An excellent explanation in how quantum computing works
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Not terribly accurate, even if it seems visually appealing.
The truth is the quantum computer calculates a superposition of all possible answers to a problem, which you must collapse to a single, real value in order to read it out. If you ask exactly the right question, you can make the most probable answer from your algorithm the correct answer to your question.
Not every problem can be suitably reframed for enhanced calculation on a quantum computer.
A simple example is Shor's algorithm for factoring large numbers, which works by finding a period in a pattern of data. The quantum computer will calculate a superposition of the period, 2x the period, 3x the period, etc. (Think of a vibrating string that can vibrate at a frequency plus all possible harmonics of that frequency simultaneously)
But when you try to read out the answer, it will only report one of them. However, the highest probability is that it will collapse to and report just 1x the period when reading out the answer. So if you run the program multiple times, whatever answer appears most often is the period you are trying to find.
Shor's algorithm is useful to factor large numbers or find the elliptic log, which is why all of our current public key cryptography is rendered useless when big enough quantum computers become commercially available.
So nothing is really perfect in an unperfect world, we can only improve on it.
Yeah, that is going to be a serious problem for asymmetric public/private key encryption (RSA, etc.)
We are going to have to find another solution.