By studying ultracold atoms trapped in artificial crystals of light, Guillaume Salomon, a postdoc at the Max-Planck-Institute of Quantum Optics and a team of scientists have been able to directly observe a fundamental effect of one-dimensional quantum systems. By detecting the atoms one-by-one, the team observed a stretching of the magnetic ordering when diluting the atoms in the lattice. The study was conducted this year in the Division led by Immanuel Bloch, a director at the Max Planck Institute of Quantum Optics and professor at the Ludwig Maximilians University in Munich. The new findings are relevant, for example, in connection to high-temperature superconductors that conduct electricity without loss.