For the free particle the solution to the SE are eigenstates of the momentum.(adsbygoogle = window.adsbygoogle || []).push({});

You get something like:

ψ = Aexp(ik(x-vt)) + Bexp(-ik(x+vt)) , where k is a constant

And my book then says that first term represents a wave travelling to the right and the second a wave travelling to the left. But I have a problem with the second statement, because doesn't the minus sign on the second term, that is the minus sign in front of (x+vt), change anything. Certainly the waves are not identical in shap because of that minus sign?

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# Eigenstates of the momentum operator

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