pith. sign in

arxiv: 2604.15550 · v1 · submitted 2026-04-16 · ⚛️ physics.optics · quant-ph

Incoherence-assisted mode excitation in non-Hermitian resonant systems

Amin Hashemi , Vinzenz Zimmermann , Armando Perez-Leija , Andrea Blanco-Redondo This is my paper

Pith reviewed 2026-05-10 09:40 UTC · model grok-4.3

classification ⚛️ physics.optics quant-ph
keywords non-Hermitian photonicstopological edge statesincoherent lightmode excitationSu-Schrieffer-Heeger modelsilicon photonicsring resonators
0
0 comments X

The pith

Incoherent light selectively excites topological edge states in non-Hermitian resonant systems without phase control.

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

The paper establishes that incoherent light can selectively excite specific modes, particularly topological edge states, in non-Hermitian resonant systems. This is shown experimentally using coupled ring resonators on a silicon chip configured as a non-Hermitian Su-Schrieffer-Heeger model. The approach removes the requirement for coherent phase control, making mode preparation more robust and passive. A reader would care because it simplifies access to topological features in photonics, potentially enabling new device designs that rely on protected states. The demonstration confirms that the incoherence works due to the engineered gain-loss profile.

Core claim

We introduce and experimentally demonstrate an approach for selective mode excitation in non-Hermitian resonant systems using incoherent light. This method eliminates the need for precise phase control that is often required in coherent excitation schemes. Using this technique on a silicon photonic platform with coupled ring resonators, we successfully excite the topological edge state of a non-Hermitian Su-Schrieffer-Heeger (SSH) model. Our work shows that incoherence-assisted excitation is a robust and passive strategy for topological state preparation, which broadens the scope of non-Hermitian topological photonics.

What carries the argument

The incoherence-assisted selective excitation mechanism, which uses the gain-loss distribution in the non-Hermitian SSH chain of coupled ring resonators to allow preferential population of the edge state by incoherent input.

If this is right

  • The topological edge state can be prepared using only incoherent illumination, without interferometric phase stabilization.
  • This provides a practical and experimentally viable tool for selective mode excitation in non-Hermitian topological photonics.
  • The method broadens the scope for studying and applying non-Hermitian effects in integrated photonic platforms.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • This technique could be extended to other non-Hermitian lattice models to test if incoherent excitation works generally for edge states.
  • It may allow simpler integration of topological modes into optical circuits for applications like robust light routing or sensing.
  • The passive nature suggests potential for scaling to larger systems where coherent control becomes impractical.

Load-bearing premise

The specific gain and loss distribution in the coupled ring resonator chain must create conditions where the edge state is preferentially excited by incoherent light compared to other modes.

What would settle it

An experiment showing that incoherent light excites the edge state and bulk modes with comparable strength, or that phase control is still required for selectivity, would falsify the central claim.

Figures

Figures reproduced from arXiv: 2604.15550 by Amin Hashemi, Andrea Blanco-Redondo, Armando Perez-Leija, Vinzenz Zimmermann.

Figure 1
Figure 1. Figure 1: FIG. 1. (a) Non-Hermitian SSH model implemented using a 1D array of seven ring resonators. Each unit cell (outlined by [PITH_FULL_IMAGE:figures/full_fig_p005_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Mismatch index [PITH_FULL_IMAGE:figures/full_fig_p005_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. Power spectrum of the ring resonators obtained from experimental measurements (red line) and TCMT analysis [PITH_FULL_IMAGE:figures/full_fig_p006_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. Power spectrum of the ring resonators obtained from experimental measurements (red line) and TCMT analysis [PITH_FULL_IMAGE:figures/full_fig_p006_4.png] view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6. Mismatch index [PITH_FULL_IMAGE:figures/full_fig_p007_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: FIG. 7. Power spectrum of the ring resonators obtained from experimental measurements (red line) and TCMT analysis (dashed [PITH_FULL_IMAGE:figures/full_fig_p008_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: FIG. 8. The spatial power distribution of the edge state (gray [PITH_FULL_IMAGE:figures/full_fig_p008_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: FIG. 9. Spatial power distribution along the ring resonators [PITH_FULL_IMAGE:figures/full_fig_p009_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: FIG. 10. Temporal evolution of the system’s mode for a coher [PITH_FULL_IMAGE:figures/full_fig_p010_10.png] view at source ↗
Figure 11
Figure 11. Figure 11: FIG. 11. Spatial power distribution along the ring resonators [PITH_FULL_IMAGE:figures/full_fig_p011_11.png] view at source ↗
Figure 12
Figure 12. Figure 12: FIG. 12. (a) Schematic of the experimental setup used to ver [PITH_FULL_IMAGE:figures/full_fig_p012_12.png] view at source ↗
Figure 13
Figure 13. Figure 13: FIG. 13. (a) Mismatch index [PITH_FULL_IMAGE:figures/full_fig_p012_13.png] view at source ↗
read the original abstract

