Implications of communication through quantum entanglement

In summary: The paper provides a detailed description of how an experimental quantum radar might be able to detect and track targets without revealing their location.
  • #1
GTOM
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I am building an SF universe. While it is very similar to ours, but casual FTL exists. I don't think Lorentz transformations shouldn't work at all, but rather extra dimensions can somehow circumvent them. One kind of FTL is direct communication through entanglement.

There can be two version of it. (Actually i plan two story arc. In the first, humans find much more advanced alien tech, that allows a rapid technological jump, that turns the fate of the whole solar system.)
In the first version, measurement breaks entanglement, but its possible to extract useful data without directly compare measurements on both sides. In the second, it is possible to communicate without depleting the set of entangled pairs, but it still has constraints like a hyperspace jump, or somekind of enemy countermeasure can break entanglement, so it isn't a good idea to rely on FTL droning (which is pretty much fun killer).

So what could be the implications of the first version of entaglement based communication?

Due to its serious limits, common people on Earth couldn't just chit-chat with people on Mars without delay times.
I think the use of it has to be restricted to very urgent, important messages. They couldn't possibly tap into it unless they directly hack the endpoints.
It can be also used to swap encryption keys. I guess even though quantum computers could crack present day encryptions fast, but they still don't have infinite calculating power, so its possible to swap so large encryption keys, that even traditional radio communication can be safe.

An interesting application would be quantum radar, send out entangled photons, keep their pairs in the radar, and notice they change, when the emitted photons hit something.
https://www.popularmechanics.com/military/a28818232/quantum-radar/(I am not sure how it actually works, theese kind of articles tend to extrapolate things, i don't intend to say it relies on FTL signaling, still, it inspired me. And in my universe, a quantum radar could really rely on FTL stuff.)

Would that mean that stealth aircraft would lose its significance? (Although simply detect something isn't the same as getting exact coordinates, or guide a missile to it.)
In space we can already say no stealth unless something can mask all heat emission, which is practically impossible with ignited rockets. That hypothetical quantum radar is still an active sensor, so it isn't that hard to locate and destroy them with directed energy (laser, EMP) weapons. That quantum radar don't ignore background, so celestial bodies still offer the possibility of stealth, hide.

What can be other issues, that i missed?
 
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  • #2
Isnt any SF literature that could help? I opened the topic, since i haven't been able to imagine something like that quantum radar.
 
  • #3
GTOM said:
Isnt any SF literature that could help? I opened the topic, since i haven't been able to imagine something like that quantum radar.

Check out a recent paper from the Institute of Science and Technology Austria by S. Barzanjeh, S. Pirandola, D. Vitali, and J. M. Fink that describes an experimental quantum radar approach.
 
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  • #4
GTOM said:
I am building an SF universe. While it is very similar to ours, but casual FTL exists. I don't think Lorentz transformations shouldn't work at all, but rather extra dimensions can somehow circumvent them. One kind of FTL is direct communication through entanglement.
...
So what could be the implications of the first version of entaglement based communication?
...
What can be other issues, that i missed?
Sorry to be a party-pooper but communication by entanglement is impossible. There is a theorem which proves it, called, would you believe?, the No-Communication Theorem. If I've understood you correctly, you are happy to introduce "extra dimensions" to get your FTL, so you don't need to use anything quantum anyway. You can use the full panoply of real quantum phenomena especially those with application in communications. They are perfectly real, but they stick to the speed limit. Of course it's a local speed limit, not an end-to-end one, so you can use your FTL mechanism for a shortcut. Just keep the FTL and the quantum stuff separate.
 

FAQ: Implications of communication through quantum entanglement

What is quantum entanglement?

Quantum entanglement is a physical phenomenon that occurs when pairs or groups of particles are generated, interact, or share spatial proximity in ways such that the quantum state of each particle cannot be described independently of the state of the others, even when the particles are separated by a large distance. The state of one entangled particle can instantaneously affect the state of the other, no matter the distance between them, a phenomenon Albert Einstein famously referred to as "spooky action at a distance".

How could quantum entanglement be used for communication?

The theoretical basis for quantum communication through entanglement involves using the entangled states of particles to transmit information. This process, often discussed in terms of quantum teleportation, would allow the state of a particle (e.g., a photon) to be transferred from one location to another, without having to move the particle itself. This is done by entangling two particles, sending one to a new location, and then manipulating the state of the particle that remained. Changes to the state of the remaining particle would instantaneously influence the state of the distant particle, thus conveying information instantaneously.

Does quantum entanglement allow for faster-than-light communication?

No, quantum entanglement does not allow for faster-than-light communication in the way we traditionally understand sending information. While the entanglement phenomenon itself is instantaneous, using it to transmit usable, classical information still requires classical communication channels, which are limited by the speed of light. The no-communication theorem in quantum mechanics states that quantum entanglement cannot be used to transmit information at speeds exceeding that of light.

What are the implications of quantum entanglement for encryption and security?

Quantum entanglement holds significant implications for future technologies in encryption and security, notably through the development of quantum key distribution (QKD). QKD uses quantum entanglement to produce a shared, random secret key known only to the sender and the receiver. The security of this method lies in the principles of quantum mechanics, as any attempt to eavesdrop on the key would inevitably alter its state, thus revealing the presence of the intruder. This could potentially lead to systems that are virtually immune to hacking.

What are the current challenges in utilizing quantum entanglement for practical communication?

There are several technical and fundamental challenges in utilizing quantum entanglement for practical communication. These include creating and maintaining entangled states over long distances without decoherence, which is the loss of quantum coherence. In practice, maintaining the entanglement of particles as they are transported over large distances or through fiber optic cables is extremely challenging and prone to interference. Additionally, the technology required to manipulate and measure entangled particles with high precision is still in its developmental stages. These challenges must be addressed to harness the full potential of quantum entanglement in practical applications like quantum computing and secure communications.

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