10:35 AM
@Vogel612 In this case though, I suppose you could say that, when f(x) = 1, it does a bit flip, but this bit flip is a basis-dependent operation, so when you apply it to |->, what you get is -|-> - but then if you have some state |a->, you get -|a->, so it's acting on 'both', if that makes sense?
If the system isn't entangled, this just gives a global phase, which you can't measure
But if the system is entangled, you're operating on a specific state, less so a specific register
I mean, there's this whole thing about how oracles abstract away a lot (often too much) detail, so I wouldn't worry too much about this - the oracle is physically acting on both registers at once, so any operation it does can change either one of the registers, or both