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Cited by 11Orbital Angular Momentum in OpticsOptical Wireless Communication TechnologiesQuantum Information and Cryptography

The DOI matches its Crossref record; 86 of the 86 references it cites were found in a registry or an index; 11 of the 49 sources its claims cite were checked for support.

Topological robustness of optical skyrmions through a real-world free-space link

Open access
Peters, Cade, Hakobyan, Vagharshak, Drozdov, Alice, Brasselet, Etienne, Cox, Mitchell, Forbes, Andrew·2026·Science Advances
DOI 10.1126/sciadv.aee2671PMC PMC13475490
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Abstract

Structured light offers a promising solution for the increasing data demands of modern optical networks, opening up degrees of freedom that can be leveraged for greater channel capacity and more bits per photon. However, its implementation is hindered by real-world distortions, for example, atmospheric turbulence in free space, with severe and rapidly evolving phase perturbations that alter the amplitude, phase, and vectorial polarization structure of the beam. Here, we demonstrate that optical topologies in the form of skyrmions are highly resilient to the effects of real-world atmospheric turbulence. We create and transmit these particle-like topologies of light through a 270-meter free-space optical link, revealing their robustness across a wide variety of conditions and turbulence strengths. While we observe severe distortion in the states’ underlying degrees of freedom, we show that the topological numbers are preserved in all cases. We account for fast changes to the medium, where the channel produces statistically averaged outcomes, by probing the state’s decoherence, showing that while the degree of polarization consequently decays, the topology remains intact. Using topology, we show that information can be transmitted through the channel with almost perfect fidelity (>98%) in most cases, only decreasing to 86% in the most severe conditions tested. This work idemonstrates the potential for optical topologies as reliable and robust information carriers in a real-world environment and points to the potential for other complex channels too, offering attractive features for classical and quantum communication alike.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

Optical skyrmions with wrapping numbers N=1,2,3 retained their topological number through a 270-m real-world atmospheric free-space link despite severe amplitude, phase, and polarization distortion. Topology also survived depolarization/decoherence and enabled image transmission with 98.70%, 86.93%, 98.60%, and 99.72% fidelity across conditions.

Key findings

  • Skyrmion numbers were preserved through the 270-m link across morning, midday, and late-afternoon turbulence. Measured values included Nexp=0.81±0.01 and 2.063±0.003 in the morning, Nexp=0.95±0.07 and 2.19±0.09 at midday, and Nexp=0.97±0.02 and 1.83±0.04 in the late afternoon for encoded N=1 and N=2.
  • Turbulence strength varied widely: average scintillation index σI²≈0.007 in the morning, σI²≈1.4 at midday, and σI²≈0.23 in the late afternoon. Even at midday, the encoded topology remained discernible.
  • Under decoherence/depolarization from averaging over 2 to 240 ms, the skyrmion number remained almost perfectly unchanged for N=1,2,3 while the degree of polarization dropped from ≈0.84 to ≈0.39.
  • Topology encoded a 512 by 560 three-color image with fidelities of 98.70% in the morning, 86.93% at midday, 98.60% in the late afternoon, and 99.72% when averaged over 240 ms.

Methods

  • A 532-nm laser was shaped with a spatial light modulator and modified Mach-Zehnder interferometer into vector beams of the form U(r)=LG_l1^0(r)e_R + LG_l2^0(r)e_L, with l1=1,2,3 and l2=0 to generate skyrmions with N=1,2,3; the transmitted beam had an embedded Gaussian waist w0=6 mm.
  • The beams were sent through a 270-m outdoor free-space link on the Braamfontein campus of the University of the Witwatersrand, Johannesburg, using a round trip to a mirror ∼135 m away, with the receiver offset by roughly 60 cm.
  • At the receiver, single-shot spatially resolved Stokes polarimetry used a 50:50 beam splitter, quarter-wave plate, and polarization-sensitive camera (Allied Vision Mako G-508B POL) to measure H, V, D, A, R, and L projections; skyrmion number was computed from the Stokes vector field via Eq. 2, with measurements over ∼120 s, 2-ms exposures, and averaging up to 240 ms.

Limitations

  • Stated in the paper: Stokes-polarimetry wrapping-number calculations are prone to errors and fluctuations from ambient noise, limited region of interest, nonsymmetrical beam profiles, and differing path lengths for polarization projections; high-speed modulation/detection is challenging because the SLM refresh rate is 120 Hz and camera acquisition time is 2 ms, and no dedicated skyrmion mode sorter exists.
  • Stated in the paper: higher-order topologies experienced stronger turbulence because LG transverse beam size scales with OAM, so a fair comparison of robustness across different N cannot be made from these results; this remains an open question.
  • Stated in the paper: skyrmion states of different N are not generally spatially orthogonal, so the scheme is index modulation rather than conventional mode-division multiplexing; quantifying cross-talk penalties for a SIC-based multiplexing scheme under realistic turbulence remains open. Evident from the text: the demonstration uses one real-world link, location, and set of time-of-day conditions, with no channel probing or pre-/post-correction, and classical light is used to infer relevance to quantum skyrmions by mathematical analogy.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1126/sciadv.aee2671

Cites

86 of 86 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

11 of 49 cited sources checked · 4 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    Skyrmionic topologies do not require the channel to be unitary, only that it be map preserving.

