Entanglement gains a size

The generation, manipulation and detection of non-classical correlations known as quantum entanglement are well-established operations in research areas such as quantum optics, quantum sensing and quantum information. Nevertheless, there are scales at which entanglement becomes difficult to observe and preserve—most notably when the entangled objects in question become macroscopic or when the distance separating them becomes large. Now two papers report experimental achievements that extend the scales over which non-classical correlations can be produced and studied: Simon Gröblacher and colleagues entangled two optomechanical oscillators in the form of nanostructured silicon beams across two chips separated by 20 centimetres, whereas Mika Sillanpää and collaborators realized the entanglement of two massive electromechanical oscillators, each composed of about 1012 atoms, by driving the devices into a steady state where entanglement is long-lived. These results could open the way to further advances in fundamental tests of quantum mechanics, quantum networks as well as precision measurements.