QUIP

[Nephew Twiddleton]

What the hell is a quantum boat?

I just made it up now for a thought experiment.

Your response though, made me laugh realizing how absurd the image of a quantum boat is.

I don't know if you've seen the other QM threads, but the basic principle I hold is this: What happens on the quantum level has no comparable metaphor in the experiential world.  All metaphors are Fail.  That's where the biggest misconception of the "Particle/Wave" thing comes from, that we're trying to describe quantum behavior in terms of billiard balls and oceans.

Ok, cool, so we have this one particle just floating around in void, and it's in a moving state and a non-moving state. Maybe I'm mistaking movement to mean something other than vibration. Does the moving state start moving away from the non-moving state?

[LMNO]

Short version:

If you have two detectors on opposite sides of an event, A and B, then changing the angle of A shouldn't change what B is detecting.



But when really fucking small, it does.  And the change happens faster than the speed of light.

So let me see if I get this - we're talking about tiny little things and tiny little distances, right? Like these detectors aren't three miles apart or anything? We're talking about no more than a couple of nanometres or some bullshit like that? So basically there is some factor (gravity, magnetic field, some new kind of shit we haven't worked out yet... etc) that is still kind of binding these two little things together? I'm picturing them flying off in opposite directions, pushing an invisible "bubble" out in front of them and if you turn the bubble around both the little things will rotate correspondingly?

How close am I?

The math says distance is not a factor.  You aren't changing what the other particle does, you're changing how the other particle interacts with the other detector.

What the hell is a quantum boat?

I just made it up now for a thought experiment.

Your response though, made me laugh realizing how absurd the image of a quantum boat is.

I don't know if you've seen the other QM threads, but the basic principle I hold is this: What happens on the quantum level has no comparable metaphor in the experiential world.  All metaphors are Fail.  That's where the biggest misconception of the "Particle/Wave" thing comes from, that we're trying to describe quantum behavior in terms of billiard balls and oceans.

Ok, cool, so we have this one particle just floating around in void, and it's in a moving state and a non-moving state. Maybe I'm mistaking movement to mean something other than vibration. Does the moving state start moving away from the non-moving state?

Rat, you brought this point up.  Care to address it?

[P3nT4gR4m]

The math says distance is not a factor.  You aren't changing what the other particle does, you're changing how the other particle interacts with the other detector.

Okay I'm definitely not getting this "interacting with detector" distinction. That's the key here isn't it? Any way you can dumb it down just a little bit more? 

[Bebek Sincap Ratatosk]

Moving can mean multiple things in quantum physics, mostly because, as LMNO pointed out, our words/metaphors are not very good for really talking about this sort of thing.

For example, in some quantum experiments we can shoot a electron from point A to point B and measure either its location or its speed, but not both.
In the example at the macro level linked above, they're discussing movement as a vibration.
In quantum entanglement, the two qbits are often said to be in a state of  'spin up' or 'spin down' .

But of course, its unlikely that any of these provide a mental picture that is really accurate. I think the terms 'energy states' and 'wave functions' get used a lot more these days.

[LMNO]

Ok, lessee...


Howabout something Visual?

Detector A = A
Tilting Detector A = A'
Detector B = B
Tilting Detecor B = B'
Nucleus event = (N)
Electron 1 = X
Electron 2 = Y

Setup:

A      (N)       B

A and B are set up with the same "up" alignment.  If the Nucleus event throws off 2 electrons equally, then one will be recorded as spin "up" and one will be spin "down".  This is more or less self explanatory. (A=up, B=down).  This is "entaglement"

A <---X (N) Y---> B


If you misalign A (making it A'), then it will cause errors in detection:  Sometimes it will be correct (A'=up, B=Down) and sometimes it will be incorrect (A'=down, B=down).

A' <---X (N) Y---> B

If you misalign both detectors, it increases the chance for error.  Bell's inequality estimates the rate of error for two misaligned detectors.

A' <---X (N) Y---> B'


However...

The QM equations, and experiments, show that the error rate is much lower than Bell's inequality.  That means that X and Y shows entaglement at a higher rate than expected.  Currently, the only thing that can account for that is information exchange at a rate that is faster than the speed of light.

[P3nT4gR4m]

Okay - I think I'm nearly there. Could you expand a bit on "misalign"

Sorry for being such a retard but I really would like to get this

[Bebek Sincap Ratatosk]

Well, if you really want to get it, you can go to school and get a doctorate in Physics and come back to explain it to us

Let's see... trying to use as little as possible in the way of metaphor:

QbitA and QbitB are placed in the same state and 'entangled'. We can use our detector to measure the state.

