Work

Multi-ion entangling gates mediated by spectrally unresolved modes

Year: 2026

Type: article

Abstract: High-fidelity entangling gates in trapped-ion processors are most commonly realized by spectrally isolating a single motional bus mode. As the ion chain grows, however, the coupling of each ion to any one mode weakens, making single-mode gates progressively slower. Existing multimode schemes offer a partial remedy but rely on perturbative driving and rotating-wave approximations, imposing trade-offs between speed and fidelity that become more severe with chain length. We introduce a nonperturbative magnetic-gradient scheme in which all axial motional modes participate collectively in mediating the entangling interaction. Exact spin-motion decoupling is enforced at the end of the protocol by construction, so that the achievable gate speed is limited only by the available gradient strength and control bandwidth. The framework supports both multiqubit gates and selective two-qubit gates between arbitrary pairs in a linear string, including simultaneous operation on multiple pairs, and remains effective as the ion number increases.

Source: Physical Review A

DOI: 10.1103/357p-y5qf

Authors: Modesto Orozco-Ruiz, Florian Mintert

Institution: Imperial College London

Language: English

Topic: Quantum Information and Cryptography

Subfield: Artificial Intelligence

Field: Computer Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $2,675

Funder: Engineering and Physical Sciences Research Council