    “Skyrmionic topologies, on the other hand, do not require the channel to be unitary, only that it be map preserving”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [68] R. de Mello Koch, B.-Q. Lu, P. Ornelas, I. Nape, A. Forbes, Quantum skyrmions in general quantum channels. APL Quantum 2, 026126 (2025). PMC11937260 40133306 source

      Section V (page unavailable) supports the point that a channel need not be unitary: Skyrmion topology is preserved when its effect is a smooth deformation of the map. But the paper does not say that merely being “map preserving” suffices; Section IX also requires conditions for the map to define an integer Skyrmion number. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
  • Findingown data

    Severe distortion is observed in the states' underlying degrees of freedom.

    “While we observe severe distortion in the states’ underlying degrees of freedom”
    Quote in the paperSubstantial claim
  • Findingown data

    Fidelity decreases to 86% in the most severe conditions tested.

    “only decreasing to 86% in the most severe conditions tested.”
    Quote in the paperSubstantial claim
  • Findingown data

    The topological numbers are preserved in all cases.

    “we show that the topological numbers are preserved in all cases.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The atmospheric turbulence channel can be treated as a smooth deformation of the skyrmion map, so that the topological wrapping number is preserved.
  • Findingown data

    Using topology, information can be transmitted through the channel with almost perfect fidelity (>98%) in most cases.

    “Using topology, we show that information can be transmitted through the channel with almost perfect fidelity (>98%) in most cases”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim. 19
  • It may state two separate claims as one. 36
  • The quote only partly states this claim. 5

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

    Premisecitation

    Nonlocal quantum skyrmions are immune to the effects of entanglement decay and isotropic noise.

    “Likewise, it has also been demonstrated that nonlocal quantum skyrmions are immune to the effects of entanglement decay (57) and isotropic noise (58).”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [57] P. Ornelas, I. Nape, R. de Mello Koch, A. Forbes, Non-local skyrmions as topologically resilient quantum entangled states of light. Nat. Photonics 18, 258– 266 (2024). source

      The ‘Topology and entanglement’ section reports that the quantum skyrme number remains intact as entanglement decays. But it falls to zero when entanglement vanishes, so ‘immune’ overstates the result: the demonstrated resilience is conditional and concerns topology, not entanglement itself. The isotropic-noise claim is attached to a different citation. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [58] P. Ornelas, I. Nape, R. de Mello Koch, A. Forbes, Topological rejection of noise by quantum skyrmions. Nat. Commun. 16, 2934 (2025). 40133306 PMC11937260 source

      The Introduction and Discussion report that nonlocal quantum-skyrmion topology remains resilient to isotropic noise while entanglement measures decay. But the Discussion says the topology collapses once no entanglement remains, so the unqualified claim of immunity overstates the result. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • It may state two separate claims as one.

    Premisecitation

    Nonuniform refractive index profiles caused by variations in temperature and pressure result in unwanted coupling within high-dimensional degrees of freedom in classical links and a loss of entanglement for quantum channels.

    “Nonuniform refractive index profiles caused by variations in temperature and pressure result in unwanted coupling within these high-dimensional DoFs in classical links (23–27) and a loss of entanglement for quantum channels (28–33)”
    Quote in the paperSubstantial claim6 of 10 sources checked
    • cites [23] J. A. Anguita, M. A. Neifeld, B. V. Vasic, Turbulence-induced channel crosstalk in an orbital angular momentum-multiplexed free-space optical link. Appl. Optics 47, 2414– 2429 (2008). 18449308 source
    • cites [24] B. Rodenburg, M. P. J. Lavery, M. Malik, M. N. O’Sullivan, M. Mirhosseini, D. J. Robertson, M. Padgett, R. W. Boyd, Influence of atmospheric turbulence on states of light carrying orbital angular momentum. Opt. Lett. 37, 3735– 3737 (2012). 22941007 source
    • cites [25] L. Zhang, F. Shen, B. Lan, A. O. Tang, Mode-dependent crosstalk and detection probability of orbital angular momentum of optical vortex beam through atmospheric turbulence. J. Opt. 22, 075607 (2020). source
    • cites [26] C. Paterson, Atmospheric turbulence and orbital angular momentum of single photons for optical communication. Phys. Rev. Lett. 94, 153901 (2005). 15904145 source
    • cites [27] M. A. Cox, L. Maqondo, R. Kara, G. Milione, L. Cheng, A. Forbes, The resilience of hermite–and laguerre–gaussian modes in turbulence. J. Lightwave Technol. 37, 3911– 3917 (2019). source

