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Long Distance "Teleportation" of Quantum Bits

03/10/2021 6:42 AM

A new distance record of Q-Bits has been achieved,opening the door just a crack for a new advanced network.

Check out this link:

https://futurism.com/researchers-achieve-first-sustained-long-distance-quantum-teleportation

The limit I see to this is the need to have a continuous fiber from end-to-end,but in metropolitan areas,this could be a real game changer.

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#1

Re: Long Distance "Teleportation" of Quantum Bits

03/14/2021 8:09 PM

"Teleportation" seems to imply that something disappears at one place (maybe with sparkles in the air ) and reappears somewhere else. Quantum teleportation doesn't work like that.

Here is the clearest explanation that I've found about how quantum teleportation works.

"How to teleport

Quantum particles can become entangled naturally, for example if a particle decays into two less massive or less energetic particles, or entanglement can be created purposefully, for example by forcing photons to mix together under specific conditions.

In contrast, quantum teleportation using entangled particles has to be set up in a particular way. The approach involves techniques from quantum information theory and quantum computing, with quantum versions of traditional computing features like “bits” and “logic operations”.

In the simplest case, there are three quantum states involved in the teleportation, generally described as “qubits”—the quantum equivalent of computer bits encoding information—or referred to as quantum particles. Two of the three qubits are in an entangled state, and the third is in an independent quantum state which contains the information to be teleported. The entangled qubits are separated, with one at the “receiving end” and the other, together with the independent qubit, at the “sending end.”

The sender performs a joint measurement on both the entangled qubit and the independent qubit, in a way that doesn’t directly measure the specific state that the entangled qubit is in. In fact, another quirk of quantum physics is that it’s actually not possible to observe the state of a single qubit, which is why the sender needs another qubit to measure alongside the entangled qubit.

The joint measurement of the two qubits serves two purposes: it changes the state of the entangled qubit at the receiving end so that it is in one of four possible states, and it gives the sender two binary values (1 or 0) which are effectively instructions for the receiver. The sender now has to get those two values to the receiver using normal, non-quantum communication methods, like sending a message over the internet. The receiver follows the instructions: for each value, a “1” tells the receiver to perform a specific measurement on the receiving qubit, and a “0” tells them not to do that measurement. As a result of those measurements (or no measurements at all if both values are “0”), the receiving qubit is in the state that the sending (non-entangled) qubit was originally in.

The particles have not moved around in space, but the information represented by the independent qubit has been teleported to the receiver.

Daniel Llewellyn, a quantum researcher at the University of Bristol, UK, said this is the biggest misconception about quantum teleportation.

“Quantum teleportation is not about the transfer of physical matter between systems, it is about the remote transfer of quantum states between systems,” he said."

https://www.vice.com/en/article/pkepxm/what-is-quantum-teleportation

https://en.wikipedia.org/wiki/Quantum_teleportation

Although the entanglement is seemingly instantaneous, to recreate the state of the photon requires that the results obtained at point A be communicated via a speed of light (or slower) channel to point B before the state of the photon can be reproduced.

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#2
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Re: Long Distance "Teleportation" of Quantum Bits

03/14/2021 10:47 PM

In my (very classical) opinion, the term "teleportation" specifically implies moving some physical object from point A to point B, so to me, "Quantum teleportation", as discussed here, is a very misleading misnomer.

I can (sort of) conceive of quantum information transfer between two directly connected points, but it's a very large jump from that to anything resembling even a very small network.

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