I was reading the wiki page on superdense coding algorithm. I am not quite sure what happens in this algorithm. When the photon which is part of entangled pair is being sent to Bob from Alice's side, does that mean that photon is not there with Alice anymore?
(I am asking this because if it is not there then to send some classical information again, we have to prepare another entangled pair or Bob has to send back that photon. Because upon projective measurement in bell basis the state won't be destroyed.)