RESUMO
Trapped atomic ions are a leading platform for quantum information networks, with long-lived identical qubit memories that can be locally entangled through their Coulomb interaction and remotely entangled through photonic channels. However, performing both local and remote operations in a single node of a quantum network requires extreme isolation between spectator qubit memories and qubits associated with the photonic interface. We achieve this isolation by cotrapping ^{171}Yb^{+} and ^{138}Ba^{+} qubits. We further demonstrate the ingredients of a scalable ion trap network node with two distinct experiments that consist of entangling the mixed species qubit pair through their collective motion and entangling a ^{138}Ba^{+} qubit with an emitted visible photon.
RESUMO
We stabilize a chosen radio frequency beat note between two optical fields derived from the same mode-locked laser pulse train in order to coherently manipulate quantum information. This scheme does not require access or active stabilization of the laser repetition rate. We implement and characterize this external lock, in the context of two-photon stimulated Raman transitions between the hyperfine ground states of trapped 171Yb(+) quantum bits.
RESUMO
We demonstrate a simple pulse shaping technique designed to improve the fidelity of spin-dependent force operations commonly used to implement entangling gates in trapped ion systems. This extension of the Mølmer-Sørensen gate can theoretically suppress the effects of certain frequency and timing errors to any desired order and is demonstrated through Walsh modulation of a two qubit entangling gate on trapped atomic ions. The technique is applicable to any system of qubits coupled through collective harmonic oscillator modes.