Could reincarnation exist as a natural phenomenon in the universe?

You sound very spritual for someone who claims to be an atheist. If you're looking for scientific proof of the existence of an immortal soul, you're not going to find it. Even the most religious people would say that's just something they have to take on faith. From a scientific standpoint, the energy you're talking about is created by chemical reactions that take place in the body. Those reactions stop at death, so it's ogous to snuffing out a candle. As much as I'd like to believe in it, no one has found a way to prove beyond a shadow of a doubt that there is life after death. Even the research on near-death experiences, as fascinating as it is, isn't absolute proof, because one could argue that if those people were revived they weren't truly dead.