It is possible to communicate faster than the speed of light

It is possible to communicate faster than the speed of light


No, it is not possible to 'communicate' faster than light.

Entangled pair can influence other pair across time instantaneously, but that feature cannot be used for communication. Because in order to pass an information, you need to 'force' an entangled particle to a particular state and messure the state of the other entangled pair at a different location to determine that information .

However, here is the problem. The moment you force one item of an entangled pair to one state, the wave function will break and the entanglement will be lost.

Ie, the second particle will no longer be dependent on the 1st particle and it will give outcome independent of the 1st particle and hence no transfer of valuable information is possible.

What you can do is simply messure the state of an entangled pair and understand the state of the other pair at a distance, but you cannot 'force' a state to an entangled particle and transfer the information to other, since it collapse wave function and hence entanglement.
 
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So you use more than one entangled pair, or a continuous beam of entangled pairs. I only need to either collapse it or not to convey a one or a nought. If I can generate photons in a way where the unaffected properties are a known, then this is possible.
 
If I can change an interference pattern at the Rx by messing with an entangled partner, I can at least produce Morse code.
 
So you use more than one entangled pair, or a continuous beam of entangled pairs. I only need to either collapse it or not to convey a one or a nought. If I can generate photons in a way where the unaffected properties are a known, then this is possible.

You cannot transfer a binary state (0 or 1) using a entangled pair. In quantum physics, measurement actually affect the objects and it's wave function.

Let's say there are 2 points A and B separated by a large distance(many light years) and you are trying to transfer a data from A to B using entangled pair,one in location A and other in location B.

A)What you can do,

Messure the state (observe) of entangled particle in location A and understand the state of other entangled particle in location B. Entanglement will be lost and wave function collapsed.

No valuable communication occurred.

B) what you cannot do,

If you want to pass a binary data like our digital communication, you need to 'Force' a state to the entangled particle and use the state of other particle to 'communicate' the information.

If you 'force' the particle in location A to a state,say 0 or 1, if the entanglement and wave function do not collapse, the state of particle in location B will be 1 or 0 (if the entangled lair relation is opposite like the polarised photon beam) we messure it and an information is communicated.

But, measurement will collapse the wave function and destroy entanglement. Ie, the moment you force particle A to a state, particle in location B is no longer an entangled pair and it behave irrespective of the state of particle A.

So, the observer in location B is looking at a particle that is acting independent of particle A,h is perception of measurement is random and hence no transfer of valuable data happened.

You can only clear the perception of uncertainty at the point B by transferring the information about the messuremnt at point A .There is no way you can pass the information 'about' the messuremet to point 'B' to clear the perception of uncertainty of measurement at location B, since such an information travel is limited by speed of light and hence the entire target of communiaction above speed of light failed.


Here is an article that explain the same situation elaborately. As I said earlier in the other thread, entangled pair experiments disproves locality, causality and relativity is still held.

Can Quantum Entanglement be used for Communication?
 
But what if you set up something similar to the interferometry experiment where the Rx is the screen containing the pattern and the Tx is the detector telling you which slit the photon passed through. By turning on and off the detector you can collapse the interferometry pattern faster than light. This would at least allow Morse code.
 
But what if you set up something similar to the interferometry experiment where the Rx is the screen containing the pattern and the Tx is the detector telling you which slit the photon passed through. By turning on and off the detector you can collapse the interferometry pattern faster than light. This would at least allow Morse code.

Interference pattern is not formed by one entangled pair, it is formed by thousands of entangled pairs combined together. How exactly will the receiver will determine which particle is corresponding to on, and which particle is corresponding to off? :) Well, you are missing the point. In interferometry experiment case, experiment is conducted in a small finite space where it is possible to 'compare' the result with respect to observation point without any uncertainty. You can actually see everything that is happening in that experiment space,you take the measurement and compare with respect to observation points. So you have no uncertainty issue that mentioned in the earlier example, but still the whole time to take measurement and comparison is still slower than speed of light.

The point of communication above speed of light come when experiment space is not a small finite space that we cannot observe/monitor entirety. When the receiver cannot see the entire experimental space in its entirety, it create an uncertainty we discussed in the earlier example, if the reciver is uncertain about the nature and observation space, he cannot decode any valuable data out of it. The observer cannot clear that uncertainty, since any information need to clear that uncertainty is limited by the speed of light.

Universe definitly is conspiring to make sure that we do not communicate faster than light.
 
Interference pattern is not formed by one entangled pair, it is formed by thousands of entangled pairs combined together. How exactly will the receiver will determine which particle is corresponding to on, and which particle is corresponding to off? :) Well, you are missing the point. In interferometry experiment case, experiment is conducted in a small finite space where it is possible to 'compare' the result with respect to observation point without any uncertainty. You can actually see everything that is happening in that experiment space,you take the measurement and compare with respect to observation points. So you have no uncertainty issue that mentioned in the earlier example, but still the whole time to take measurement and comparison is still slower than speed of light.

The point of communication above speed of light come when experiment space is not a small finite space that we cannot observe/monitor entirety. When the receiver cannot see the entire experimental space in its entirety, it create an uncertainty we discussed in the earlier example, if the reciver is uncertain about the nature and observation space, he cannot decode any valuable data out of it. The observer cannot clear that uncertainty, since any information need to clear that uncertainty is limited by the speed of light.

Universe definitly is conspiring to make sure that we do not communicate faster than light.
A single photon will produce an interference pattern unless you observe which slit it passes through. The interference pattern is the infinite integral of the probability amplitude of all the possible paths it could take.

Yes, extending the range would be a problem, could fibre optics be used?
 
A single photon will produce an interference pattern unless you observe which slit it passes through. The interference pattern is the infinite integral of the probability amplitude of all the possible paths it could take.

Yes, a single photon do undergoes interference and assume a location in the screen in accordance with the interference path. However, its just one dot in the screen(which comply interference pattern), we can only observe an interference pattern in screen when we continuously send a number of interference photons through slit without observing which slit.

For the receiver, single photon in screen is just a dot and indistinguishable from a photon that underwent interference or no interference. It will only be distinguishable when a large number of such dots(formed by interference) create an interference pattern in screen.

Yes, extending the range would be a problem, could fibre optics be used?

I am afraid not. Since traveling through optical fiber is limited by speed of light, we end up with communication less than the speed of light.
 
Yes, a single photon do undergoes interference and assume a location in the screen in accordance with the interference path. However, its just one dot in the screen(which comply interference pattern), we can only observe an interference pattern in screen when we continuously send a number of interference photons through slit without observing which slit.

For the receiver, single photon in screen is just a dot and indistinguishable from a photon that underwent interference or no interference. It will only be distinguishable when a large number of such dots(formed by interference) create an interference pattern in screen.



I am afraid not. Since traveling through optical fiber is limited by speed of light, we end up with communication less than the speed of light.
Umm no. A single photon will make an interference pattern for its duration by interfering with itself.
Single Photon Interference
Interference - Young's experiment with single photons: Physclips - Light

So you continuously send a stream of photons and then use the Tx to collapse and restore the wave function of subsequent photons.

But travelling through space is also limited by the speed of light, but it does not affect quantum entanglement.