Dresden 2017 – scientific programme

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MA: Fachverband Magnetismus

MA 18: Transport: Quantum Coherence and Quantum Information Systems - Theory (jointly with MA, HL)

MA 18.8: Talk

Tuesday, March 21, 2017, 11:30–11:45, HSZ 103

Generating Entangled Quantum Microwaves in a Josephson-Photonics Device — •Simon Dambach, Björn Kubala, and Joachim Ankerhold — Institute for Complex Quantum Systems, Ulm University, Ulm, Germany

The realization of efficient sources for entangled microwave photons is of paramount importance for many promising applications of quantum technology. In this talk, we demonstrate that Josephson-photonics devices are logical candidates for this task since they allow to create a broad range of different bi- and multipartite entangled states in a surprisingly simple way [1].

In a Josephson-photonics device, a Cooper pair tunneling across a dc voltage-biased Josephson junction simultaneously creates photons in several series-connected microwave cavities. The interplay of this multiphoton creation process and subsequent individual photon leakage from the cavities leads to a stationary state with complex entanglement properties. Sophisticated pulse-shaping schemes as required in conventional circuit-QED architectures are thus not necessary here. Varying experimental parameters in situ or by construction then allows to access the rich wealth of entangled states differing, e.g., in the number of entangled parties or the dimension of state space. Such devices, besides their promising potential to act as a highly versatile source of entangled quantum microwaves, may be also an excellent playground for the abstract branch of quantum information theory to test entanglement criteria on naturally existing quantum states.

[1] S. Dambach, B. Kubala, and J. Ankerhold, arXiv:1609.08990