5 days ago • 92%

First demonstration of quantum teleportation over busy Internet cables

news.northwestern.edu First demonstration of quantum teleportation over busy Internet cables

Northwestern University engineers are the first to successfully demonstrate quantum teleportation over a fiber optic cable already carrying Internet traffic.

Advance opens door for secure quantum applications without specialized infrastructure

35 comments

#Hey Kids! Guess which word is getting shoehorned into EVERY technology discussion in 2025 until it becomes meaningless?

41
- AI?
  
  5
Only limited by the speed of light,

What exactly do you think the normal ip data is limited by on the same optical cable?

I thought we were talking about quantum entaglement and spooky action at a distance, which is famously not limited by the speed of light?

Am I missing something obvious?

33
- Yes, quantum entanglement occurs without the speed of light, but we famously cannot interpret information from it faster than the speed of light - it isn't FTL communication.
  
  25
  
  famous potatoes
  
  6
The article starts by doing the "quantum" thing that really irks me, where they use confusing terminology to make it sound like "FTL communication" without actually saying it. This is garbage that doesn't actually matter to the article.

Basically, they found a way to send quantum entangled photons (which exist in a very delicate unobserved state) through existing fiber optic infrastructure without interfering with the standard internet information already travelling through the fiber. A lot of the difficulty with this is due to signal noise that needs to be filtered out. This will be useful communicating quantum measurements over long distances.

64
- It should be a legal requirement to link the actual research paper at the top of science articles
  
  12
  
  I've seen a lot of articles that were like "scientists do this!!" And never link to the actual study (not including this article)
  
  What happened to citing your sources?
  
  3
  
  2nd paragraph wasn't good enough, huh?
  
  3
- "Only limited by the speed of light..."
  
  16
  
  They then go on to describe what sounds like
  
  transmitting a single specific photon through ‘the internet’, implying start-to-finish with routing (not possible without special infrastructure)
  
  Use that photon to then send information instantly by manipulating its entangled sibling (also not possible)
  
  So yeah this article is a crock of shit.
  
  9
- The article starts by doing the "quantum" thing that really irks me
  
  Basically, they found a way to send quantum entangled photons
  
  4
This is a cool progress forward.

TLDR; Researchers used a 30km optical fiber. They found a wavelength that was off-to-the-side that would mean the quantum entangled photons could ride in the same fiber without interfering (or being interfered with) the classical fiber optic communications. One current shortcoming for scaling this up is that the quantum photons would not survive optical repeaters commonly used for extremely long distant fiber runs. That doesn't take away from the success of their research, just puts it in perspective for the next researchers to tackle at some point in the future.

37
- Is the reason (Im assuming you ment) it can't survive a repeater survive a repeater because it collects and recreates the particle? These cables are ment for logical data transport.
  
  13
  
  Yes. Keep in mind nothing in the article talks about the fiber repeater. That is my addition with some knowledge of telecommunications infrastructure. Because fiber optic cable isn't perfect, there is light loss over distance. Different grades of fiber have different levels of loss across distance. An example of high end fiber would be ZBLAN. There is experimental level manufacturing (successful in small quantities already) of producing ZBLAN fiber in space to improve the fiber quality, but that makes it much more expensive. Once the limits of the fiber are reached a telecommunications provider can place a fiber repeater to double the length by intercepting the light (signal) and reproducing it (blinking new laser light) into the next segment of fiber.
  
  However, these repeaters create NEW light, and that would mean the quantum information is not carried over in present day fiber repeaters. Even measuring the entangled photon to recreate it would break the quantum state of the entangled photon at the source, so current means can't be used as a repeater for quantum data.
  
  11
So they've shown they can send light over a cable designed to transfer light.

The impressive thing is of course managing to get one specific photon to one specific location. Still, what benefits does that have over the standard encoding?

I guess this technique might have a lower error rate and higher distance, because it's binary by nature with no quantization needed. But you don't need the quantum entanglement part at all for this.

Edit: Reading is hard! This is indeed exciting for security. I wonder how it fairs against a very powerful MitM though.

8
- It's physically impossible to intercept an entangled photon without disrupting the entanglement. The act of observing the photon collapses the quantum uncertainty of it's state, so even the most sophisticated MitM attempt is going to immediately break the link.
  
  4
  
  But can you detect the link being broken by someone other than your intended communication partner?
  
  If A sends a particle to B, couldn't M intercept A's particle and send a different particle to B? Kind of like intercepting Diffie Hellman. A and B will both share some information with M, but not with each other.
  
  3
If I understand it right, this could enable real time connectivity between client and server.

-2
- Nope, quantum entanglement can't enable FTL communication. "Real time" still involves lightspeed lag.
  
  What it does is allows random bits of information to be transmitted in an entangled state. You send an entangled pair of photons, and find out afterwards who got a 1 or a 0 when the photons are observed at either end. They call it 'quantum teleportation' because both ends know what the other got, and the information about who got what can't be intercepted without disrupting the enganglement.
  
  Once they can figure out how to preserve that uncertainty through repeaters, switches, and routers, then we can have a quantum internet that uses encryption based on shared quantum random numbers. It's likely to be necessary soon since quantum computers might only be a few years from breaking current common encryption techniques.
  
  30
  
  I also want to clarify, we can create asymmetrical encryption algorithms that are quantum resistant but not quantum themselves
  
  Quantum encryption probably won't be in mass use anytime soon, but for extra sensitive applications
  
  2
  
  Thank you for your explanation.
  
  5
  
  Yup, definitely. Took the words right out of my mouth.
  
  0
not sure why I read this

-6
- Are you not sure because you don't understand the subject matter or don't care about it? The first is easy to fix it you'd like. The second would have me just as curious as you are.
  
  6
  
  the first, I understood nothing but still read it entirely hoping to make some sense of it 😅
  
  1
- Why not?
  
  3
- i didnt
  
  -1

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