4 ms·

Could someone explain the implications of this? If locality is broken, would that mean that sending a message faster than light would be possible (theoreticall

by enkid 9y ago

Could someone explain the implications of this? If locality is broken, would that mean that sending a message faster than light would be possible (theoretically)?

krastanov 9y ago
The result from the experiment is not surprising and it has been done in less stringent fashion many times before. It is just a real-world realization of the though experiment behind Einstein's spooky action at a distance (look up Bell measurements / Bell experiment / EPR "paradox"). This gives you way more obfuscated information than you probably want: https://en.wikipedia.org/wiki/Bell_test_experiments https://en.wikipedia.org/wiki/Bell_test_experiments Basically, if you set up an experiment where two entangled particles are send far apart and you are not very careful with the derivations, it would look like you can communicate faster than light between the two entities holding the two particles. Turns out that it does not work, and while it does give fascinating insights about the weirdness of quantum mechanics it is not useful for FTL communication. However, it is definitely useful for encrypting messages that can not be decrypted no matter how much computational power you have (even if you have fancy computational oracles).
jrue 9y ago
Faster than light communication would violate causation, meaning you could send a message that would arrive before it was sent. What happens if you instruct yourself to not send it in the first place? This is the paradox. So, how to get around that? Perhaps parallel universes? Other dimensions? Or maybe just that the quantum world is designed to violate locality in very precise ways that don't affect the macroscopic world, or break any causation rules. I always find it fascinating how a concept like entanglement — two particles that are connected by some faster-than-light phenomenon — can coexist with the macroscopic world, yet perfectly prevent messages from being sent between two points. Same with quantum teleportation. The science says that it can happen, but the no-cloning theorem prevents duplicates from being made through teleportation. As strange as the quantum world is, it somehow doesn't seem to ever break causation rules (yet).
- oldandtired 9y ago
  The problem is that (as far as we know) we cannot determine when two (remote from each other) events take place relative to each other when we are constrained by the speed of light. We cannot determine which occurred first. This is a limitation due to the information communication limit. So the theoretical basis (for consistency purposes) is that faster than light motion would violate causality. If on the other hand, there is an absolute frame of reference, then all events can be related (in time) to this absolute frame of reference. In this case, no matter how much faster we can move above the speed of light, no violation of causality would be possible, we could always determine the relative positions in time of any and every event, no matter how remote from each other. Since we do not know (as in, we cannot determine if such a frame of reference actually exists) of any such absolute reference frame, we are unable to determine in reality what would happen in the event of faster than light motion. The mathematical basis of the prevalent theories give causality violations in such events. The universe is much stranger and more unknown than what is purported to be understood. Always keep in mind that no matter what theories are currently in vogue, they are a very pale and simplistic understanding of the reality that we live in. Every theory we currently use is flawed and fails in some way. That is not to say that they don't have utility. They do, but they are also limited in that utility. The problem that is faced today is that people (quite intelligent people for that matter) forget that the mathematical descriptions they use in formulating theories and models of the universe around are always simplified models. There are always simplifying assumptions made. Too often, these assumptions are so hidden that those promulgating the theories get so caught up in their theories success that they forget that it is a limited and faulty description of reality. This then leads to some of the fantastical beliefs that they will then propagate. This effects things all areas of science and the upshot is that when problems are highlighted with specific parts of the theories in question, there is a great amount of effort undertaken to defend the theory instead of applying critical thinking to the problem and looking for better alternative descriptions. An example is the Standard Model of Subatomic Particles. One of the basic assumptions is that the Big Bang occurred. This underpins the entire model. Yet how often does this particular assumption actually get stated as being a fundamental assumption for the theory/model. In conflict with this is the Theory of General Relativity. One of the "results" of the GR Theory is these strange entities called "black holes". Singularities that are quite problematic in any finite universe. Simply put, a universe in which "black holes" exist cannot be started by a "big bang". The singularity that is the "big bang" won't go bang since the gravity is way above anything escaping. So we have impasse and hence, we have illogical assumptions underpinning some of our quite workable theories/models at the macro and micro levels. We must always remember that, though our theories are useful, they are a very flawed and incomplete model of reality. The other thing to remember is that it should be fun to try and discover more about our reality. Too often, many who support one view or another (in terms of what theory or theories are applicable - witness the conflict between string theory and non-string theory defenders), come across as being afraid of their opponents. Having a robust defence of your view is fine, but when it descends to ad hominem attacks, then all I see is fearful little people and not intelligent critical thinkers.
deepnotderp 9y ago
Locality != causality Sending a message faster than light violates causality (sidenote, it would mean the end of free will). Fortunately , information cannot be sent faster than light via quantum entangled particles, the formal theorem is called the "no communication theorem".
- oldandtired 9y ago
  Free will is not determined by a limitation on the speed of light. The problem is that we cannot determine via an absolute frame of reference when two events have occurred in time. The assumption is that causality will be violated if we are able to send a message faster than the speed of light, this is a mathematical solution only in the event that there is no absolute frame of reference. Since we do not know if there is one or not, we make the simplifying assumption that there is none. Whether or not this assumption is correct is not determinable at this time. If we are able to send messages at some speed faster than the speed of light (by any factor you wish), we will still be in the same situation as we are now, not being able to determine when two events have occurred relative to one another. If we find that we are able to send instantaneous message between any two points, we will then have found the absolute frame of reference to measure when two events have take place. Causality will not be violated in either scenario.
- n4r9 9y ago
  The No Communication Theorem only guarantees against instantaneous communication. Quantum theory on its own says nothing about the speed of light.
lisper 9y ago
No. See this video for an explanation: https://www.youtube.com/watch?v=dEaecUuEqfc https://www.youtube.com/watch?v=dEaecUuEqfc Or this paper: http://www.flownet.com/ron/QM.pdf http://www.flownet.com/ron/QM.pdf
k400 9y ago
No. Correlation is nonlocal, causality is not.