We then move these QBITS far away from each other keeping Detector A with QbitA and Detector B with Qbit B.

Now we change the state of QbitA, and immediately measure the state of Qbit B.

We find that QbitB has also changed states.

If you want to imagine the 'state' as spinning or tilting or whatever it doesn't really matter.

The important, interesting totally weird bit... is that the change in state happens more quickly than a photon could get from one location to the other. As far as we know, nothing can travel faster than the speed of light... except whatever is telling Qbit B that it needs to change states.

EDIT: and I fell into metaphor at the end damint!

[P3nT4gR4m]

AHA! I got it. So this "entagled" thing, this is a process you have to do to the qbits before they'll behave this way? Like two "unentagled" qbits don't have the link?

[Nephew Twiddleton]

Is the entanglement indefinite or do they become disentangled at some point?

[Bebek Sincap Ratatosk]

When particles decay in to other particles, these decays must obey the various conservation laws. As a result, pairs of particles can be generated that are required to be in certain quantum states. For ease of understanding, consider the situation where a pair of these particles are created, have a two state spin and one must be spin up and the other must be spin down. As described in the introduction, these two particles can now be called entangled since you can not fully describe one particle without mentioning the other. This type of entangled pair where the particles always have opposite spin is known as the spin anti-correlated case. The case where the spins are always the same is known as spin correlated.

Now that entangled particles have been created, quantum mechanics also holds that an observable, for example spin, is indeterminate until a measurement is made of that observable. At that instant, all of the possible values, that the observable might have had, "collapse" to the value that is measured. Consider, for now, just one of these created particles. In the singlet state of two spin, it is equally likely that this particle will be observed to be spin-up or spin-down. Meaning if you were to measure the spin of many like particles, the measurement will result in an unpredictable series of measurements that will tend to a 50% probability of the spin being up or down. However, the results are quite different if you examine both of the entangled particles in this experiment. When each of the particles in the entangled pair is measured in the same way, the results of their spin measurement will be correlated. Measuring one member of the pair tells you what spin of the other member is without actually measuring its spin.

The controversy surrounding this topic comes in once you consider the ramifications of this result. Normally under the Copenhagen interpretation, the state a particle occupies is determined the moment the state is measured. However, in an entangled pair when the first particle is measured, the state of the other is known at the same time without measurement, regardless of the separation of the two particles. This knowledge of the second particle's state is at the heart of the debate. If the distance between particles is large enough, information or influence might be traveling faster than the speed of light which violates the principle of special relativity. One experiment that is in agreement with the effect of entanglement "traveling faster than light" was performed in 2008. the experiment found the "speed" of quantum entanglement has a minimum lower bound of 10,000 times the speed of light.[5]

From Wikipedia...

[P3nT4gR4m]

Is the entanglement indefinite or do they become disentangled at some point?

Jesus, I've seen the future - we get a fuckton of these entangled qbits and then we break them up and put them in seperate routers and then we mould even more of them into a controller and the rest into the console ... BAM ... You got no input lag and no ping in your online game

QUANTUM GAMING WILL BE FUCKING AWESOME!

[Bebek Sincap Ratatosk]

Is the entanglement indefinite or do they become disentangled at some point?

Jesus, I've seen the future - we get a fuckton of these entangled qbits and then we break them up and put them in seperate routers and then we mould even more of them into a controller and the rest into the console ... BAM ... You got no input lag and no ping in your online game

QUANTUM GAMING WILL BE FUCKING AWESOME!

I think it would be safe to say that such an application would be more likely than teleporting or interstellar travel

[Nephew Twiddleton]

When particles decay in to other particles, these decays must obey the various conservation laws. As a result, pairs of particles can be generated that are required to be in certain quantum states. For ease of understanding, consider the situation where a pair of these particles are created, have a two state spin and one must be spin up and the other must be spin down. As described in the introduction, these two particles can now be called entangled since you can not fully describe one particle without mentioning the other. This type of entangled pair where the particles always have opposite spin is known as the spin anti-correlated case. The case where the spins are always the same is known as spin correlated.

