Eigenstate Eigenstates are eigenvectors of Operator. A^∣ψ⟩=λ∣ψ⟩\begin{gather*} \hat{A}\left\lvert \psi \right\rangle=\lambda\left\lvert \psi \right\rangle \end{gather*}A^∣ψ⟩=λ∣ψ⟩