Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the Earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible today to exploit quantum properties specifically for technical applications. The team led by the Innsbruck quantum computer pioneer Rainer Blatt controls individual atoms very precisely in experiments with ion traps. The deliberate entanglement of these quantum particles not only opens up the possibility of building aquantumcomputer, but also creates the basis for the measurement of physical properties with previously unknown precision. The physicists have now succeeded for the first time in demonstrating fully-controlled free-space quantum interference of single photons emitted by a pair of effectively-separated entangled atoms.