Einstein's 'Spooky Action' Has Been Demonstrated On a Massive Scale For the First Time (sciencealert.com)

schwit1 shares a report from ScienceAlert: For the first time, scientists have managed to show quantum entanglement -- which Einstein famously described as "spooky action at a distance" -- happening between macroscopic objects, a major step forward in our understanding of quantum physics. Quantum entanglement links particles in a way that they instantly affect each other, even over vast distances. On the surface, this powerful bond defies classical physics and, generally, our understanding of reality, which is why Einstein found it so spooky. But the phenomenon has since become a cornerstone of modern technology. Still, up until now quantum entanglement has only been demonstrated to work at the smallest of scales, in systems based on light and atoms, for example. Any attempt to increase the sizes has caused problems with stability, with the slightest of environmental disturbances breaking the connection. But new research changes all of this, by demonstrating that this "spooky action" can indeed be a reality between massive objects. We're not talking massive in the black hole sense but in the macroscopic sense -- two 15-micrometer-wide vibrating drum heads. And the next step will be to test whether those vibrations are being teleported between the two objects. The research has been published in the journal Nature.

Comments

"Massive" scale?

[UnknownSoldier]

Massive is relative.

15 micrometer is only 0.015 mm. Massive would be 1,500 meters.

0.015 mm is massive compared to 10^-10 m.

Context matters.

Re: "Massive" scale?

[Lanthanide]

Entanglement is poorly understood. You don't "change one and the other changes".

Entangled particles vibrate/spin/whatever the same way. You don't know what that way of movement is until you measure it. When you measure A and discover it to be spinning clockwise (or whatever), then you also know that B is spinning clockwise. Both A and B were spinning clockwise from the time they were entangled, there is no "change" involved, just the fact that measuring the spin of A lets you also know the spin of B.

The bottom line is you CAN'T use this to transmit information instantly across distances: if it were the case that you could cause B to spin the same way as A by changing A's spin, then you could transmit information. That's not how entanglement works.

Re: "Massive" scale?

[swillden]

Both A and B were spinning clockwise from the time they were entangled, there is no "change" involved, just the fact that measuring the spin of A lets you also know the spin of B.

Nit: They have opposite spin, not the same spin.

You're citing the "hidden variable" theory, which has been definitively disproven. An oversimplified-to-the-point-of-being-wrong explanation: There are multiple possible axes of measurement and it's impossible for the two particles to have opposite spin in all of them. Yet when we measure one particle in one axis, then measure the other in the same axis, we find that they always have opposite spin, regardless of which axis we picked.

Re: "Massive" scale?

[GuB-42]

A very important part of the delayed choice quantum eraser experiment that is not always mentioned is the coincidence counter. And this is what prevents instant transmission of information.

The experiment is often described as "create a pair of entangled particles, do weird stuff and see where each particle go". But the truth is: most particles involved in the experiment aren't actually entangled, so if you just look at the detectors, the only thing you see is noise. You need the coincidence counter to tell you that two blips in the noise pattern are actually two entangled particles, but only after the two have arrived. That's the important part, you only know after the fact, you can't watch the thing happen.

You can't use a delayed choice quantum eraser to build a useful machine that allows you to transfer data faster than light. With the current understanding of physics, it is simply impossible, and no experiment disproved that. The "information traveled back in time" interpretation is just one of many.

Currently, science isn't settled on a correct interpretation of quantum mechanics. In fact, scientists have no fucking idea how all that stuff work. The maths work, experiments match predictions, engineers put it to good use, but we don't know how to interpret the results.

Soooo spoooooky?

[Anonymous Coward]

>which is why Einstein found it so spooky

Which is why you have no clue what Einstein was talking about. He wasn't spooked you knucklehead, he was mocking it as magic.

Fundamental misunderstanding of entanglement

[Anonymous Coward]

>"In quantum teleportation, properties of physical bodies can be transmitted across arbitrary distances using the channel of 'spooky action at a distance'," says one of the team, Caspar Ockeloen-Korppi from Aalto University in Finland.

This is a fundamental misunderstanding of entanglement. It is not a mechanism for teleportation, it is a dual destination verification mechanism (ie. one must be opposite the other if they maintain entanglement). You cannot set the value at one end and have it appear on the other.

