Southwest Quantum Information and Technology

Raman scattering errors in metastable 40Ca+ trapped-ion qubits and implementation of Raman gates

Presenting Author: Isam Moore, University of Oregon
Contributing Author(s): Jeremy Metzner, Alexander Quinn, Sean Brudney, Gabe Gregory, Wes Campbell, Eric Hudson, David Wineland, David Allcock

Trapped-ion qubits encoded in metastable states (m qubits) are of interest for their use in the omg qubit scheme, which allows multi-species functionality with a single ion species (See Allcock et al., Appl. Phys. Lett., 119 (2021)). We present an implementation of m qubits in the D5/2 manifold of 40Ca+. Single-qubit stimulated-Raman gates in m qubits are demonstrated and characterized. We use 976 nm laser beams (detuned 44 THz red of the 854 nm P3/2 ↔ D5/2 transition) in order to achieve low spontaneous Raman scattering errors. We compare these observed scattering errors to theory, accounting for effects relevant at large detunings. We also consider these effects in models for scattering in stimulated-Raman driven qubits in the S1/2 manifold (g qubits) and predict markedly different scattering behavior in the far-detuned regime than previous models. Finally, we present experimental progress towards implementing a two-qubit light-shift gate on m qubits using far-detuned Raman beams. Support from ARO.

(Session 5 : Thursday from 5:00 pm - 7:00 pm)