      The Atmospheric Turbulence section links varying refractive indices mainly to temperature variations and convective processes. The Introduction says turbulence causes modal crosstalk in free-space optical links, supporting the classical-link portion of the sentence. Our copy does not identify pressure variations as a cause; the separate quantum-channel clause is attached to a different citation range. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites [28] A. K. Jha, G. A. Tyler, R. W. Boyd, Effects of atmospheric turbulence on the entanglement of spatial two-qubit states. Phys. Rev. A 81, 053832 (2010). source
    • cites [29] A. Hamadou Ibrahim, F. S. Roux, M. McLaren, T. Konrad, A. Forbes, Orbital-angular-momentum entanglement in turbulence. Phys. Rev. A 88, 012312 (2013). source
    • cites [30] C. Gopaul, R. Andrews, The effect of atmospheric turbulence on entangled orbital angular momentum states. New J. Phys. 9, 94 (2007). source

      The Conclusions report that joint detection probabilities for entangled OAM photons decay as atmospheric turbulence increases and discuss the implications for quantum communication. The paper does not directly measure or establish a loss of entanglement itself. The classical-link coupling clause is attached to a different citation group and is not judged here. (LLM, conf=0.83)

      Experimental — accuracy not yet measured
    • cites [31] B.-J. Pors, C. H. Monken, E. R. Eliel, J. P. Woerdman, Transport of orbital-angular-momentum entanglement through a turbulent atmosphere. Opt. Express 19, 6671– 6683 (2011). 21451694 source

      The experimental-setup section reports refractive-index fluctuations produced by mixing hot and cold air, and the Abstract reports that stronger turbulence degrades the quantum channel’s Shannon dimensionality. This supports turbulence-related degradation in a quantum OAM link, but the paper measures channel dimensionality rather than directly establishing a loss of entanglement; it does not identify pressure variations as a cause. The classical-link coupling clause is attached to other citations, not this source. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites [32] N. D. Leonhard, V. N. Shatokhin, A. Buchleitner, Universal entanglement decay of photonic-orbital-angular-momentum qubit states in atmospheric turbulence. Phys. Rev. A 91, 012345 (2015). source

  • Probably not a substantial claim.

    Premisecitation

    The mapping from real-space to a given parameter space is preserved so long as the channel can be described as a smooth deformation of the map.

    “where the mapping from real-space to a given parameter space is preserved, so long as the channel can be described as a smooth deformation of the map.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [52] Y. Shen, Q. Zhang, P. Shi, D. Luping, X. Yuan, A. V. Zayats, Optical skyrmions and other topological quasiparticles of light. Nat. Photonics 18, 15– 25 (2024). source

      The 'Skyrmions in free-space fields' section says that an optical skyrmion’s topology and skyrmion number remain invariant during propagation and are resilient to perturbations, except catastrophic events such as strong scattering. Box 1 discusses mappings between parameter space and real space. The copy does not state the claim’s specific condition that a channel preserves the mapping whenever it acts as a smooth deformation; it supports preservation of topology in the optical settings discussed, not that general criterion. (LLM, conf=0.82)

      Experimental — accuracy not yet measured

  • It may state two separate claims as one.

    Premisecitation

    There is now no analogous sorter for skyrmion states, unlike OAM for which mode sorters based on log-polar transformations exist.

    “Unlike OAM, for which mode sorters based on log-polar transformations exist (78), there is now no analogous sorter for skyrmion states.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [78] G. Ruffato, M. Massari, G. Parisi, F. Romanato, Test of mode-division multiplexing and demultiplexing in free-space with diffractive transformation optics. Opt. Express 25, 7859– 7868 (2017). 28380904 source

  • The quote only partly states this claim.

    Findingown data

    The topology remains intact despite the decay in degree of polarization.

    “the topology remains intact.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The skyrmion number computed from the normalized Stokes vector remains a valid topological invariant for partially depolarized beams, even when the degree of polarization is as low as 0.39.

  • It may state two separate claims as one.

    Findingown data

    Optical skyrmions were created and transmitted through a 270-meter free-space optical link, revealing robustness across a wide variety of conditions and turbulence strengths.

    “We create and transmit these particle-like topologies of light through a 270-meter free-space optical link, revealing their robustness across a wide variety of conditions and turbulence strengths.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The 270-meter free-space link in Johannesburg is representative of real-world free-space optical channels.

  • The quote only partly states this claim.

    Findingreasoning

    The degree of polarization decays with averaging time through the turbulence channel.

    “showing that while the degree of polarization consequently decays”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    Experimentally computed sphere coverage Nexp=0.97 and Nexp=1.98 are extremely close to the encoded values, indicating successful generation and detection of the desired topologies before turbulence.

    “Quantitatively, the experimentally computed sphere coverage of Nexp=0.97 and Nexp=1.98 calculated using Eq. 2 is also extremely close to the encoded values indicating the successful generation and detection of the desired topologies before being exposed to turbulence.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    The midday measured skyrmion number fluctuates noticeably around the encoded value, but each topology is discernible and close enough to determine the initially encoded topology.

