Comment by rstuart4133

Quoting from TFA:

> the normal mathematical description of the state of n qubits involves 2n variables. For example, for 4 qubits, there are 16 variables: v[0000], v[0001], v[0010], and so on through v[1111]. ... The variables always have these squares adding up to 1, so the total probability is 1 as you'd expect.

^blink^

Why did I not know this? I've read many explanations of quantum mechanics, qubits, entanglement and I've never twigged to this drop dead simple model of what is going on. It gets better. His linked description of how a quantum works [0] is so simple a 5 year could understand it.

But it raises so many questions. A quantum computer is entangled group of qubits, right? So does that mean it gets it's speed because a time it takes gate to operate on N qubits doesn't depend on N? Is that somehow related to "spooky action at a distance" - meaning it doesn't matter how much distance separates two entangled particles, they instantaneously collapse to state consistent with the laws of the universe? Probably not, because that would make faster than light information exchange possible. Just separate break an entangled group of qubits into two, separate them, then push them though a few gates to put them in a state that favours one outcome over the other.

So one puzzle solved, but it just reveals how much more I don't know.