by enkid 9y ago

Could someone explain the implications of this? If locality is broken, would that mean that sending a message faster than light would be possible (theoretically)?

krastanov 9y ago

The result from the experiment is not surprising and it has been done in less stringent fashion many times before. It is just a real-world realization of the though experiment behind Einstein's spooky action at a distance (look up Bell measurements / Bell experiment / EPR "paradox"). This gives you way more obfuscated information than you probably want: https://en.wikipedia.org/wiki/Bell_test_experiments https://en.wikipedia.org/wiki/Bell_test_experiments Basically, if you set up an experiment where two entangled particles are send far apart and you are not very careful with the derivations, it would look like you can communicate faster than light between the two entities holding the two particles. Turns out that it does not work, and while it does give fascinating insights about the weirdness of quantum mechanics it is not useful for FTL communication. However, it is definitely useful for encrypting messages that can not be decrypted no matter how much computational power you have (even if you have fancy computational oracles).

jrue 9y ago

Faster than light communication would violate causation, meaning you could send a message that would arrive before it was sent. What happens if you instruct yourself to not send it in the first place? This is the paradox. So, how to get around that? Perhaps parallel universes? Other dimensions? Or maybe just that the quantum world is designed to violate locality in very precise ways that don't affect the macroscopic world, or break any causation rules. I always find it fascinating how a concept like entanglement — two particles that are connected by some faster-than-light phenomenon — can coexist with the macroscopic world, yet perfectly prevent messages from being sent between two points. Same with quantum teleportation. The science says that it can happen, but the no-cloning theorem prevents duplicates from being made through teleportation. As strange as the quantum world is, it somehow doesn't seem to ever break causation rules (yet).

