ρ := ∑ n p n | n ⟩ ⟨ n | {\displaystyle \rho :=\sum \limits _{n}{{p}_{n}}\left|n\right\rangle \left\langle n\right|}
EIGENSCHAFTEN Normierung
Tr ( ρ ) = 1 {\displaystyle \operatorname {Tr} \left(\rho \right)=1}
Hermitizität
ρ = ρ † {\displaystyle \rho ={{\rho }^{\dagger }}}
Positivität
⟨ ψ | ρ | ψ ⟩ ≥ 0 ∀ ψ :⇔ ρ ≥ 0 {\displaystyle \left\langle \psi \left|\rho \right|\psi \right\rangle \geq 0\,\,\forall \psi :\Leftrightarrow \rho \geq 0}