We introduce and experimentally demonstrate an approach for selective mode excitation in non-Hermitian resonant systems using incoherent light. This method eliminates the need for precise phase control that is often required in coherent excitation schemes. Using this technique on a silicon photonic platform with coupled ring resonators, we successfully excite the topological edge state of a non-Hermitian Su-Schrieffer-Heeger (SSH) model. Our work shows that incoherence-assisted excitation is a robust and passive strategy for topological state preparation, which broadens the scope of non-Hermitian topological photonics thereby providing a practical and experimentally viable tool for selective mode excitation.

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.

Referee Report

1 major / 2 minor

Summary. The manuscript introduces an incoherence-assisted approach for selective mode excitation in non-Hermitian resonant systems that avoids the phase control required by coherent schemes. It experimentally demonstrates this on a silicon photonic platform consisting of coupled ring resonators, where broadband incoherent light selectively populates the topological edge state of a non-Hermitian Su-Schrieffer-Heeger (SSH) chain while suppressing bulk modes.

Significance. If the experimental results hold, the work provides a practical, passive strategy for topological state preparation in non-Hermitian photonics. The use of incoherent drive on a standard silicon platform removes a significant experimental barrier and could enable broader exploration of non-Hermitian topological phenomena without complex coherent control setups.

major comments (1)
  1. [Experimental Results] Experimental Results section (around Figure 4): the intensity localization data for the edge state under incoherent excitation is presented without quantitative error bars or repeated-measurement statistics; this weakens the claim of robust selectivity relative to bulk modes, as fluctuations in fabrication or source spectrum could mimic the observed localization.
minor comments (2)
  1. [Theory] The gain-loss parameter definition in the theoretical model (Eq. 3) is used inconsistently between the SSH Hamiltonian and the resonator coupling terms; a single consistent notation would improve clarity.
  2. [Figure 3] Figure 3 caption does not specify the normalization procedure for the incoherent versus coherent spectra, making direct visual comparison of selectivity difficult.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their positive summary, recognition of the work's significance, and recommendation for minor revision. We address the single major comment below.

read point-by-point responses

  1. Referee: Experimental Results section (around Figure 4): the intensity localization data for the edge state under incoherent excitation is presented without quantitative error bars or repeated-measurement statistics; this weakens the claim of robust selectivity relative to bulk modes, as fluctuations in fabrication or source spectrum could mimic the observed localization.

    Authors: We agree that the lack of error bars and repeated-measurement statistics in Figure 4 weakens the quantitative support for robustness. In the revised manuscript we will add error bars to the intensity localization data, obtained from measurements on multiple independently fabricated devices and across several realizations of the incoherent source spectrum. These additions will directly quantify the variability due to fabrication tolerances and source fluctuations, thereby strengthening the evidence that the observed edge-state selectivity is not an artifact of such variations. revision: yes

Circularity Check

0 steps flagged

No significant circularity

full rationale

The paper's central result is an experimental demonstration of selective excitation of a topological edge state via incoherent light in a fabricated non-Hermitian SSH chain of coupled silicon ring resonators. No derivation chain, fitted parameters renamed as predictions, or self-referential definitions appear in the abstract or summary; the claim rests on physical device realization and observed steady-state response rather than any mathematical reduction to its own inputs. The SSH model and non-Hermitian gain-loss profile are standard external references, not constructed from the present data.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

Review based on abstract only; no explicit free parameters, invented entities, or detailed axioms are extractable. The work relies on the standard non-Hermitian SSH model as a domain assumption.

axioms (1)
  • domain assumption The non-Hermitian Su-Schrieffer-Heeger model accurately captures the behavior of the coupled ring resonator system for topological edge states.
    Invoked to identify the target mode being excited.

pith-pipeline@v0.9.0 · 5402 in / 1245 out tokens · 64300 ms · 2026-05-10T09:40:24.414236+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

39 extracted references · 39 canonical work pages

  1. [1]

    If the field coupled to the system matches the eigenvector associated with the edge state, the mismatch index is zero. Conversely, as the field cou- pled to the system deviates further from this eigenvector, the system response increasingly differs from the edge state, leading to a higher mismatch index. The spatial distribution of field amplitudes across...

    work page

  2. [2]

    K.¨Ozdemir, S

    S ¸. K.¨Ozdemir, S. Rotter, F. Nori, and L. Yang, Parity– time symmetry and exceptional points in photonics, Na- ture Materials18, 783 (2019)

    work page 2019

  3. [3]

