If we were to able to detect gravitons then is it not that the basic assumption over which the general theory of relativity is flawed ?
Yeah, he is assuming we stay in the solar system, and that there do not happen to be any unusually close PBH.An interesting paper. I'm a bit puzzled by the assumptions made there (e. g. to get equation 6.2). A Jupiter-sized detector is perfectly fine, but we can't get it closer than 100,000 light years to a black hole? Build it around the primordial black hole and you get R=100,000 km, a factor 1013 closer, or 1026 higher detection rate. Alternatively, you get the same detection rate with just 20 kg of detector material. The neutrino background stays a problem, of course.
The assumption that the detector readout happens at the surface of the Jupiter-sized detector only (p16) is odd as well.