

Einstein’s ‘spooky action at a distance’: 10,000 times faster than light - mynameismiek
http://www.extremetech.com/extreme/150207-chinese-physicists-measure-speed-of-einsteins-spooky-action-at-a-distance-at-least-10000-times-faster-than-light

======
jerf
"If it turns out that we actually can communicate data via quantum
entanglement, we now know that it’ll be much faster than the speed of light."

No, no, no, no, no. No. No. No. Quantum entanglement can not be used to
communicate in that manner, on its own. This is well-established, and given
the how mathematical the establishment is, it's not going to change anytime
soon.

No. No. No. Stop that. No.

~~~
nessus42
Yes, they shouldn't get their hopes up too much. Since the Many Worlds
Interpretation is the simplest one, it is also the most likely one. With MWI
there is no spooky action at a distance, and nothing is actually transmitted
faster than the speed of light.

~~~
wamatt
_> Since the Many Worlds Interpretation is the simplest one, it is also the
most likely one_

The simplest defeasible claim in 2013, is still: "we don't know".

Consider, 'How does the sun come up every day?'

 _Answer A:_ God makes it happen.

 _Answer B:_ The earth is a spinning geoid that rotates eastwards, once about
it's axis, roughly every 24 hours. However most of the effect is not related
to the orbits of either the sun or earth, with respect to each other. The sun
"rises" is more an observational effect of a stationary observer on the
surface of the earth, having their field of view rotated.

(For the record, answer B can be improved of course, though that's not the
point here)

"Simplicity" does not mean a catchall (Answer A). It also does not necessarily
mean linguistic brevity either. There is debate around what it means and it's
beyond the scope of my comment[1]. This is the problem with string theory,
that also tends to be popular among the MWI crowd too. It's overly broad and
the math looks pretty, but those are not sufficient conditions for a good
scientific theory. (Oblig xkcd [1])

MWI, like string theory, makes little if any falsifiable and testable claims.

 _[1]<http://plato.stanford.edu/entries/simplicity/> _

_[2]<http://xkcd.com/171/> _

~~~
Eliezer
Um, no. MWI is simplest in the strict, formal, information-theoretic,
Kolmogorov-complexity sense, while fitting the data to equal precision with
any competitor. That's kinda the whole point of MWI.

<http://lesswrong.com/lw/q3/decoherence_is_simple/>

[http://lesswrong.com/lw/q4/decoherence_is_falsifiable_and_te...](http://lesswrong.com/lw/q4/decoherence_is_falsifiable_and_testable/)

~~~
wamatt
From your link: _"This is Bayes's Theorem. I own at least two distinct items
of clothing printed with this theorem, so it must be important." - Eliezer_

 _cringe_. "Here's a bunch of _math_ so I must be really smart. Trust me
guys." Math is awesome, but waving it around as if to automatically lends
credibility to your argument is a poor showing IMHO.

Specifically, quantum decoherence is simply not accepted as a thing that
exists on a macro scale. You're post presents no claim that is testable,
despite the bold headline to the contrary.

Lets look at an example of a what physicists consider to be a falsifiable
claim: The Standard Model predicts the existence of a new elementary particle,
the Higgs Boson. This could be tested experimentally in theory, and later it
was tested in practice, once the capability existed (LHC).

Or another example: orbital mechanics predicts the location of the asteroid
Apophis will pass unusually close (<100 000KM) to earth in 2029.[1]

Now of course if Apophis fails to show up, or shows up overly late or in the
wrong place etc, that doesn't necessarily invalidate the theory, but there
does eventually need to be a credible explanation.

The simplest is usually measurement error, or silly human error etc. But every
now and then, there are discrepancies that just don't go away, and those are
often the ones that lead interesting new theories pushing science forward.

TBH I don't think your post does that.

The failing of physicists to take your above link seriously, does not
epistemically speaking invalidate the claim of course, but it should be pause
for concern.

 _[1]<http://en.wikipedia.org/wiki/99942_Apophis> _

~~~
nessus42
MWI certainly _does_ make falsifiable claims. It's just that different
interpretations of QM are _extremely_ difficult to experimentally distinguish
with any technology we are likely to have in the foreseeable future.

The only well-known interpretation of QM that is experimentally
indistinguishable--in theory--from MWI is Bohm's Interpretation. And I think
it would be a difficult row to hoe that Bohm's Interpretation is simpler than
MWI, as Bohm's universe contains the MWI universe as a subset in the form of
pilot waves that never collapse. I.e., the only difference between MWI and
Bohm is that in Bohm, one of the "worlds" is granted reality, while the others
are not.

Of course, there's nothing in MWI that grants all the worlds reality either.
Someone can certainly remain agnostic about that. E.g., Stehphen Hawking has
said that MWI is obviously true, though he is agnostic on the reality of the
other worlds.

For more information on this, including a tutorial on all the linear algebra
that you need to understand, see the book _Quantum Mechanics and Experience_
by David Albert.

