Gravity amplifier Just a hypothetical question. Is it possible to increase or amplify gravitational interactions between two or more bodies  ( without  changing the mass)?
Will changing the graviton count(theoretically, of course) have an effect?
 A: Short answer: no.
Longer answer:
In Newtonian gravity: definitely no. The gravitational attraction between two bodies depends only on their masses and separation. There is nothing else for the "amplifier" to couple to. 
In general relativity: practically speaking, no. For one thing in all "mundane" situations the predictions will be identical to those of Newton. 
But just for fun assume one has infinite technology. Then I think the answer in GR is yes. In two ways:


*

*Relativistic gravity couples not only to the masses of the objects, but also to their pressures. So, you could amplify the gravity by increasing the pressure density, and this could in principle be done without changing the masses (i.e. the energy densities). I think this isn't really what you have in mind though.

*One could, I suppose, place a very strong gravitational lens between the two bodies, in just such a way as to focus gravitational radiation (etc) upon them. This could in principle be calibrated in such a way as to increase the attractive force between the bodies. 
While I'm reasonably certain (I'm not 100% sure though) this is technically possible, it is likely a very delicate set-up, requiring absurdly difficult engineering (I am basically suggesting one somehow hold two black holes in place at precisely chosen locations), resulting in a very small increase in force. It's hard to imagine a civilization capable of doing this would not be able to simply pull the objects together directly.
In modified-gravity theories one typically does not have an equivalence principle: therefore gravity can couple to things besides the energy/pressure directly (i.e. there are 'extra charges' that the gravity cares about). By manipulating the distribution of the extra charge between the masses one could presumably create an amplifying effect. I'm thinking of something like the 'spontaneous scalarization' of binary neutrons stars in scalar-tensor gravity people have been looking into lately.
