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Quantum Teleportation Achieved Over Internet For The First Time (www.sciencealert.com)

submitted 2 months ago by ploot to c/science@lemmy.world

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[-] LostXOR@fedia.io 89 points 2 months ago

TLDR: Researchers were able to send and receive entangled photons over a fiber optic cable that was simultaneously carrying a classical (non-quantum) signal typical of high speed telecommunications. They managed to accomplish this without the classical signal significantly interfering with the quantum measurements.

This was all done in a laboratory using a combination of standard telecommunications equipment for the classical signal and specialized equipment for the quantum signal. It was NOT done on a fiber carrying real internet traffic as the article would suggest.

[-] Whirling_Ashandarei@lemmy.world 34 points 2 months ago

Correct, but still amazing because it means quantum internet is achievable over existing infrastructure. Not needing to lay down all new lines around the world for quantum transmissions will mean it gets adopted much faster. Even if specialized equipment is needed on either end of the cable, the hope/assumption would be that specialized equipment on either end will become cheaper as tech advances and scales upward - still a long ways off but cut down significantly.

[-] LostXOR@fedia.io 14 points 2 months ago

Yeah it's absolutely an awesome accomplishment, it just bugs me whenever articles spread straight up false information.

[-] Markuso213@lemmy.ml 3 points 2 months ago

There are still massive hurdles for using optical fibre networks for quantum information transmission. The biggest lies in attenuation, where information is lost as the optical signal traverses the fibre. This is an exponential decay, so the signal is lost very quickly for longer distances. This is also the case for normal fibre communication, but these signals can be amplified using conventional amplifiers (aka repeaters in some fields), which are conveniently placed every 80 km or so in order to boost the signal. In contrast, quantum states can not be amplified in a similar manner and have to rely on quantum repeaters which, well, are more of a theoretical concept at this point in time.

So, while the specialized equipment you refer to is indeed needed at both ends, the real challenge still lies in the quantum repeaters. Fortunately, satellite based communication is not as heavily punished by attenuation and would require fewer repeating steps (as compared to fibres) to transmit a quantum state from one end of the globe to the other. A handful of few repetition steps is a lot less daunting then the several hundreds that would be required for globe-scale quantum transmissions via fibre.

[-] 58008@lemmy.world 6 points 2 months ago

What's the upshot of this, even if the article's hyperbole is accurate? I'm assuming it's not as spooky or sci-fi as the terminology sounds to a monkey like me.

[-] LostXOR@fedia.io 12 points 2 months ago

It shows that it's possible to send entangled photons over existing fiber infrastructure without building something totally new, which as I understand it has applications in cryptography, secure communications, and quantum computing.

[-] Hamartiogonic@sopuli.xyz 4 points 2 months ago

That’s a common problem with these titles. If you want to make them short and snappy, you’ll either end up with something vague or straight up incorrect.

[-] humanspiral@lemmy.ca 3 points 2 months ago

IIUC, quantum entanglement at a distance provides for faster than light/instant communication of state changes. High frequency trading, and dark orderbooks, is the only known economic application (space communications a far off application). I'm not sure why article avoided talking about this purpose.

[-] SpacetimeMachine@lemmy.world 14 points 2 months ago

You don't understand correctly. Entangled particles do not allow for faster than light communication.

[-] smeenz@lemmy.nz 7 points 2 months ago* (last edited 2 months ago)

While the entangled photons may be thought of as changing state simultaneously, in practice, it's not possible to use this to convey information, as doing so would break causality, and effect would be able to happen before its cause. Remember that what is commonly termed 'the speed of light' is actually better expressed as 'the speed of causality'. The most useful application of what this experiment performed would be in the area of quantum cryptography.

[-] Bear_pile@lemm.ee 2 points 2 months ago

So honest question here:

Why can't it be used to transmit information? Wouldn't we be able to capture the state and use that be turned into instructions the same way we use binary currently?

Binary is essentially just a series of "on" and "off" states that we capture and translate into instructions, so why can't we do that with entangled particles? Like position 6 translates into instructions F and position 2 triggers instructions B.

I know this is overly simplified but I do not follow that we can't send information this way when looking at it through this lense.

[-] smeenz@lemmy.nz 1 points 2 months ago* (last edited 2 months ago)

Watch these videos that explain the answer. Basically, the problem is that you can only use this to convey random information , which would be indistinguishable from not sending anything at all.

https://youtu.be/0xI2oNEc1Sw

https://youtu.be/BLqk7uaENAY

[-] peteyestee@feddit.org 1 points 2 months ago* (last edited 2 months ago)

So you're telling me my Bitcoin is quantum now?

[-] itslilith 2 points 2 months ago

that's not how that works, quantum entanglement can not be used to transmit information and thus doesn't violate causality

[-] dharmacurious@slrpnk.net 2 points 2 months ago

Someone smarter than me, please go ahead and explain how this is going to be used to make life worse for all of us, probably in a deeply disturbing political reality that screams "the world Quinn from Sliders slid into and had to jump early because fuck this timeline"

[-] noctivius@lemm.ee 7 points 2 months ago

Monkeys learned to send signals faster. Now monkeys can bomb other monkeys they don't like faster.

[-] ploot 7 points 2 months ago* (last edited 2 months ago)

It could actually be a good thing, since it opens up the possibility of unsnoopable channels of communication, using encryption that would be disrupted by any attempt to intercept it.

[-] oyo@lemm.ee 3 points 2 months ago

Also the ability to crack any of our current encryption almost instantly...

[-] humanspiral@lemmy.ca 7 points 2 months ago

Quantum entanglement is different than quantum computing.

[-] oyo@lemm.ee 1 points 2 months ago

Not exactly; entanglement is a critical element of quantum computing for the encryption and decryption referenced.

[-] humanspiral@lemmy.ca 1 points 2 months ago

Not what I understand. The encryption referenced is about having an immutably certain shared data source from entanglement that can be used as encryption/decryption input. Quantum computing does promise to crack current encryption technology in the future.