Below a certain frequency threshold, the quantum fluctuations of empty space may contribute to dark energy -- much the way some materials become superconductors below a critical temperature. In 2004, Michael Mackey, of McGill's Centre for Nonlinear Dynamics in Physiology and Medicine (Associate member in the Department of Mathematics & Statistics and the Department of Physics), and Christian Beck of Queen Mary, University of London, claimed that the quantum fluctuations of empty space could be the source of dark energy and suggested a test for this idea. They didn't know then why it might work, but now the pair has come up with the theory behind the experiment.