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arXiv · 2601.03383

Non-Markovian dynamics of the giant atom beyond the rotating-wave approximation

Mei Yu·Walter T. Strunz·Stefan Nimmrichter
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Abstract

We study the non-Markovian dynamics of a giant artificial atom coupled to a one-dimensional acoustic waveguide beyond the rotating-wave and weak-coupling approximations. By combining an optimized ESPRIT-based decomposition of the bath correlation function with the hierarchical equations of motion (HEOM), we achieve numerically exact simulations in regimes with long memory times, finite temperature, and strong system-bath coupling. Benchmarking against analytical results reveals the breakdown of perturbative non-Markovian approaches such as Redfield theory even at weak coupling in the presence of delay-induced memory. We further show that non-Markovian features, including excitation revivals, remain robust at finite temperature and can be enhanced by increasing the system-bath coupling strength. Our approach provides a versatile framework for studying non-Markovian quantum dynamics in structured environments relevant to giant-atom platforms.

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Mei Yu, Walter T. Strunz, Stefan Nimmrichter. 2026-01-06. Non-Markovian dynamics of the giant atom beyond the rotating-wave approximation. https://arxiv.org/abs/2601.03383

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