    “The measured skyrmion number over the measurement period is not as steady as seen in the morning data and fluctuates noticeably around the encoded value. However, despite these fluctuations, the value of each topology at almost every point in time is discernable from every other point and close enough to the encoded value to determine what the initially encoded topology was.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingnone given

    The work demonstrates not only the robustness of these topological states to this highly complex medium but also their ability to faithfully transmit data through such channels with ease.

    “We have demonstrated in this work not only the robustness of these topological states to this highly complex medium but also their ability to faithfully transmit data through such channels with ease.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingcitation

    The robustness of the topology is in stark contrast to how OAM performs, which shows decreased fidelity, high cross-talk, and significant modal scattering.

    “The robustness of the topology is in stark contrast to how OAM itself performs, showing decreased fidelity, high cross-talk, and significant modal scattering (see the Supplementary Materials).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Supplementary Materials

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • It may state two separate claims as one.

    Findingown data

    After a 2-ms exposure through the turbulence channel, the Stokes parameters are distorted but the beam's DoP is still relatively high, having decreased primarily because of ambient thermal light such as sunlight.

    “The Stokes parameters are distorted, but the beams DoP is still relatively high, having decreased primarily because of the presence of ambient, thermal light such as sunlight.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingreasoning

    Midday data show the most severe distortion, with separate lobes developing in the intensity profiles and far more rapid variations in the SoPs.

    “The midday data show the most severe distortion, with separate lobes developing in the intensity profiles of the beams and far more rapid variations in the SoPs.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Findingown data

    The afternoon measured skyrmion number fluctuates over the measurement but remains close to the encoded value, allowing identification of the transmitted topology.

    “Here, we again see that the measured skyrmion number fluctuates over the course of the measurement but still remains close to the encoded value, allowing us to easily identify what the transmitted topology was through the distorting channel.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    The demonstration covered conditions ranging from morning to midday and late afternoon, with turbulence strength varying from σI2≈0.007 to σI2≈1.4.

    “This was demonstrated over a wide variety of conditions, ranging from morning to midday and late afternoon, where the strength of the experienced turbulence varied from σI²≈0.007 to σI²≈1.4.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    After averaging for 25 ms, the DoP is 0.59 and the computed skyrmion number remains close to the encoded value of N=1.

    “The DoP of this state is 0.59, indicating that a portion of the field measured is now partially incoherent/depolarized. However, the computed skyrmion number still remains close to the encoded value of N = 1.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The skyrmion number computed from the normalized Stokes vector remains a valid topological invariant for partially depolarized beams, even when the degree of polarization is as low as 0.39.

  • The quote only partly states this claim.

    Findingown data

    For midday data, measured skyrmion numbers are Nexp=0.95±0.07 and 2.19±0.09 for N=1 and N=2, respectively.

    “We also see good agreement between the encoded and measured skyrmion numbers of Nexp=0.95±0.07 and 2.19±0.09”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    For morning data, computed wrapping numbers are Nexp=0.81±0.01 and 2.063±0.003 for N=1 and N=2, respectively.

    “These features agree well with the computed wrapping numbers of Nexp=0.81±0.01 and 2.063±0.003, respectively.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    After averaging for 120 ms, the DoP is 0.39 and the measured wrapping number is N=0.98, still close to the encoded value.

    “This is further supported by the calculated DoP for this state, which is 0.39. The measured wrapping number for this beam is N = 0.98, still close to the encoded value.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The skyrmion number computed from the normalized Stokes vector remains a valid topological invariant for partially depolarized beams, even when the degree of polarization is as low as 0.39.

  • It may state two separate claims as one.

    Findingown data

    For afternoon data, measured skyrmion numbers are Nexp=0.97±0.02 and Nexp=1.83±0.04 for N=1 and N=2, respectively.

    “The experimentally evaluated values of the distorted beams of Nexp=0.97±0.02 and Nexp=1.83±0.04 again very closely match the encoded values.”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Findingreasoning

    Late afternoon data show much more severe distortion in both amplitude and polarization than morning data.

    “The data taken in the late afternoon show much more severe distortion in both amplitude and polarization.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Findingown data

    The skyrmion number for each tested topology N=1,2,3 remains fairly consistent over the morning measurement period, with only small fluctuations in the N=2 topology in the second half.

    “The skyrmion number for each of the tested topologies, N=1,2,and3, remains fairly consistent over the measurement period, with only small fluctuations in the N = 2 topology in the second half of the measurement.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisenone given

    It is not yet known which channels meet the smooth-deformation criterion.

    “It is not yet known which channels meet this criterion, and finding the channels that do is an active area of research.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Premisecitation

    Prior studies used single phase screens and were limited to only weak perturbations and did not venture to dynamic media with decoherence effects.

    “These studies used single phase screens and thus limited to only weak perturbations and did not venture to dynamic media with decoherence effects.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it.

