Viewing a single comment thread. View all comments

NZGumboot t1_j9o5cvl wrote

Reply to comment by Plzbanmebrony in Physicists Use Quantum Mechanics to Pull Energy out of Nothing by Vailhem

No. Part of the process to extract energy involves the experimenters sending information from one entangled particle to the other (presumably along a wire). Thus it doesn't matter if the energy transfer itself is instantaneous, information still can't be transferred faster than the speed of light.

5

Plzbanmebrony t1_j9o8ouo wrote

If you can tell it happen right away that is data right? So if you could sync two from any distance you could send data in binary.

1

NZGumboot t1_j9ocwzl wrote

The energy fluctuations appear random, just like if the particle was not entangled. It's only with the information you got from the other entangled particles that the fluctuations become non-random.

Here's an analogy. You roll a die repeatedly and you need to guess when the die rolls six. But the die rolls are perfectly random, so with lots of rolls you can't guess right more than (on average) 1/6 of the time.

But this is a quantum die and your friend has another die that is linked to yours and rolls the exact same sequence of numbers as your one (though in isolation it's still perfectly random, just like your die). Now you can guess the six consistently; your friend just has to tell you what they rolled.

But even though the die are linked by some spooky method that travels faster than light, you cannot use this to transfer information faster than light. Because there's no way to influence what the sequence of numbers will be.

5

Plzbanmebrony t1_j9od78q wrote

Ok. Thank I truly just didn't understand how you might use this.

2

Iapetus_Industrial t1_j9ovpy3 wrote

> The energy fluctuations appear random, just like if the particle was not entangled. It's only with the information you got from the other entangled particles that the fluctuations become non-random.

Well that's fucking useless then. What's the point if you still need a light-speed channel? We want FTL!

2

apple-pie2020 t1_j9p0v8m wrote

This is a nice explanation that I did not understand prior. Thank you.

Now how about this 26 entangled particles. That don’t roll 1-6 but are either up or down. Your friend in isolation flips all particles down except one for A and so forth. Now could a message be sent faster than light?

2

Kantrh t1_j9r4n1f wrote

No, you'll need to compare measurements to see what the other did.

2

NZGumboot t1_j9q0ivr wrote

The entanglement is very delicate, so much so that the act of "flipping" destroys the entanglement.

1

HolyPommeDeTerre t1_j9pcfo8 wrote

Just trying to understand.

If the other part sends 1 continuously and you know that (communication initialisation). You send 1 to ack "alignment". Then do the same with 0.

The question is. If I send 1 continuously, will the resulting behaviour in the entangle particule be the same or similar in anyway? Or will it change randomly and so we can't "align" on something without another communication method before?

1

NZGumboot t1_j9q2gh0 wrote

The information you send over a wire doesn't change the entangled particles in any way (or do you mean sending a 1 using the entangled pair? That's not possible, the entanglement breaks). What does change the particles is any attempt to measure or change the particle's properties. (With regard to OPs article I believe they are measuring the environment around the particle, not the particle itself, in order to maintain the entanglement.)

2

HolyPommeDeTerre t1_j9q4m9k wrote

Yes my intuition was "input 1 in one of the particle" (change it's state in a expected way) to observe the behaviour of the other entangled particle. But as you state that, influencing the state of the particle will break entanglement.

But, from there, how are we sure the particles are entangled if we can't act on any of them and reflect a resulting change in the other particle.

I guess we can observe both particles surrounding environment and see that there are similitudes ?

Anyway thank you for your time helping me understand :)

1

NZGumboot t1_j9q7l51 wrote

Basically what they do is create a huge number of entangled particles, separate each pair into locations A and B, then measure each the state of all of the particles at both locations (this breaks the entanglement, but that's okay.)

The measurements at A and B appear perfectly random according to all the tests of randomness that we have. But when you bring the measurements from A and B together, you find that they are correlated -- each pair might be e.g. in the same state, or the opposite state, depending on how the entanglement was created. A and B can be arbitrarily far apart.

You might think, well that's easy to explain, when you created the entanglement it set the state of each at that point. But no, you can prove that isn't the case, and that it must be the case that the entangled particles both have an indefinite state until they're measured, and the measurement of one affects the state of the other across any distance. (The proof is called Bell's inequality, see this video for more: https://youtu.be/ZuvK-od647c)

2

HolyPommeDeTerre t1_j9q94lp wrote

Thank you very much. You are gluing multiple things I have in my head together. It's a very clear explanation.

1

Montgomery0 t1_j9p52r4 wrote

So this is more wormhole than FTL? Somehow entanglement causes wormhole like behavior and not faster than light travel?

1

NZGumboot t1_j9q5n5w wrote

You could argue it's not really like a wormhole since nothing physical is moving (energy is a property of matter, it is not itself physical). And that it is FTL because even though the thing being transferred is non-physical it is still in some sense transferring from one place to another faster than light. But the laws of physics conspire in such a way that you can't send a message using entanglement. Which perhaps makes sense as faster-than-light messaging would appear to enable sending messages back in time, which opens a huge can of worms 😀

1