A question of magics

[Sancria]

there is the hole rifts world of magic thats dependant on ley lines as in ley walkers and ley focuses

I believe that's called geomancy.

While we're at it, add Fung Shui. I think that's how you spell it..

[Lochar]

Thanks.

This works for what I need. Hopefully I might have something in a month or so if someone wants to read it. Still world building, as well.

[ANTIcarrot]

Unfortunately anticarrot, you are both right and wrong about FTL.
As a practical matter, at this moment the scientific community agrees with you

No, as an absolute matter, the scientific community agrees with me. (At least until new evidence comes along.) You cannot disprove the existance of the flying spegetti monster, the invissible pink unicorn, or the flying teapot. Saying that this lack of proof thus makes them indisputably real, or even possible, is a false statement. In that sentiment, FTL is at the very least, a form of religion. Secondly, while there are theoretical ways of getting to the nearest star in less than 5 years. But to the best of my knowledge none of them violate relativity locally.

FTL requires the sending of information faster than light. If that was possible, we should be able to see it when we look up at the stars. We haven't seen it yet. Hubble's Constant doesn't count, until we see the same thing happening on a scale and manner we can duplicate and control.

[Isengrim]

How does that fit with quantum entanglement? Particularly where the state of one particle is effected by changes in it's partner over distances making the ftl transfer of information seems, to a layperson, like the only explanation.

Also, is "information" a technical term in this context?

[darkhand]

anti, I said as a practical matter you where correct however there are theoretical theories other then the hubble constant that state it is possible to move faster then light.

We have observed certain things that make the speed of light just a wall not impenetrable barrier. Some of these include the Casimir Effect and Quantum Tunnelling.

These don't work as any kind of travel or communication device but it is possible to break the speed of light in vaccum

[ANTIcarrot]

How does that fit with quantum entanglement? Particularly where the state of one particle is effected by changes in it's partner over distances making the ftl transfer of information seems, to a layperson, like the only explanation.
Also, is "information" a technical term in this context?

Information is the ability to send a readable message. Quantum entanglement can't do this for ... complex reasons. You *can* in theory affect a distant particle through QE, but not in a way that any potential detector can reliably measure. Essentially, you can send a message, but they can't read it, or even know you're doing so. Relativity doesn't forbid FTL, just matter or information (same thing) from going FTL. Hence shadows can move FTL, but not carry information.

Casimir Effect and Quantum Tunnelling

There is as much proof for either of these ideas (as a method for FTL) as there is for cold fusion. None. Theories without proof are also known as useless crackpot ideas. See String Theory.

[Isengrim]

How does that fit with quantum entanglement? Particularly where the state of one particle is effected by changes in it's partner over distances making the ftl transfer of information seems, to a layperson, like the only explanation.
Also, is "information" a technical term in this context?

Information is the ability to send a readable message. Quantum entanglement can't do this for ... complex reasons. You *can* in theory affect a distant particle through QE, but not in a way that any potential detector can reliably measure. Essentially, you can send a message, but they can't read it, or even know you're doing so. Relativity doesn't forbid FTL, just matter or information (same thing) from going FTL. Hence shadows can move FTL, but not carry information.

I think I'm missing something. Given that it is possible to affect a distant particle, it ought to be possible to affect a continuous sequence of particles. All you need then is to get the guy at the other end of the line a codebook (presumably at subluminal speeds) and he ought to be able to read messages from the states of those particles. On the surface of it such a setup looks like it ought to work, so why won't it work? Or is no information being sent ftl in the setup I've described?

[Aightaight]

Back when I did my BSc (Hons) in physics in 2003 we had a quantum physics/relativity lecture where we explored 4 different possibilities for beating the speed of light limit. On close inspection none of them was actually capable of beating the speed of light. If I recall correctly the third of the possibilities that we covered was quantum entanglement (we also looked at an interesting situation where the forefront of a propagating wavepacket can actually travel slightly faster than FTL, but the peak of the packet (which triggers the passing of information) was limited to the speed of light).

On the question of how Quantum entangled states work:

Firstly, we know from experimental physics that entangled states and FTL correlation do exist - "spooky action at a distance" to quote Einstein is in fact a real phenomenon. An experiment by a group in Geneva, Switzerland reported in Nature in 2008 determined that the "speed" of influence of quantum entanglement correlations has a minimum lower bound of 10,000 times the speed of light. (http://www.nature.com/nature/journal/v4 ... 07121.html).