    Interpretationreasoning

    Optical topologies point to potential for other complex channels.

    “and points to the potential for other complex channels too”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. It may state two separate claims as one.

    Premisecitation

    Classical skyrmions are robust to certain optical transformations, scattering media, and simulated atmospheric turbulence in controlled laboratory studies.

    “It has recently been demonstrated in controlled laboratory studies that classical skyrmions are robust to certain optical transformations (53), scattering media (54), and simulated atmospheric turbulence (55, 56).”
    Quote in the paperSubstantial claim0 of 4 sources checked
    • cites [53] A. A. Wang, Z. Zhao, Y. Ma, Y. Cai, R. Zhang, X. Shang, Y. Zhang, J. Qin, Z.-K. Pong, T. Marozsák, B. Chen, H. He, L. Luo, M. J. Booth, S. J. Elston, S. M. Morris, C. He, Topological protection of optical skyrmions through complex media. Light Sci. Appl. 13, 314 (2024). 39572554 PMC11582597 source

      Checked before — its earlier verdict is held back until a new check runs.

    • cites [54] C. Peters, K. Everts, T. Kleine, P. Ornelas, A. Forbes, Seeing through randomness with topological light. arXiv:2508.12305 [physics.optics] (2025). source

      Checked before — its earlier verdict is held back until a new check runs.

    • cites [55] L. Wang, S. Liu, G. Chen, Y. Zhang, C. Li, G. Guo, The robustness of skyrmion numbers of structured optical fields in atmospheric turbulence. Opt. Commun. 579, 131568 (2025). source

      Checked before — its earlier verdict is held back until a new check runs.

    • cites [56] Z. Guo, C. Peters, N. Mata-Cervera, A. N. Vetlugin, R. Guo, P. Zhang, A. Forbes, Y. Shen, A. Forbes, Y. Shen, Topological robustness of classical and quantum optical skyrmions in atmospheric turbulence. arXiv:2509.05727 [physics.optics] (2025). PMC12953630 41593073 source

      Checked before — its earlier verdict is held back until a new check runs.

  • The quote only partly states this claim.

    Interpretationreasoning

    The channel produces statistically averaged outcomes when probed over timescales greater than the coherence time.

    “We account for fast changes to the medium, where the channel produces statistically averaged outcomes, by probing the state’s decoherence”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    Only a handful of studies make use of real-world atmospheric channels.

    “but only a handful of studies making use of real-world atmospheric channels (34–39).”
    Quote in the paperNot a substantial claim0 of 6 sources checked
    • cites [34] M. Krenn, R. Fickler, M. Fink, J. Handsteiner, M. Malik, T. Scheidl, R. Ursin, A. Zeilinger, Communication with spatially modulated light through turbulent air across vienna. New J. Phys. 16, 113028 (2014).

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [35] M. Krenn, J. Handsteiner, M. Fink, R. Fickler, R. Ursin, M. Malik, A. Zeilinger, Twisted light transmission over 143 km. Proc. Natl. Acad. Sci. U.S.A. 113, 13648– 13653 (2016). 27856744 PMC5137742 source

      Checked before — its earlier verdict is held back until a new check runs.

    • cites [36] Y. Ren, Z. Wang, P. Liao, L. Li, G. Xie, H. Huang, Z. Zhao, Y. Yan, N. Ahmed, A. Willner, M. P. J. Lavery, N. Ashrafi, S. Ashrafi, R. Bock, M. Tur, I. B. Djordjevic, M. A. Neifeld, A. E. Willner, Experimental characterization of a 400 gbit/s orbital angular momentum multiplexed free-space optical link over 120 m. Opt. Lett. 41, 622– 625 (2016). 26907439 source

      Checked before — its earlier verdict is held back until a new check runs.

    • cites [37] M. P. J. Lavery, C. Peuntinger, K. Günthner, P. Banzer, D. Elser, R. W. Boyd, M. J. Padgett, C. Marquardt, G. Leuchs, Free-space propagation of high-dimensional structured optical fields in an urban environment. Sci. Adv. 3, e1700552 (2017). 29075663 PMC5656425 source

      Checked before — its earlier verdict is held back until a new check runs.

    • cites [38] M. Krenn, J. Handsteiner, M. Fink, R. Fickler, A. Zeilinger, Twisted photon entanglement through turbulent air across vienna. Proc. Natl. Acad. Sci. U.S.A. 112, 14197– 14201 (2015). 26578763 PMC4655531

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [39] A. Sit, F. Bouchard, R. Fickler, J. Gagnon-Bischoff, H. Larocque, K. Heshami, D. Elser, C. Peuntinger, K. Günthner, B. Heim, C. Marquardt, G. Leuchs, R. W. Boyd, E. Karimi, High-dimensional intracity quantum cryptography with structured photons. Optica 4, 1006– 1010 (2017). source

      Checked before — its earlier verdict is held back until a new check runs.

