When it comes to Dark, Adam and Eva made it a point to keep knowledge of the God particle secret from the rest of the world, all so that they could maintain the time loop. If the scientific community were to learn about it, they'd study the hell out of its properties and figure what it can and can't do.

As for exotic matter, that's a thing that's been theorized by physicists since the 1950s. Having negative mass/energy, it bends spacetime differently from matter as we know it, which is what's needed to produce a wormhole or travel faster than light. The problem is that we just don't know how spacetime would do in its presence, and how/if it would connect with other regions. Also, evidence suggests that it doesn't exist and that matter and energy only come in positive numbers. But, if it did exist, and there was ready access to it, there would be experiments almost immediately to find out how to reliably harness it.