5 papers
An asymmetric atom-photon architecture for device-independent quantum key distribution over 25 km
Jonas Meiers, Christian Haen, Max Bergerhoff +4
Device-independent quantum key distribution (DIQKD) can guarantee security without trusting the internal workings of the measurement devices, but extending it to fiber networks dem…
Telecom-compatible polarization-to-time-bin conversion of atom-photon entanglement for heterogeneous quantum networks
Christian Haen, Julian Groß-Funk, Max Bergerhoff +5
A key enabling feature of future quantum networks is interoperability between platforms that operate at different wavelengths and with different qubit encodings. We demonstrate an…
Quantum repeater segment with free-space coupled co-trapped ions using telecom photon interference
Max Bergerhoff, Pascal Baumgart, Christian Haen +5
A quantum repeater segment is a basic building block of a quantum repeater, generating buffered entanglement of quantum memories to connect quantum repeater cells. It also enables…
Indistinguishability of photonic qubits emitted from trapped Ca ions via pulsed excitation
Pascal Baumgart, Max Bergerhoff, Jonas Meiers +2
We investigate the indistinguishability of Raman photons generated from two trapped Ca ions using few-nanosecond excitation pulses. We elucidate how spontaneous scatteri…
Demonstration of quantum network protocols over a 14-km urban fiber link
Stephan Kucera, Christian Haen, Elena Arenskötter +9
We report on the implementation of quantum entanglement distribution and quantum state teleportation over a 14.4-km urban dark-fiber link, which is partially underground, partially…