Operators have time dependence. |α,t0;t⟩H=|α,t0⟩. AH(0)=AS(0). AH(t)=U^†(t,t0)AS(0)U^(t,t0).
⟨b|A′|a⟩=⟨b|U†AU|a⟩.
iℏ∂∂t(U^)|Ψ⟩=H^U^|Ψ⟩⇒−iℏ∂∂t(U^†)=U^†H^
ddtAH=∂∂t(U^†)ASU^+U^†∂∂t(AS)U^+U^†AS∂∂t(U^)=∂∂t(U^†)ASU^+U^†AS∂∂t(U^)=1iℏ(−H^U^†ASU^+U^†ASU^H^)=−iℏ[AH,H] (Note that the time evolution operator uses the Hamiltonian as its generator, i.e. it is a function of the Hamiltonian and because any function of an operator commutes with the operator).
ddtAH=−iℏ[AH,H].
Author: Christian Cunningham
Created: 2024-05-30 Thu 21:19
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