Recent content by macduy

I think we are getting confused now. Let's keep it simple. I have a single qubit system, with a basis. I prepare a qubit which is a superposition of the basis vectors. Then I measure it in the basis. Do I get a mixed state?

There's been a misunderstanding, |+><+|+|-><-| is not a state (it can be but it isn't here), it's a measurement, with which I'm measuring the qubit. It's not the same thing because if I measure the qubit |+> with it, then I get |+> 100 percent of the time as the outcome, which clearly is not...

Right, |S_x;+> would still be a pure state. However, let's say now that you measure it using (|+><+| + |-><-|). Then, the state will either become |+> or |->, with equal probabilities. Either way, the state will still be pure *but* because we have no knowledge which one it would be, we refer to...

Hi zygi, thanks for the answer. It's not quite what I was asking though I admit my phrasing isn't clear. Let me try ask a different question: Would measuring a state in equal superposition of two quantum states |0> and |1> give me the totally mixed state?

Hi, I would like to ask some questions in regards to preparing mixed states. Assuming I am allowed to prepary any pure quantum state, perform measurements and apply unitaries, I am asked to prepare a single qubit quantum state of maximum entropy. As I understand, a 1-qubit quantum...