    H. Meng, Y. S. Ang, and C. H. Lee, Exceptional points in non-hermitian systems: Applications and recent devel- opments, Applied Physics Letters124, 060502 (2024)

    work page 2024

  4. [4]

    W. Suh, Z. Wang, and S. Fan, Temporal coupled-mode theory and the presence of non-orthogonal modes in loss- less multimode cavities, IEEE Journal of Quantum Elec- tronics40, 1511 (2004)

    work page 2004

  5. [5]

    Takata and M

    K. Takata and M. Notomi, Photonic topological insulat- ing phase induced solely by gain and loss, Phys. Rev. Lett.121, 213902 (2018)

    work page 2018

  6. [6]

    S. Liu, S. Ma, C. Yang, L. Zhang, W. Gao, Y. J. Xiang, T. J. Cui, and S. Zhang, Gain- and loss-induced topolog- ical insulating phase in a non-hermitian electrical circuit, 13 Phys. Rev. Appl.13, 014047 (2020)

    work page 2020

  7. [7]

    H. T. Teo, H. Xue, and B. Zhang, Topological phase tran- sition induced by gain and loss in a photonic chern insu- lator, Phys. Rev. A105, 053510 (2022)

    work page 2022

  8. [8]

    Hashemi, E

    A. Hashemi, E. L. Pereira, H. Li, J. L. Lado, and A. Blanco-Redondo, Observation of non-hermitian topol- ogy from optical loss modulation, Nature Materials 10.1038/s41563-025-02278-8 (2025)

    work page doi:10.1038/s41563-025-02278-8 2025

  9. [9]

    Hatano and D

    N. Hatano and D. R. Nelson, Localization transitions in non-hermitian quantum mechanics, Phys. Rev. Lett.77, 570 (1996)

    work page 1996

  10. [10]

    Yao and Z

    S. Yao and Z. Wang, Edge states and topological in- variants of non-hermitian systems, Phys. Rev. Lett.121, 086803 (2018)

    work page 2018

  11. [11]

    Zhang, T

    X. Zhang, T. Zhang, M.-H. Lu, and Y.-F. C. and, A review on non-hermitian skin effect, Advances in Physics: X7, 2109431 (2022)

    work page 2022

  12. [12]

    Price, Y

    H. Price, Y. Chong, A. Khanikaev, H. Schomerus, L. J. Maczewsky, M. Kremer, M. Heinrich, A. Szameit, O. Zil- berberg, Y. Yang, B. Zhang, A. Al` u, R. Thomale, I. Carusotto, P. St-Jean, A. Amo, A. Dutt, L. Yuan, S. Fan, X. Yin, C. Peng, T. Ozawa, and A. Blanco- Redondo, Roadmap on topological photonics, Journal of Physics: Photonics4, 032501 (2022)

    work page 2022

  13. [13]

    Q. Yan, B. Zhao, R. Zhou, R. Ma, Q. Lyu, S. Chu, X. Hu, and Q. Gong, Advances and applications on non- hermitian topological photonics, Nanophotonics12, 2247 (2023)

    work page 2023

  14. [14]

    Nasari, G

    H. Nasari, G. G. Pyrialakos, D. N. Christodoulides, and M. Khajavikhan, Non-hermitian topological photonics, Opt. Mater. Express13, 870 (2023)

    work page 2023

  15. [15]

    Hashemi, M

    A. Hashemi, M. J. Zakeri, P. S. Jung, and A. Blanco- Redondo, Topological quantum photonics, APL Photon- ics10, 010903 (2025)

    work page 2025

  16. [16]

    Blanco-Redondo, I

    A. Blanco-Redondo, I. Andonegui, M. J. Collins, G. Harari, Y. Lumer, M. C. Rechtsman, B. J. Eggleton, and M. Segev, Topological optical waveguiding in silicon and the transition between topological and trivial defect states, Phys. Rev. Lett.116, 163901 (2016)

    work page 2016

  17. [17]

    Blanco-Redondo, B

    A. Blanco-Redondo, B. Bell, D. Oren, B. J. Eggleton, and M. Segev, Topological protection of biphoton states, Science362, 568 (2018)

    work page 2018

  18. [18]

    Y. Pang, J. E. Castro, T. J. Steiner, L. Duan, N. Tagli- avacche, M. Borghi, L. Thiel, N. Lewis, J. E. Bowers, M. Liscidini, and G. Moody, Versatile chip-scale platform for high-rate entanglement generation using an AlGaAs microresonator array, PRX Quantum6, 010338 (2025)

    work page 2025

  19. [19]

