Physicists have long struggled to unite quantum mechanics—the theory governing tiny particles—with Einstein’s theory of gravity, which explains the behavior of stars, planets, and the structure of the universe. Researchers at TU Wien have now taken a new step toward that goal by rethinking one of relativity’s core ideas: the paths particles follow through curved spacetime, known as geodesics. By creating a quantum version of these paths—called the q-desic equation—the team showed that particles moving through a “quantum” spacetime may deviate slightly from the paths predicted by classical relativity.