# Square of Laplace–Runge–Lenz vector in Hydrogen atom [closed]

I have a problem. I've tried this question, but I don't get the correct expression. Can someone give me some ideas? Thanks!

Consider the Hydrogen Atom Hamiltonian:
$$H = (\mathbf p^2/2 \mu)-(e^2/r)$$ Define a vector operator: $$\mathbf M = (1/2 \mu)(\mathbf p\times\mathbf L - \mathbf L\times\mathbf p)-(e^2/r)\mathbf r$$

Show that: $$\mathbf M^2 = (2H/\mu)(\mathbf L^2+ \hbar^2) + e^4$$

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## closed as too localized by David Z♦Feb 27 '12 at 1:45

This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

Welcome to Physics! This is a site for conceptual questions about physics, not general homework help. If you can edit your question to ask about the specific physics concept that is giving you trouble, I'll be happy to reopen it. See our FAQ and homework policy for more information. – David Z Feb 27 '12 at 1:46
sorry about that. I'm new to this forum. I will do that the next time. – Pishi Feb 27 '12 at 1:52
This is the quantum analog of the Lens-Thirring vector, and you should check the classical identity first. – Ron Maimon Feb 27 '12 at 4:11
Just a comment, it would help at least one future, that means present, visitor, so the reasoning is already false. :P – user74200 Nov 24 '15 at 23:05