Manipulating single photons from disparate quantum sources to be indistinguishable [Invited]

Quantum information networks will likely require different quantum systems for different functionality within the network. Indistinguishable photons can be used to interconnect these different subsystems. We discuss methods for coherently manipulating the single photons from different quantum systems and experimentally demonstrate spatial, temporal, and frequency matching of single photons using quantum dot and heralded parametric down-conversion single photons. The bosonic nature of light insures that when two indistinguishable photons are superimposed on a beam splitter, they will form a single two-photon state, a process we call coalescence. This coalescence property can be used as both a fundamental test of indistinguishability and in quantum networks -connecting and propagating quantum information.