A UK consortium led by Imperial physicists has signed an agreement with Fermilab in the US to build a 100-meter-long quantum experiment. The Matter-wave Atomic Gradiometer Interferometric Sensor (MAGIS-100) experiment is currently under construction at the US Department of Energy’s Fermi National Accelerator Laboratory (Fermilab). It will enable scientists to demonstrate the superposition of atoms and advance the search for ultralight dark-matter particles.