{
  "abstract": "Reaction-diffusion systems with two species that mutually annihilate through $A+B\\to\\emptyset$ reactions display a slow decay of the total density $ρ$ which follows an anomalous power law in low dimensions. For hardcore particles in one dimension, this decay follows $ρ\\sim t^{-1/4}$ under symmetric diffusion and $ρ\\sim t^{-1/3}$ under asymmetric diffusion without relative bias between the two species. The $t^{-1/3}$ behavior, in particular, has so far been observed exclusively in systems with hardcore exclusion. Here we construct a model of particles without hardcore exclusion that reproduces this same $t^{-1/3}$ scaling. In our model, both species undergo asymmetric diffusion with a rate that depends nonlinearly on the local density, a form of transport that, in the absence of the other species, is superdiffusive and falls into the Kardar-Parisi-Zhang universality class. The scaling behavior of $t^{-1/3}$ occurs when at least one of the two species undergoes asymmetric diffusion induced by microscopic processes involving pairs of particles, while asymmetric processes involving groups of three particles lead to $t^{-1/4}$ scaling associated with symmetric diffusion. This demonstrates that the pair annihilation density decay exponent is not determined exclusively by the transport properties of the isolated particle species.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.30630",
  "author_total": 2,
  "authors": [
    {
      "name": "Su-Chan Park"
    },
    {
      "name": "Foster Thompson"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/a84akk2yaw9pd.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.30630",
  "fulltext_url": null,
  "id": "a84akk2yaw9pd",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.30630",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.stat-mech"
    ],
    [
      "openalex",
      "2610|Stochastic processes and statistical mechanics"
    ]
  ],
  "openalex": "W7204927681",
  "pdf_url": "https://arxiv.org/pdf/2608.30630",
  "pmcid": null,
  "pmid": null,
  "published": "2026-08-31",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/a84akk2yaw9pd.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:41Z",
      "native_id": "2608.30630",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.30630"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.stat-mech",
      "subfield": "statistical-nonlinear"
    }
  ],
  "title": "Effective Hardcore Exclusion Without Exclusion: Two-Species Pair Annihilation Revisited",
  "title_text": "Effective Hardcore Exclusion Without Exclusion: Two-Species Pair Annihilation Revisited",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:41Z",
  "url": "https://research.draconitic.com/paper/a84akk2yaw9pd",
  "venue": "arXiv",
  "versions": []
}