Debunking and closing quantum entanglement 'loopholes'

Please don't down-vote this, its just a question. Is it true that Quantum Entanglement is analogous to the following:

You have two balls in a bag, where one is red, the other blue. You don't know the colour of either, but when you pull one out, and see that it is red, you instantly know what colour the other one will be when you look at it (blue), even if the bag is the size of a galaxy and the blue ball is all the way on the other side of it.

Is that right or is there some other aspect to it that makes it something more profound than this?

Pretty much, except Quantum Mechanics insists that both balls are blue and red at the same time until you grab one and look at it.

The act of looking at the ball turns it into either color, which means that the second ball must then become the opposite color the very instant you look at the first, because there was a red and a blue ball that went into the bag. You couldn't pull out two red balls.

And this is problematic, because it means that the information about you observing the color of the ball travels down to the other one faster than light.

Though there's a further problem.

To any third observer, who has not yet checked which ball you picked up from the bag, you have picked a ball that is both blue and red, and thus no information about the color of the ball has yet travelled between them.

Is that right or is there some other aspect to it that makes it something more profound than this?

The latter, ie, it is more profound. It is not simply a matter of not knowing, but of instantaneous influence (non-locality).

And this is problematic, because it means that the information about you observing the color of the ball travels down to the other one faster than light.

It isn't problematic because no actual signal or information is transmitted and so the speed of light (or information) limit is preserved.

It isn't problematic because no actual signal or information is transmitted and so the speed of light (or information) limit is preserved.

Color me incorrect, but isn't there a way to indirectly measure if a particle is in superposition?

Then suppose you have an entangled pair of particles, separated by a million miles, and you continuously measure the state of superposition of one of them. Your measurement should change whenever the other particle is observed, collapsing its wavefunction and forcing the pair into a definite state.

Thus, one bit of real actual information travels instantaneously across a vast distance.

Thus, one bit of real actual information travels instantaneously across a vast distance.

No, there is no information transfer. You cannot use this system to, for example, transmit information FTL. This is well known. The entangled particles cannot be considered as individual objects separated by distance, but are part of a single system which responds to further interactions.

It is more profound. The balls are half red, half blue. When you pull one out it become blue or red completely and the rest is the opposite. It also may be possible to make one ball more blue or red without taking it out and the rest will become more the opposite and this manipulation may be measurable on it without taking it out. Meaning instant communication. There are some evidence that it might be possible (look for weak measurement), but that violate the official theory that require balls to be taken out for reading and also the belief that information cannot travel instantly. It can be explained by wormhole that exists between these (entangled) balls that will be destructed when ball is taken out.

Obsession with the concept of the observer... which is understandable because physics is founded on observation.

In my opinion (more of a gut feeling that of course has no real value to anyone other than myself) the next leap forth will come from a mathematical insight that will be directly related to understanding prime numbers.... quantize (there is a 'one' of something) and something rather peculiar happens mathematically.

This thing about not being able to measure things without settling their properties and invoking the voodoo about their being in multiple states at the same time seems to me to be a lot simpler than the mystique physicists cloak it with.

When we measure macroscopic things we don't alter their states because we measure them by their emissions, for instance determining something's color or temperature by infrared. Anything that measures directly affects what you are measuring, for instance measuring how fast something is turning by pressing a wheel against it. The problem with measuring particles is that they have no emissions that we know of so any measurement affects it.

One theory is that the states of entangled pairs are set at the time of creation of the pair and that there is no action at a distance. I'll believe the states of both halves of an entangled pair are set at the time of measurement or indeterminate when we can measure them without affecting them, which may be never.

This thing about not being able to measure things without settling their properties and invoking the voodoo about their being in multiple states at the same time seems to me to be a lot simpler than the mystique physicists cloak it with.

It isn't.

I think it's more accurately described as a coin toss between two coins. When one lands on heads, you can be certain the other will land on tails. Both coins have the potential to land on either heads or tails, but they always land at odds with one another despite being two separate coins.

Considering that, I agree with the idea that there must be a hidden variable. It's practically certain, there's a clear information exchange at the point of entanglement, each coins fate must have been decided at the moment of entanglement ... and that the perception of both coins having the same potential to land either side up is an illusion.

