What is this Time Travel Theory called?
It is called Quantum Theory. Albert Einstein have worked on two theories: the Relativity Theory and the Quantum Theory. While his Theory on Relativity had been explored extensively and put into actual use, not much have been done to explore his Quantum Theory. Einstein was among the first to propose the possibility of time travel but in order to do so, one must be travelling faster than the speed of light. That idea, at this point, seems very impossible to achieve. About your topic of going into the past to try to change something, there are certain rules that must be followed if supposing time travel is already possible. No one must change anything in the past because that would also change the future and you may not be able to get back there anymore. Other rules include: don’t bring anything from the present to the past, or bring anything from the past back to the present, never interfere with anyone in the past who will have a direct link to your existence, never attempt to meet you
