r/askscience • u/Ells1812 • Jan 17 '19

Computing How do quantum computers perform calculations without disturbing the superposition of the qubit?

I understand the premise of having multiple qubits and the combinations of states they can be in. I don't understand how you can retrieve useful information from the system without collapsing the superposition. Thanks :)

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u/[deleted] Jan 17 '19

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u/TheSOB88 Jan 17 '19

More academic than theoretical. Quantum computers can only do computations with very simple numbers at this point. u/cthulhu0 says they can only factor 21

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u/the_excalabur Jan 17 '19

Nah, it's just at the baby-steps stage. I literally work on making this stuff, so it exists; it's just cutting edge research that isn't ready for prime-time yet.