Tel-Aviv University demos quantum superconductors locked in a magnetic field.

When two metal plates are separated by a very small gap which contains empty space, quantum physics predicts a very slight attractive force between them, caused by the quantum behavior of empty space itself. This is called the Casimir effect and has been verified experimentally.

In 2008, research showed that introducing other materials, such as a surrounding liquid, could turn the Casimir force repulsive. Now, scientists are saying the surrounding liquid may not be needed, if the two plates are made from newly-created materials called topological insulators.