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arxiv: 2604.15799 · v1 · submitted 2026-04-17 · 🪐 quant-ph · physics.atom-ph· physics.comp-ph· physics.optics

Spectral design principles for local-excitation retention in impurity-assisted atomic arrays

Junpei Oba This is my paper

Pith reviewed 2026-05-10 08:30 UTC · model grok-4.3

classification 🪐 quant-ph physics.atom-phphysics.comp-phphysics.optics
keywords designlocal-excitationretentionspectralarraysatomicdecaydynamics
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The pith

Spectral design via biorthogonal modes and a surrogate objective enables inverse design of atomic positions that concentrate initial excitation on a single subradiant mode for enhanced local-excitation retention.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

Groups of atoms can interact through light they emit, creating collective modes where some decay slowly. In this setup, one atom starts excited while others are not. The key insight is that how long the excitation stays local depends on how much it overlaps with each slow-decaying mode, not only the slowest one. The authors define a score that rewards arrangements where most of the initial excitation sits in one slow mode. They then adjust atom positions, keeping them from getting too close, and find irregular patterns that keep the excitation alive longer than regular grids.

Core claim

the survival dynamics are jointly governed by the decay rates of the eigenmodes and their overlaps with the initial excitation. ... introduce a physically motivated spectral surrogate objective that favors both small weighted decay rates and an initial-state weight concentrated on a single subradiant mode. As a proof of principle ... obtain nontrivial aperiodic configurations with enhanced local-excitation retention.

Load-bearing premise

The effective non-Hermitian Hamiltonian plus biorthogonal decomposition fully captures the no-drive dynamics, and the numerical optimization under minimum-distance constraints reaches configurations that are both physically realizable and globally superior to periodic ones.

Figures

Figures reproduced from arXiv: 2604.15799 by Junpei Oba.

Figure 1
Figure 1. Figure 1: FIG. 1. Conceptual diagram of considered system. [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Atomic configurations. The orange dot indicates the storage atom prepared in the excited state at [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. (a) Decay dynamics for different atomic configurations. The gray dotted line indicates the free-space decay dynamics [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. (a) Example of pronounced oscillations in excitation [PITH_FULL_IMAGE:figures/full_fig_p005_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5. Optimized atomic configurations for [PITH_FULL_IMAGE:figures/full_fig_p006_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6. Real parts of eigenstates with the largest weights for [PITH_FULL_IMAGE:figures/full_fig_p007_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: FIG. 7. (a) Relationship between integrated dimensionless [PITH_FULL_IMAGE:figures/full_fig_p008_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: FIG. 8. Scatter plots comparing surrogate score [PITH_FULL_IMAGE:figures/full_fig_p009_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: FIG. 9. Same as Fig. 5 but for [PITH_FULL_IMAGE:figures/full_fig_p010_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: FIG. 10. Same as Fig. 6 but for [PITH_FULL_IMAGE:figures/full_fig_p010_10.png] view at source ↗
Figure 13
Figure 13. Figure 13: shows the corresponding dependence on the perturbed ring seeds for n = 10. As in the n = 12 case, the results for rmin/λ0 = 0.2 are concentrated in a rela￾tively narrow range, whereas those for rmin/λ0 = 0.1 are more broadly distributed and reach lower cost-function values, reflecting the enlarged search space under the re￾laxed minimum-distance constraint. The most frequent structure in [PITH_FULL_IMAGE… view at source ↗
Figure 12
Figure 12. Figure 12: FIG. 12. (a) Distribution of weight and decay rate of eigen [PITH_FULL_IMAGE:figures/full_fig_p011_12.png] view at source ↗
Figure 14
Figure 14. Figure 14: FIG. 14. Excitation dynamics of optimized structures (solid lines). The dashed lines show the median over 100 fluctuation [PITH_FULL_IMAGE:figures/full_fig_p012_14.png] view at source ↗
read the original abstract

Enhanced local-excitation retention in atomic arrays allows to exploit cooperative radiative effects to suppress emission and prolong excited-state lifetimes. We consider an impurity-assisted setting involving a single storage atom being initially excited and study the survival of local excitation under neither write nor retrieval fields. Because the corresponding dynamics can involve multiple interfering collective modes, the survival dynamics cannot determined from the smallest collective decay rate alone. Thus, using a biorthogonal eigenmode decomposition of an effective non-Hermitian Hamiltonian, we show that the survival dynamics are jointly governed by the decay rates of the eigenmodes and their overlaps with the initial excitation. Large oscillations occur when multiple long-lived modes have comparable weights. Accordingly, we introduce a physically motivated spectral surrogate objective that favors both small weighted decay rates and an initial-state weight concentrated on a single subradiant mode. As a proof of principle of this spectral design, we apply the surrogate to constrained atom-position optimization under minimum-distance constraints and obtain nontrivial aperiodic configurations with enhanced local-excitation retention. Our findings unveil spectral design principles for local-excitation retention in impurity-assisted atomic arrays and provide a proof of principle for their inverse design.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Circularity Check

0 steps flagged

No significant circularity; surrogate is a derived heuristic for independent optimization

full rationale

The paper first derives (via biorthogonal decomposition of the position-dependent non-Hermitian Hamiltonian) that local-excitation survival depends on both eigenmode decay rates and initial-state overlaps. It then defines a surrogate objective that penalizes weighted decay rates while favoring concentration on one subradiant mode. This surrogate is applied as an objective for numerical position optimization under distance constraints. The resulting configurations are evaluated for actual retention improvement. This constitutes standard model-based design rather than any self-definitional loop, fitted-input prediction, or self-citation chain; the optimization searches the configuration space using the model, and the retention claim rests on the simulated dynamics of the discovered arrays, not on the surrogate by construction. No load-bearing step reduces to its own inputs.

Axiom & Free-Parameter Ledger

1 free parameters · 1 axioms · 0 invented entities

The central claim rests on standard open-quantum-system modeling plus a newly defined surrogate; no new particles or forces are postulated.

free parameters (1)
  • minimum inter-atom distance constraint
    Hard constraint in the position optimization; its specific value is chosen for physical realism but not derived from first principles.
axioms (1)
  • domain assumption Effective non-Hermitian Hamiltonian plus Markovian approximation accurately describes the collective radiative dynamics in the absence of external fields
    Invoked when the biorthogonal eigenmode decomposition is introduced to analyze survival dynamics.

pith-pipeline@v0.9.0 · 5500 in / 1292 out tokens · 28640 ms · 2026-05-10T08:30:45.928129+00:00 · methodology

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