Gravity speed

[undidly]

Superluminal Phenomena,

My understanding here is, physical phenomena, where the speed of
information, and energy transfer, is higher than light speed, exist. Furthermore have been observed in lab. experiments.

this exp. is very cool!
http://www.sciencedaily.com/releases/20 ... 141137.htm

My Conclusion is,
Quantum information transfer, and quantum energy transfer, via particles
have a light speed. finite speed. "c"
Quantum information transfer and quantum energy transfer, (tunneling, entanglement, teleportation)
via "x" are immediate. Or have infinite speed.
where x = unknown

note: When physicists say "teleportation", they are describing the transfer of key properties (like spin) from one particle to another, without a physical link. My understanding is the transfer of key properties is indeed information, as it could be used to transfer say dialogue or data, actual information.

Thanks for the science daily link.
Too much for me to understand in one read but now I have it bookmarked.
If anything at all can travel FTL then maybe gravity can also.
Light is LIMITED in speed by the magnetic and electrical characteristics of space time .
Things that are not electromagnetic are not LIMITED by space time,but maybe limited by something else.
Gravity is not electromagnetic.

[darkmatter4brains]

Quantum information transfer and quantum energy transfer, (tunneling, entanglement, teleportation)
via "x" are immediate. Or have infinite speed.
where x = unknown

note: When physicists say "teleportation", they are describing the transfer of key properties (like spin) from one particle to another, without a physical link. My understanding is the transfer of key properties is indeed information, as it could be used to transfer say dialogue or data, actual information.

This isn't quite correct. Although there is definitely an "instantaneous" connection between two particles that are entangled, you cannot actually use them to send a message. Every thought experiment I've heard of, or thought up myself, gets shot down either by the probablistic nature of QM, and/or by the fact that quantum mechanical particles are utterly indistinguishable, and probably other reasons that aren't coming to me right now.

Likewise with the "teleportation" - although you could say that it is quantum "information" being transferred, you would be hard pressed to find a way to send an actual message with it.

[harper05]

I dont know what you mean by not quite correct, so ill restate my conclusions,

Quantum information transfer, and quantum energy transfer, via particles
have, at a maximum, light speed. finite speed. "c" -in a vacuum.

Quantum information transfer and quantum energy transfer between "entangled" particles, (tunneling, teleportation, ect) via "x", are either instantaneous, occur at infinite speed, or less, and with no exchange of particles.
But in most cases greater than c. (at least the exp. were interested in.)
where x = unknown

I always,.. pretty much,.. 100% of the time,.... come to no conclusions.

This field is advancing rapidly, and new exp.s prove new and old ideas every day.
A team of physicist from Stolckholm U. proved experimentally that six photon qubits are robust, and should be able to reliably carry information over long distances.
Its true, the technology to encode useful information on the qubits and subsequently read it back is still lacking, but once those problems are solved, we will be well on our way to an accurate, reliable, and very speedy quantum communication.

Their experiment is reported in Physical Review Letters and Physical Review A and highlighted in the October 5 issue of Physics
http://physics.aps.org

Apparently six entangled photons can encode information that can take a beating!
Btw, sciencedaily has a wealth of info on a number of very recent break throughs

[darkmatter4brains]

Hi harper,

I was referring to these two things you said

"Quantum information transfer and quantum energy transfer, (tunneling, entanglement, teleportation)
via "x" are immediate. Or have infinite speed."

"My understanding is the transfer of key properties is indeed information, as it could be used to transfer say dialogue or data, actual information."

It sounded like you were implying information, potentially in the form of a type of SIGNAL, could be propagated or sent at faster than light speed. But, maybe I misunderstood you or read too much into this.

If those two statements are related, I would recommend checking out the Appendix in David Griffiths classic textbook on Quantum Mechanics. Check out the section on the EPR paradox, specifically the last few paragraphs where he talks about the fact that there is indeed an instantaneous connection between entangled particles, but that you CANNOT use them to send a signal, i.e. you cannot send information in a useful way (like to send a message or signal) at faster than light speed.

There are a lot of subtleties in QM that make some of the QM articles in popular magazines and science web sites misleading at times. (For example, QM teleportation which, as you mentioned, isn't quite what most ppl picture teleportation as) Griffiths explanation is the clearest, shortest and easiest to read that I've seen and it provides some elucidation on a basic example of why you cannot send a signal faster than light.

[ramparts]

Superluminal Phenomena,

My understanding here is, physical phenomena, where the speed of
information, and energy transfer, is higher than light speed, exist. Furthermore have been observed in lab. experiments.

this exp. is very cool!
http://www.sciencedaily.com/releases/20 ... 141137.htm

My Conclusion is,
Quantum information transfer, and quantum energy transfer, via particles
have a light speed. finite speed. "c"
Quantum information transfer and quantum energy transfer, (tunneling, entanglement, teleportation)
via "x" are immediate. Or have infinite speed.
where x = unknown

note: When physicists say "teleportation", they are describing the transfer of key properties (like spin) from one particle to another, without a physical link. My understanding is the transfer of key properties is indeed information, as it could be used to transfer say dialogue or data, actual information.

