Theorem: chi = log 2 for ensemble (1/2, |0><0|), (1/2, |1><1|) (orthogonal basis)

Theorem (Holevo-orthogonal-basis canonical): for the maximally distinguishable ensemble {(1/2, |0><0|), (1/2, |1><1|)}, rho-bar = (|0><0| + |1><1|)/2 = I/2. Each pure-state component has S(rho_i) = 0; S(rho-bar) = -tr((I/2) log(I/2)) = log…