One theory is that the states of entangled pairs are set at the time of creation of the pair and that there is no action at a distance. I'll believe the states of both halves of an entangled pair are set at the time of measurement or indeterminate when we can measure them without affecting them, which may be never

You need to reread this article. What you are proposing is Yet Another Hidden Variables Theory, which is precisely what Fedrizzi & Zeilinger demonstrate doesn't work, along with all other Bell tests that have been performed. The results predicted by hidden variables theories don't match those obtained from experiments while the results predicted by QM do. Nature doesn't care if you believe it or not, and it doesn't care how you feel about it; that's just how it is. (At least as far as we can test.)

Superposition sounds like superstition to me. Why do physicists try to make it sound more complicated just because there's a quantum soup of mechanics? The cat is dead.

Question: Is it correct, that if an observer doesn't know, that a particle is entangled with another particle (he hasn't been told that someone else has made the two particles entangled) then it is not possible for him to make a local observation or measurement, that proves the entanglement?

If this is so, it must be impossible to make a distinction between these two situations:

1) You are observing a particle that is not entangled with any other particle.

2) You are observing a particle that you don't KNOW is entangled with another particle.

No, there is no information transfer. You cannot use this system to, for example, transmit information FTL. This is well known. The entangled particles cannot be considered as individual objects separated by distance, but are part of a single system which responds to further interactions.

I understand that is the assumption.

But in the scenario I presented, another person observing the other particle would notice when a measurement was made on its pair by observing that it drops out of superposition, which means that information about the other observer travels between the particles instantaneously.

I might be incorrect in stating that it's possible to observe a superposition without collapsing it, which is why I'm asking it.

If it is possible to determine whether a particle is in superposition or not when it arrives to your detector, then it would be possible to send entangled particle streams to two observers, and one of them would either measure or not measure his particle, which would make the other see a stream of particles that alternate between superposition and not superposition, allowing one to send a sort of quantum morse code that acts instantly over distance.

I can find one flaw though: without measuring if the sending party has measured his particle, the counterpart might exhibit some sort of "metaposition" where it is both in superposition and not, and measuring it would yield either state randomly.

Superposition sounds like superstition to me. Why do physicists try to make it sound more complicated just because there's a quantum soup of mechanics? The cat is dead.

Gawad, stated it correctly; Reallty doesn't really care how you think it should be. The fact that you think it's superstition demonstrates that you don't understand the measurement problem.

Eikka, it is not possible to make use of entanglement to send previously unknown information to another observer.

As mentioned above, both entangled particles should be considered as part of a single entity.

Each observation, by which I mean apparatus and conceptual frame work, in effect conforms Reality within an relatively artificial scheme,.. our a-priori intuitions of space, time, and causality,... which alters Reality from how it exists of itself, unconceptualized. Although Bohr didn't articulate it in terms of Kant's transcendental deduction, this was basically his point, and is why there only APPEARS to be an underlying reality beyond qm, but in fact there is not. The walls are closing in on such bias fantasies.

Or what if the particles are simply touching in the n:th dimension and aren't actually that far away from each other in the first place?

The job of modern physics is no longer to provide explanations compatible with our intrinsic intuitions, but to formulate a means of making predictions. If string theory is able to do this, it will not mean that the universe is made of strings. It is not valid to over reach into speculation (multiverse) in order to save an explanatory role for physics. QM is a lesson in epistemology as much as it is of physics.

"Bohr became in effect, through his idea of complementarity, the successor to Kant in Philosophy" - Abraham Pais

Or what if the particles are simply touching in the n:th dimension and aren't actually that far away from each other in the first place?

A dimension is a degree of freedom, and so a hidden variable. I mean SOMETHING is going on, but it appears not compatible with any type of observation (definition above) that can be made of it. One interesting thing, and I don't know how it can relate to the problem of entanglement is that from the "referend frame" of a photon traveling from one side of the universe to the other, no time , and nor distance have elapsed at all, however qm entanglement occurs for massive particles as well, not just photons.

No you can't tell if a particle is entangled. Or put another way every particle is entangled with countless other particles always. There is nothing special about the entangled particles used in experiments except you know what other particle they are entangled with and how. This allows you to see the strange non-classical correlation but does not allow you to send information. It does allow quantum encryption of information.

I might be incorrect in stating that it's possible to observe a superposition without collapsing it, which is why I'm asking it.

