laser1
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- Homework Statement
- A particle is described by the equation Psi, which is ##5x^2## if ##-L\leq x \leq L##. The normalisation constant is ##A=\sqrt {1/10L^5}##. Calculate ##<p^2>##.
- Relevant Equations
- N/A
When I do this I keep getting a negative answer. Why?
My workings: ##<O> = \int \psi* O \psi dx## in general. And ##\hat{p}=\frac{\hbar}{i} \frac{d}{dx}## so ##\hat{p^2} = -\hbar^2 \frac{d^2}{dx^2}##... And by plugging in ##\Psi##, I get ##<p^2>=-\frac{10\hbar^2}{3L^2}##.
Any thoughts on why ##<p^2>## is negative, which isn't possible?
My workings: ##<O> = \int \psi* O \psi dx## in general. And ##\hat{p}=\frac{\hbar}{i} \frac{d}{dx}## so ##\hat{p^2} = -\hbar^2 \frac{d^2}{dx^2}##... And by plugging in ##\Psi##, I get ##<p^2>=-\frac{10\hbar^2}{3L^2}##.
Any thoughts on why ##<p^2>## is negative, which isn't possible?