Postulate 2: operation Evolution: The evolution of a closed quantum system is described by a unitary transformation That is, if a system is in state 11 at time ti and in state l 2 at time t2 then there is a unitary transformation U s t ly2)=U/y1) Unitary transformation Ut=u-1 Recall: Ut=(U)*, transpose complex conjugate You can think of it as a rotation operationPostulate 2: operation • Evolution: The evolution of a closed quantum system is described by a unitary transformation. • That is, if a system is in state 𝜓1 at time 𝑡1, and in state 𝜓2 at time 𝑡2, then there is a unitary transformation 𝑈 s.t. 𝜓2 = 𝑈 𝜓1 . • Unitary transformation: 𝑈 † = 𝑈 −1 – Recall: 𝑈 † = 𝑈 𝑇 ∗ , transpose + complex conjugate – You can think of it as a rotation operation