Antimatter gravity could explain Universe's expansion: As Villata explains, the current formulation of general relativity predicts that matter and antimatter are both self-attractive, yet matter and antimatter mutually repel each other. Unlike previous antigravity proposals – such as the idea that antimatter is gravitationally self-repulsive – Villata’s proposal does not require changes to well-established theories. The study is published in a recent issue of EPL (Europhysics Letters).
“The significance of this study is actually twofold,” Villata told PhysOrg.com. “On one side, that of physics in general, it is to have shown that one of the most heretical concepts debated in the last several decades, i.e., that of antigravity, can be found as a prediction of the coupling of two of the best-established theories of the last century, providing the extension of general relativity to antimatter, considered as space-time-reversed matter, as requested by CPT symmetry. On the other side, the cosmological implications of this finding have shown antigravity as an alternative to (or explanation of) the wooly concept of dark energy for the accelerated expansion of the Universe.”