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    "headline": "LIGO Quieted Quantum Back-Action by 47%",
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    "dek": "Correlated measurement noise partly canceled radiation-pressure motion in the observatory’s 40-kilogram mirrors.",
    "summary": "Correlated measurement noise partly canceled radiation-pressure motion in the observatory’s 40-kilogram mirrors.",
    "body_text": "A LIGO experiment trapped the differential motion of its 40-kilogram mirrors in a sub-hertz-linewidth optomechanical mode where radiation-pressure back-action dominated. By engineering the quantum state entering the dark port, the team created correlations between readout imprecision and back-action that partly canceled their contributions, reducing observed motion near resonance by about 47%. The analysis separates the two noise terms and their correlation. This is a macroscopic demonstration of quantum back-action evasion inside a gravitational-wave detector, not a 47% improvement across LIGO’s full observing band.",
    "why_it_matters": "Correlated measurement noise partly canceled radiation-pressure motion in the observatory’s 40-kilogram mirrors.",
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      "This is a macroscopic demonstration of quantum back-action evasion inside a gravitational-wave detector, not a 47% improvement across LIGO’s full observing band."
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        "text": "Correlated measurement noise partly canceled radiation-pressure motion in the observatory’s 40-kilogram mirrors.",
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        "qualification": "This is a macroscopic demonstration of quantum back-action evasion inside a gravitational-wave detector, not a 47% improvement across LIGO’s full observing band."
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    "tags": [
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      "quantum measurement",
      "optomechanics"
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      "source_id": "source-2026-09-20-001",
      "title": "arXiv preprint 2609.19317",
      "publisher": "arXiv",
      "url": "https://arxiv.org/abs/2609.19317",
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      "published_at": "2026-09-16T14:33:09.000-04:00",
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    "title": "LIGO Quieted Quantum Back-Action by 47%",
    "publisher": "The Machine Press",
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