Hello guys, 1. The problem statement, all variables and given/known data the problem goes as follows: "Which measurement should you do on a statistical ensemble of qubits in order to distinguish between the pure state |Ψ>= cos(θ)|0> + sin(θ)|1> and the mixed state ρ=cos^2(θ)|0><0| + sin^2(θ)|1><1| " 2. Relevant equations I am not even sure I grasp the atmosphere of the problem... 3. The attempt at a solution I understand the basic differences between superposition and mixture, but still I can't work a solution inside my head. So... any help would be much appreciated. Thank you in advance!