I'm pretty sure that you cannot passively know anything about it without measuring it. If you know ANYTHING about it, you must have observed it, thus destroying superposition. As was said above, if you observed a red ball, you don't know if the sender collapsed the wave function by observing a blue ball, sending you a red ball, or if you collapsed the wave function into a red ball, thus you became the sender of a blue ball. You could always call them to see who peeked first, but that kind of destroys the point of FTL communication.

As was said above, if you observed a red ball, you don't know if the sender collapsed the wave function by observing a blue ball, sending you a red ball, or if you collapsed the wave function into a red ball, thus you became the sender of a blue ball. You could always call them to see who peeked first, but that kind of destroys the point of FTL communication.

What would happen though if we agreed on pre-determined time intervals to check. Say for example, every morning at 8am you observed your particles to collapse the wave funstion and force them into a particular state, then at 8:05am (taking into account any time differences of course) I observed my particles to "read" your message.

Im familiar with the concept of not being able to send information FTL, and I am aware that everyone says entanglement doesn't allow the transfer of information. What I don't understand is why wont the situation I described result in FTL communication?

Please don't down-vote this, its just a question. Is it true that Quantum Entanglement is analogous to the following:
...
Is that right or is there some other aspect to it that makes it something more profound than this?

Yes, as far as it goes. But there is more to it. First, you can't "cheat" and peek at your ball and put it back.

Second, more profoundly (and the subject of Bell), you are not limited to one variable. Here you chose red/blue pairs. But you can have another variable, say hard/soft pair, such that if you measure red/blue you scramble the hard/soft setting and vice versa. I'm sure you've heard the momentum/position thing?

If you don't know which measurement will be made when the pair is created, you get the "spooky" stuff.

Considering that, I agree with the idea that there must be a hidden variable. It's practically certain,

No, "hidden variables" are [i]excluded[/i] from any explanation that works. Read up on Bell's Inequalities, which is what is being discussed in this article.

@zed123, the main problem is I cannot control the outcome of my measurement, so cannot "set" a value (opposite) to send to you. Further there is no way to tell the difference between a collapsed wave function and an uncollapsed wave fuction from your end,..so we can't even use collapsed=1 and uncollapsed=0 to send a binary message.

@Noumenon
Thanks for the clairifcation. I thought there was a way to measure the particles in such a fashion so as to "Set" values for them. But then, I'm no scientist! :)

Regarding your second point though, if I KNOW that I'm measuring my particles after you've measured yours (pre-determined time interval) then I would know that what I observe is a collapsed wave function and a result of you already measuring your particles. Is that right?

If so, then it seems that the only reason we can;t transmit information is because we can;t control the input of the system. If we could somehow find a way to do that then using this method presumably you could send information to me as long as I knew I was measuring my particles after you had measured yours? (Thats where the pre-determined time intervals come in).

Right, ...in fact the phenomenon of entanglement can not even be recognized as such unless both sets of measurements are brought back together and compared.

An interesting twist: Although you cannot use entanglement to transfer information FTL, you could nevertheless give information about the result of a lottery based on random numbers! (if the random numbers are generated by measuring some entangled particles).

An interesting twist: Although you cannot use entanglement to transfer information FTL, you could nevertheless give information about the result of a lottery based on random numbers! (if the random numbers are generated by measuring some entangled particles).

You can already get QM based random number generators, for your PC even (with USB or PCIe interfaces).
http://www.idquan...pci.html

Anyone seen Dr. Prins here lately.

His idea, if I have it right, of there being NO particles just waves fits the evidence in this test. The particles in the test can be considered as a single waveform that will form two pointlike concentrations when observed. The waveform has a shape determined by the experimental structure. Measuring the particles-waves changes the structure the waves are shaped by. Thus in standard terms collapsing the single probability wave into particles.

I go back and forth on this. I like the Wheeler Multiverse myself as it too fits the experiment.

I like the Standard Copenhagen Model the least. It just seems to confuse the issue without contributing anything useful at all. The math apparently works the same in all three ways of looking at it.

Ethelred

IF "there is no way to tell the difference between a collapsed wave function and an uncollapsed wave function from your end" ... then logically no difference exists and they are therefore exactly the same thing. The fact is that entanglement (if it exists) cannot be demonstrated until the information (measurement) has been transported for comparison and therein lies the hidden variable.

