Korea Advanced Institute of Science and Technology Researchers identify exotic metals in unexpected quantum systems Figure: Phase diagram of two-orbital systems. Various metals emerge depending on the values of electron interactions denoted by U (x-axis) and Hund’s coupling J/U (y-axis). Electrons are ubiquitous among atoms, subatomic tokens of energy that can independently change how a system behaves—but they also can change each other. An international research collaboration found that collectively measuring electrons revealed unique and unanticipated findings. The researchers published their results on May 17 in Physical Review Letters. “It is not feasible to obtain the solution just by tracing the behavior of each individual electron,” said paper author Myung Joon Han, professor of physics at KAIST. “Instead, one should describe or track all the entangled electrons at once. This requires a clever way of treating this entanglement.”