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”
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.
Also the ability to crack any of our current encryption almost instantly…
Quantum entanglement is different than quantum computing.
Not exactly; entanglement is a critical element of quantum computing for the encryption and decryption referenced.
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.
You sound quite miserable, maybe you should stop thinking like this
I thought the whole point of entangled communication is that you didn’t need to “send” anything. It automatically flips the entangled bit on the other end, all that “spooky action at a distance” bidness. Why do the need to “send” entangled photons?
Quantum physicist here. Your idea is effectively correct, but the issue lies in generating entanglement at a distance, which is a gargantuan task. You can’t start with two qubits (in the current discussion the photons are qubits, holders of quantum information) and simply proclaim them to be entangled over long distances (even centimeters can be considered long in the quantum realm). One of the more promising methods to achieve entanglement at a distance is to create entangled photons locally in your friendly neighborhood lab, and send them on their merry way. Photons are incredibly good at travelling far. When they have reached their destination you are free to do the next complicated part, the ‘spooky action at a distance’ as you call it ;) I just call it magic.
The two standardized method of sending photons over earthly distances is either a) via air (e.g., lasers, radiowaves or satellite communication) or b) via fibre optics. Since the fibre optics network is so developed across the globe, quantum information engineers would love to tap into that infrastructure - which is the main motivation for the work done in the main article. Here, they proved that the entanglement survives the journey through the optical cable, which was expected (but not a given) for short distances. Entanglement is sensitive business and is lost very easily. 30 km of travel through an optical cable can be considered very, very long based on these premises - but also around the upper limit of what can be achieved without significant advances of quantum repeaters which replaces the functionality of amplifiers in traditional optical fibre networks.
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.
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.
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.
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.
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.
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.
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.
