There exists a physical operator F whose eigenvalues are a or b. Normalised eigenstate is A and B for each. The average value of F was f when measured from a certain system. Describe the eigenstate of this system in terms of A and B.


closed as off-topic by Emilio Pisanty, ZeroTheHero, ACuriousMind Jul 29 '17 at 10:52

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Homework-like questions should ask about a specific physics concept and show some effort to work through the problem. We want our questions to be useful to the broader community, and to future users. See our meta site for more guidance on how to edit your question to make it better" – Emilio Pisanty, ZeroTheHero, ACuriousMind
If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ Hi and welcome to physics.SE! Please note that homework-like questions and check-my-work questions are generally considered off-topic here. We intend our questions to be potentially useful to a broader set of users than just the one asking, and prefer conceptual questions over those just asking for a specific computation. $\endgroup$ – ACuriousMind Jul 29 '17 at 10:52

I am just a physics student so I could be wrong, just trying to help you: using Dirac bracket notation you can write your system state $ |psi \rangle $ as a superposition of the eigenstates, with complex coeficients α and β, $$| \psi \rangle =\alpha |a\rangle + \beta |b\rangle, $$ and you can write the expected value as: $$\langle \psi | \hat F | \psi \rangle =f.$$ Knowing that $\hat F |a\rangle =a|a\rangle,\ \hat F |b\rangle =b|b\rangle$ I think that you should be able to finish.


Not the answer you're looking for? Browse other questions tagged or ask your own question.