Can multiple timelines exist according to theoretical physics? Multiple timelines is not a reality yet (as of 2016's science and technology), but exists only in Marvel/DC universe. It is something that is used to explain the paradox of time-travel. If you go back in time and kill yourself, the paradox is that you can't do that since you have just wiped off the physical existence of your future self by doing that.
So, multiple timeline theory explains that there will be two continuous parallel realities - one in which you will stay alive, and another in which you will be dead. Time, essentially splits/branches like a river from the point in time where such an event occurred (Watch X-Men - Back to the Future if you need to understand this in detail).
I want to know what is the physics scientist's opinion in this regard? I've heard somewhere (Stephen Hawkings perhaps) that there is some evidence of multiple parallel universes. Can this explain the multiple timeline theory?
 A: The book you need to read is Fabric of Reality by David Deutsche
He is probably the current best known proponent of the Many Worlds Interpretation of Quantum Mechanics. There, you have a potentially infinite number of "parallel time lines"
A: 
Can multiple timelines exist according to theoretical physics?

No. It's science fiction I'm afraid. 

Multiple timelines is not a reality yet (as of 2016's science and technology), but exists only in Marvel/DC universe. It is something that is used to explain the paradox of time-travel. If you go back in time and kill yourself, the paradox is that you can't do that since you have just wiped off the physical existence of your future self by doing that.

And time travel is science fiction too. There is no way that you can move such that everything else not only moved back to where it was, but never moved at all. See this answer for more information. 

So, multiple timeline theory explains that there will be two continuous parallel realities - one in which you will stay alive, and another in which you will be dead. Time, essentially splits/branches like a river from the point in time where such an event occurred (Watch X-Men - Back to the Future if you need to understand this in detail).

This sort of stuff makes for a nice movie. There's lots of really good movies that feature time travel. I mentioned some of them in this article. But they're just movies, not physics.  

I want to know what is the physics scientist's opinion in this regard? I've heard somewhere (Stephen Hawkings perhaps) that there is some evidence of multiple parallel universes. Can this explain the multiple timeline theory?

There is no evidence of parallel universes, sorry. And no, it can't explain "multiple timeline theory".  
