▁one ▁they ▁came ▁from ; ▁it ' s ▁been ▁argued ▁that ▁since ▁the ▁travel er ▁arriv es ▁in ▁a ▁different ▁universe ' s ▁history ▁and ▁not ▁their ▁own ▁history , ▁this ▁is ▁not ▁" gen u ine " ▁time ▁travel . ▁The ▁accepted ▁many - world s ▁interpretation ▁suggests ▁that ▁all ▁possible ▁quantum ▁events ▁can ▁occur ▁in ▁mut ually ▁exclusive ▁histor ies . ▁However , ▁some ▁variations ▁allow ▁different ▁univers es ▁to ▁interact . ▁This ▁concept ▁is ▁most ▁often ▁used ▁in ▁science - f iction , ▁but ▁some ▁phys ic ists ▁such ▁as ▁David ▁Deutsch ▁have ▁suggested ▁that ▁a ▁time ▁travel er ▁should ▁end ▁up ▁in ▁a ▁different ▁history ▁than ▁the ▁one ▁he ▁started ▁from . ▁On ▁the ▁other ▁hand , ▁Stephen ▁Haw king ▁has ▁argued ▁that ▁even ▁if ▁the ▁M WI ▁is ▁correct , ▁we ▁should ▁expect ▁each ▁time ▁travel er ▁to ▁experience ▁a ▁single ▁self - cons istent ▁history , ▁so ▁that ▁time ▁travel ers ▁remain ▁within ▁their ▁own ▁world ▁rather ▁than ▁travel ing ▁to ▁a ▁different ▁one . ▁The ▁phys ic ist ▁Allen ▁Ever ett ▁argued ▁that ▁Deutsch ' s ▁approach ▁" in vol ves ▁modifying ▁fundamental ▁principles ▁of ▁quantum ▁mechan ics ; ▁it ▁certainly ▁goes ▁beyond ▁simply ▁adopt ing ▁the ▁M WI ". ▁Ever ett ▁also ▁arg ues ▁that ▁even ▁if ▁Deutsch ' s ▁approach ▁is ▁correct , ▁it ▁would ▁imply ▁that ▁any ▁macro scop ic ▁object ▁composed ▁of ▁multiple ▁particles ▁would ▁be ▁split ▁apart ▁when ▁travel ing ▁back ▁in ▁time ▁through ▁a ▁w orm hole , ▁with ▁different