But a traditional repeater destroys the quantum states of the photons, such as their planes of polarisation.
Each atom could be in one of two quantum states, which served as the 1 and 0.
And all this is done without looking at the photons and destroying their quantum states at least, not until after the teleportation.
The "quantum states" of atoms, light particles known as photons, molecules and even objects big enough to be seen have been extensively studied.
Dr Shields's photon detector, however, permits cryptographers to use a phenomenon called quantum entanglement to make a repeater that does not destroy quantum states.
The experimenters discovered that adding additional laser beams to fire at the quantum fluid, they could create ever more complicated quantum states, right before their eyes.
One theory, the primary proponent of which is Luca Turin, purports that the secret lies in the ability to detect the quantum states of the odorants.
They've shown that a synthetically grown sample of herbertsmithite crystal (what you see above) behaves as a quantum spin liquid: a material where fractional quantum states produce a liquid-like flux in magnetic orientations, even if the material is solid.
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That does not matter for classical telecoms, but matters very much for quantum cryptography, which relies on the fact that no eavesdropper can intercept the message without changing those quantum states, and thus giving away the fact that he is on the line.
Since B and C have the same quantum states, that means C also has the same quantum state as A. If A and B are different, they will come out of the beam-splitter in one of three different places, depending on exactly which way they are different.
They are called quantum because it takes a packet of energy of a very specific size - a quantum - to create the states.
It was part of a thought experiment intended to illustrate the bizarre nature of the quantum world, in which particles can persist in two states at once and, as a consequence, a cat can be both dead and alive.
Quantum key distribution does this by encoding the information in the polarisation states of individual photons, the particles of light, which are sent from Alice to Bob over an optical fibre.
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It would gain enormous processing power through the ability of quantum systems (such as a collection of atoms) to be in many different states at once.
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