Cloning Quantum Information from the Past - A Solution For Time Travel Paradoxes

Popular television shows such as "Doctor Who" have brought the idea of time travel into the vernacular of popular culture. But problem of time travel is even more complicated than one might think. LSU's Mark Wilde has shown that it would theoretically be possible for time travelers to copy quantum data from the past.

For example, would it be possible to travel back in time to kill one's grandfather? In the Grandfather paradox, a time traveler faces the problem that if he kills his grandfather back in time, then he himself is never born, and consequently is unable to travel through time to kill his grandfather, and so on. Some theorists have used this paradox to argue that it is actually impossible to change the past.

Deutsch solved the Grandfather paradox originally using a slight change to quantum theory, proposing that you could change the past as long as you did so in a self-consistent manner.

"Meaning that, if you kill your grandfather, you do it with only probability one-half," Wilde said. "Then, he's dead with probability one-half, and you are not born with probability one-half, but the opposite is a fair chance. You could have existed with probability one-half to go back and kill your grandfather."

www.sciencedaily.com...

Interesting article.

Never believed on time travel because of the paradoxes related to it.

Any thoughts ?

reply to post by CosmicDude


I remember a SF story (by Heinlein?) where the person goes back over and over again to kill his grandfather, then his father, then eventually the first life on earth, and nothing changes for him. That was an early story in the many-worlds explanation of quantum mechanics, and taught the point well while at the same time being entertaining.

reply to post by CosmicDude

I don't see any way past the main paradox. It was addressed in the remake of The Time Machine.

The main character wants to go back to keep his fiance from dying. So he invents the time machine. He fails at every attempt to save her life. She dies over and over, in different ways. What he doesn't realize is, he would never have built the time machine if she had not died in the first place. Hence, he cannot change the past, because changing it means the time machine was never invented, and he never went back...

The thing with time travel these days from what modern scientists say, is that it almost impossible to figure out how to go back in time. They know it possible to go forward due to what happened to an astronaut moving a few seconds forward in time.

"For a long time, Avdeyev held the record for time dilation experienced by a human being.[1][2][3] In his 747 days aboard Mir, cumulative across three missions, he went approximately 27,360 km/h and thus aged roughly 0.02 seconds (20 milliseconds) less than an Earthbound .......they did go faster than Avdeyev, but they were only in space for a few days."
Sergei Avdeyev, wikipedia

I also remember seeing a documentary about time travel, saying that time paradoxes could be impossible, as the universe will simply not allow it happen for some odd reason. I can't recall what documentary it is, I think it was 'The Universe" on time travel.
My guess(im going to use a cartoon story plot) is that time could split off in different directions, much like it did in DBZ.

The character Trunks goes back time, to give the main char. medicine as he will die from a new heart virus, as well as preparing them for the new villains. However, when he goes back to his time(the future, call it time line #1"), nothing has changed at all, but when he goes back to the point in time (timeline #2) where he warned the others, that future ends up being split off and has nothing to do with #1 timeline. Meaning he had no effect on his time line at all, even though they win in timeline #2. I think it a perfect example of parallel spliting off, as well as lazying writing.

Who knows how the universe actually plays.

I always like the method of time travel in Timeline.

Its more dimensional travel, just so many out there that you could go to the time you need, not really time travel but accomplishes the same thing.

As an example, you go from your dimension that is at say 2013, to one that is 1980 to do something, wouldn't change yours timeline just the one in the dimension you went to.

In timeline however, it just so happens that Another "you" from a timeline far ahead of yours (so when yours was at 1980, theirs where at 2013) and just happened to time travel back into yours, like you did to someone elses.

The end result being they time traveled, but not really. Which in the infinite worlds theory of quantum physics would make sorta sense.

I view time travel as the person doing the travel is absolutely singular in the whole concept, you may travel to the future like say....10 days, but you would never meet yourself since you have already taken that one spot in the past where you exist, and just moved it to another in the future, like moving a soda from the refrigerator to the table, it's on the table now and not in the refrigerator.


While traveling back to kill your grandfather may not matter either, you are already present in the universe, you exist before killing your grandfather, and will exist after killing him, and while some people feel i should obey the concept of the paradox could it just not be a paradox also? As humans we do not understand everything, sure it seems rational that i should stop existing at the moment grandpa dies, but there's also the concept that you just made another timeline branch, one future that the universe would not let you go to since hey, you just killed grandpa, nothing for you that way good sir, and the one you came from where you did not kill grandpa, now no matter how many times you go back to kill him or HOW you kill him, the fact will remain that he died, the branch is already made and you are not going to dead grandpa future no matter what since you do not exist there, so you did, and did not kill grandpa at the same time, schrodinger's cat theory made reality.

reply to post by cruddas


A doom paradox line, a refractural( it not in the dictionary, and it make sound smart :duh echo like the from Futurama , when bender makes constant copies, and they end up being destroy by physics.

Meaning the events are temporary, and the original branch will continue on.

reply to post by Specimen

I also remember seeing a documentary about time travel, saying that time paradoxes could be impossible, as the universe will simply not allow it happen for some odd reason.

I don't really see it as an odd reason, it's more like, "what goes up must come down." With no gravity, the universe would be a gooey mess, and with no linear time it would be chaotic.

Read Hawkings books where he tries to describe time/entropy in reverse, it doesn't really work…

reply to post by boncho

I couldn't remember the reason really, as it was time ago when I saw the documentary.

And yes, the universe would completely messed, and time and space in our definition would cease to exist because there is no linear structure, or "water to flow in the river".

Or someone cut of the tree branch at the beginning and that time in space, died off. Like an anti-virus program.

Specimen
The thing with time travel these days from what modern scientists say, is that it almost impossible to figure out how to go back in time. They know it possible to go forward due to what happened to an astronaut moving a few seconds forward in time.

Time dilation and time travel are not the same. At all.

Time dilation is like hitting the fast forward or slow button on your DVD. Time travel is like jumping to the end of the movie.

I think the most likely way time travel would exist is to travel to alternate universes. No Paradox then.

OccamsRazor04
I think the most likely way time travel would exist is to travel to alternate universes. No Paradox then.

That`s the only way I see it possible and understandable as well