In class we went through the derivation of the energy of a perturbed system, ive dug my old notes out and found a bra ket derivation of the same thing, theres just one step that doesnt look right and was wondering if someone could tell me if its a misprint or actually correct (and why).(adsbygoogle = window.adsbygoogle || []).push({});

[tex]E_{n}^{1}\left \langle \Psi _{k}^{0} |\Psi _{n}^{0} \right \rangle = E_{n}^{0}\delta _{kn}[/tex]

im assuming its a misprint, but then its presented in the final solution.i.e. you need everything in terms of [tex]E_{n}^{0}[/tex] for it to work.

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# Quick question regarding a step in a bra ket derivation

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