High purity single photons entangled with an atomic qubit

Abstract

Trapped atomic ions are an ideal candidate for quantum network nodes, with long-lived identical qubit memories that can be locally entangled through their Coulomb interaction and remotely entangled through photonic channels. The integrity of this photonic interface is generally reliant on purity of single photons produced by the quantum memory. Here we demonstrate a singlephoton source for quantum networking based on a trapped 138 Ba + ion with a single photon purity of g 2 (0) = (8.1 ± 2.3) × 10 −5 without background subtraction. We further optimize the tradeoff between the photonic generation rate and the memory-photon entanglement fidelity for the case of polarization photonic qubits by tailoring the spatial mode of the collected light.

High‐Purity Triggered Single‐Photon Emission from Symmetric Single InAs/InP Quantum Dots around the Telecom C‐Band Window

“…[2,[10][11][12] In this spectral range, QDs are the sources providing the purest single photons with the second-order correlation function at zero time delay g (2) (0) value of (7.5 ± 1.6) x 10 −5 [13] and the highest emission rates. [14] Regarding single-photon purity, only single ions could be competing candidates, [15] but these are much less practical in terms of integration and scalability.…”

Any-to-any connected cavity-mediated architecture for quantum computing with trapped ions or Rydberg arrays

“…3 correspond to the clock states |F = 2, m F = 0 and |F = 1, m F = 0 in the 6S 1/2 ground-state manifold, and the states |r 0 and |r 1 correspond to |F = 2, m F = 0 and |F = 0, m F = 0 in the metastable 5D 3/2 state manifold, while the excited state |e is the state |F = 3, m F = 0 in 6P 3/2 . Then rotations between |0 and |1 and between |r 0 and |r 1 can be driven via Raman transitions [46]. The states |r 0 and |r 1 in 5D 3/2 are chosen because of the small branching ratio from 6P 3/2 to 5D 3/2 [47], which strongly suppresses spontaneous decay back into |r 0 and |r 1 .…”

Ion-Photonic Frequency Qubit Correlations for Quantum Networks

“…Ion-ion entanglement mediated by frequency photonic qubit [11], and ion-photonic polarization qubit [22,23] have been shown, but no direct measurement of ion-photonic frequency qubit has yet been measured. Characterizing the performance of the ionfrequency qubit state is essential for benchmarking a quantum network with arbitrary topology that uses this type of encoding and has applications in memory-assisted quantum communication [24].…”