Expectation value of a combination of operators

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SUMMARY

The discussion focuses on calculating the expectation value of a combination of quantum mechanical operators, specifically the expression

/

. The operators X and P represent position and momentum, respectively, with their corresponding actions defined as X |x> = x |x> and P |p> = p |p>. The solution involves utilizing the canonical commutation relation between the operators to rearrange their order in the expectation value, ultimately leading to the correct answer.

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  • Knowledge of canonical commutation relations between position and momentum operators.
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Homework Statement



I will denote operators by capital letters. The question is calculate

<p | XXPP | x> / <p | x >

Homework Equations


X |x> = x |x> P |p> = p |p> P |x> = -i(hbar)d/dx X |p> = i(hbar)d/dp

The Attempt at a Solution


If I start on the RHS and take PP out I get -(hbar)^2 d^2/dx^2 outside the bracket then I can take the XX outside if it operates on the |x> as x^2 but to be honest I'm not getting anywhere
 
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Use the canonical commutation relation between the operators X and P. With that you can reverse the order of the operators in the expectation value.
 
Thanks. I finally got the answer.
 

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