THE nature of dark energy could be revealed by a simple table-top experiment. Earlier this year, Christian Beck of Queen Mary University of London and Michael Mackey of McGill University in Montreal, Canada, showed that an extremely thin layer of insulator sandwiched between two superconducting layers, a device known as a Josephson junction, could help pin it down.
That鈥檚 because, in 1982, a team of Californian researchers showed that the jitter of the quantum vacuum could cause high-frequency fluctuations in a Josephson junction鈥檚 current. The team measured these fluctuations up to a frequency of 600 gigahertz, but Beck and Mackey point out that if dark energy is caused by vacuum fluctuations, the current fluctuations in a Josephson junction should peter out at frequencies above about 1700 gigahertz. 鈥淪o it is necessary only for someone to improve on this experiment by a factor of 3,鈥� Beck says.