Published August 29, 2022 | Version v1
Journal article Open

Entanglement of trapped-ion qubits separated by 230 meters

Creators

  • 1. Institut für Quantenoptik und Quanteninformation, Osterreichische Akademie der Wissenschaften, Technikerstr. 21A, 6020 Innsbruck, Austria, Institut für Experimentalphysik, Universit¨at Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
  • 2. Institut für Experimentalphysik, Universit¨at Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
  • 3. Department of Physics, Georgetown University, 37th and O Sts. NW, Washington, DC 20057 USA
  • 4. Department of Applied Physics University of Geneva, 1211 Geneva, Switzerland
  • 5. Institut für Quantenoptik und Quanteninformation, Osterreichische Akademie der Wissenschaften, Technikerstr. 21A, 6020 Innsbruck, Austria, Institut für Experimentalphysik, Universität Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
  • 6. Institut für Experimentalphysik, Universität Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
  • 7. Institut de Physique Th´eorique, Universit´e Paris-Saclay, CEA, CNRS, 91191 Gif-sur-Yvette, France

Description

We report on an elementary quantum network of two atomic ions separated by 230 m. The ions
are trapped in different buildings and connected with 520(2)m of optical fiber. At each network
node, the electronic state of an ion is entangled with the polarization state of a single cavity photon;
subsequent to interference of the photons at a beamsplitter, photon detection heralds entanglement
between the two ions. Fidelities of up to (88.2+2.3−6.0)% are achieved with respect to a maximally
entangled Bell state, with a success probability of 4×10−5. We analyze the routes to improve these
metrics, paving the way for long-distance networks of entangled quantum processors.

Notes

This work was supported by the European Union's Horizon 2020 research and innovation program under grant agreement No. 820445 and project name "Quantum Internet Alliance," by Projects F 7109 and Y 849 of the Austrian Science Fund (FWF), and by the U.S. Army Research Laboratory's Center for Distributed Quantum Information under Cooperative Agreement Number W911NF-15-2-0060. We acknowledge funding for S.B. by an FWF Erwin Schrödinger fellowship (No. J 4229), for V. Krutyanskiy by the Erwin Schrödinger Center for Quantum Science & Technology (ESQ) Discovery Programme, for B.P.L. by the CIFAR Quantum Information Science Program of Canada, for A.M. by the U.S. National Science Foundation under Grant No. PHY- 1915130, for N.S. by the Commissariat a' l'Energie Atomique et aux Energies Alternatives (CEA), and for M.T. by the Early Stage Funding Program of the Vice-Rectorate for Research of the University of Innsbruck.

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Additional details

Funding

European Commission
QIA - Quantum Internet Alliance 820445
FWF Austrian Science Fund
Quantum Frequency Conversion for Ion-Trap Quantum Networks Y 849
FWF Austrian Science Fund
Quantum Information Systems Beyond Classical Capabilities F 71
FWF Austrian Science Fund
QuantNet: Spins in Diamond for a Quantum Network J 4229