~~~
wamatt
_> MWI certainly does make falsifiable claims._

Would you mind stating an example of such a claim?

~~~
nessus42
Another way in which MWI is falsifiable is that it would be proven wrong if
those Chinese physicists were able to show a speed limit on the spooky action
at a distance. MWI says that there is no such speed limit, since there is no
spooky action at a distance.

Additionally, there are collapse theories that are much easier to test than
consciousness-based ones. By "much easier", I still mean fantastically
difficult, but should the day come that one of these collapse theories is
proven correct, then MWI will clearly have been falsified.

------
fjorder
Contrary to the claims of the extremetech article, they have not closed all
loopholes in this experiment. Specifically, the detection loophole has not
been closed. This loophole is caused by not being able to detect a high enough
portion of the photons your source emits. A paranoid person might argue that
the ones you do detect are not a representative sample. For example, some
devious third party could be choosing which photons you detect in such a way
that your results are skewed. Yes... This is a paranoid suggestion, but
closing loopholes is all about satisfying the paranoid.

In this paper they invoke the assumption of "fair sampling". i.e. They assume
what they do detect is representative. Ergo, they have _not_ closed the
detection loophole in this experiment. Fair sampling is a perfectly reasonable
assumption to make and is very commonly used, so this should _not_ be
interpreted as invalidating their results. It just leaves room for improvement
in the future, since single photon detectors with sufficient efficiency to
close the detection loophole do now exist (They are very bleeding edge).

Note that the paper is correct and does not make the claim that "all
loopholes" have been closed. The extremetech article got it wrong.

~~~
pdonis
_the detection loophole has not been closed._

Not completely, but if I'm reading the paper correctly, they claim a detection
rate of 91%, which is pretty high. Previous experiments had much lower
detection rates. So while it may not completely close the loophole, it does
make the detection loophole argument ("the photons you detected weren't a
representative sample") much more "paranoid", to use your word.

------
alanctgardner2
Maybe I'm mistaken, but I thought Einstein coined 'spooky action'
sarcastically, to try and point out that it was absurd and violated his
theories. I guess there aren't any better, sexy physicist names to put in the
headline to attract clicks.

~~~
Scriptor
I think that's what happend. Schrodinger's cat was also initially conceived to
ridicule the idea of quantum superposition.

~~~
ars
The name Big Bang was also coined to ridicule the idea.

~~~
olalonde
I had never heard of that so I tried to find a reference and it appears to be
true. <http://en.wikipedia.org/wiki/Big_Bang#Etymology>

------
wjnc
It's even better in German: "spukhafte Fernwirkung"

------
oneandoneis2
> One half of the pair was then observed, and the time for the other half to
> assume the same state is measured.

How??

How is it possible to observe whether or not an entangled particle has had its
state resolved by the other particle being observed?

~~~
sbashyal
In a pair of quantum particles [1], when one is spinning-up, other is spinning
down even when they are separated. Therefore it is possible to find out about
the state of one by looking at the other.

[1] <http://en.wikipedia.org/wiki/Quantum_entanglement#Concept>

~~~
colanderman
Yes but doing so _collapses the wavefunction_. Hence there's no way to observe
_when_ the wavefunction collapses.

~~~
aroberge
Many (most?) interpretations of quantum mechanics do not involve a "collapse"
of the wavefunction. The Copenhagen interpretation, which is the oldest and
better known, does, but the many-worlds interpretation (which I dislike),
which is favoured by many working in cosmology and quantum gravity, does not
involve a collapse of the wavefunction.

------
jivatmanx
The speed of light ought to be enough for anyone.

~~~
Xcelerate
Well, actually it poses a lot of problems. Communications that have back-and-
forth transfers can be very slow.

For instance, if I wanted to do a distributed computation with a server on the
other side of the world, it would be limited by the speed of light. From where
I am to Australia is about 48 ms. So if I want to communicate there and
receive a reply, that's about 1/10 of a second right there. I can only do that
10 times a second then. Not so good.

Not to mention the Mars mission has to wait anywhere from 8-19 minutes to get
data between earth and the rover.

We could certainly use > c if it was possible.

~~~
martindale
I believe the poster of this comment was being sarcastic, in the spirit of
Bill Gates' [debatably misattributed] quote: "640K ought to be enough for
anybody."

------
ars
How does this rule out hidden variables?

I am aware of Bells inequality, but how do they show that for this specific
experiment there were no hidden variables in play?

~~~
fjorder
They test a CHSH Bell inequality in this paper. This rules out local hidden
variable theories. Non-local hidden variable (NLHV) theories are another
matter entirely. Indeed, some NLHV theories may reproduce the predictions of
quantum theory exactly.

------
nolanpro
Screw that, faster than the speed of light should be _back_ in time. I want
the information _before_ it was sent!

------
Raz0rblade
It is so simple, this is the same object seen over 2 places. Think of a
fishing tank, the side glass wall and the front glass wall show the same fish.
And that's i hope an easy to understand example of an extra dimension, it
solves many physics problems add a dimension.. As the fish swims in the tank,
both walls show change in position to and no need for communication at all,
its just one fish.

you need proof for extra-dimensional existence just take all those experiments
that could be solved by it .. double split... spooky action .... and many
more.. (even quantum computers inner working)

------
bornonmars
Quantum internet is "starting to become feasible"? It will be in their daily
lives so much faster than that.

