Apologies in advance if my question seems misinformed. I am a software developer, and neither quantum mechanics nor physics are my specialties.
The exact physical mechanism at work within the quantum computer is somewhat theoretically complex and intuitively disturbing. Generally, it is explained in terms of the multi-world interpretation of quantum physics, wherein the computer performs calculations not only in our universe but also in other universes simultaneously, while the various qubits are in a state of quantum decoherence.
The amazing power of the quantum computer stems from the fact that if you have a collection of qubits – a register – in which each qubit is in an indeterminate state, then the register effectively represents all possible numbers at once. If you then perform a single computation on the register, the computation works on every possible number, simultaneously. David Deutsch explains the process using the idea of parallel universes – although we see only the single register in our universe, it actually exists in many other universes too, one for each of its possible states. By operating on the register in our universe, we kick off computations in all the other unseen universes, and then magically retrieve the answer.
Assuming the multiverse interpretation of quantum mechanics is correct, does this mean that a quantum computer is capable of considering all possible solutions to a problem simultaneously because it delegates the consideration of (calculations for) each possible solution to a different universe?