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## Main Question or Discussion Point

hi. I have been looking at a QM example in a book. It works out the expectation value for momentum which I know should be a real number but I can't see how or why the following number is real

α and β are complex numbers with | α |

-i ( α

Can anyone tell me if this is a real number and why?

Thanks

α and β are complex numbers with | α |

^{2}+ | β |^{2}= 1 and ω and t are real-i ( α

^{*}β e^{-iωt}-αβ^{*}e^{iωt})Can anyone tell me if this is a real number and why?

Thanks