



01526nas a2200133   4500008004100000245011300041210006900154260001400223520105400237100002001291700002001311700002401331856003701355       2020                        eng d00aThe Character of Motional Modes for Entanglement and Sympathetic Cooling of Mixed-Species Trapped Ion Chains0 aCharacter of Motional Modes for Entanglement and Sympathetic Coo  c4/16/20203 a<p>Modular mixed-species ion-trap networks are a promising framework for scalable quantum information processing, where one species acts as a memory qubit and another as a communication qubit. This architecture requires high-fidelity mixed-species entangling gates to transfer information from communication to memory qubits through their collective motion. We investigate the character of the motional modes of a mixed-species ion chain for entangling operations and also sympathetic cooling. We find that the laser power required for high-fidelity entangling gates based on transverse modes is at least an order of magnitude higher than that based on axial modes for widely different masses of the two species. We also find that for even moderate mass differences, the transverse modes are much harder to cool than the axial modes regardless of the ion chain configuration. Therefore, transverse modes conventionally used for operations in single-species ion chains may not be well suited for mixed-species chains with widely different masses.</p>1 aSosnova, Ksenia1 aCarter, Allison1 aMonroe, Christopher  uhttps://arxiv.org/abs/2004.0804501264nas a2200157   4500008004100000245006300041210006300104520077600167100002100943700002100964700002000985700002001005700002001025700002401045856003701069       2018                        eng d00aHigh Purity Single Photons Entangled with an Atomic Memory0 aHigh Purity Single Photons Entangled with an Atomic Memory3 a<p>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 single-photon source for quantum networking based on a trapped 138Ba+ ion with a single photon purity of g2(0)=(8.1&plusmn;2.3)&times;10&minus;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.&nbsp;</p>1 aCrocker, Clayton1 aLichtman, Martin1 aSosnova, Ksenia1 aCarter, Allison1 aScarano, Sophia1 aMonroe, Christopher  uhttps://arxiv.org/abs/1812.01749