Thanks for the science daily link.
Too much for me to understand in one read but now I have it bookmarked.
If anything at all can travel FTL then maybe gravity can also.
Light is LIMITED in speed by the magnetic and electrical characteristics of space time .
Things that are not electromagnetic are not LIMITED by space time,but maybe limited by something else.
Gravity is not electromagnetic.

Undidly, I would recommend that when you don't know physics, you learn it, rather than assert whatever you happen to believe. Gravity is not electromagnetic, but neither is spacetime. It doesn't have magnetic and electrical characteristics. c is a fundamental constant of spacetime, and is not inherently an electromagnetic phenomenon (in fact, you can look at the electric and magnetic constants as being set by the speed of light, rather than the other way around). Any massless particle travels at c, regardless of its electrical or magnetic properties.

[harper05]

Hi Dark,
Great text book! I have intro to qm 2nd eddition, 2005, by griffith. My uncle has the 94 copy.

My point is it is 2010 almost, and the new quantum gates just recently developed(maybe 3 months ago), were also thought in 05 unattainable, they are stellar, unimaginable in performance. The electric manipulation of quibits,(like a switch) also thought in 05 unattainable, The stability of 6 photons entangled with another set, pretty unimaginable. it goes on and on if I had the time i could prob. list 10 more exciting breaks in 09 alone, all of which were thought unattainable in 05, let alone 94.

Maybe i do need to read my text book again,... yes, i most def. need to read it again, who could memorize that.
Maybe the countless amount of physicist, students, and financiers around the world, working relentlessly on accomplishing this goal, need to read griffiths intro to qm.

"My understanding is the transfer of key properties is indeed information, as it could be used to transfer say dialogue or data, actual information."

I admit this statement is a bit "elementary" no pun intended

what I mean is the change in state or property, of two unconnected entangled particles over a distance could be "interpreted" as info. say Morse code for simplicity. you have a set, i have a set, they are entangled. I use one of these cool new electrical switches to change the spin say on my set, the spin on your set changes instantly, regardless of distance, they are entangled. Then i change your set around in a specified order. We have communicated. We are on the very cusp of this as we speak. Maybe I am too enthusiastic, but it is a well based opinion. I hope

[SpeedFreek]

what I mean is the change in state or property, of two unconnected entangled particles over a distance could be "interpreted" as info. say Morse code for simplicity. you have a set, i have a set, they are entangled. I use one of these cool new electrical switches to change the spin say on my set, the spin on your set changes instantly, regardless of distance, they are entangled. Then i change your set around in a specified order. We have communicated. We are on the very cusp of this as we speak. Maybe I am too enthusiastic, but it is a well based opinion. I hope

How does one measure the spin of one of the particles without changing it? I.e. to know the spin has changed, you have to know what the spin was before it changed, but to know that you have to measure the spin and this will have an effect on its entangled particle.

Also, how do you "monitor" the particle, to check whether its spin has changed or not, without interfering with it?

[darkmatter4brains]

okay, I think we're basically saying the same thing

For example, I agree with what you said here.

what I mean is the change in state or property, of two unconnected entangled particles over a distance could be "interpreted" as info

That's why I never completely liked the statement, "information cannot be transferred faster than the speed of light". I sorta think it can. The only catch is that thanks to the nature of Quantum Mechanics, you cannot use it to send a message faster than the speed of light. In other words, it's not really a signal.

It's kind of like a shadow, which can be seen to "move" faster than the speed of light. But, the catch here is that there is no real energy content in a shadow that can be used to send a signal. In QM, the catch is probability, as well as other QM properties, that get in the way of using these various phenomenon to send messages faster than the speed of light.

I guess it all boils down to what you define information as. I'm not sure there is a strict definition that physicists have come up with. Is there? If not, it all boils down to arguing semantics I guess.

Also, if a way was actually found to send a signal faster than light, it would be REALLY BIG news. And, I'd be willing to bet most of it would be phrased in terms of "Albert Enstein Proved Wrong!!". Also, causality would go out the window.

[darkmatter4brains]

what I mean is the change in state or property, of two unconnected entangled particles over a distance could be "interpreted" as info. say Morse code for simplicity. you have a set, i have a set, they are entangled. I use one of these cool new electrical switches to change the spin say on my set, the spin on your set changes instantly, regardless of distance, they are entangled. Then i change your set around in a specified order. We have communicated. We are on the very cusp of this as we speak. Maybe I am too enthusiastic, but it is a well based opinion. I hope

How does one measure the spin of one of the particles without changing it? I.e. to know the spin has changed, you have to know what the spin was before it changed, but to know that you have to measure the spin and this will have an effect on its entangled particle.

