/sci/ - Science & Math

I learnt everything I know about science from wikipedia too

I thought quantum entanglement couldn't transmit information.

Holy fuck :O.

This might actually work!!!

No wonder we've never found any alien signals. Communicating with photons is so primitive!

>>3189686
> my face when this

>>3189686
Not faster than light.

>>3189673
No, wikipedia clearly states that this is bullshit. Quantum entanglement does not permit FTL communication.

>>3189686

course it can. How else would they have ever been able to verify it's existance in labs had they not been able to measure the spin of both particles?

Behold - a phasing bullet!
1. Make a bullet and entangle it with something local
2. Shoot the bullet at something big, say moon
3. Don't observe!
4. Quantum tunneling causes the bullet to pass through
5. Observe local object, thus destroying the entanglement
6. ????
7. Bullet at the other side of the moon

Someone explain quantum entanglement better than this. Because this is how I view it.

Take spinning two balls and bounce them of each other at some angle. Do this in a dark room so you cannot see them. Now look at the spin of one. From knowledge of their initial spins and conservation of momentum, you now know the spin of the other ball. The act of observing did not instantaneously force the other ball to pick a spin. Before you measured they already had spins which.were unknown to you.

>>3189673
I actually passed few exams thank to wikipedia.

Articles about "boring" science such as microbiology tend to be accurate and well written.

>>3189727
Not bad, but there's a catch: You can verify that they were in a superposition before, meaning that they didn't even *have* a definite state. In your example, which is classical, they had definite states of which you were simply unaware.

>>3189727
"Two spinning balls"
Bounce them "off" each other

>>3189727
You have an infinite amount of infinitesimally probable particles. The sum of all (particle times its probability) is 2 balls. Then you... Shit...

Well, the balls would have to be magical and hold their probabilities. Those probabilities would interact without first being forced into actual numbers.
If your version was true, dual slit experiment wouldn't work.

>>3189747
The expected value of the gayness operator is reaching a new high.

>>3189755
Does the introduction of angular momentum increase the gayness operator?

>>3189736

I don't understand how observing one forces the other to instantaneously choose a spin. Doesn't this violate causality?

>>3189766
I don't see how it violates causality - but it does violate some concepts from classical physics. Einstein wasn't a fan of this "spooky action at a distance" either.
http://en.wikipedia.org/wiki/Quantum_nonlocality

>>3189653

>>3189727
Read this:
http://cdsweb.cern.ch/record/142461/

>>3189762
In most cases no, but if the position is changing with speed close to sine of time, the particle is subject to an effect called "prancing", which noticeably increases the gayness.

How does the "communication" take place? I feel like superposition is a result of insufficient data. For example, currently I'm in a superposition of a human, a duck and a dolphin. In fact I'm all three until I'm observed. Who wants to look at me? False, I'm always a human, but until you look I may be the other ones to someone who is not aware of what I really am.

>>3189785
Looks interesting, but I'm disappointed with the missing figures.

>>3189766
In short:
No, because the all the particles are "prepared" for such an occurrence. Entanglement does nothing if you have only 1 particle - it can be only noticed when you have "the other end".

>>3189799
The figures are at the end.

>>3189798
>How does the "communication" take place? I feel like superposition is a result of insufficient data.
Indeed, this was the logical assumption. But upon testing it, we find that there are no local hidden variables.
Bell's Theorem really threw us all for a loop, or rather, seeing Bell inequalities violated in experiment.

I presume this paper is also covering the same topic:
>>3189785

>>3189803

could you quadruple entagle some particles?

>>3189824
Not sure what configuration you mean. Unfortunately, even if you proposed something specific, I wouldn't be able to give you a definite answer - I don't know.

I have two entangled particles. I send one a lightyear (or any arbitrary distance) away. I then observe the spin of the particle on my local end.

I now know the spin of this other particle from this arbitrary distance (and this might affect the other particle too).

I have now altered and observed the state of a distant particle.

Isn't this information being sent at FTL speeds?

As you can tell, I clearly do not study physics and am uneducated in the field, but I'm still curious.

>>3189824
Yes.
Though you can't force them to have conflicting states.
If you're entangling their spins (in a way that forces them to have opposite spins), say in pairs: A-B, B-C, C-D, measuring A to be + will force C to be + too.
I'm no expert, but I'm pretty sure I'm only dispensing certain information at the moment.

>>3189835
What you can't do is use that to send a message. If the guy on the other end measured the particle before you did, he has a 50/50 chance of getting either result. If he measures it after you, not knowing what result you got, he still has a 50/50 chance of getting either result.

