Entangling ions with engineered light gradients
Abstract
Spectral crowding of collective motional modes limits the fidelity of entangling interactions in trapped-ion quantum processors by inducing off-resonant coupling to spectator modes. We introduce a geometric-phase entangling interaction driven by a transverse, time-dependent structured-light force. By applying the force in a plane orthogonal to the optical propagation direction, we reduce the effects of spectral crowding while preserving single-ion addressing. The scheme is compatible with arbitrary qubit encodings, provided that the qubit states experience a differential AC Stark shift. We experimentally realise high-fidelity two-qubit gates with error rates below in ion crystals containing up to 12 ions confined within a single potential well. These results establish gradient-field light-shift gates as a scalable approach to high-fidelity entangling generation in spectrally crowded trapped-ion systems.
Cite
@article{arxiv.2603.07548,
title = {Entangling ions with engineered light gradients},
author = {Tommaso Faorlin and Lorenz Panzl and Phoebe Grosser and Pablo Viñas and Alan Kahan and Walter Joseph Hörmann and Yannick Weiser and Giovanni Cerchiari and Thomas Feldker and Alexander Erhard and Georg Jacob and Juris Ulmanis and Rainer Blatt and Alejandro Bermudez and Thomas Monz},
journal= {arXiv preprint arXiv:2603.07548},
year = {2026}
}