/sci/ - Science & Math

https://en.wikipedia.org/wiki/Hong%E2%80%93Ou%E2%80%93Mandel_effect#Mathematical_description

Why are the signs of [math]\hat{d}^\dagger[/math] different, but not [math]\hat{c}^\dagger[/math]? It sounds like it's got something to do with the electric fields, but I don't see why transmission from the b mode is any different from transmission from the a mode.