# Some quantum misconception

1. Nov 21, 2012

### M. next

Is this equation only for continuous spectra?
they have used it to find the eigenvalues of energy spectra case of infinite potential well and we know that this case means discrete spectra..
can this equation in the attachment be used like in this case???

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2. Nov 21, 2012

### cattlecattle

Sigma should be used in place of integral sign for discrete spectra.

3. Nov 22, 2012

### M. next

but check the attachment, he used it, check the question, and the solution.. i didnt include all questionsbut thr solution is an answer for the question.. find A so that psi(x,0) is normalized

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• ###### 2012-11-22 09.13.34.jpg
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4. Nov 22, 2012

### soothsayer

Even if spectra are discrete, there's nothing wrong with integrating over the whole wavefunction in order to normalize, or find probabilities. The discreteness factors in when you realize that our expressions for $\psi$ and energy take on discrete values, usually separated by some integer factor n, but the wavefunctions themselves are continuous, so we can integrate over them.

5. Nov 22, 2012