Efficient optical configurations for trapped-ion entangling gates
Phys. Rev. A 113, 042424 – Published 10 April, 2026
DOI: https://doi.org/10.1103/ly5s-tjk2
Abstract
High-fidelity and parallel realization in scalable platforms of the two-qubit entangling gates fundamental to universal quantum computing constitutes one of the largest challenges in implementing fault-tolerant quantum computation. Integrated optical addressing of trapped ions offers routes to scaling the high-fidelity optical control demonstrated to date in small systems. Here we show that capabilities practically enabled by integrated optics can additionally alleviate laser powers required for both light-shift and Mølmer-Sørensen geometric phase gates acting on long-lived ground-state qubit encodings in a broad range of ion species. We present a theoretical analysis of spontaneous photon scattering (SPS) in stimulated Raman processes driven by spatially structured drive fields, which we employ to assess trapped-ion gates utilizing carrier nulling via ion positioning at phase-stable standing-wave (SW) nodes. Our calculations indicate that suppressed SPS at intensity nodes allows for gate drives operating at smaller Raman detunings and, as a result, approximately an order-of-magnitude lower power (with significantly larger enhancement in certain parameter regimes) for gates of a given duration and scattering-limited fidelity as compared with gates using running-wave fields. The SW schemes have the additional benefit of eliminating undesired coherent couplings that can limit gate speeds. Our work quantifies power requirements for multiple ion species and enhancements to be expected from carrier-nulled configurations practically enabled by integrated delivery, and informs experiments and systems for the realization of fast and power-efficient laser-based entangling gates in scalable platforms. Our analysis further suggests potential for structured drive fields to mitigate power and scattering limitations in stimulated Raman processes coupling to atomic motion more broadly in both trapped ions and neutral atoms.
