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matpompili OP t1_isq0qyp wrote

Reply to comment by StuckinbedtilDec in Experimental demonstration of entanglement delivery using a quantum network stack by matpompili

Hi! The quantum entanglement itself does happen instantaneously, but it cannot be used to send messages faster than the speed of light. A good analogy is the following, from John Bell:

«The situation is further complicated by the fact that there are things which do go faster than light. British sovereignty is the classical example. When the Queen dies in London (may it long be delayed) the Prince of Wales, lecturing on modern architecture in Australia, becomes instan taneously King.»

So the entanglement effect is instantaneous, like the transfer of sovereignty, but until the information reaches the other side it is not known. So you cannot use entanglement to communicate faster than the speed of light.

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StuckinbedtilDec t1_isq1qn3 wrote

Someone's been bullshitting people for years into believing that quantum entangled particles would change their combined spin instantly across any distance.

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matpompili OP t1_isq2kpe wrote

LOL, they do go into one of their joint possible states instantly across any distance! The "issue" is that you cannot extract any faster-than-light messaging technology from this.

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SomeoneSomewhere1984 t1_isqab2c wrote

I think we just don't know how to use if for that yet, but think we'll figure out a way at some point in the distant future.

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Specialist-Doctor-23 t1_isqf0oq wrote

Of course we could. One only needs the remote means to detect, in real time, any of the states of the remote particle and the ability to control the same state of its twin. Of course, this only confers an advantage when the distance (and therefore the time required for a light-speed message) between pairs exceeds the response time of such quantum state message system.

Oh! And some way to establish and sustain control and observation of entangled pairs😏

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Exodus111 t1_isreqlt wrote

It could likely be used for interstellar communication.

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runswithcoyotes t1_isrt18g wrote

Why not? Any change is itself a message.

Edit: to whoever downvoted me, you obviously don’t understand signaling. Any change in states, is at the very least a binary message. Couple that with timing, and multiple bits, and you’ve got yourself a full-fledged messaging platform. Egg heads like OP here aren’t able to explain why this wont work. I’m happy to listen to an explanation, if one could just be provided.

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LaPommeDeTerre t1_it1nkp7 wrote

I think this explains why: https://www.forbes.com/sites/chadorzel/2016/05/04/the-real-reasons-quantum-entanglement-doesnt-allow-faster-than-light-communication/?sh=cc285313a1eb

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runswithcoyotes t1_it4yed7 wrote

Ah, thanks! So I this explains why you can’t send specific values:

If you force one side to change, it breaks the entanglement. UNLESS you modify the state in a way that you can compare the changes that led to the state later. I don’t really understand why that is, and will need to dig into the nested links to find out.

> Alice and Bob end up with measurements that are perfectly correlated, no information passes between them. They can only see the correlation when they get back together and compare lists, and they have to do that at or below the speed of light.

But! My question wasn’t actually about specific states, it was about changes in states. Which.. to me still seems possible.

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SuperSpread t1_isqmtqe wrote

It’s the same fallacy as saying a shadow travels faster than the speed of light when you turn a light on. The shadow was already there. With entangled particles you are merely resolving information.

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Powerful_Range_4270 t1_isrybaj wrote

I think the common phrase of "anything is possible with Quantum physics" is what's causing this.

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crumbshotfetishist t1_isre0mk wrote

Wow. I have never felt so close to feeling like I might actually have some grasp of what quantum entanglement actually means.

What are the limits to the analogy drawn here between this ‘sovereign entanglement’ and quantum entanglement? In other words, what can and can’t Bell’s example help explain about quantum entanglement?

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