>>3189785
I'm reading this paper (really very accessible to the layman), and let me tell you, I LOVE physics.

Great. Someday in the future, guys will be 100 light years away, and credit card companies will STILL be asking, "When are you expected to make a payment?"

>>3189886
In the future, people might be less retarded with debt and credit. Maybe.

>>3189898
In the future people will exist as pets for robots. Just like cats do today.

>>3189921
Most people wouldn't mind. The rest will become robots.

>>3189653
in the future humans will be able to use quantum entanglement to feelsbadman about not being able to communicate instantaneously across vast interstellar distances

>>3189851

Right, except I'm not saying that we're sending information as a message for humans to use. I'm still measuring the spin of a distant particle, many lightyears away, instantaneously.

For all intents and purposes, I've received a message from the other particle and that message is "My spin is X", regardless of whether someone else set it spinning that way.

Information has travelled, it's just not information that has any real particular use.

>>3189982
That's not what "transmitting information" means. Information has a location, it isn't just *about* a location.

But you seem to understand this, basically.

As though things we anticipate for the future aren't already happening in the nested loop above ours.

>>3189987

But isn't the knowledge of the spin of the distant particle information?

I'm not talking about communications here, just the knowledge of the spin itself.

>>3190036
But the information is *here*. It has not traveled.

>>3190053

But hasn't it? By observing the entangled particle on this end, I know the state of the particle on the other end. Through this observation I know what is going on an arbitrary distance away.

I gained knowledge of the state of a distant particle long before any light from its location could have reached me.

>>3190074
This doesn't even require any spooky QM.

If I have someone put two socks, one black and one white, in separate shoeboxes without telling me, and then ships one of them to the moon, opening up my box and looking at the sock then tells me about the other sock.

But nothing strange is going on there - there was just information I didn't know. The QM case is even weirder - there is no hidden information that will let you predict which "sock" you have ahead of time.
This paper really is useful, if you have some time:
>>3189785

Gaining information about currently distant objects does not necessarily imply the information traveled from there to here.

>>3190074
You don't know. You're just making a guess at the other particles state. If nothing has disturbed it you'll be right, but it may also have come into contact with something and had its spin changed, and you won't know until that information reaches you in the traditional way

I think the point of quantum teleportation is that because they are entangled, the location is one in the same, from the perspective of the entangled objects.

Information is transmitted, but it doesn't "move" as far as quantum physics is concerned.

It occupies two points in space at the same time to the ouside observer, but to itself, it is all the same.

http://www.livescience.com/13715-teleportation-schrodingers-cat-quantum-light.html

>>3190098
That's just ignoring the problem - you really can have entangled states like this, and the messiness of Nature isn't going to stop you every time.

>>3190113
It just doesnt strike me as impressive. Theres nothing magic about finding my keys in one pocket, and deducing my other pocket is empty. Its impressive they're able to keep these particles pristine for so long, but it doesnt to me suggest there's a faster than light link between them

>>3190154
>but it doesnt to me suggest there's a faster than light link between them
Good, because there isn't. HOWEVER, the really neat thing that is that it isn't just a problem of hidden information - there are no local hidden variables which, if known, would allow you to predict the outcome of the measurement. Emphasis on "local" however - Bohm theory depicts the universe as deterministic but nonlocal.

>>3190174
> the really neat thing that is that it isn't just a problem of hidden information - there are no local hidden variables
why is that neat?

>>3189982
>Information has travelled, it's just not information that has any real particular use.

As long as we can develop a system that reliably transmits or mimics two distinct states of objects light years apart instantly, we have transmission of information.

All you need for binary code or morse code is two distinct states.

I don't care how it works, why it works, or what physics it violates. All I care about is that IT WORKS.

Make a machine that can alter and read the state quickly and transmit information by bloody binary, and reconstruct it into ASCII.

You've just received email from across the galaxy in a few minutes.

>>3190197
We can't induce one of the pair to a certain state and expect the other to follow suit. If we could, that would work for what you want, but we can't

>>3190227

0/10

haven't you read any of this thread?

>>3190256
Link me to where it shows we can

>>3190227
But, we CAN do this.

http://www.livescience.com/13715-teleportation-schrodingers-cat-quantum-light.html

It's just not efficient.

when we're to the point where communicating to plants on the far end of the perseus arm from earth, waiting a few hours for a message to be completed will be a lot better than waiting for a light-speed transmission.

>>3190300
All that said was "rebuild the light in the exact configuration at the other location". They don't specify how they rebuilt it, or what "configuration" means