I watched a recent documentry regarding the recent time travel experiments using two devices. A basic explanation: Device A sends a photon which device B recieves, device B however recieves the message before Device A sends it. My question regarding this is: If device B recieves the photon before the message is sent, then what happens if you switch off Device A during the period between Device B recieving the message and Device A sending it? If device B still actually recieves the message, but device A is unable to send it then could we be looking at a parrallel universe sending the message in the first place? Indeed, could this be an experiment for testing for a parallel universe. For if device A is unable to send the message (it is switched off), then how on earth can device B recieve it? Thanks for your thoughts.