Towards spin-spin, spin-boson, and boson-boson coherent control in a multi-ion crystal*

Control over the phase of optical addressing fields in the trapped-ion platform enables coherent manipulation of the spin and motional states of the ion. Precise phase control in both traveling-wave and standing-wave configurations has been demonstrated in recent years. This capability is a resource for fast spin-spin entangling gates [1]; spin-boson interactions and preparation of Gaussian and non-Gaussian ion motional states [2,3]; and boson-boson interactions, such as two-mode squeezing in the radial modes of a single trapped ion. We report on the implementation of this suite of interactions, and progress toward a linear chain of ⁴⁰Ca⁺ ions with individually addressed phase-stable standing waves. Together, these experiments open the door for intermediate-scale, fast, and high-fidelity any-to-any two-qubit gates, continuous variable quantum computation, quantum simulation of chemical processes and many-body physics, and quantum computation of Feynman diagrams [4].

[1] S. Saner, O. Băzăvan, et al., Phys. Rev. Lett. 131, 220601 (2023). 

[2] O. Băzăvan, S. Saner, et al., arXiv:2403.05471 (2024). 

[3] S. Saner, O. Băzăvan, et al., arXiv:2409.03482 (2024). 

[4] S. Varona, et al., arXiv:2411.05092 (2024).