quantum Internet': Towards realization of solid-state quantum network

More information: B. Hensen et al. Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometres, Nature (2015). DOI: 10.1038/nature15759

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37 comments

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OdinsAcolyte
1 / 5 (3) Oct 21, 2015
Entanglement is such a trip. Spooky.
OdinsAcolyte
1 / 5 (3) Oct 21, 2015
Entanglement is such a trip. Spooky.
Yohaku
2 / 5 (4) Oct 21, 2015
Or there is something faster than light.
Shootist
1 / 5 (3) Oct 21, 2015
Or there is something faster than light.


Not really. The electrons are simply-connected or 1-connected.
antonima
2 / 5 (4) Oct 21, 2015
Can we communicate with Greater Beings using crystals?
docile
Oct 21, 2015
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docile
Oct 21, 2015
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docile
Oct 21, 2015
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NMvoiceofreason
2 / 5 (4) Oct 21, 2015
Perhaps there is nothing wrong with the speed of light. Perhaps you are measuring the distance wrong. Under string theory, the additional dimensions can have a 1/R relationship to the three visible dimensions. thus the actual distance traversed would be 1/1300000 meters, which would be a fraction of a millionth of a billionth of a second. The Universe is still local, still real, just somewhat stranger in the other seven dimensions of our ten dimensional Universe (with time as a virtual dimension).
njckatkins
1 / 5 (3) Oct 21, 2015
bold claims for work that hasn't been independently verified
theon
2 / 5 (4) Oct 21, 2015
The information will have traveled with the entangled pair. The contextuality loophole can not be closed.
Captain Stumpy
2.7 / 5 (7) Oct 22, 2015
in dense aether model
this is called pseudoscience, zeph, no matter how many sock puppets you use to post or up-vote your own BS, it is still pseudoscience
why?
because of the evidence: http://exphy.uni-...2009.pdf

with that one link (actually improved already to the 10^-18 level) you are proven to post pseudoscience, no matter how many "waterstriders", transverse waves or sock puppets you use
meerling
4 / 5 (4) Oct 22, 2015
Can we communicate with Greater Beings using crystals?

Yes, it's called a crystal radio. Of course the definition of 'greater' may need some further definition.
docile
Oct 22, 2015
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janful
3.5 / 5 (8) Oct 22, 2015
Key phrase: "...appear individually random..."

Assuming that absolute physical causality is true, then there is no such thing as random, so this experiment doesn't demonstrate communication, but rather it demonstrates that the two pairs of electrons unsurprisingly were subjected to very similar causality.

However, what is more relevant is that these guys have a nice (apparently) random number generator.
Eikka
3.2 / 5 (9) Oct 22, 2015
Isn't the whole experiment begging the question that the random number generator is random?

If the universe is deterministic, then the output of the random number generator is dependent on the pair of electrons - or rather, on the same cause as the electrons - and therefore the result will always agree anyways. The universe has conspired to make the device give out particular numbers that find the spins in agreement because it has to by causality.

In other words, the sequence of the number generator follows from the same cause as the sequence of the electrons' spins, and the proof is invalid because it attempts to prove randomness by assuming randomness.

douglaskostyk
2.5 / 5 (4) Oct 22, 2015
The price of accepting entanglement and relativity is the loss of free will, the results have all been predetermined, and our choices, and the random number generators are just illusions.
antialias_physorg
2.6 / 5 (9) Oct 22, 2015
The price of accepting entanglement and relativity is the loss of free will,

Not really, as the two (QM and Relativity) haven't been reconciled, yet. QM does permit free* will - and probably even requires true randomness to exist.

* 'free' in the sense of 'not predetermined/predeterminable beyond a certain timespan'...not in the sense of 'can do anything'

In the end it doesn't matter if we have free will or just "free will as close as cannot be descriminated". It wouldn't affect us either way.
Noumenon
3.4 / 5 (5) Oct 22, 2015
The only rational way of explaining this is that the attributes being measured simply do not exist prior to measurement,... which is to say that the act of measurement creates the attributes. The measurement system itself (apparatus, interpretation, conceptual assumptions, etc) , ....always done at the macro-scopic scale, .....supplies the conceptual form for the otherwise formless underlying realty,... i.e. it will be a 'wave' if the experimental apparatus and a conscious capacity to recognize a wave pattern is arrange for that result.
Peter Morgan
3 / 5 (3) Oct 22, 2015
`"Local realism" attempts to explain the same phenomena with less mystery, saying that the particles must be pointing somewhere, we just don't know their directions until we measure them.'
For future reference, this is only correct for particle-like interpretations. For fields, a modest "Local realism" proposes only that there might be a well-defined state of the field everywhere in space-time, but that experimental results are contextually determined by the preparation and measurement apparatus together.
Further, Einstein locality, taking the speed of light as characteristic, is an empirical principle that conditions only effective quantum field theories at current scales; experiments that rule out Einstein locality do not rule out local models that have an incoherent unobservable dynamics that has very much faster characteristic speeds but that do not allow signalling.
Peter Morgan
3.5 / 5 (4) Oct 22, 2015
Free will is mentioned a few times above in comments. "Stochastic superdeterminism", for which probability densities evolve deterministically, is never ruled out (see Jan-Åke Larsson, J. Phys. A: Math. Theor. 47 (2014) 424003 (33pp) doi:10.1088/1751-8113/47/42/424003). That is, we have the freedom to make individual choices, but if we make ourselves part of an experiment, the statistics of our choices are constrained by the experimental protocol.
Torbjorn_Larsson_OM
2.3 / 5 (8) Oct 22, 2015
This is one of those awful articles where you go "Huh!?"

