QUIP

[LMNO]

So, Twid and Vitriol have asked about it.  It's both weird and banal, and (as most QM) neither makes sense in the macro world, nor is applicable to it.

Anyway, most of the following is paraphrased or quoted from Beneath Reality:

First off, we need to be clear: Nearly all the information we can read from a single measurement is inserted ahead of time as we set up our detectors. When the detectors click, all we know is at that instant the part of nature under inspection actually possesses the attributes for which the detectors were tuned.  It is probably better to think about it as we are not measuring nature, we are registering clicks on our detectors.

So, we can learn from nature only what we are clever enough to build detectors for. From this perspective, a principal aim of physics is to discover how many essentially different kinds of detectors we can make. The Standard Model is, among other things, an inventory of detector types. That Nature produces clicks in them gives evidence that this is Nature's inventory too. But Nature is also intertwined with the detectors we have built.

So, we put a detector in a location, and tell it which piece of the Standard Model we're looking for.  You then tell it what it's Reference Frame is (if a particle can be "spin up" or "spin down", you need to tell it what "up" means).  Simple enough, right?  The weird bits happen when you start using more than one detector.

It is easy to imagine apparatus that will produce clicks in two separate detectors that are correlated in some way (I mean for the pattern of clicks to be correlated, not the detector settings, which are always under our control).

For example, an excited nucleus might shed energy by radiating two electrons and nothing else. Imagine that two detectors, A and B, are set up to register them. If the original nucleus were standing still (zero momentum), then the electrons would necessarily be detected moving with identical speeds in opposite directions, because momentum is conserved even in the quantum world (equal and opposite momenta add to zero).

So the momenta are perfectly correlated. Similarly, if the excited nucleus had no spin then the observed spins of the emitted electrons must also cancel (to conserve angular momentum). If the spin detectors are both set at the same angle, we can be sure this apparatus of stationary radiating nucleus plus detectors will cause one detector to register "up" and the other one "down."

Therefore the detector registrations in opposite settings at the two different detectors will be perfectly correlated. This implies that for this system looking at detector A suffices to to determine the result at detector B. The electron excitations at A and B in this case are said to be entangled.

Translation: if you have two detectors, and a nucleus throws off two electrons in equal and opposite direction, the detectors will show a relationship between the two electrons.  Not weird yet.

Ok, so if you take the detectors and you misalign one of them, then you're going to get some errors in detection: there will appear to be no correlation between the two electrons.  After a bunch of theoretical math, a guy named Bell came up with a theorem that predicted an upper limit of errors (called "Bell's Inequality").  However, when you do a bunch of QM equations, the numbers violate Bell's Inequality.  And when they did experiments, the results also violated Bell's Inequality.  So, something else was going on that couldn't be accounted for.  Weird.

The only assumption Bell made was that the two ways of getting an error (misaligning detector A and misaligning detector B) are independent of each other.  I can tilt Detector A, and that shouldn't have an effect on what happens at detector B.  But because of the experiments and QM equations, somehow the orientation of the detector at A must influence what happens at B and vice versa so as to introduce an additional correlation between events at the two detectors.

Another weird thing: Nothing in the QM equations say how quickly changing A will influence B.  The A orientation can be changed just prior to the click of the detector, so there is essentially no time for a signal propagating at the speed of light to reach from A to B. Experiments show the extra quantum correlation even in this case, suggesting that the influence travels essentially instantly from A to B, that is, faster than the speed of light. Physicists call this kind of influence "nonlocal".



And that's QUIP.  Changing detector A will influence what happens at detector B instantly, which shouldn't be the case.

The main reason this is such a freak out for physicists comes from a paper by Einstein and others, which appears to be more philisophical than anything else.  It was not really about physics at all, but about what a physical theory should look like. The authors asserted that a complete theory should have symbols in it that correspond to each "element of physical reality," for which they adopted the following definition: "If, without in any way disturbing a system, we can predict with certainty ... the value of a physical quantity, then there exists an element of physical reality corresponding to this physical quantity."

That is to say, Einstein decided what reality "should" look like, and decided that since QM didn't match up, it couldn't possibly be right.  What is very clear, however, is that QUIP is not compatible with any picture of nature in which the object under inspection is isolated from the instruments of detection.  


Now, feel free to make the case for telepathy and teleportation.

[Nephew Twiddleton]

Ok, this is going to take a bit of processing.

[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.

[Bebek Sincap Ratatosk]

Good summary LMNO!!!