Re:Fundamental misunderstanding of entanglement

[FranklinWebber]

You are right about quantum entanglement. But the team member was talking about quantum teleportation, not just entanglement, and I suspect that you misunderstand the difference.

'You cannot set the value at one end and have it appear on the other.'

Right, about entanglement.

'properties of physical bodies can be transmitted across arbitrary distances'

Right, where the properties are quantum states.

'This is a fundamental misunderstanding of entanglement.'

No, it's not. Quantum teleportation depends on having an entangled state, which is used to move some other quantum state from here to there. It also depends on sending some information from here to there in another communication channel, possibly classical (i.e., non-quantum). I suggest you read more about quantum teleportation, e.g.:
https://en.wikipedia.org/wiki/...

Re:Is this faster than light?

[Trogre]

Actual physicists, please correct me if I'm wrong:

Yes it apparently is faster than light in a vacuum, but it doesn't seem to matter. The change in spin happens instantaneously at both places, but since you can't deliberately change the spin yourself, merely observe it, no information is actually propagated. Thus you're not transmitting anything faster than light, and the universe therefore doesn't explode.

Clarification needed

[FranklinWebber]

I find the summary in great need of clarification. Let me attempt to clarify it in the hope that will be useful to other readers.

First, the linked article links to a much better summary written by one of the team members, Matt Woolley. I recommend you read it instead:
https://theconversation.com/ex...

Second, the summary conflates *mass* with *distance*. The experimenters claim to have entangled remarkably massive objects (compared to the mass of atoms, for example). But the summary says 'any attempt to increase the sizes has caused problems with stability' and that, taken literally, is not true. For example, here's an experiment from 1998 in which entanglement was maintained over a distance of kilometers:
https://en.wikipedia.org/wiki/...

Finally, the summary claims 'a major step forward in our understanding of quantum physics' but I doubt that. It sounds to me like a major accomplishment but one that *confirms* our previous understanding of quantum physics in more massive systems.

Re:Cold Fusion Rides Again

[Anonymous Coward]

It's not quite the same as the cold fusion. With cold fusion there wasn't any cold fusion and some combination of noise and bad experimental setup made it look like there was. With entanglement, the entanglement part is not actually science. There isn't any way to disprove that measuring one particle affects the other particle. Science requires that a hypothesis be falsifiable.

Re:Is this faster than light?

[Jeremi]

Or try this older-technology test, which is equivalent:

1) Obtain two empty boxes
2) Into the first box, place a red marble and a blue marble
3) Put on a blindfold so you can't see anything
4) While blindfolded, reach into the box with the marbles and take out one of the marbles, and put it into the other box
5) Close both boxes and seal them shut
6) Remove the blindfold
7) Mail one of the boxes to Alpha Centauri
8) When it gets there, open the box you didn't mail, and note what color marble is in it
9) Enjoy the "faster than light communication" -- you just "instantaneously" learned the color of a marble located four light years away!

Re:Is this faster than light?

[Cacadril]

Improving the analogy a little:

1. Get two WHITE marbles, each with the property that if you shake it, it will randomly turn blue or red.
2. Put the marbles in boxes and mail one box to Alpha Centauri. Wait until you know it has arrived.
3. Open your box and shake your marble, and watch it become red. Now you know that the other marble will turn blue, or already turned blue as your fellow Alpha Centauri scientist shakes or shook his marble. This is because of a law of nature dictating that the total number of blue and red marbles in the Universe must balance.

Nobody can tell in a meaningful way who shook his marble first. Depending on the velocity of the observer, it could be either one of you who "instantly" programmed the other marble to assume the opposite color. (This is the part that most people forget when describing the spooky instantaneous, FTL action at a distance.)

Remember once more, none of you had any control over what color your marble turned.

Anyone of you may instead paint your marble to force it into the color of your preference, but that breaks the quantum spooky action at a distance. If/when your fellow shakes his marble, it may assume any color. But your fellow won't know the difference until you tell him that you cheated.

If you later communicate with your fellow and learn that his marble turned the wrong color, it just means that the marbles failed to become properly entangled.