Binary Shannon entropy H₂(p) = −p·log(p) − (1−p)·log(1−p); dephasing-channel capacity Q = 1 − H₂(p)

Binary entropy and dephasing-channel quantum capacity. From framework F7, the von Neumann entropy on a two-level mixed state with eigenvalues {p, 1−p} equals the binary Shannon entropy H₂(p) = −p·log(p) − (1−p)·log(1−p). For the qubit…