In a practical encryption application, the detectors hold a specific number of quantum bits. The direction these bits 'spin' in make up a 'key'. If we change the spin in detector A, the spin changes nonlocally in detector B. Ergo, if we change the spin, we change the key instantly.

Generally, encryption requires some method to securely transport the key from point A to point B. This application makes it no longer necessary, we simply need to get detector B to the endpoint... and then make up a key.

In true quantum fashion, it also means if someone tries to 'snoop' on the key by measuring it, it will change states and the sender/receiver will know someone is trying to snoop on them.

Quantum = Weird Shit.

[Nephew Twiddleton]

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.

Gotcha, thanks man

[Bebek Sincap Ratatosk]

http://www.nature.com/news/2010/100317/full/news.2010.130.html

A team of scientists has succeeded in putting an object large enough to be visible to the naked eye into a mixed quantum state of moving and not moving

So if trillions of atoms can be put into a quantum state, why don't we see double-decker buses simultaneously stopping and going? Cleland says he believes size does matter: the larger an object, the easier it is for outside forces to disrupt its quantum state.

[Nephew Twiddleton]

http://www.nature.com/news/2010/100317/full/news.2010.130.html

A team of scientists has succeeded in putting an object large enough to be visible to the naked eye into a mixed quantum state of moving and not moving

So if trillions of atoms can be put into a quantum state, why don't we see double-decker buses simultaneously stopping and going? Cleland says he believes size does matter: the larger an object, the easier it is for outside forces to disrupt its quantum state.

That's a little hard to wrap my mind around as well

[Bebek Sincap Ratatosk]

http://www.nature.com/news/2010/100317/full/news.2010.130.html

A team of scientists has succeeded in putting an object large enough to be visible to the naked eye into a mixed quantum state of moving and not moving

So if trillions of atoms can be put into a quantum state, why don't we see double-decker buses simultaneously stopping and going? Cleland says he believes size does matter: the larger an object, the easier it is for outside forces to disrupt its quantum state.

That's a little hard to wrap my mind around as well

Me too...

[Nephew Twiddleton]

http://www.nature.com/news/2010/100317/full/news.2010.130.html

A team of scientists has succeeded in putting an object large enough to be visible to the naked eye into a mixed quantum state of moving and not moving

So if trillions of atoms can be put into a quantum state, why don't we see double-decker buses simultaneously stopping and going? Cleland says he believes size does matter: the larger an object, the easier it is for outside forces to disrupt its quantum state.

That's a little hard to wrap my mind around as well

Me too...

So with all this weird quantum stuff,  wait ok, before I ask that question, I have another one- So, lets say we have a quantum boat going in a forward direction. So when it's moving-notmoving, are there then two of the quantum boat? We'll ignore that the water would disrupt it's quantum state for now.

Original question, so does QUIP have possible applications for feasible interstellar travel? I guess this goes under the teleportation category mentioned by LMNO

[LMNO]

What the hell is a quantum boat?

[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.

[Bebek Sincap Ratatosk]

http://www.nature.com/news/2010/100317/full/news.2010.130.html

A team of scientists has succeeded in putting an object large enough to be visible to the naked eye into a mixed quantum state of moving and not moving

So if trillions of atoms can be put into a quantum state, why don't we see double-decker buses simultaneously stopping and going? Cleland says he believes size does matter: the larger an object, the easier it is for outside forces to disrupt its quantum state.

That's a little hard to wrap my mind around as well

Me too...

So with all this weird quantum stuff,  wait ok, before I ask that question, I have another one- So, lets say we have a quantum boat going in a forward direction. So when it's moving-notmoving, are there then two of the quantum boat? We'll ignore that the water would disrupt it's quantum state for now.

1 quantum object, 2 states simultaneously.

Original question, so does QUIP have possible applications for feasible interstellar travel? I guess this goes under the teleportation category mentioned by LMNO

Who knows? The biggest breakthrough is that we can now see quantum behavior in a "mechanical resonator made of aluminium and aluminium nitride, measuring about 40 µm in length and consisting of around a trillion atoms".

So that is technically 'visible' but just barely... Also it had to be at Absolute 0 (well nearly) to be able to detect it.

I think that it may provide us with a lot better understanding of quantum mechanics, and maybe even help with figuring out a Grand Unified Theory... but teleporting or interstellar travel? I dunno.

[LMNO]

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.

[P3nT4gR4m]

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?

[Bebek Sincap Ratatosk]

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?

No, they can be extremely far away... in fact we have yet to test a distance that doesn't work....