is-quantum-communication-faster-than-the-speed-of-light?

nsaspook

Joined Aug 27, 2009
16,503
Hi Wendy,

Well that's the way it is NOW, and the reason i believe we have to say this is because we simply just do not know how to do it YET without bothering the entanglement itself. If we look back in time though we can see many things we did not know how to do simply because we did not know how to perturb something fragile in a way that would not destroy it. Then some time later we learned that something more delicate in nature could be used to probe these more fragile objects and that allowed us to be able to understand the objects better as well as control them. Every day we use light to probe many objects and it works because light interacts with large objects in a way that does not destroy them yet allows us to discover their properties without too much difficulty, and when done we still have the object intact.
Physics is always evolving so it may just be a matter of time until we can deal with entanglement in a more useful way.
I'm sorry but we already know how to make it possible, by rewriting the basic laws of physics we use into something incompatible with the current laws of physics and the current physical reality of how things work. Physics is always evolving but it's a building process, not a negation of current understanding. Your reasoning is fatally flawed just like using entanglement for FTL communications is fatally flawed. Entanglement is natural process in nature that it seems our current universe has set limits to to preserve the universe by saying 'this can't happen' at some immutable structural level.
 
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nsaspook

Joined Aug 27, 2009
16,503
OMG, what a typical hype article. The actual paper is just about multiplexing photons on the same fiber.
The classical channel always carries the actual information in these QM networks.

https://www.sciencefocus.com/news/impossible-quantum-teleportation
‘Nobody thought it was possible’: Quantum teleportation is here

Published in the journal Optica, the new research proposes that the breakthrough could make these communications super secure and nearly instantaneous – limited only by the speed of light.

https://www.quora.com/What-are-comm...-quantum-mechanics-in-popular-science-fiction

Perhaps the most prevalent misconception is about quantum entanglement. Entanglement plays a key role as a plot device, for instance, in the famous novel, The Three-Body Problem, in which entangled quantum systems are used for instantaneous communication across interstellar distances. While it is a wonderful plot device (and as I often stress, science-fiction authors are certainly entitled to introduce their own laws of physics in fictitious universes) it has no basis in reality. Quantum entanglement indeed means correlation between distant observations but it most definitely does NOT permit communication. No information, no energy-momentum is transmitted from one observational location to the other, even if, after the fact, when the two observations are compared, a correlation between them is observed.
 

nsaspook

Joined Aug 27, 2009
16,503
If anything is possible then I want my magic unicorns. She's correct to think (it's fun and clickable) about it but if all of that exists, it's really meaningless for us. Those wormholes (if wormholes exist and work the way we think they do) might be transversable but that doesn't mean they are useful and are inescapable to the 'normal' universe when inside.
https://phys.org/news/2019-04-wormholes.html
Travel through wormholes is possible, but slow

This means there can be no traveling faster than light over long distances by going through one.

https://arxiv.org/pdf/1608.05687
Traversable Wormholes via a Double Trace Deformation
After turning on an interaction that couples the two boundaries of an eternal BTZ black hole, we find
a quantum matter stress tensor with negative average null energy, whose gravitational backreaction renders
the Einstein-Rosen bridge traversable. Such a traversable wormhole has an interesting interpretation in the
context of ER=EPR, which we suggest might be related to quantum teleportation. However, it cannot be
used to violate causality. We also discuss the implications for the energy and holographic entropy in the dual
CFT description.
 

nsaspook

Joined Aug 27, 2009
16,503
https://www.sciencedaily.com/releases/2026/01/260107225544.htm

Scientists tried to break Einstein’s speed of light rule
Einstein’s speed-of-light rule just survived its toughest cosmic stress test yet.
Date:January 8, 2026Source:Universitat Autonoma de BarcelonaSummary:Einstein’s claim that the speed of light is constant has survived more than a century of scrutiny—but scientists are still daring to test it. Some theories of quantum gravity suggest light might behave slightly differently at extreme energies. By tracking ultra-powerful gamma rays from distant cosmic sources, researchers searched for tiny timing differences that could reveal new physics. They found none, but their results tighten the limits by a huge margin.
 

MrAl

Joined Jun 17, 2014
13,859
Hello again,

I see there has been a little activity on this subject recently.

From what I understand now, I think we can form an analogy for what quantum entanglement is or at least how it acts. I talked about this idea before but am discovering more details as time goes on.

We start with a regular sine wave of peak amplitude A and constant frequency w and constant phase ph:
v(t)=A*sin(w*t+ph)

This is a description over all time, not just at one particular time t.
This is interesting because, for one, 'A' describes the amplitude such that we can reduce this to just:
V=(A,ph)

which is just the frequency domain representation when we assume 'w' is constant.
This means we 'know' the wave over all time, and if it was a wave in space we would know its character anywhere we looked.

