Far out ideas: something like a Z-boson condensate (whatever that means)... or a dense flux of W or Z bosons orthogonal to the path of neutrinos... something along those lines. I was just looking for some food for thought... something to think about over the next say 5 years and hopefully end...
All good points. "Repulsive" was a poor choice of words without further explanation. What I was trying to ask is something like the following:
Consider two particles in otherwise empty space; these two particles experience normal gravitational interaction between themselves. Now consider a...
If you consider empty space case (energy-momentum tensor is zero), the curvature of space is Ricci-flat but the Riemann tensor is not necessarily zero, which allows for gravity waves in empty space. It's not difficult to see that the waves would have to be transverse (analogous to EM waves)...