oldandtired 9y ago
The problem is that (as far as we know) we cannot determine when two (remote from each other) events take place relative to each other when we are constrained by the speed of light. We cannot determine which occurred first. This is a limitation due to the information communication limit. So the theoretical basis (for consistency purposes) is that faster than light motion would violate causality. If on the other hand, there is an absolute frame of reference, then all events can be related (in time) to this absolute frame of reference. In this case, no matter how much faster we can move above the speed of light, no violation of causality would be possible, we could always determine the relative positions in time of any and every event, no matter how remote from each other. Since we do not know (as in, we cannot determine if such a frame of reference actually exists) of any such absolute reference frame, we are unable to determine in reality what would happen in the event of faster than light motion. The mathematical basis of the prevalent theories give causality violations in such events. The universe is much stranger and more unknown than what is purported to be understood. Always keep in mind that no matter what theories are currently in vogue, they are a very pale and simplistic understanding of the reality that we live in. Every theory we currently use is flawed and fails in some way. That is not to say that they don't have utility. They do, but they are also limited in that utility. The problem that is faced today is that people (quite intelligent people for that matter) forget that the mathematical descriptions they use in formulating theories and models of the universe around are always simplified models. There are always simplifying assumptions made. Too often, these assumptions are so hidden that those promulgating the theories get so caught up in their theories success that they forget that it is a limited and faulty description of reality. This then leads to some of the fantastical beliefs that they will then propagate. This effects things all areas of science and the upshot is that when problems are highlighted with specific parts of the theories in question, there is a great amount of effort undertaken to defend the theory instead of applying critical thinking to the problem and looking for better alternative descriptions. An example is the Standard Model of Subatomic Particles. One of the basic assumptions is that the Big Bang occurred. This underpins the entire model. Yet how often does this particular assumption actually get stated as being a fundamental assumption for the theory/model. In conflict with this is the Theory of General Relativity. One of the "results" of the GR Theory is these strange entities called "black holes". Singularities that are quite problematic in any finite universe. Simply put, a universe in which "black holes" exist cannot be started by a "big bang". The singularity that is the "big bang" won't go bang since the gravity is way above anything escaping. So we have impasse and hence, we have illogical assumptions underpinning some of our quite workable theories/models at the macro and micro levels. We must always remember that, though our theories are useful, they are a very flawed and incomplete model of reality. The other thing to remember is that it should be fun to try and discover more about our reality. Too often, many who support one view or another (in terms of what theory or theories are applicable - witness the conflict between string theory and non-string theory defenders), come across as being afraid of their opponents. Having a robust defence of your view is fine, but when it descends to ad hominem attacks, then all I see is fearful little people and not intelligent critical thinkers.

deepnotderp 9y ago

Locality != causality Sending a message faster than light violates causality (sidenote, it would mean the end of free will). Fortunately , information cannot be sent faster than light via quantum entangled particles, the formal theorem is called the "no communication theorem".

oldandtired 9y ago
Free will is not determined by a limitation on the speed of light. The problem is that we cannot determine via an absolute frame of reference when two events have occurred in time. The assumption is that causality will be violated if we are able to send a message faster than the speed of light, this is a mathematical solution only in the event that there is no absolute frame of reference. Since we do not know if there is one or not, we make the simplifying assumption that there is none. Whether or not this assumption is correct is not determinable at this time. If we are able to send messages at some speed faster than the speed of light (by any factor you wish), we will still be in the same situation as we are now, not being able to determine when two events have occurred relative to one another. If we find that we are able to send instantaneous message between any two points, we will then have found the absolute frame of reference to measure when two events have take place. Causality will not be violated in either scenario.
n4r9 9y ago
The No Communication Theorem only guarantees against instantaneous communication. Quantum theory on its own says nothing about the speed of light.

lisper 9y ago

No. See this video for an explanation: https://www.youtube.com/watch?v=dEaecUuEqfc https://www.youtube.com/watch?v=dEaecUuEqfc Or this paper: http://www.flownet.com/ron/QM.pdf http://www.flownet.com/ron/QM.pdf

k400 9y ago

No. Correlation is nonlocal, causality is not.