knightly the Sneptaur

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Joined 2 years ago
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Cake day: July 5th, 2023

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  • It’s real, but the jargon is unintuitive.

    “Teleportation” in the field of quantum mechanics refers to the process by which a quantum state can be copied from one place to another.

    This process is like Shrodinger’s Cat, both alive and dead until you open the box to check. Quantum information simply does not exist until a measurement collapses it into back into classical information, so copying a quantum state literally involves teleporting the information about it from sender to receiver without allowing the box to be opened during the transition.





  • As confusing as it seems, they’re correct. A physical medium is still necessary to enable the two parties to interact with each other, but the information that travels through it doesn’t exist until it is received.

    The photons that carry the information are Shrodinger’s Cat, both alive and dead until the box is opened. It’s impossible to know one way or another without checking, so the information about the contents of the box doesn’t physically exist until then.

    This has been proven via the double-slit experiment. Shining a beam of light at a card with two slits in it causes the resulting shadow to show a diffraction pattern. This is caused by the photons interacting with themselves as they pass through both slits simultaneously. However, if you put a photon detector in front of one slit to try and measure which slit the photon passes through, the diffraction pattern dissapears because the act of measuring it collapses the quantum uncertainty and prevents the photon from passing through both slits and interacting with itself. The information about which slit the photon actually passed through simply does not exist, and can’t be measured without destroying the quantum diffraction pattern.





  • “Previous demonstrations of quantum teleportation have focused on transferring quantum states between physically separated systems,” said Dougal Main, from the Department of Physics at the University of Oxford, who led the study.

    "In our study, we use quantum teleportation to create interactions between these distant systems. By carefully tailoring these interactions, we can perform logical quantum gates – the fundamental operations of quantum computing – between qubits housed in separate quantum computers.

    “This breakthrough enables us to effectively ‘wire together’ distinct quantum processors into a single, fully-connected quantum computer.”

    To simplify, they’re not just entangling pairs of photons and sending them out to two systems, but entangling entire qubits that exist on separate systems. This allows the qubits on separate systems to interact with each other without collapsing their superposition, enabling the quantum equivalent of parallel processing.

    Rather than two identical Shrodinger’s Cats as in entangled photons, the entangled qubits act as one Shrodinger’s Cat that’s in two places simultaneously.




  • Think of it like an identical pair of Shrodinger’s Cats. You can’t know if the cat is alive or dead 'til you open the box, but because they’re identical you know that the other box will show the same result as your own.

    The lasers don’t transmit information, they transmit a quantum superposition. The act of measuring this quantum state creates information, and because the photons are entangled, this information includes what was received at both ends.

    So the photons that carry the information aren’t teleported, but the information itself is because it doesn’t exist until it is observed.


  • Correct. The speed of light is the speed limit of information in the universe.

    Entanglement is neat because it allows us to transmit a quantum superposition to two places at once.

    It’s like an identical pair of Shrodinger’s Cats. You can’t know if the cat is alive or dead until you open the box, but you do know that the other box will show the same result as yours regardless of where it ends up.

    The new thing they’ve figured out in this article is how to entangle qubits between separate quantum computers, essentially creating a single Shrodingers’ Cat that exists in two computers simultaneously which allows them to do the quantum equivalent of parallel processing.


  • Allow me to oversimplify for the sake of understanding:

    Quantum entanglement is a process where the measurable properties of two particles become linked. For example, an entangled pair of photons might share the same polarization, so that when you measure one, you’d also learn the polarization of the other without having to measure it.

    That’s quantum teleportation in a nutshell, send out an entangled pair of photons and each of the recipients will know what the other got without having to ask. They call it ‘teleportation’ because the information about who got what doesn’t exist until the photons are measured, and can’t be intercepted in transit because the act of measuring an entangled particle breaks the entanglement. You physically cannot tap or eavesdrop on a QE link. To do so successfully you would have to be able to capture a photon on the line and transmit an identical copy in its place simultaneously, but the act of measuring takes a non-zero amount of time and even a nanosecond of delay would be obvious to the intended recipient.

    Entangled photons are like a pair of identical Shrodinger’s Cats, you can’t know if they are alive or dead until you open the box, but you do know that both boxes will show the same result regardless of where they end up.

    What’s new in this article is that they’ve managed to entangle entire qubits between separate computers, like a single Shrodinger’s Cat that exists in two places at once. They’ll be able to use this technique to develop the quantum equivalent of parallel processing.