- #1

Niles

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## Homework Statement

Hi all.

An operator is given by:

[tex]

\widehat O = \sum\limits_i {\sum\limits_j {O_{ij} \left| {\psi _i } \right\rangle \left\langle {\psi _j } \right|} }

[/tex]

Am I allowed to move the bra and the ket around to achieve the following?

[tex]

\widehat O = \sum\limits_i {\sum\limits_j {O_{ij} \left\langle {\psi _j } \right|\left| {\psi _i } \right\rangle } }.

[/tex]

Thanks in advance.Niles.