I'd like to axe what I believe is a common misconception about quantum computers: "The reason Quantum computers are more powerfull than classical computer is NOT because they perform operations on 2 to the n different data points at the same time."
They can't do this because in the end the superposition of states must collapse to a single state when measured. This collapse occurs randomly, meaning that its almost as though each of the n original q-bits were randomly chosen to be either 0 or 1. While this would allow for true random algorithms, it would be of no practical use in terms of computing efficiency.
From what I've been able to learn, the key to quantum computing is INTERFERENCE not SUPERPOSITION. It is true that quantum computers use superposition in order to create interference, however laymens like me reallly get the wrong impression when focus is put on the superpostion of states part which seem to imply that quantum computers are much more powerfull than they really are.
Hence, it seems that interference allows for making operations in constant time that are impossible to do with a classical computer. Think of it as being able to use the interference gate on top of the traditional AND and OR gates. Diagram B in parent's linked article shows how this interference might work. The actual workings of this "interference gate" and how we can actually use it to improve performance is highly non-trivial. In fact its probably so complex that the real PQs can't put it into laymens terms. So they just give up and say: "look with 500 q-bits we have a superposition of 2^500 states. And thats a REALLY, REALLY big number! So obviously quantum computers are faster!"
Anyway, that's my best estimate of what's really going on given my current understanding of things.
The laymen's version of this post: "no, you can't download all porn movies at the same time by using 10 billion q-bits 'cause that'd be just too good to be true and would unravel the fabric of the universe"
Interesting how pdf was chosen as the file format to distribute the document. In my opinion, that was the best example of horseless carriage thinking in the entire document.
Slashdot Mirror
Disclaimer: IANAQP
I'd like to axe what I believe is a common misconception about quantum computers:
"The reason Quantum computers are more powerfull than classical computer is NOT because they perform operations on 2 to the n different data points at the same time."
They can't do this because in the end the superposition of states must collapse to a single state when measured. This collapse occurs randomly, meaning that its almost as though each of the n original q-bits were randomly chosen to be either 0 or 1. While this would allow for true random algorithms, it would be of no practical use in terms of computing efficiency.
From what I've been able to learn, the key to quantum computing is INTERFERENCE not SUPERPOSITION. It is true that quantum computers use superposition in order to create interference, however laymens like me reallly get the wrong impression when focus is put on the superpostion of states part which seem to imply that quantum computers are much more powerfull than they really are.
Hence, it seems that interference allows for making operations in constant time that are impossible to do with a classical computer. Think of it as being able to use the interference gate on top of the traditional AND and OR gates. Diagram B in parent's linked article shows how this interference might work. The actual workings of this "interference gate" and how we can actually use it to improve performance is highly non-trivial.
In fact its probably so complex that the real PQs can't put it into laymens terms. So they just give up and say: "look with 500 q-bits we have a superposition of 2^500 states. And thats a REALLY, REALLY big number! So obviously quantum computers are faster!"
Anyway, that's my best estimate of what's really going on given my current understanding of things.
The laymen's version of this post: "no, you can't download all porn movies at the same time by using 10 billion q-bits 'cause that'd be just too good to be true and would unravel the fabric of the universe"
Interesting how pdf was chosen as the file format to distribute the document.
In my opinion, that was the best example of horseless carriage thinking in the entire document.