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arXiv:2606.25587

Controlling radiative dynamics of a giant $Λ$-type atom via interference induced by the vacuum of a waveguide

Ci-Ming Deng, Ge Sun, Jing Lu, Lan Zhou

quant-phSubmitted Jun 24, 2026• Announced Jun 25, 2026• 0 citations
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Abstract

We investigate the dynamics of a $Λ$-type giant atom (GA) whose both transition coupled to the guided modes of a one-dimensional (1D) waveguide at two spatially separated points with the GA initially excited and the electromagnetic (EM) modes of waveguide in vacuum. The spontaneous emission properties of this GA is investigated by solving the delay-differential equation for the amplitude of the 3GA in its excited state. Signatures of non-Markovian behavior is manifested in a population trapping in the excited state of the GA in the regime where the distance $d$ of the coupling points is smaller or comparable to the coherent length $L$ characterizing the width of the emitted wave packet. And an exact Markovian dynamics is also found when $d\geq L$ via the inference by adjusting the energy spacing and the inherent time delay besides the complex phases in the atom-light coupling, matching the behavior of a small atom coupled to a waveguide.

Comments
9 pages, 5 figures

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Controlling radiative dynamics of a giant ΛΛΛ-type atom via interference induced by the vacuum of a waveguide
We investigate the dynamics of a ΛΛΛ-type giant atom (GA) whose both transition coupled to the guided modes of a one-dimensional (1D) waveguide at two spatially separated points with the GA initially excited and the electromagnetic (EM) modes of waveguide in vacuum. The spontaneous emission properties of this GA is investigated by solving the delay-differential equation for the amplitude of the 3GA in its excited state. Signatures of non-Markovian behavior is manifested in a population trapping in the excited state of the GA in the regime where the distance ddd of the coupling points is smaller or comparable to the coherent length LLL characterizing the width of the emitted wave packet. And an exact Markovian dynamics is also found when d≥Ld\geq Ld≥L via the inference by adjusting the energy spacing and the inherent time delay besides the complex phases in the atom-light coupling, matching the behavior of a small atom coupled to a waveguide.
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