Where's my hoverboard?

Real, levitating hoverboards do exist, thanks to quantum mechanics and the interplay between superconductors and magnetic fields. Today is the future. Specifically, it's the day to which Marty McFly and Emmett "Doc" Brown travel in the 1989 film Back to the Future II. But where are our hoverboards? It turns out: They do exist! They're just not exactly what the movie predicted they would be. Real hoverboards, such as the one the University of Geneva in Switzerland (see video below), can levitate ...