A new computational approach uses the real electronic structure of materials to predict a classic quantum effect far more accurately than simplified models.

Seven magnetic atoms embedded one at a time in copper have given physicists a new way to test whether computers can predict the behavior of real quantum materials without first reducing them to simplified models.

For most of the seven transition-metal impurities, calculations developed by researchers at Caltech and Yale University improved on the accuracy of conventional model-based predictions by as much as two orders of magnitude. The test involved the Kondo effect, a classic quantum problem whose general physics has been understood for decades even though its precise behavior in specific materials has remained difficult to calculate.