I Quick question regarding creation/annihilation operators

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Given the matrix element of an annihilation operator, can we consider it to be a creation operator acting to its left?
I'm reading a textbook and it states the following:

Screenshot 2025-04-09 121748.png


For whatever reason latex previewing is not working for me right now.. but the way I was thinking about this was to take the complex conjugate of the entire left, act with the ensuing creation operator on |x_1 ... x_N-1> to get |x_1...x_N>, and then take the complex conjugate of <y_1...y_N | x_1....x_N>* to get back the final result.

Is that the right way to think about it mathematically? And can I just generally think about it as a creation operator acting to its left?
 
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MaestroBach said:
Is that the right way to think about it mathematically? And can I just generally think about it as a creation operator acting to its left?
Yes an annihilation operator for the kets can act as a creation operator on the bras. Also note that you would usually use just a Latin letter like ##\hat{a}, \hat{b},\hat{c},\hat{f}##, rarely we use ##\hat{\psi}## for annihilation/creation operators.
 
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