It cannot be proved that any instantaneous action occurs because you must confirm the results at light speed or less.

Pretty much, except Quantum Mechanics insists that both balls are blue and red at the same time until you grab one and look at it.

The act of looking at the ball turns it into either color, which means that the second ball must then become the opposite color the very instant you look at the first, because there was a red and a blue ball that went into the bag. You couldn't pull out two red balls.

And this is problematic, because it means that the information about you observing the color of the ball travels down to the other one faster than light.

I thought if you were to pull out a ball and it was red, the other ball in that pair would be red also, not blue.

I really can't base this on anything, but it just seems to me that there is another dimension in the universe that links the particle pairs, like perhaps a long string (literally, thinking string theory here) although the string is in another dimension independent/outside of our 3-brane universe.

It cannot be proved that any instantaneous action occurs because you must confirm the results at light speed or less.

Confirming at light speed an instantaneous action would only show that the action occurred prior to the confirmation. There's never been any problem showing that two events in the past occurred simultaneously. What you have to show is that the two events that constitute are correlated (linked) and a carefully set up experiment could do that by using high energy photons or neutrino beams deep underground (assuming such instantaneous action is possible). I don't think demanding "proof" would mean much either here as there are some who just can't wrap their heads around QM and will always act as foils (which is o.k.), but certainly experiments could take us to six-sigma+.

"that constitute the action"

Particle (entangled or not) can take big volume in space. When it is measured its energy collapses instantly into single point. QM postulates that this is the only way to learn something about particle. But it is just postulate, noting supports that expect it was not possible to do more delicate measurements then. But it might be possible now and then the light speed limit for information transfer is removed. Connection between entangled particles is nothing else then the long sought wormhole of course. That do not mean that there must be fourth dimension, this wormhole like connection do not have dimension like properties, length does not exist there.

But it is just postulate, noting supports that expect it was not possible to do more delicate measurements then.

Nothing except ALL the experiments that have been done.

There either is or is not entanglement. If there is not then there is no way to use it to transmit information. If there IS entanglement, and the evidence supports it, then you cannot observe either particle without either becoming part of the entanglement or disrupting it. Ether way there is no way to beat light speed. Especially since you can't control which particle has which property.

This despite the way SF writers use it for information transmission. I know, for instance, that Charles Stross is fully aware that he was handwaving in the Eschaton novels. He just needed it for the plot.

Ethelred

Can someone explain how changes to one of the particles are reflected instantly in the other, when simultaneity is relative? To whom are the changes simultaneous?

Can someone explain how changes to one of the particles are reflected instantly in the other, when simultaneity is relative? To whom are the changes simultaneous?

You can use synchronized atomic clocks and compare the results later.

I think ALL particles are connected but that may not be true nature of what "entangled" really means. It's possible that every photon, electron, quark, and all others are all clones from a central source - or copies projected from a "master" into this reality, or even a holographic reality. Why are the basic building blocks the same and are identical across the entire observable universe? Take a Lego block design, make a mold, and repeat infinitely until you have your universe. Or project it from a 2-D event horizon if you dig the holo-verse. And if all are clones maybe they are attached back to the source and mirror source properties, possibly "looping through" the source back to other particles. Maybe the act of entanglement enables a loop-through. Could multiple 2-D projections form a 3-D interference pattern that we see as matter? No offense intended. I have a very limited knowledge of this (made obvious now I know)

I think ALL particles are connected...

Thing is, even if they're 'connected' by some means, it still doesn't help to explain instantaneous action. If you had two balls connected by a string or even a rigid beam, tugging on one ball will not make the other ball 'feel' the tug instantly - there will be a propagation delay.

As for the rest of your post...well, what can I say? :)

If the "connect points" pass immediately out of this reality and into the quantum foam, or whatever it is we are immersed in and is bubbling around us, that connection could be vanishingly small, whereas here the entangled particles could be light years apart. I think we will soon be able to "copy" a particle's attributes, store or transmit this info in a classical sense, then paste this into another particle elsewhere. This modified particle could then be entangled to the "master" at a central location. Just wondering that's all.

If the "connect points" pass immediately out of this reality and into the quantum foam, or whatever it is we are immersed in and is bubbling around us, that connection could be vanishingly small, whereas here the entangled particles could be light years apart. I think we will soon be able to "copy" a particle's attributes, store or transmit this info in a classical sense, then paste this into another particle elsewhere. This modified particle could then be entangled to the "master" at a central location. Just wondering that's all.