    Koch and J

    F. Koch and J. C. Budich, Quantum non-hermitian topo- logical sensors, Phys. Rev. Res.4, 013113 (2022)

    work page 2022

  20. [20]

    McDonald and A

    A. McDonald and A. A. Clerk, Exponentially-enhanced quantum sensing with non-hermitian lattice dynamics, Nature Communications11, 5382 (2020)

    work page 2020

  21. [21]

    Miri and A

    M.-A. Miri and A. Al` u, Exceptional points in optics and photonics, Science363, eaar7709 (2019)

    work page 2019

  22. [22]

    Vahala, Optical Microcavities (WORLD SCIEN- TIFIC, 2004)

    K. Vahala, Optical Microcavities (WORLD SCIEN- TIFIC, 2004)

    work page 2004

  23. [23]

    Van, Optical Microring Resonators (CRC Press, 2017)

    V. Van, Optical Microring Resonators (CRC Press, 2017)

    work page 2017

  24. [24]

    Zimmermann, A

    V. Zimmermann, A. Hashemi, K. Busch, A. Blanco- Redondo, and A. Perez-Leija, Coherence-independent non-hermitian topological filters, Phys. Rev. A112, 063519 (2025)

    work page 2025

  25. [25]

    D. G. Baranov, A. Krasnok, and A. Al` u, Coherent vir- tual absorption based on complex zero excitation for ideal light capturing, Optica4, 1457 (2017)

    work page 2017

  26. [26]

    Longhi, Coherent virtual absorption for discretized light, Opt

    S. Longhi, Coherent virtual absorption for discretized light, Opt. Lett.43, 2122 (2018)

    work page 2018

  27. [27]

    Zhong, L

    Q. Zhong, L. Simonson, T. Kottos, and R. El-Ganainy, Coherent virtual absorption of light in microring res- onators, Phys. Rev. Res.2, 013362 (2020)

    work page 2020

  28. [28]

    S. Fan, W. Suh, and J. D. Joannopoulos, Temporal coupled-mode theory for the fano resonance in optical resonators, J. Opt. Soc. Am. A20, 569 (2003)

    work page 2003

  29. [29]

    Paul and J

    W. Paul and J. Baschnagel, Stochastic Processes: From Physics to Finance (Springer, 2013)

    work page 2013

  30. [30]

    Øksendal, Stochastic Differential Equations (Springer, 2003)

    B. Øksendal, Stochastic Differential Equations (Springer, 2003)

    work page 2003

  31. [31]

    MANDEL and E

    L. MANDEL and E. WOLF, Coherence properties of op- tical fields, Rev. Mod. Phys.37, 231 (1965)

    work page 1965

  32. [32]

    J. W. Goodman, Statistical Optics, 2nd ed. (Wiley, 2015)

    work page 2015

  33. [33]

    Hashemi, K

    A. Hashemi, K. Busch, D. N. Christodoulides, S. K. Ozdemir, and R. El-Ganainy, Linear response theory of open systems with exceptional points, Nature Communi- cations13, 3281 (2022)

    work page 2022

  34. [34]

    W. P. Su, J. R. Schrieffer, and A. J. Heeger, Solitons in polyacetylene, Phys. Rev. Lett.42, 1698 (1979)

    work page 1979

  35. [35]

    Lieu, Topological phases in the non-hermitian su- schrieffer-heeger model, Phys

    S. Lieu, Topological phases in the non-hermitian su- schrieffer-heeger model, Phys. Rev. B97, 045106 (2018)

    work page 2018

  36. [36]

    Hashemi, A

    A. Hashemi, A. Shiri, B. E. A. Saleh, A. Blanco-Redondo, and A. F. Abouraddy, Programmable on-chip synthesis and reconstruction of partially coherent two-mode optical fields (2026), arXiv:2601.09802 [physics.optics]

    work page arXiv 2026

  37. [37]

    Hashemi, A

    A. Hashemi, A. Shiri, B. E. A. Saleh, A. Blanco- Redondo, and A. F. Abouraddy, On-chip control of the coherence matrix of four-mode partially coherent light: rank, entropy, and modal stokes parameters (2026), arXiv:2601.18797 [physics.optics]

    work page arXiv 2026

  38. [38]

    Parra, J

    J. Parra, J. Navarro-Arenas, and P. Sanchis, Silicon thermo-optic phase shifters: a review of configurations and optimization strategies, Advanced Photonics Nexus 3, 10.1117/1.apn.3.4.044001 (2024)

    work page doi:10.1117/1.apn.3.4.044001 2024

  39. [39]

    Binder and D

    K. Binder and D. W. Heermann, Monte Carlo Simulation in Statistical Physics, 5th ed. (Springer, 2010)

    work page 2010