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Q: Fachverband Quantenoptik und Photonik
Q 54: Quantum Information (Quantum Repeater)
Q 54.4: Talk
Thursday, March 17, 2022, 14:45–15:00, Q-H12
Larmor precession-free atom-photon entanglement using Raman scattering from a single 40Ca+ ion — •Matthias Kreis, Jelena Ritter, Stephan Kucera, and Jürgen Eschner — Universität des Saarlandes, Experimentalphysik, 66123 Saarbrücken
Atom-photon entanglement is an essential resource for a sender-based quantum repeater scheme. One implementation is a flying qubit, encoded in the polarization of an emitted photon, which is entangled with a stationary qubit, encoded in the internal state of a single ion. If Zeeman leves are used for the ionic qubit, the phase of the generated atom-photon state depends on the emission time of the photon, due to the magnetic energy splitting [1,2].
In order to make the phase time-independent, one can use an ion trapped inside a cavity [3]. In this scheme, a bi-chromatic laser with the same frequency difference as the involved Zeeman-shifted transitions in the ion is used.
Here, we report on a alternative scheme using a single 40Ca+-ion together with an external cavity that acts as a quantum eraser. The cavity filter removes unwanted spectral components, which results in detection-time independent atom-photon entanglement. We present the generation of phase-stable atom-photon entanglement at 393 nm and at 854 nm wavelength with fidelity 0.95.
[1] C. Kurz et al., Phys. Rev. A 93, 062348 (2016).
[2] M. Bock et al., Nat. Commun. 9, 1998 (2018).
[3] A. Stute et al., Nature 485, 482-485 (2012).