Using math and physics he has created a formula that describes a method for time travel. The metric gab g a b in this case is just the identity matrix which tells us that the line element is. Backward time travel is another matter.
An example of a traversable wormhole metric is the following.
Using math and physics he has created a formula that describes a method for time travel. People think of time travel as something as fiction says. The math itself is complex but it boils down to something fairly simple. Using math and physics he has created a formula that describes a method for time travel.