2

So basically you want to distinguish the state $| + \rangle \langle + | $ from the dephased state $\frac{1}{2}(| 0 \rangle \langle 0 | + | 1 \rangle \langle 1 | ) = \frac{\mathbb{I}}{2}$. Here's a simple experiment: apply a Hadamard to both states and then measure in the $\sigma_{z}$ basis. For the ``true superposition'', this transforms it into the state ...


Only top voted, non community-wiki answers of a minimum length are eligible