This dissertation reports on an experimental quantum optics project performed at ICFO to advance in the research of long-distance quantum communications. It describes in detail several crucial engineering contributions to the project, like a pulse sequencer named Hydra. These contributions are presented in the framework of both the theoretical background and the first successful proof-of-principle experiments. An example of these experiments would be a bandwidth-tunable single-photon source.

The experimental setup consists of two ions traps -so far the only ones in Spain, and one out of a few similar setups worldwide- located in two different vacuum chambers separated by approximately one meter of distance. In each apparatus, single trapped ions are manipulated with laser light, allowing us to control the energy level of their valence electron to perform quantum information processing. One main goal of the experiment is to create entanglement between two distant ions -one in each trap-, a mandatory resource to perform quantum communications between them. Therefore, each vacuum chamber can be understood as a transceiver, or node, in a quantum network scenario. Such a network could be used, for example, to create more secure communication links using quantum cryptography; or to extend the power of two quantum processors located at a distance by means of the interchange of quantum information between them, e.g. using quantum teleportation.


Thursday, September 30, 11:00. ICFO Auditorium

Thesis Advisor: Prof. Jürgen Eschner