Can someone explain this news article about quantum entanglement?

As far as I can make out they’ve sent a photon down some optical fibre. Where does the teletransportation bit come into it? 🙂

http://www.bbc.co.uk/news/science-environment-37408013

The only thing that is teleported is information.

1. Entangle two photons.

2. Send one photon along fibre optic.

3. Change state of local photon and the far photon undergoes the same change in state.

TBH. Not entirely sure what state is being modified. Direction of spin?

Aiui entanglement is a weird property of quantum mechanics where 2 particles have their state locked together, regardless of how far apart they are. So Joe and Bob Photon are entangled, which means that whenever Joe stands up, sneezes or scratches his nose then Bob does the samr whether he’s next to Joe or on the other side of the world. From the article it looks like they’ve used this entanglement property to transfer information about a quantum state without the information passing through the points between the start and the end.

As to how and why entanglement works, even Einstein was baffled so you won’t get much sense from a bunch of middle aged audi driving bike owners.

Thanks people! Great explanation there. Not sure why it was left out of the article though, maybe the author didn’t understand either! 🙂

Also, the reason that you may think that this is in the bike forum is because it is simultaneously existing in both the bike forum and the chat forum, and only exhibits itself in one or the other when it is being observed lol #quantumhumour

Nice one Shermer 😆

From the article it looks like they’ve used this entanglement property to transfer information about a quantum state without the information passing through the points between the start and the end.

I didn’t think anyone knew how this information was actually being passed, but the big deal was that it was instantaneous (or at least much faster than the speed of light.) I should probably read the article!

I should probably read the article!

It’s not very good, there must be better ones out there!

Einstein famously derided entanglement as “spukhafte Fernwirkung” or “spooky action at a distance.” 😆

Looking at the study and the BBC article I suspect the journalist only half understood it. Only did basic quantum physics as part of my chemistry degree and it was best part of 20 years ago so I have barely a clue reading the study.

Certainly looked like it’s the Bell State Measurement that’s key rather than the entanglement and the journo doesn’t even mention that.

I’m probably wrong too.

So if you have a photon on a conveyor belt, right….

Is it better when the photons are 650b chubsters?

This is good on quantum entanglement and other eldritchery, offspring was watching it at breakfast:

whether he’s next to Joe or on the other side of the world

Much further apart than that. Anywhere in the universe. Instantaneously. Yep, faster than the speed of light. Which is impossible right? Entanglement is seriously weird.

There is an alternative universe where I have a full comprehension of quantum physics 🙄

That is proper crazy!

Yep, very hard to get your head round. Can only assume we can’t because we think in three dimensions, this could be a factor of fourth/fifth dimensions where the distance between the entangled particles means nothing/has no influence on them.

Good video! Thanks for posting 🙂

it’s how homeopathy works, innit

Edit: use the force?

spukhafte Fernwirkung

Bless you!

So FTL commincation/ data transfer could be a real probability if this is correct, then?

yep it’s why Einstien wasn’t keen on it, violating his math 🙂

I think the research team have been reading too much Alistair Reynolds… Chasm City slug technology?

I was having a chat with a prof at a Scibar recently who was at pains to point out that “information” in quantum physics is not the same thing as “information” in the general sense (such as data). I wondered if someone might be able to explain to the proles at the Scibar – he thought probably not.

So FTL commincation/ data transfer could be a real probability if this is correct, then?

In one respect yes, but you still have to move your entangled particle to where you want to receive the information and you can only do that at < c. So in any remotely practical sense No.

IANAQM

In one respect yes, but you still have to move your entangled particle to where you want to receive the information and you can only do that at < c. So in any remotely practical sense No.

Though in the distant future, exploring the stars, entangle a particle before you set off, then have instant comms between your space ship and home, that would be very useful indeed.

Even for a Mars mission, it can take about 22 mins for radio waves to travel back to earth. Send a entangled particle there and it’s instant.

In one respect yes, but you still have to move your entangled particle to where you want to receive the information and you can only do that at < c. So in any remotely practical sense No.
Though in the distant future, exploring the stars, entangle a particle before you set off, then have instant comms between your space ship and home, that would be very useful indeed.

Even for a Mars mission, it can take about 22 mins for radio waves to travel back to earth. Send a entangled particle there and it’s instant.

Just what I was thinking. Also, could you somehow “discover” particles that were subject to quantum entanglement (and, more importantly, where their counterparts were)?

To answer “surely this is FTL communications”, good old wikipedia to the rescue: https://en.wikipedia.org/wiki/No-communication_theorem

No, you can’t use this for FTL communication.

What they said ^^^

As far as I understand it the wavefunction collapses faster than light

But just because something moves faster than light doesn’t mean you can send any data on it

Take a laser pointer and wave it back and forth over the moon. If you can wave it fast enough that the red dot crosses the moon’s surface in under 0.01 seconds then the red dot will move faster than light! But good luck using it to carry info from one side of the moon to the other.

Probably a poor analogy. In other news
https://xkcd.com/465/

By the way if you don’t use Chrome and aren’t unreasonably afraid of Java applets, have a go at my quantum game.

http://tropic.org.uk/~crispin/quantum/

(it won’t explain entanglement though)

I went to save that xkcd cartoon so I could post it on Facebook and it came up with a really cool little caption about newspaper headlines for science stories. Impressive! 🙂

It looks like the point of it is to communicate in a way that can be eavesdropped.