Also, how do you "monitor" the particle, to check whether its spin has changed or not, without interfering with it?

Speedfreak is on to some of the "catches" here - that QM particles are utterly indistinguishable. Take pairs of particles with their spin states entangled. To do the morse code thing, you would have to measure one particle at a time. Spin up could be long (or a 1) and spin down short (or a 0). In other words you have an ensemble (or set) of pairs of particles and each pair is entangled. On my end, I would have to measure the particle in the corresponding pair in which you have just caused the other particle's wave function to collapse to a certain spin value. But, since QM particles are indistinguishable, I would have no way of knowing which to measure. In addition, there would be no labeling scheme or predefined ordering to the measurements that we could use to get around the problem

Also, the other catch - probability. Since the QM particle is in a superposition of states before the measurement, and all you can do is predict probabilities of certain outcomes, you don't even know what message you're going to send until you've already sent it. In other words, you've sent random gibberish. It's only afterwards when the two parties get together and compare notes that they can make sense of what actually happened - which sort defeats the point of FTL communication

I've come up with semi-elaborate thought experiments that modify this simple example in an attempt to get around these problems, but got burned each time.

[undidly]

Superluminal Phenomena,

Undidly, I would recommend that when you don't know physics, you learn it, rather than assert whatever you happen to believe. Gravity is not electromagnetic, but neither is spacetime. It doesn't have magnetic and electrical characteristics. c is a fundamental constant of spacetime, and is not inherently an electromagnetic phenomenon (in fact, you can look at the electric and magnetic constants as being set by the speed of light, rather than the other way around). Any massless particle travels at c, regardless of its electrical or magnetic properties.

I think it is you who should learn physics.
Google "permittivity and permeability of space".
These are the electrical and magnetic characteristics of space.
The numbers are almost the same in air and were known to MAXWELL who predicted and calculated the speed of the then unknown radio waves as the same as light speed.
HERTZ built the equipment to generate and also to detect radio waves.

I said "Gravity is not electromagnetic".
Why are you telling me what I have already said?.

[ramparts]

Hi undidly,

Yes, we gave them the names "of space", but they're not fundamental properties of spacetime itself, as described by general relativity (the theory of spacetime). They're properties of the electromagnetic force. The one constant that does come into play in spacetime is the speed of light, as a scaling parameter between dimensions of length and time. If you think that this is caused by electromagnetic properties (rather than the other way around), I suggest you consider why it is that any massless particle - including W and Z bosons and, yes, probably gravitons - all travel at c as well.

As for gravity not being electromagnetic, I was just agreeing with you there. But if you'd like me to be less agreeable, I'd be more than happy to do that, too

[harper05]

"Also, how do you "monitor" the particle, to check whether its spin has changed or not, without interfering with it?"

You might need a couple of charged particle spin polarimeters, capable of resolving
with high efficiency the magnetic moment of a charged particle.

a pair of convex and concave magnetic poles to apply a magnetic
field with gradient to an incident charged particle.

a pair of plain plate electrodes to apply, (to a charged particle), an electric field for canceling a Lorenz force
that the charged particle receives from the magnetic field.
Hence, the magnetic moment in the magnetic field direction of a charged particle is
resolved by the interaction between the gradient of the magnetic field and the
magnetic moment of the charged particle.

A couple of quantum gates.

maybe a couple of quantum point contacts.(a short quantum wire- made from the semiconductor
indium arsenide to generate generate strongly spin-polarized current by tuning the
potential confinement of the wire by bias voltages of the gates that create it)

A couple of all electric spintronics devices would be cool.

Maybe some chromium..

The ss enterprise...
Fine... Im a dreamer I could make these in my garage

[undidly]

Hi undidly,

I suggest you consider why it is that any massless particle - including W and Z bosons and, yes, probably gravitons - all travel at c as well.

www.answers.com/topic/w-and-z-bosons

Massless?.

How do you know gravitons travel at C.
They have never even been detected.

[darkmatter4brains]

Maybe some chromium..

The ss enterprise...
Fine... Im a dreamer I could make these in my garage

I've got a Tricorder if you'd like to borrow one

that and a couple of isolinear optical chips should do the trick

[ramparts]

Hi undidly,

I suggest you consider why it is that any massless particle - including W and Z bosons and, yes, probably gravitons - all travel at c as well.

http://www.answers.com/topic/w-and-z-bosons

Massless?.

You're right; my apologies. I meant gluons. I assumed the weak force carrier was also massless, but I need to learn more particle physics If we must appeal to sites like Wikipedia and answers.com:

http://en.wikipedia.org/wiki/Massless_particle

See the section "special relativity": as I've been telling you, any massless particle travels at c regardless of its electromagnetic properties. That's why I brought that up; because you were claiming (mistakenly) that the speed of light is fundamentally an electromagnetic phenomenon and therefore gravity should have nothing to do with it.

