Practical Noise Mitigation for Quantum Annealing via Dynamical Decoupling: Toward Industry-Relevant Optimization using Trapped Ions

TL;DR

This paper demonstrates that applying dynamical decoupling pulses can significantly reduce environmental noise in quantum annealing, improving solution fidelity in trapped-ion systems and other hardware, thus advancing practical quantum optimization.

Contribution

It introduces a noise mitigation protocol using dynamical decoupling tailored for quantum annealing in trapped-ion platforms, showing its effectiveness across various problem sizes and models.

Findings

Dynamical decoupling restores annealing fidelity under magnetic field fluctuations.

Fidelity scales universally with noise amplitude and pulse interval.

Protocol is applicable to diverse quantum annealing hardware implementations.

Abstract

Quantum annealing is a framework for solving combinatorial optimization problems. While it offers a promising path towards a practical application of quantum hardware, its performance in real-world devices is severely limited by environmental noise that can degrade solution quality. We investigate the suppression of local field noise in quantum annealing protocols through the periodic application of dynamical decoupling pulses implementing global spin flips. As test problems, we construct minimal Multiple Object Tracking QUBO instances requiring only five and nine qubits, as well as cutting stock instances of five and six qubits. Moreover, using the Sherrington--Kirkpatrick model, we demonstrate the robustness of our protocol to problem structure and size. To further place our results in a practical context, we consider a trapped-ion platform based on magnetic gradient-induced coupling as a reference architecture, using it to define experimentally realistic noise and coupling parameters. We show that external magnetic field fluctuations, typical in such setups, significantly degrade annealing fidelity, while moderate dynamical decoupling pulse rates, which are achievable in current experiments, restore performance to near-ideal levels. Our analytical and numerical results reveal a universal scaling behavior, with fidelity determined by a generalized parameter combining noise amplitude and dynamical decoupling pulse interval. While our analysis is grounded in the trapped-ion platform, the proposed noise mitigation strategy and resulting performance improvements are applicable to a broad range of quantum annealing implementations and establish a practical and scalable route for error mitigation in near-term devices.