[
  {
    "id": "ARR-2026-2WNM69XY548JHVMC-v1",
    "type": "article",
    "title": "Classical limits and Gaussian-average gaps for compound bosonic fading channels",
    "author": [
      {
        "literal": "Lluis Eriksson"
      }
    ],
    "issued": {
      "date-parts": [
        [
          2026,
          10,
          26
        ]
      ]
    },
    "publisher": "AIRR.SCIENCE",
    "archive": "AIRR.SCIENCE",
    "archive_location": "ARR-2026-2WNM69XY548JHVMC",
    "version": "v1",
    "genre": "Research preprint",
    "URL": "https://airr.science/papers/ARR-2026-2WNM69XY548JHVMC/versions/v1/",
    "note": "Research preprint; ARR-2026-2WNM69XY548JHVMC v1. Not peer reviewed by AIRR. Working paper; not admitted to the AIRR accepted collection.",
    "abstract": "We study unassisted classical communication through memoryless mixtures of noisy, phase-insensitive bosonic Gaussian channels. Both thermal noise and photon budget scale with an energy parameter. An explicit measure-prepare representation converts every quantum block code, including entangled codewords and collective receivers, into a classical code with identical error and an exactly quantified cost increment. The same simulation works for an unknown fixed mixing law. A Gaussian-smoothing estimate and a uniform finite-alphabet reduction give an explicit O(E^-1) comparison with a classical compound variational value. This value optimizes one input distribution before taking the worst mixing law. We also prove a strict separation between classical optimal modulation and the time-sharing hull of Gaussian coherent modulations for a matched-reset example. Matching bounds determine the high-energy limit of a regularized Holevo functional for ensembles with an exactly Gaussian average quantum state, permitting squeezed and entangled averages. Its gap from the unknown-fixed-phase operational capacity remains strictly positive in that limit. The classical coding tools and Gaussian measure-prepare representations are established ingredients. The Gaussian-average restriction is an ensemble condition, not a converse for every finite codebook described as Gaussian."
  }
]