Diamond and Silicon Get Entangled

When it comes to semiconductors, it is well known that one shouldn’t bet against silicon. Now it appears that silicon may also be the key to quantum technologies based on diamond. A team of scientists from Harvard University, Ulm University in Germany, and Tsukuba University and the National Institute for Materials Science, both in Japan, has demonstrated that two separated silicon-vacancy (SiV) centers in diamond can emit photons that are indistinguishable [1], i.e., have identical properties (except for their position): same wavelength, same polarization, and when the photons are combined on a beam splitter, the same output directions. Such indistinguishability is one of the most important enablers of quantum information based on atom-photon interactions.