1. The problem statement, all variables and given/known data So say I have a 1 qubit normalised state |ψ> = 1/√N(c1|z+> - c2|z->) and I make the measurement Sx and the measurement yields +hbar/2 as |x+> is a superposition of both z+ & z- basis eigenstates does the collapsed state end up the same as the original state? Or would I need to take the inner product of <x+|ψ> to find the collapsed state? Confused. . 2. Relevant equations 3. The attempt at a solution Its not really a direct homework problem its more of an understanding thing so my attempt is above in 1.