Linking trapped-ion quantum nodes

Nina Podoliak, Hiroki Takahashi, Matthias Keller +1 more

The realisation of efficient ion-photon quantum interfaces is an essential step towards developing operational quantum information networks. Individual trapped ions have been shown as promising candidates for quantum information processing nodes, while effective ion manipulation and photonic links between nodes can be realised by deterministic coupling of ions to optical cavities. However, integrating optical cavities into ion traps remains a challenge as the trapping potential is affected by the presence of any dielectric or conductor.

D. Main

Florian R. Ong, Klemens Schüppert, Pierre Jobez +8 more

The realization of a quantum network requires linking distant nodes via a quantum channel. To realize this link, it seems natural to use single photons to transmit or to share the quantum state of a static qubit. In this direction, a trapped ion in cavity has already been used to perform ion-photon entanglement [1] and ion-to-photon state mapping [2].

Christopher R. Monroe

Q. A. Turchette, B. E. King, Christopher J. Myatt +6 more

George Toh, Jameson P. O'Reilly, Sagnik Saha +4 more

Trapped ions are one of the leading platforms for quantum computation and networking, with long coherence times and high fidelity qubit operation. We exploit these attributes to build a quantum network with the use of three trapped ion modules connected via photonic links. In each of these systems, we have ions of different species for use as memory or communication qubits. Our newest module contains two high NA=0.8 objectives, each covering 20% of the solid angle of photons emitted from the ion, making it suitable for use as the middle node of the network. Photons are collected from each chamber, and we generate remote entanglement between each pair of nodes by interfering the photons on a beamsplitter. This heralds entanglement of the communication ions in the pair of network nodes, which we then swap onto the memory qubits. I will discuss our progress towards creating a Greenberger–Horne–Zeilinger (GHZ) state between the memory ions in the three nodes.