  • It may state two separate claims as one.

    Interpretationown data

    When these states pass through atmospheric turbulence, the beam's amplitude profile and polarization structure are severely distorted, but the mapping from the transverse plane to the Poincaré sphere and the topological wrapping number N are maintained.

    “As illustrated in Fig. 1, when these states pass through atmospheric turbulence, the beam’s amplitude profile and polarization structure are severely distorted, but the mapping from the transverse plane to the Poincaré sphere and, consequently, the topological wrapping number N are maintained.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The atmospheric turbulence channel can be treated as a smooth deformation of the skyrmion map, so that the topological wrapping number is preserved.

  • It may state two separate claims as one.

    Interpretationreasoning

    The invariant passes through the channel as if it was transparent, and no knowledge of the channel is required.

    “Here, the invariant passes through the channel as if it was transparent, and no knowledge of the channel is required.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

    Premisecitation

    Nonseparability of vectorial light can be measured using integrated intensity measurements, making it easier and faster to detect with current technologies.

    “While the nonseparability of vectorial light can be measured using integrated intensity measurements, making it easier and faster to detect with current technologies”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [50] I. Nape, K. Singh, A. Klug, W. Buono, C. Rosales-Guzman, A. McWilliam, S. Franke-Arnold, A. Kritzinger, P. Forbes, A. Dudley, A. Forbes, Revealing the invariance of vectorial structured light in complex media. Nat. Photonics 16, 538– 546 (2022). source

      Checked before — its earlier verdict is held back until a new check runs.

  • It may state two separate claims as one.

    Interpretationreasoning

    The use of topology as an information carrier overcomes the fundamental physical limitations hampering both classical and quantum FSOC (i.e., mode coupling and decoherence) and mitigates some practical restrictions placed on these systems by misalignment, background noise, and the need for adaptive optics.

    “We have shown in this work that the use of topology as an information carrier not only overcomes the fundamental physical limitations hampering both classical and quantum FSOC (i.e., mode coupling and decoherence) but also mitigates some of the more practical restrictions placed on these systems by misalignment, background noise, and the need for adaptive optics.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. It may state two separate claims as one.

    Study design and conductcitation

    Appropriate optics were used to ensure that the entire beam is collected, accounting for divergence and beam wander, to ensure that the measurement itself is topology preserving.

    “Appropriate optics have been used to ensure that the entire beam is collected, accounting for divergence and beam wander (see the Supplementary Materials), to ensure that the measurement itself is topology preserving.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Supplementary Materials

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • It may state two separate claims as one.

    Interpretationreasoning

    Beams will have the same size at the transmitter but would still be different as they propagate through the link as it is a thick, extended medium.

    “This also means that beams will have the same size at the transmitter but would still be different as they propagate through the link as it is a thick, extended medium.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Study design and conductcitation

    These factors can be mitigated to a certain degree, sometimes through more sophisticated measurement schemes, but they can never be fully removed, resulting in noticeable fluctuations in the measured data.

    “While these factors can be mitigated to a certain degree, sometimes through more sophisticated measurement schemes (73), they can never be fully removed resulting in noticeable fluctuations in the measured data.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [73] A. McWilliam, C. M. Cisowski, Z. Ye, F. C. Speirits, J. B. Götte, S. M. Barnett, S. Franke-Arnold, Topological approach of characterizing optical skyrmions and multi-skyrmions. Laser Photonics Rev. 17, 2300155 (2023). source

      Checked before — its earlier verdict is held back until a new check runs.

  • It may state two separate claims as one.

    Interpretationown data

    The wrapping number of generated optical skyrmions typically remains unchanged through these channels, meaning it can safely encode data through the link.

    “In contrast, the wrapping number of the generated optical skyrmions typically remains unchanged through these channels, meaning that it can safely encode data through the link.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The atmospheric turbulence channel can be treated as a smooth deformation of the skyrmion map, so that the topological wrapping number is preserved.

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    A skyrmion mode sorter is yet to be fully realized.

    “a skyrmion mode sorter that is yet to be fully realized (80).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [80] H. Bezuidenhout, C. Peters, R. Kumar, A. Forbes, I. Nape, Deep diffractive optical neural networks for detecting skyrmionic topologies of light. arXiv:2512.11115 [physics.optics] (2025). source

      Checked before — its earlier verdict is held back until a new check runs.

  • It may state two separate claims as one.

    Interpretationreasoning

    To normalize the beam sizes would mean that higher-order skyrmions diverge faster in propagation, making their dynamics significantly more challenging to unify through a single link, especially over a distance as large as the one used in this experiment.

    “To normalize the beam sizes would mean that higher-order skyrmions diverge faster in propagation, making their dynamics significantly more challenging to unify through a single link, especially over a distance as large as the one used in this experiment.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Interpretationnone given

    The generation of skyrmions from LG beams with the same embedded Gaussian waist w0 implies that each beam has the same Rayleigh range and comparable propagation dynamics.