How do you know gravitons travel at C.
They have never even been detected.

I mean, I don't know. If general relativity is the correct large-scale theory of gravity, then they do travel at c. If there's some other component to gravity, then they might not. What I do know is that they can't travel faster than c because of special relativity, as we've discussed. I know that if they do have mass, they have to travel slower than c, based on everything we currently know about physics.

It is possible that gravity propagates faster than c in the same way that it's possible invisible unicorns exist; we can't definitively prove it false, but it violates well-established physics which we have no reason to believe is wrong.

This is starting to sound a lot like the points I made a while back - see my post near the bottom of the first page, 7:57 PM Monday night. You ignored it, but still seem to push (for some bizarre reason) this gravity faster than light thing.

[FlatEarth]

Hi guys. This is a fascinating subject, and there are a number of very informative posts here. If harper05 is right and we are on the brink of a breakthrough in quantum tech, it goes without saying that this would be almost as big as discovering gravity control!

Regarding the transfer of information on a quantum level, wouldn't it require that quantum particles be physically positioned in a remote location (therefore limited in speed to c), but once in place the transfer of information to paired particles would be instantaneous?

[undidly]

Hi undidly,



I mean, I don't know. If general relativity is the correct large-scale theory of gravity, then they do travel at c. If there's some other component to gravity, then they might not. What I do know is that they can't travel faster than c because of special relativity, as we've discussed. I know that if they do have mass, they have to travel slower than c, based on everything we currently know about physics.

It is possible that gravity propagates faster than c in the same way that it's possible invisible unicorns exist; we can't definitively prove it false, but it violates well-established physics which we have no reason to believe is wrong.

This is starting to sound a lot like the points I made a while back - see my post near the bottom of the first page, 7:57 PM Monday night. You ignored it, but still seem to push (for some bizarre reason) this gravity faster than light thing.

I started this topic saying why the big deal if gravity does not travel faster or slower than light.

I don't believe in invisible unicorns ,gluons or gravitons.All made up to explain something until a more sensible answer is found.

"" What I do know is that they can't travel faster than c because of special relativity.""
Relativity is an explanation and not a set of rules imposed on the universe. by humans.

[undidly]

Hi guys. This is a fascinating subject, and there are a number of very informative posts here. If harper05 is right and we are on the brink of a breakthrough in quantum tech, it goes without saying that this would be almost as big as discovering gravity control!

Regarding the transfer of information on a quantum level, wouldn't it require that quantum particles be physically positioned in a remote location (therefore limited in speed to c), but once in place the transfer of information to paired particles would be instantaneous?

If we are very lucky aliens have already positioned entangled particles(or equivalent) where we can find them so we can
join the cosmic internet without waiting years to log on.
Only technically advanced civilizations would be welcome so the particles or device would be hard to find.
On the moon maybe..........(2001 film).

[FlatEarth]

Hi guys. This is a fascinating subject, and there are a number of very informative posts here. If harper05 is right and we are on the brink of a breakthrough in quantum tech, it goes without saying that this would be almost as big as discovering gravity control!

Regarding the transfer of information on a quantum level, wouldn't it require that quantum particles be physically positioned in a remote location (therefore limited in speed to c), but once in place the transfer of information to paired particles would be instantaneous?

If we are very lucky aliens have already positioned entangled particles(or equivalent) where we can find them so we can
join the cosmic internet without waiting years to log on.
Only technically advanced civilizations would be welcome so the particles or device would be hard to find.
On the moon maybe..........(2001 film).

Perhaps the Big Bang generated paired particles throughout the universe ready to be accessed. Otherwise the network would need to be assembled under the constraints of GR. (Unless there is a way to wink out of normal space and reappear elsewhere.) I too have speculated about a cosmic internet, and if it exists, would probably be how interstellar communication would be done. I wonder what the monthly charge would be?

[harper05]

Note; undidley, you misquoted me, I never said the, you don't know physics bit, that was Ramparts.

But by all means, believe in gluons...

The first direct experimental evidence of gluons was found in 1979(30 years ago). when three-jet events were observed at the EPC at PETRA. However, just before PETRA appeared on the scene, the PLUTO experiment at DORIS showed event topologies suggestive of a three-gluon decay.

Experimentally, confinement is verified by the failure of free quark searches. Hence free gluons have not been directly observed or confined. This may be old information though as I am writing from memory, Ill check it out for sure.

Also, quark-gluon plasma has been found recently at the RHIC at BNL. (Relativistic heavy ion collider)

You could choose not to believe in glueballs if you like, but not for long...

http://www.osti.gov/energycitations/pro ... id=6804222