Now let's look at two such waves:
V1=(A,ph1) and V2=(A,ph2)

These are two waves of the same frequency but with two different phase shifts.
Now assume that we can lock ph2 to ph1 so that the difference is constant diff=ph2-ph1.
If we go back to the time equations, we see that the phase is always different in this manner. It's always different by ph2-ph1.

So what does this tell us?
This tells us that if the phase was different when we locked them, it will still be different when we look at them anywhere in space. We don't need any hidden variable either because the phases were locked to begin with. If there was zero difference to start with, then there would be zero difference anywhere we looked, and if they were phase flipped by 180 degrees so ph2-ph1=180 degrees, then they would always have that property.
That 0 or 180 degrees is not a local property, it is global in that it shows up anywhere we look no matter how far out we go.

A mechanical analogy would be where we have two wires where we lock the phases of two sine waves, one on each wire, then move the wires apart. We still have the same phase relationships.
Another would be where we have two ponds and drop a pebble in each one at the same time. The phases stay the same even though they are separate.

This is a rough analogy but it's an illustration of how we can change something locally and not affect something globally. Also because we moved the two wires apart, we might be able to say that we can view the change as changing the phase relationships, but that's not true if we move them apart 'sideways' while keeping them parallel as that would not change any phase relationship.
This I believe is an illustration of the current theory on quantum entanglement which is usually at the heart of faster than light communication discussions.
If this basic idea changes I think something would have to change in quantum mechanics itself. This of course leads to the conclusion that faster than light communication is not possible using quantum entanglement.

I might be able to come up with more detail on this in the future using ideas from quantum field theory. I have limited time on this and limited energy for this as well :)
 

MrAl

Joined Jun 17, 2014
13,859
Hello again,

I ran into this by accident. I thought it was interesting enough and not that long to read.
I will warn though that it does not say that we found a way to prove that light does not always travel at the same speed with the usual limit. It just talks about the precision that we have now for measuring effects that MIGHT be seen if we COULD find two light sources that act differently for apparently no reason. So far no differences, just a pretty big increase in the precision used for the measurements which I think is interesting in itself.
I respected the title because it never says that we found different light speeds, just what we know about the speed we currently believe is the limit and perhaps other behavior, and also interesting is why we might be looking for this with higher precision.

New discovery rewrites what we know about the speed of light
 

WBahn

Joined Mar 31, 2012
33,310
Hello again,

I ran into this by accident. I thought it was interesting enough and not that long to read.
I will warn though that it does not say that we found a way to prove that light does not always travel at the same speed with the usual limit. It just talks about the precision that we have now for measuring effects that MIGHT be seen if we COULD find two light sources that act differently for apparently no reason. So far no differences, just a pretty big increase in the precision used for the measurements which I think is interesting in itself.
I respected the title because it never says that we found different light speeds, just what we know about the speed we currently believe is the limit and perhaps other behavior, and also interesting is why we might be looking for this with higher precision.

New discovery rewrites what we know about the speed of light
While the article was interesting and informative, I DO feel that the title is very misleading. If someone claims that a discovery rewrites what we know about something, the very strong implication is that what we knew and believed about it has changed. We are always making more accurate and precise measurements about almost everything. Does that mean that every time this happens that we have "rewritten" what we know about it? Also, what is the discovery that has been made? Nothing? They have analyzed existing data in a way that makes it more organized and potentially allows future measurements to do an even better job of tightening down the limits. That's not a discovery.
 

MrAl

Joined Jun 17, 2014
13,859
While the article was interesting and informative, I DO feel that the title is very misleading. If someone claims that a discovery rewrites what we know about something, the very strong implication is that what we knew and believed about it has changed. We are always making more accurate and precise measurements about almost everything. Does that mean that every time this happens that we have "rewritten" what we know about it? Also, what is the discovery that has been made? Nothing? They have analyzed existing data in a way that makes it more organized and potentially allows future measurements to do an even better job of tightening down the limits. That's not a discovery.
Quoting the original title:
"New discovery rewrites what we know about the speed of light"

Well, from what I have been seeing on the web these days that is incredibly mild compared to the others.
I am used to seeing this kind of BS:
"Scientists found the new speed of light breaking all previous records"
"Speed of light may no longer be the speed limit of the universe"
"Leaked classified documents show that Nikola Tesla was able to travel faster than light and was actually an alien that came from the black hole M87"
"Finally Washington signs treaty with Ancient Aliens who threatened to make all humans have bright red hair if they didn't". :)

In fact, I just read one yesterday that claimed they cut a photon in half using an apparatus like a camera shutter, and in response it created an infinite number of new photons, yet on each side of the shutter it looked like just one photon.

Also, now we can go back in time and correct mistakes.

The list goes on and on, and so the 'discovery' was just an increase in the precision of the measurement, and it does in fact increase what we 'know' about the speed of light, so it seemed much more mild to me. It may have been a little on the 'catchy' side of creative title writing, but nothing as exaggerated as I have seen in the past.