    “The generation of skyrmions from LG beams with same embedded Gaussian waist w0 implies that each beam has the same Rayleigh range and comparable propagation dynamics.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Premisecitation

    Detection of skyrmion states requires either full Stokes polarimetry with spatial resolution or single-shot projective metasurfaces followed by computational classification, or the development of dedicated optical elements that can efficiently separate skyrmion states.

    “Detection therefore requires either full Stokes polarimetry with spatial resolution or with single shot-projective metasurfaces (79) followed by computational classification or the development of dedicated optical elements that can efficiently separate skyrmion states”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [79] C. Li, C. Liu, C. Peters, H. Yu, S. A. Maier, A. Forbes, H. Ren, Disorder-enabled synthetic metasurfaces. arXiv:2507.04696 [physics.optics] (2025).

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [80] H. Bezuidenhout, C. Peters, R. Kumar, A. Forbes, I. Nape, Deep diffractive optical neural networks for detecting skyrmionic topologies of light. arXiv:2512.11115 [physics.optics] (2025). source

      Checked before — its earlier verdict is held back until a new check runs.

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    The morning scintillation index is comparable to strengths seen in other free-space link experiments.

    “comparable to strengths seen in other free-space link experiments (63).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [63] D. McDonald, R. Bellossi, S. Gladysz, Field demonstration of turbulence-resilient self-coherent free-space optical communications. J. Lightwave Technol. 43, 6146– 6153 (2025). source

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Interpretationcitation

    Working with different N does not necessarily come with footprint drawbacks.

    “This tells that working with different N does not necessarily come with footprint drawbacks.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

    Premisenone given

    Opposite signs of N, even at fixed |N|, necessarily correspond to distinct field structures.

    “It is also worth recalling that opposite signs of N, even at fixed ∣N∣, necessarily correspond to distinct field structures.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Premisecitation

    Nonseparability of vectorial light is susceptible to noise at lower values and requires the channel to be unitary.

    “it is susceptible to noise at lower values and requires the channel to be unitary.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [50] I. Nape, K. Singh, A. Klug, W. Buono, C. Rosales-Guzman, A. McWilliam, S. Franke-Arnold, A. Kritzinger, P. Forbes, A. Dudley, A. Forbes, Revealing the invariance of vectorial structured light in complex media. Nat. Photonics 16, 538– 546 (2022). source

      Checked before — its earlier verdict is held back until a new check runs.

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    Perfect vortex structures have a transverse intensity distribution independent of the topological charge.

    “as has been shown recently (82), whose transverse intensity distribution is independent of the topological charge.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [82] X. Zeng, J. Fang, H. Wu, J. Wang, Y. Chen, Y. Zhou, X. Yang, C. Wang, D. Wei, H. Chen, H. Gao, Y. Shen, Tailoring ultra-high-order optical skyrmions. Laser Photonics Rev. 19, e00732 (2025). source

      Checked before — its earlier verdict is held back until a new check runs.

  • Probably not a substantial claim.

    Premisereasoning

    From a topological perspective, all beams of a given N belong to an equivalence class defined by their skyrmion number.

    “from a topological perspective, all beams of a given N belong to an equivalence class defined by their skyrmion number”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Premisecitation

    The requirement of unitarity holds for phase and amplitude distortions but does not occur when one experiences decoherence/depolarization.

    “This is the case for the phase and amplitude distortions but does not occur when one experiences decoherence/depolarization (72).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [72] F. S. Roux, Infinitesimal-propagation equation for decoherence of an orbital-angular-momentum-entangled biphoton state in atmospheric turbulence. Phys. Rev. A 83, 053822 (2011). source

      Checked before — its earlier verdict is held back until a new check runs.

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    Several experiments have simulated the effects of these channels on optical skyrmions, with promising results demonstrating possible resilience.

    “Several experiments have simulated the effects of these channels on optical skyrmions, with promising results demonstrating possible resilience (68).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [68] R. de Mello Koch, B.-Q. Lu, P. Ornelas, I. Nape, A. Forbes, Quantum skyrmions in general quantum channels. APL Quantum 2, 026126 (2025). PMC11937260 40133306 source

      Checked before — its earlier verdict is held back until a new check runs.

  • Probably not a substantial claim. It may be too vague to check against evidence.

    Premisereasoning

    Topology is a global property that is unrelated to its underlying structure.

    “our main point is that topology is a global property that is unrelated to its underlying structure.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. The paper may give no reason why it holds.

    Premisenone given

    Atmospheric turbulence typically distorts more common forms of structured light, leading to severe cross-talk if no compensation techniques are used.

    “Atmospheric turbulence typically distorts more common forms of structured lights, leading to severe cross-talk if no compensation techniques are used to mitigate its effects.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Interpretationreasoning

    The Gouy phase effect does not affect the skyrmion mapping and only changes the polarization texture.

    “This effect does not affect the skyrmion mapping and only changed the polarization texture.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Interpretationown data

    Topology makes a useful alphabet for transmitting information through the free-space link, only showing a noticeable drop in performance in the most extreme cases.