Depends on how you stand in regards to creedence within "Information Theory" which is more a philosophy than a theory as it isn't actually testable.

That ALL experiments that have been done collapse particles is not true any more, make search for Weak Measurement. They claim before and after that it does not contradict any fundamental concept, but they avoid more precise explanations. What they actually measure do not violate anything, but the fact that this measuring was possible violate QM fundamental postulates, indicating they are not laws but just rules - true usually, but not absolute. I suspect that these no contradiction claims are just required to make publication possible.

It agree well with Dr. Prins work and then the possibility for faster then light communication is just logical conclusion - if particle can exchange information instantly and if you can measure it without destructing particle then you have it.

As usual in math the same result can be obtained also differently - the connection between entangled particles can be interpreted as wormhole. And wormhole is instant communication channel by definition, it makes two points in space neighboring. So, it actually agrees well wit GR.

if particle can exchange information instantly and if you can measure it without destructing particle then you have it.

Except that measuring is not equated with setting, and particles don't exchange information, they react to being disturbed,.. thus disturbed,.. ohhh darn.

if particle can exchange information instantly and if you can measure it without destructing particle then you have it.

But it doesn't, and you can't.

You have a bag with two balls in it, one red, one blue.

You're assuming that if you pull the red ball out, the blue one is left in the bag, logical conclusion.

Entanglement is two balls of unknown color in the bag. You take one out and put it in a different bag without looking at it, what color is the second ball? You have no idea. If you look in the first bag you affect the color of the first ball. You look at the second bag and you affect the color of the second ball. But you have no idea what colors the two balls going into the bags were. So you have to check both bags, which means any information carried is useless until you check both ends of the entanglement. So you're limited to standard speed communication to determine what the information in the entangled particles actually is.

I try again. The maximum speed that you can confirm entanglement is at the rate of information transfer. Unless both particles occupy the same physical position you cannot know if the action was instanteous. Thats not to detract from a seemingly high statistical correlation that shows some unknown type of interaction with a possible cause a hidden variable of which this article further narrows. Perhaps in time, the detection loophole may be closed too and we just will never know.

http://physics.aps.org/articles/v1/34

Once the entanglement is broken it is not retrievable. Wave form collapse is one thing, entanglement is another.

It might help if people start using the analogy of a twin, rather than thinking of the entangled particles as connected.

Reconsider the entanglement as putting the two particles "in quantum synch". If you don't disturb their quantum state you can make simultaneous measurements and know what the second measurer got elsewhere. This doesn't transmit any information, but you know what they saw too.

With the same thinking. If the entanglement is "broken", the wave forms are no longer "in quantum synch". You have changed one of the twins. You may be able to return it to its uncollapsed condition, but it is no longer a copy of its twin (entangled). You may be able to re-entangle it to its twin, but (in my understanding) that would require locality so what is the point?

Note: all of this is "wrong" but hopefully it is helpful in conceptualizing.

I have a question.

I have two particles which are entangled. They are both in a given energy state but separated by distance. If I add energy to one of the particles changing its energy state, what happens to the energy state of the other?

@Waterdog,
Good question. Here is a previous article related to this.
http://www.physor...481.html
Ultimately if you can transmit, or not transmit, energy you can transmit information. Our current understanding is that you can't send information FTL, so my thinking is that energy transmission is still rather distant on the horizon if it is at all possible.

In my thinking entanglement is when particles waveforms join and form a single waveform. Meaning broking entanglement and collapsing particle is exactly the same thing. I do not know will it allow FTL information and energy transfer, but what I want to show is that there is nothing we know that forbid it.

Entanglement loophole closed
A long-distance experiment rejects a challenge to quantum physics.
http://www.scienc...e_closed

An old USSR joke:
Question: Is it true that the USSR-made car "Volga" makes a 90-degree turn at 100 km/hr?
Answer: Yes.... but only once.

- Is entanglement a "yes, but only once" affair for each entangled objects pair/group?
and, if so indeed,
- Are the states-of-systems of entangled objects decided upon separation of the objects, not upon their measurment?


Dov Henis
(Comments From The 22nd Century)
DNAnomics Is Not Genomics
http://www.the-sc...y/57814/