At the heart of entanglement is the fact that measuring an unknown quantum state will change that state in some way. The quantum states of two (or more) separate objects can become linked together in such a way that they must be described by a combined quantum superposition, not as individual objects. Once entangled the act of measuring the entangled quantity of one object will affect the other at FTL. This does not however mean that information can be passed instantaneously using that method.

The first problem with using entanglement to transfer information is that the entangled particles have to be separated - eg Alice gets one and Bob gets the other. Unfortunately the speed of light limit applies here - there is no way to move the two components of the entangled state apart from each other faster than the speed of light. Also once you measure the state, the entanglement is over permanently so you can't simply reuse the same particles over & over again.

The next problem is that you can't simply encode data directly into the entangled states. For example, lets look at a typical protocol using entangled states.

The Ekert (E91) scheme uses entangled pairs of photons. The photons are distributed so that Alice and Bob each end up with one photon from each pair (but remember, they can't be distributed faster than the speed of light). The entangled states are perfectly correlated in the sense that if Alice and Bob both measure the polarization state of their particles, they will always get the same answer with 100% probability. Thus if Alice measures with a vertical polarizer and gets a photon out, Bob will too (a vertically polarized photon). If Alice measures with a vertical polarizer and gets no photon, Bob will too (a horizontally polarized photon). The same is true if they both measure any other pair of complementary (orthogonal) polarizations.

You might think that this means that once the system was set up (at speed of light transmission rates) Alice and Bob could later on start sending information at FTL - but you would be wrong. The problem is that the particular results are completely random - it is impossible for Alice to predict if she (and thus Bob) will get vertically polarized or horizontally polarized photons for any given entangled pair. Whenever you measure a quantum state it will randomly 'collapse' into one of the possible eigen states, but it is impossible to know which one it will be in advance. Measuring one member of the pair tells you what the state of the other particle would be if you measured it, but the results themselves are random. Bob and Alice can measure particles until the cows come home but they cannot pass information in this way.

What about Alice telling Bob before he leaves that they will use a code where the very fact that his particle has become polarised is the signal to do something (eg to buy 1000 shares in Vulpine Industries)? This still won't work because there is no way for Bob to know when to measure his particle. He cannot know if the photon is polarised UNLESS he measures it, and if he measures before Alice does then HE will be the one responsible for collapsing the entangled state, not Alice.

Even though you can't beat the speed of light this way, you can still make use of the correlation effect of entanglement for other purposes. For example, Alice can start measuring randomly using both a vertical polarizer and a circular polarizer, and Bob can do the same. They can then send each other a list of which polarizer they measured with at which time (over a speed of light link), and based on the results they can select out a random list of photons for which they both did the same measurement. This random string of 1's and 0's can then be used as a key for information encryption - and the benefit is that by looking at the list they can tell whether their key was intercepted by an eavesdropper! (see Quantum Encryption on wikipaedia for further info on how this works). Other applications of entanglement are superdense coding and quantum state teleportation.

[Lochar]

Oddly enough, Scientist create the first programmable quantum computer

[Isengrim]

Aightaight, I think I see why it won't work, but to confirm my understanding.

Even if Alice and Bob use a continuous stream of entangled particles Alice can't force Bob's side to take on one of a pair of clearly defined states in some determined sequence.

If that's not true, what prevents Alice and Bob from sending messages using a special set of machines set up in a particular way so that "talking" measurements are taken half a meter ahead of "listening" measurements?

Granted such a setup would require a machine generating entangled pairs. Then send each of the particles to the measuring instruments so that they arrive at the correct time. Also granting that Alice and Bob would need something like ASCII or Morse Code to understand the messages being sent.

[Aightaight]

Even if Alice and Bob use a continuous stream of entangled particles Alice can't force Bob's side to take on one of a pair of clearly defined states in some determined sequence.

Yep, that's exactly right! Alice can force Bob's particle into the same state as her own particle, but she can't pre-determine what state that will be.

To use the Morse Code analogy Alice can create a random string of dots and dashes, and Bob will get the same random string of dots and dashes, but there is no way for Alice to force the entangled state into the series of dots and dashes that she wants.

what prevents Alice and Bob from sending messages using a special set of machines set up in a particular way so that "talking" measurements are taken half a meter ahead of "listening" measurements?

Alice can certainly do this, and that is exactly what you would do to set up a quantum encryption channel in practice. But without the ability to code valid data the correlation effect of quantum entangled states is useless for sending information at FTL.