Now that entangled particles have been created, quantum mechanics also holds that an observable, for example spin, is indeterminate until a measurement is made of that observable. At that instant, all of the possible values, that the observable might have had, "collapse" to the value that is measured. Consider, for now, just one of these created particles. In the singlet state of two spin, it is equally likely that this particle will be observed to be spin-up or spin-down. Meaning if you were to measure the spin of many like particles, the measurement will result in an unpredictable series of measurements that will tend to a 50% probability of the spin being up or down. However, the results are quite different if you examine both of the entangled particles in this experiment. When each of the particles in the entangled pair is measured in the same way, the results of their spin measurement will be correlated. Measuring one member of the pair tells you what spin of the other member is without actually measuring its spin.

The controversy surrounding this topic comes in once you consider the ramifications of this result. Normally under the Copenhagen interpretation, the state a particle occupies is determined the moment the state is measured. However, in an entangled pair when the first particle is measured, the state of the other is known at the same time without measurement, regardless of the separation of the two particles. This knowledge of the second particle's state is at the heart of the debate. If the distance between particles is large enough, information or influence might be traveling faster than the speed of light which violates the principle of special relativity. One experiment that is in agreement with the effect of entanglement "traveling faster than light" was performed in 2008. the experiment found the "speed" of quantum entanglement has a minimum lower bound of 10,000 times the speed of light.[5]

From Wikipedia...

Holy shit 10000+ times the speed of light?!?

So, I think I get it now. Damn. And they do not become disentangled because they're halves of the same particle.

[Nephew Twiddleton]

Is the entanglement indefinite or do they become disentangled at some point?

Jesus, I've seen the future - we get a fuckton of these entangled qbits and then we break them up and put them in seperate routers and then we mould even more of them into a controller and the rest into the console ... BAM ... You got no input lag and no ping in your online game

QUANTUM GAMING WILL BE FUCKING AWESOME!

I think it would be safe to say that such an application would be more likely than teleporting or interstellar travel

Not nearly as cool though. But fuck it would do a lot for computing.
Might lead to that AI breakthrough Sig seems to want.

[Bebek Sincap Ratatosk]

When particles decay in to other particles, these decays must obey the various conservation laws. As a result, pairs of particles can be generated that are required to be in certain quantum states. For ease of understanding, consider the situation where a pair of these particles are created, have a two state spin and one must be spin up and the other must be spin down. As described in the introduction, these two particles can now be called entangled since you can not fully describe one particle without mentioning the other. This type of entangled pair where the particles always have opposite spin is known as the spin anti-correlated case. The case where the spins are always the same is known as spin correlated.

Now that entangled particles have been created, quantum mechanics also holds that an observable, for example spin, is indeterminate until a measurement is made of that observable. At that instant, all of the possible values, that the observable might have had, "collapse" to the value that is measured. Consider, for now, just one of these created particles. In the singlet state of two spin, it is equally likely that this particle will be observed to be spin-up or spin-down. Meaning if you were to measure the spin of many like particles, the measurement will result in an unpredictable series of measurements that will tend to a 50% probability of the spin being up or down. However, the results are quite different if you examine both of the entangled particles in this experiment. When each of the particles in the entangled pair is measured in the same way, the results of their spin measurement will be correlated. Measuring one member of the pair tells you what spin of the other member is without actually measuring its spin.

The controversy surrounding this topic comes in once you consider the ramifications of this result. Normally under the Copenhagen interpretation, the state a particle occupies is determined the moment the state is measured. However, in an entangled pair when the first particle is measured, the state of the other is known at the same time without measurement, regardless of the separation of the two particles. This knowledge of the second particle's state is at the heart of the debate. If the distance between particles is large enough, information or influence might be traveling faster than the speed of light which violates the principle of special relativity. One experiment that is in agreement with the effect of entanglement "traveling faster than light" was performed in 2008. the experiment found the "speed" of quantum entanglement has a minimum lower bound of 10,000 times the speed of light.[5]

From Wikipedia...

Holy shit 10000+ times the speed of light?!?

So, I think I get it now. Damn. And they do not become disentangled because they're halves of the same particle.

Actually, some scientists have observed what is called "entanglement sudden death" which basically results is a clean break between the two particles. Though last I read, no one has figured out what the hell is going on there.

I think being a quantum physicist must be fun... get up in the morning, observe an experiment, become confused, go get drunk and go to bed.


EDIT: Apparently its more correctly called "early-stage disentanglement"
http://www.sciencemag.org/cgi/content/abstract/323/5914/598
http://www.scientificamerican.com/article.cfm?id=quantum-entanglement-sudden-death

It's interesting that they tie this to environmental 'noise' . Maybe its related to the earlier discussion of macro effects which 'get canceled out by other forces', I dunno...