    “Overall, we see that topology makes a useful alphabet for transmitting information through the free-space link, only showing a noticeable drop in performance in the most extreme cases, where the distortion is severe.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

    Premisenone given

    Modern MIMO systems routinely operate with nonorthogonal spatial channels and rely on signal processing at the receiver to separate them.

    “modern Multiple-Input-Multiple-Output (MIMO) systems (such as those in everyday Wi-Fi routers with multiple antennas) routinely operate with nonorthogonal spatial channels and rely on signal processing at the receiver to separate them.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim.

    Study design and conductreasoning

    The simultaneous measurement of polarization projections is essential to ensure that the full state of polarization is determined for a given atmospheric configuration within the coherence time of the channel.

    “The simultaneous measurement of these projections is essential to ensure that the full state of polarization (SoP) of the beam is determined for a given atmospheric configuration within the coherence time of the channel.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Study design and conductnone given

    All measurements were performed with no probing of the medium and no pre- or postcorrection to compensate for channel distortion.

    “All measurements are performed with no probing of the medium and no pre- or postcorrection is made to compensate for the channel distortion.”
    Quote in the paperSubstantial claim
55 of 55

  • The paper relies on this without support.

    The atmospheric turbulence channel can be treated as a smooth deformation of the skyrmion map, so that the topological wrapping number is preserved.

    “so long as the channel can be described as a smooth deformation of the map.”

  • The paper relies on this without support.

    The skyrmion number computed from the normalized Stokes vector remains a valid topological invariant for partially depolarized beams, even when the degree of polarization is as low as 0.39.

    “The measured wrapping number for this beam is N = 0.98, still close to the encoded value.”

  • The paper relies on this without support.

    The 270-meter free-space link in Johannesburg is representative of real-world free-space optical channels.

    “through a 270-m free-space optical link located on the Braamfontein campus of the University of the Witwatersrand, in the center of Johannesburg, South Africa.”

  • The paper relies on this without support.

    Skyrmion states of different N are not, in general, spatially orthogonal to one another.

    “It is worth noting that skyrmion states of different N are not, in general, spatially orthogonal to one another”

  • The paper relies on this without support.

    Prior investigations of robustness of topological light through complex channels were performed in controlled laboratory settings.

    “These investigations, while valuable, were performed in controlled laboratory settings.”

  • The paper relies on this without support.

    Structured light in real-world atmospheric turbulence has seen only a handful of tests.

    “Structured light in real-world atmospheric turbulence has seen only a handful of tests.”
6 of 6

Citations

Cites

Flagged first, then by citations

Research works printed but not linked: 3

  1. D. Tse P. Viswanath. Fundamentals of Wireless Communication (Cambridge Univ. Press 2012).
  2. C. Li C. Liu C. Peters H. Yu S. A. Maier A. Forbes H. Ren Disorder-enabled synthetic metasurfaces. arXiv:2507.04696 [physics.optics] (2025). · arXiv
  3. H. Bezuidenhout C. Peters R. Kumar A. Forbes I. Nape Deep diffractive optical neural networks for detecting skyrmionic topologies of light. arXiv:2512.11115 [physics.optics] (2025). · arXiv

Cited by

Sorted by citations

Related

Metadata

Authors
Peters, C., Hakobyan, V., Drozdov, A., Brasselet, E., Cox, M., & Forbes, A.
Affiliations
  • University of the Witwatersrand (ZA)
  • Centre National de la Recherche Scientifique (FR)
Corresponding author
Forbes, Andrew
ORCID
Venue
Science Advances
Publisher
American Association for the Advancement of Science (AAAS)
Published
2026-08-14
Volume
12
Issue
33
Pages
eaee2671-eaee2671
ISSN
2375-2548 (ISSN-L)
DOI
10.1126/sciadv.aee2671
PMC
PMC13475490
OpenAlex
W7128078788
Cited by
11
References
86
Citations by year
2026: 11
FWCI
14.42
Type
journal article
Language
en
Open access
Licence
cc-by-nc
Locations
  • Science Advances (publishedVersion, cc-by-nc)
  • PubMed (publishedVersion)
  • PubMed Central (publishedVersion, cc-by-nc)
  • arXiv (Cornell University) (submittedVersion, cc-by)
  • arXiv (Cornell University) (cc-by)
Funders
  • South African Quantum Technology Initiative
  • South African National Research Foundation/CSIR Rental Pool Programme
  • IdEx University of Bordeaux
Topics
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Orbital Angular Momentum in Optics
  • Physical Sciences › Engineering › Electrical and Electronic Engineering › Optical Wireless Communication Technologies
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum Information and Cryptography
Keywords
optical skyrmions, topological robustness, free-space optical communication, atmospheric turbulence, structured light, topological number, information fidelity, quantum communication

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

A language model drew the claims from the paper on 2026-11-10, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).

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