Interference in the matter

Abstract

Like any particle, electrons are also waves that can interfere with each other. Remarkably, this interference can even happen between electrons from different sources that have never physically interacted. The experimental demonstration of an elusive fundamental effect is reported this week: quantum interference between two particles that are indistinguishable and that come from independent sources. Such interference can be observed only by recording a joint probability of finding the particles in two detectors in separate places. Experiments with photons have not so far succeeded in producing two-particle interference, but this time the experiment was with electrons that were manipulated in a cleverly designed interferometer fabricated in a semiconductor two-dimensional electron gas.