Experimental research over the last decade has established that solid-state spins allow for a faithful representation of quantum information over long timescales in integrated devices. Photons on the other hand, are ideal for transfer of quantum information. As a consequence, realization of a quantum interface between spins and photons has emerged as a promising direction for solid-state quantum information processing.
Entanglement plays a central role in fundamental tests of quantum mechanics as well as in the burgeoning field of quantum information processing. Particularly in the context of quantum networks and communication, some of the major challenges are the efficient generation of entanglement between stationary (spin) and propagating (photon) qubits, the transfer of information from flying to stationary qubits and the efficient generation of entanglement between distant stationary (spin) qubits. We have recently succeeded in demonstrating entanglement between the spin of a single quantum dot and a single emitted photon, teleportation from a photonic qubit to a spin qubit and generation of heralded entanglement between two distant hole spins. These results constitute the first steps towards the development of solid-state quantum networks.