"Local realism" was mooted long ago by this type of Bell test experiments, most or all loopholes have been eliminated by now, and the claim that entanglement connects causally so that it transmits information (implicitly faster than the universal speed limit) is wrong. 'Realism/reality' are basically philosophical notions, as soon as we observe that nature exists we are done, which is a simplest, non-mysterious explanation.
Torbjorn_Larsson_OM
2 / 5 (8) Oct 22, 2015
Speaking of philosophy/theology, 'free will' is such a superfluous notion too. Our body is a biochemical machine, there is no quantum stochasticity or classical chaos that changes that fact.

Everything else is experential generated to make us work effectively: "Other researchers have show [sic] that sound, touch, and sight are also inextricably connected. This leads Katz to a grand hypothesis—all our senses belong to a single system. We have only one sense. It's meaningless, for example, to talk of the taste of food because "taste" is equally a function of what you sense on your tongue as it is of what you see, touch, smell, and hear. We don't taste food. We have an experience of food." [ http://medicalxpr...ans.html ]

"WTF, Evolution? You make people think they can make magical voluntary choices? Go home evolution, you are drunk!" [ http://wtfevoluti...blr.com/ ]
Grallen
1 / 5 (1) Oct 22, 2015
I've have had a strange theory for a while. That photons(and maybe many simple particles) are wormholes linking two points in space/time... We cause the wormhole to exit where we attempt to measure. Linking those two points points in time. I *think* it would have to be a one way trip. But it might be possible that it's just going to find something of lower energy to connect to.

The reason for my idea is because of my dislike of wave particle duality. I was thinking of a way that a particle could behave as if it was two things, yet not be.

(More)
Grallen
2 / 5 (2) Oct 22, 2015
The weirdest consequence on my theory is that when an atom emits light(reducing its energy level), it means that the light "photon" would already be "destined" to interact with something else in the future(Yeah, I don't like that it means the future would already be determined either).

I know I'm probably wrong. But I would like opinions on the theory. This experiment made be think twice about my probability of being wrong(briefly), so I thought I would bring it up and let others mull it over (and beat it up).
ralph638s
1 / 5 (2) Oct 22, 2015
The case for retrocausality, and if nothing else, a short and entertaining read:

http://arxiv.org/...12v1.pdf
SuperThunder
1 / 5 (3) Oct 22, 2015
*moon-howling*
I would personally be more inclined to believe that entanglement just doesn't determine what I do causally than to buy into free-will. Free-will takes metaphysics of a level above a ton of metaphysics that doesn't even require free will. You could reverse time and free-will still would not emerge.
*/moon-howling*
Ryan1981
2 / 5 (4) Oct 23, 2015
I've have had a strange theory for a while. That photons(and maybe many simple particles) are wormholes linking two points in space/time... We cause the wormhole to exit where we attempt to measure. Linking those two points points in time. I *think* it would have to be a one way trip. But it might be possible that it's just going to find something of lower energy to connect to.

The reason for my idea is because of my dislike of wave particle duality. I was thinking of a way that a particle could behave as if it was two things, yet not be.

(More)


I don't have the knowledge to prove you're wrong but I love your creative thinking. There is a movie script in here somewhere! And hey you should submit your idear to XKCD.

Shame you can only be rewarded for correctness and not for creativity on this website :P
docile
Oct 23, 2015
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docile
Oct 23, 2015
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docile
Oct 23, 2015
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margotmaggie
1 / 5 (4) Oct 23, 2015
Isn't this article just emphasizing wholeness, that everything is interconnected and nothing exists isolated in the universe? Which is what classical physics denies giving us the illusion of isolation / separation....
docile
Oct 23, 2015
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docile
Oct 23, 2015
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my2cts
1 / 5 (1) Oct 25, 2015
Isn't this article just emphasizing wholeness, that everything is interconnected and nothing exists isolated in the universe? Which is what classical physics denies giving us the illusion of isolation / separation....

Absolutely. This proves that we are all one and need to love thy neighbour..
QM is love.
Urgelt
3 / 5 (2) Oct 26, 2015
Correct me if I'm wrong, but thus far we still haven't seen an experiment which verifies that a human-composed message can be sent faster than light using quantum entanglement. Nor has such an experiment been designed.

It may be a mistake to describe what happens in this experiment as 'communication' at all.
znamhocumogu
not rated yet Nov 24, 2015
IDEA: If both electrons must follow the same pattern then they no needs to communicate each other (?)
EXPLANATION: If "space material" have some specific shape what repeats and repeats its pattern (string therory look like) then both electrons from pair have the same speed and the same starting points... If they must follow specifis space pattern during their "trip" then at the same moment both will have the same direction.
EXCLUSION: If space density (caused by gravity), or nearby gravity (caused by space density) is not the same arrond both electron from pair then this phenomen will last only during some definite time. (bigger gravity difference- shorter harmony)

I'm not phisicist and my idea is just my try for practical explanation of this phenomen.

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