It's also interesting how we can find ways to increase the precision of measurements which usually interests me. A wild example is if we take an analog voltmeter with a fine movement and place a small light behind the needle so that the light can shine on the white ceiling of room, we can draw a scale on the ceiling that allows us to increase the resolution of the reading by a pretty large factor. It's a funny way to do it but kind of cool. Of course the precision still has a lot to do with the meter movement itself but the size of the scale would have gone up a lot meaning now an arc distance of 0.1 inch on the ceiling could correlate to 0.001 inch of movement of the needle, which would be hard to see on a regular analog meter face plate. This of course would have been better before digital meters became popular.
 

joeyd999

Joined Jun 6, 2011
6,483
A wild example is if we take an analog voltmeter with a fine movement and place a small light behind the needle so that the light can shine on the white ceiling of room, we can draw a scale on the ceiling that allows us to increase the resolution of the reading by a pretty large factor...
... and fundamentally limited by the wavelength of light used in your apparatus.
 

MrAl

Joined Jun 17, 2014
13,859
... and fundamentally limited by the wavelength of light used in your apparatus.
I used X rays (just kidding).

Yes, but it was not meant to go that far unless we could cast a shadow on the moon, which would provide incredible resolution if the meter movement was nearly perfect.

But then again, if we were in deep space it would give even higher resolution, but as the needle moves would we even be able to see it pass our viewing field. It would go by so fast we probably would not see it.
So the light would sort of 'wash' over us. Makes you wonder if there could be processes out there right now that have that kind of light source, and we never see it, especially if it is a one-time event.
 

WBahn

Joined Mar 31, 2012
33,310
Quoting the original title:
"New discovery rewrites what we know about the speed of light"

Well, from what I have been seeing on the web these days that is incredibly mild compared to the others.
True, but I evaluate exaggeration and misrepresentation on its own merits, not on how it stacks up to other exaggerations and misrepresentations.

It's also interesting how we can find ways to increase the precision of measurements which usually interests me. A wild example is if we take an analog voltmeter with a fine movement and place a small light behind the needle so that the light can shine on the white ceiling of room, we can draw a scale on the ceiling that allows us to increase the resolution of the reading by a pretty large factor. It's a funny way to do it but kind of cool. Of course the precision still has a lot to do with the meter movement itself but the size of the scale would have gone up a lot meaning now an arc distance of 0.1 inch on the ceiling could correlate to 0.001 inch of movement of the needle, which would be hard to see on a regular analog meter face plate. This of course would have been better before digital meters became popular.
You will run into a number of effects that quickly limit things. The biggest is probably the nature of the light source itself. It needs to be extremely small and bright to get the factor of 100 you are talking about, and at those distances air turbulence starts playing a role, too. The better technique is for the meter movement to move a tiny mirror and track the reflected image of your light source on a distant scale.
 

Futurist

Joined Apr 8, 2025
950
The constancy of the SOL actually emerges straight from Maxwell's equations not Einstein's. People didn't understand though, that the SOL was not energy propagation in an "aether" a medium, and that belief is what stumped people, it implies the SOL is relative to the aether.

Get rid of the aether hypothesis and it all becomes consistent as Einstein showed, Einstein didn't postulate the speed of light was constant, he postulated there was no aether, as soon as you do that then Maxwell's equations imply a constant SOL for all (inertial) observers, it was the interpretation of Maxwell that people initially struggled with.
 
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robp1956

Joined Jun 12, 2026
121
This article says maybe.
Seems a lot like the duality of light. doing the double slit experiment. Is light a particle thing or is it a wave thing. the simple act of observing it will and does change it's nature. So what is it particle or wave the answer is really both. that same observational shit is present with observing the spin direction Just the simple act of observing it will and does change it's spin. so you come up empty handed with no usable information from the entanglement.
 

WBahn

Joined Mar 31, 2012
33,310
The constancy of the SOL actually emerges straight from Maxwell's equations not Einstein's. People didn't understand though, that the SOL was not energy propagation in an "aether" a medium, and that belief is what stumped people, it implies the SOL is relative to the aether.

Get rid of the aether hypothesis and it all becomes consistent as Einstein showed, Einstein didn't postulate the speed of light was constant, he postulated there was no aether, as soon as you do that then Maxwell's equations imply a constant SOL for all (inertial) observers, it was the interpretation of Maxwell that people initially struggled with.
Although I haven't read Einstein's 1905 paper, "On the Electrodynamics of Moving Bodies", in the original German, I have read it in the English translation and he very much did hypothesize that the speed of light was a constant -- that was, in fact, the second of two postulates upon which he built his special theory of relativity. His two postulates were:

1) The laws of physics are the same in all inertial reference frames (first put forth by Galileo).
2) The speed of light in a vacuum is the same for all observers.
 
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