Entangled photons are an ideal choice for large-scale networks employing quantum encryption or similar, as photons can use fiber-optical cables to transmit them. One issue with using existing commercial fiber-optic lines for this purpose is that these have imperfections which can disrupt photon entanglement. This can be worked around by delaying one member of the pair slightly, but this makes using the pairs harder. Instead, a team at New York-based startup Qunnect used polarization entanglement to successfully transmit and maintain thousands of photons over the course of weeks through a section of existing commercial fiber, as detailed in the recently published paper by [Alexander N. Craddock] et al. in PRX Quantum (with accompanying press release).
The entangled photons were created via spontaneous four-wave mixing in a warm rubidium vapor. This creates a photon with a wavelength of 795 nm and one with 1324 nm. The latter of which is compatible with the fiber network and is thus transmitted over the 34 kilometers. To measure the shift in polarization of the transmitted photos, non-entangled photons with a known polarization were transmitted along with the entangled ones. This then allowed for polarization compensation for the entangled photos by measuring the shift on the single photons. Overall, the team reported an uptime of nearly 100% with about 20,000 entangled photons transmitted per second.
As a proof of concept it shows that existing fiber-optical lines could in the future conceivably be used for quantum computing and encryption without upgrades.
The kind of entanglement guys would be comfortable with.
As long as it’s not imperial
Well that’s the real trick isn’t it?
Ok, but how is it better than HTTPS?
As I understand it, it’s at least 100% more quantum than HTTPS.
That’s a lotta quantum!
It is not a replacement for HTTPS. HTTPS is at the application layer (the highest layer in the network stack). This is at the foundation of the stack, aka the physical layer. Both could/would be used simultaneously. I believe the benefit of transmission using entangled photons is it allows detection of interception as a retransmission would not possess the entangled properties of the original transmission.
“uptime of nearly 100%” means almost nothing. Both of 90% and 99.9999% can be considered “nearly 100%”, but whatever it is you are doing, the difficulty increases steeply with the number of “nines”.
No, this isn’t reliability, it’s uptime. The article gives the exact number (99.84%) – the reason for reporting it is to demonstrate how much time the compensation mechanism takes (as opposed to other work which required significant time with either manual or automatic optimization).
So the 0.16% drop is coming from the overhead of the compensation. Little bit weird of a way to describe it.
So Heisenberg Compensators are real now?!? There’s a very stoic Irishman who’s extremely happy somewhere right now!
His name was “Scotty”…
I’m going to put my quantum harmonizer in your photonic resonation chamber!