If by soul you mean consciousness, I agree with Sartre that the soul is nothingness, which means that there isn't really anything to bring back except the content of consciousness, including, in normal humans, a body, environment, and stream of thought with a history engraved on them (e.g. the rust on iron). To bring back a person partly entails reconstituting a sufficient number of those things which carry evidence of the person's identity in them to make the resulting configuration of existence a coherent continuation of their life. That alone isn't enough, of course. If I were to build a clone of myself and put him on a clone of this world and at the same moment destroy myself, I would not suddenly be seeing the world through his eyes (except in the shallow sense that I see the world through everyone's eyes). My story would continue on through the fragments of my destroyed body and its environment, which would not carry any personally meaningful sense of my previous self in them. My body would need to be put back together or otherwise tied causally to such an environment in such a way as would allow me to pick up my previous life where I left off. It could be done if we had the necessary technology and a psychological rather than purely physical understanding of the causal ties connecting a living person to a corpse to whatever it might proceed to become after that. That's rather difficult to do, as there isn't any clear center of consciousness like a functioning brain left. When a person's body decays, it's as though their consciousness undergoes fission after fission; which child should be resurrected? All of them or any of them would seem to be the answer, except "any of them" would be a frightening prospect for *you,* whichever bit of what used to be you is the one you're carrying along as your body. It would be a very difficult lottery to win.
I imagine if you were to fragment yourself in just the right way--for example, if they were to slice your brain in half at just the right location and during just the right instant of thought--the results would be very interesting indeed, provided both halves of the self could be preserved. Which one would have priority as a causal continuation? If the answer were both, then instantaneous communication between two places any distance apart would be possible. This might be happening on a very tiny level whenever little causal streams split off from a person, such as when a limb is severed. If so, the situation of decay might be the scattering of little seeds of consciousness, not diminished or cut off from each other but only rarified; and eventually some of them might simultaneously take root and sprout in far-apart places. Except I imagine the consciousness would experience these places as being somewhat in proximity to each other. There might be a consciousness that, when it claps its hands, is very quickly and easily sending a signal from what would look to us like one end of the cosmos to the other.