Nikolai Lauk, University of Calgary
Realization of a quantum network that enables ecient long-distance entanglement distribution would allow for multiple impressive applications with quantum key distribution being the most prominent one.
Using the same underlying principles such a network could be further exploit for other quantum cryptographic paradigms such as blind quantum computing and private data queries. Entanglement can also be used for realizing more accurate clocks and more precise telescopes. It is almost certain that the long-distance transmission of quantum information will be performed using optical photons and the ability of the future quantum networks to operate at telecommunication wave-lengths would allow for the usage of already existing infrastructure.
In this talk I will present our proposal for a quantum repeater scheme that is based on individual Erbium and Europium ions. Erbium ions are attractive because they emit photons at telecommunication wavelength, while Europium ions oer exceptional spin coherence for long-term storage. Entanglement between distant Erbium ions is created by photon detection. The photon emission rate of each Erbiumion is enhanced by a microcavity with high Purcell factor, as has recently been demonstrated. Entanglement is then transferred to nearby Europium ions for storage. CNOT-gates between nearby ions could be realized using electric dipole-dipole coupling. These gate operations allow entanglement swapping to be employed in order to extend the distance over which entanglement is distributed. The deterministic character of the gate operations allows improved entanglement distribution rates in comparison to atomic ensemble-based protocols. Finally I will propose an approach that utilizes multiplexing in order to enhance the entanglement distribution rate even further.