Hello, I didn't know where to post this since it deals with both topics, but I thought here would be the best choice. So I have a research paper I have to do in Physics this semster and its about me researching somebodys research they're currently doing or just finshed. So I've been looking around and found an article in Science Direct (I'll post the link at the end) that deals with unifing QM and GR in the fifth dimension. The only problem is this is only my 3 semestor of introductory physics and this stuff is really complicated. With that being said however I just have to discuss the research they're doing/did and not really show all the calculations they did. So I know it will be a great challenge to even understand what's going on, but I think I could handle it. The abstarct for Paul S. Wesson's article is: "In 5D, I take the metric in canonical form and define causality by null-paths. Then spacetime is modulated by a factor equivalent to the wave function, and the 5D geodesic equation gives the 4D Klein–Gordon equation. These results effectively show how general relativity and quantum mechanics may be unified in 5D." And I've been trying to pick apart this and when I got to the 4-D Klein-Gordon equation it got tricky. I roughy understand the concept of how its a relativistic version of the Schrödinger equation, and it's the equation of motion for a feilds spinless quanta. However what gets me is how the particle can go forward and backward in time? I just can't seem to wrap my head around that concept. So if anyone could help me with that or any part of the article I greatly appericate it. -Adam G.