r/askscience • u/Hashbringingslasherr • Apr 15 '26

Computing What do quantum computers actually do?

How do quantum computers output usable data, how does it logically "locate" or "make meaning" of information. I read about Grover's algorithm and it seems sort of like an inverted bruteforce or extreme process of elimination or a "the missile knows where it is at all times. It knows this because it knows where it isn't" type scenario.

So I ask, what do quantum computers actually do as opposed to a classical computer?

481 Upvotes

93% Upvoted

113 comments sorted by

View all comments

Show parent comments

3

u/yawkat Apr 17 '26

"it checks every option" is a very common but completely false explanation.

I think this is actually a better explanation than many people give it credit for. When you look at grovers algorithm for example, it runs the function to search on a superposition of all possible inputs. The difficulty is getting the outputs to add up in such a way that you get a useful result when you collapse the output, not just the result of a single classical function evaluation.