"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.
"As of our current understanding of quantum mechanics, though, it is impossible to send data using quantum entanglement, preserving the theory of relativity. A lot of work is being done in this area, though, and some physicists believe that faster-than-light communication might be possible with some clever manipulation of entangled particles."
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.
> 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.
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.
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.
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.
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.
You can set up complicated and impractical experiments (for us, but perhaps not for inconceivably advanced aliens) that can experimentally distinguish between MWI and other interpretations of QM. (With the exception of Bohm.) Do you really want to know all the gory details? They are rather obscure.
The executive summary is that it is in theory possible to determine whether a system is in a specific superposition of states, if you know exactly what superposition of states it might be in. So, let's say you wish to see if MWI is true vs a version of Copenhagen that relies on a conscious entity experiencing the results of a measurement in order to cause the wave collapse. If you have an accurate enough model down the very last particle of the entity's brain, and everything else the entity would have to interact with for it to perform an experiment, you can in theory then experiment on the entity to determine if it (plus everything it interacted with) is in the specific superposition of states that MWI would predict.
As I said, not very practical.
Well, David Deutsch argues that it might be practical when the day comes that we have AI's living in quantum computers. (And his experiment is also a bit different from what I described, and a bit more conceivable for us to do with technology we might someday have.) A problem there, is that naysayers will no doubt claim that the AI's aren't conscious.
Also, while Eliezer does sometimes plays with the argument from authority (like in the piece of humour you cited), I have never caught him actually using it to win an argument.
Oh, and one of the points (not the main one!) is to tell that those physicists, with all their authority, are wrong. (Well, at least those in favour of the Copenhagen Interpretation.)
Physicists would hardly be intimidated by being shown the algebra of Bayes's Theorem. I will take into account your de facto information that non-physicists may see the opening as an attempt to intimidate, but it was mostly aimed at people mathematical enough to own their own T-Shirts with equations on them, and hence to laugh at the joke.
Regarding the rest of your comment, this is addressed in the second linked post.
>Physicists would hardly be intimidated by being shown the algebra of Bayes's Theorem.
Well no they probably wouldn't, but my point wasn't about intimidation and not sure how it's relevant.
Personally I'm a huge fan of Bayes theory both theoretically and practically speaking, I'm using it in two side projects I'm currently working on. My only issue was a stylistic quibble with the author, and I will have to accept it if you frame it as humor. I'll grant I probably should have left it out in retrospect, since it deals with interpersonal subject matter.
>Regarding the rest of your comment, this is addressed in the second linked post.
No you haven't I was specifically referring to the second post.
I made two central claims, neither were responded to.[1]
1. Decoherence is not a thing on the macro scale.
2. Physicists do not take your claim that MWI is falsifiable seriously.
A fair definition of "simplicity" is relying on the fewest (or simplest) assumptions. "God made it happen" relies on the most complicated assumption possible, that of an omnipotent god. It is never the simplest answer, except linguistically.
There are skeptics who maintain that the various "no-signaling theorems" in physics are simply "begging the question" and rely on hypotheses that are too strong, e.g. http://people.uleth.ca/~kent.peacock/FQXi_v2.pdf
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.
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.
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.
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.
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."
Except HFT traders. I'm sure somewhere some poor ops guy is being harangued with "Hey I hear the Chinese have this tech that is faster than light, I want that shit on my fiber right now dammit, I don't care if its alpha quality ok? What? No I don't need to know about physics, I pay you guys to know about physics, get me that tech now."
> I want that shit on my fiber right now dammit, I don't care if its alpha quality ok?
Tell your boss you found a company with a scheme that can transmit bits over a quantum optical link, but only with a fidelity of 50%. Then get a friend to found that company and charge your boss' company $5 million for the device.
On Earth, it's fine. Communicating with elements outside of Earth, the speed of light is way too slow. Talking with Mars is anywhere from 3 minutes to a 22 minute delay[1]. Wouldn't it be nice to be able to control a rover or talk with Mars settlers in real time?
It's not fast enough for high frequency traders. That's why all the major HF traders pay large sums of money to rent space for their servers at the site of the exchanges.
I thought that HF traders are just paying to be faster than their competitors. If the exchange servers had a 1 mile (or 10ms, or whatever) exclusion zone around them, everyone would be huddling up against that instead.
Our communications run at about 90% of the speed of light through copper and about 66% through glass. Even at terrestrial distances, the latency is noticeable.
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.
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.
How is it possible to observe whether or not an entangled particle has had its state resolved by the other particle being observed?
It isn't. All they can detect immediately (i.e., when each photon is detected) is the measured polarization of each individual photon. They can't know the correlation between the two, which is what tests the entanglement, until the results from both measurements are brought together, which happens slower than light.
Well, for entangled light, figuring out the path taken by one part of the pair forces both to produce no interference patterns. Their superpositions both collapse into a set state. I assume there's a similar effect for electron deflection or whatever they are using. Electron beams can similarly produce interference patterns.
They're using photons, not electrons, but they're not using any interference patterns for detection since they're not bringing the entangled photons back together. They are detected separately.
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.
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)
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.