Eigenphase
= Eigenphase
{title2=$\theta\pmod1$}
An eigenphase of a <unitary operator> is a real number $\theta$ modulo one specifying an <eigenvalue> $e^{2\pi i\theta}$. Every unitary eigenvalue has <modulus> one. <Quantum phase estimation> records the eigenphase corresponding to an input <eigenvector>; a superposition retains the corresponding labels coherently before measurement.