hokhani's latest activity
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Hhokhani posted the thread I Validity of identical eigenfunction of commutating operators in Quantum Physics.I got confused about an elementary statement in quantum mechanics: As far as I know, the two commuting operators like ##\hat {\mathbf...
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Hhokhani replied to the thread I Direction of time-evolution in time reversed wave functions.Thanks, but suppose you take a movie from time ##0## to ##t##. If you run it backwards, in fact you are playing the frames back from...
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Hhokhani replied to the thread I Phase and group velocity for the wave function.You say that the contribution of the components with k far from the peak of α(k) (at ##k_0##) is negligible and the wave pocket moves...
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Hhokhani replied to the thread I Direction of time-evolution in time reversed wave functions.Thanks, it was a very good elementary source. But I didn't find there the answer to my question. let me explain clearly: In the...
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Hhokhani replied to the thread I Direction of time-evolution in time reversed wave functions.Thank you for attention to this matter. The function ##\psi_r(t)## implies time reversed wave function at ##-t##. Also, I didn't see...
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Hhokhani reacted to JimWhoKnew's post in the thread I Phase and group velocity for the wave function with
Like.
The group velocity is often motivated (and justified) by the stationary phase approach. It goes something like this: Consider a wave... -
Hhokhani posted the thread I Direction of time-evolution in time reversed wave functions in Quantum Physics.Consider the time reversal operator as ##\Theta## so that ##\psi_r(t)=\Theta \psi(t)## where ##\psi_r(t)## is time reversed of...
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Hhokhani replied to the thread I Phase and group velocity for the wave function.Thank you very much. If my post #9 is correct, then ##v_g(k)=\frac{\partial \omega}{\partial k}=\frac{\hbar k}{m}=2 v_{ph}(k)## because...
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Hhokhani reacted to div_grad's post in the thread I Phase and group velocity for the wave function with Like.
@hokhani You're wrong when you claim in post #7 above that the group velocity is the average phase velocity. To resolve this, let us go...
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Hhokhani replied to the thread I Phase and group velocity for the wave function.The expansion is in the basis of Right, but the expansion is in the basis of free particles and so the time evolution is under free...
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Hhokhani replied to the thread I Phase and group velocity for the wave function.@div_grad: If I understood correctly, your argument says the group velocity of a wave pocket around ##k_0## (with ##k_0## at centre) is...
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Hhokhani reacted to div_grad's post in the thread I Phase and group velocity for the wave function with Like.
@hokhani Note that this issue of group velocity of a wave packet can be equally well formulated in, e.g., classical electromagnetism...
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Hhokhani replied to the thread I Phase and group velocity for the wave function.Yes, suppose that the wave is also propagating in the free particle Hamiltonian. Then, we have ##\psi(x,t)=\sum_k \alpha_k...
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Hhokhani replied to the thread I Phase and group velocity for the wave function.Thank you for modifying the question. I would like to know if we have a typical wave function, for example ##\psi(x)=exp(-\alpha x^2)##...
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Hhokhani reacted to olivermsun's post in the thread I Phase and group velocity for the wave function with Like.
Maybe start with this question: if you write ##\omega## as a function of ##k##, what does ##\omega(k)## represent? (Think about light in...