Quantum network and repeaters

Ion-light interface


A challenge on the road towards the quantum computer is the transport of information between different instances of computers. Here, the photon turns out to be an excellent long distance carrier of qubits.
We aim with this experiment to develop an interface for mapping the quantum state of a photon to a single ionized atom, and back again.
For trapping and storing we use the same linear, segmented Paul Trap design as in the quantum computer project. For transmitting the laser-imprinted information from the ion to a photon, a microoptical fiber resonator was integrated into the trap. We intend to use the segments of the trap to transport the ion into the resonator, where its quantum state is mapped onto a single photon. This can now be sent to a receiver over a connected optical fiber.

Because of the tiny mode volume of this resonator, the distance between the ion and its mirrors is also very small. This means, that the ion is heating up quickly, loosing its initial quantum state. To understand and minimize this effect, we study the influence of our trap structure dimensions and the trap temperature on the heating rate. Using a cryostat, we are able to trap ions at different temperatures in order to measure heating effects.

The goal of this experiement is the implementation of a quantum repeater,  which can be used to transmit quantum information over large distances. Financially we are supported by the BMBF, the DFG, the EU-project AQUTE, as well as IARPA.