{
  "abstract": "Maximizing the number of addressable spins within a fixed volume can improve ensemble quantum sensor sensitivity, but dense packing usually increases dipolar interactions and excited-state transport, shortening coherence and suppressing optical readout. Here we report a 2:1 cocrystal of 6,13-dihydropentacene and pentacene (DHP/Pc) containing 33.3 mol% pentacene ($3.3\\times10^{5}$ ppm; $9.51\\times10^{20}$ cm$^{-3}$), a volumetric spin-site density more than two orders of magnitude above previous benchmarks, NV-diamond and pentacene-doped p-terphenyl (PDP). Despite this density, DHP/Pc exhibits microsecond spin coherence, room-temperature optically detected magnetic resonance and coherent control. Time-resolved measurements indicate that the long-lived triplet population is generated predominantly by intersystem crossing and exhibits strong, non-thermal sublevel polarization. Density-functional theory calculations further suggest that the native cocrystal geometry weakens electronic coupling between neighboring pentacenes, while the higher DHP triplet energy creates a barrier to triplet migration. These results identify molecular packing and coformer triplet energetics as complementary design parameters for preserving coherence in high spin-site density systems, demonstrating cocrystallization as a promising route to dense, optically addressable spin materials for room-temperature ensemble quantum sensing.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.28912",
  "author_total": 16,
  "authors": [
    {
      "name": "Noella D'Souza"
    },
    {
      "name": "Guangzhao Chen"
    },
    {
      "name": "Madhur Parashar"
    },
    {
      "name": "Wern Ng"
    },
    {
      "name": "Brandon Wallace"
    },
    {
      "name": "Tatiana Lindahl"
    },
    {
      "name": "Tanner S. Volek"
    },
    {
      "name": "Lam Lam"
    },
    {
      "name": "Joseph Garrett"
    },
    {
      "name": "Emanuel Druga"
    },
    {
      "name": "Sean T. Roberts"
    },
    {
      "name": "Jeffrey Reimer"
    },
    {
      "name": "Harpreet Singh"
    },
    {
      "name": "Liang Z. Tan"
    },
    {
      "name": "Riccardo Montis"
    },
    {
      "name": "Ashok Ajoy"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5czvnjxvg7vt6.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.28912",
  "fulltext_url": null,
  "id": "5czvnjxvg7vt6",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.28912",
  "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",
      "quant-ph"
    ],
    [
      "openalex",
      "2504|Magnetism in coordination complexes"
    ]
  ],
  "openalex": "W7214290854",
  "pdf_url": "https://arxiv.org/pdf/2609.28912",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-24",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5czvnjxvg7vt6.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:24:11Z",
      "native_id": "2609.28912",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.28912"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Dense pentacene cocrystal demonstrates room-temperature coherent control",
  "title_text": "Dense pentacene cocrystal demonstrates room-temperature coherent control",
  "type": "preprint",
  "updated_at": "2026-10-30T12:24:11Z",
  "url": "https://research.draconitic.com/paper/5czvnjxvg7vt6",
  "venue": "arXiv",
  "versions": []
}