Advanced LIGO can detect strains as small as roughly 10^-23, corresponding to a change in its 4-kilometer arm length thousands of times smaller than the width of a proton — widely cited as the most precise length-change measurement ever achieved by any scientific instrument, made possible by squeezed-light quantum noise reduction techniques added in subsequent LIGO upgrades.
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Advanced LIGO can detect strains as small as roughly 10^-23, corresponding to a change in its 4-kilometer arm length thousands of times smaller than the width of a proton — widely cited as the most precise length-change measurement ever achieved by any scientific instrument, made possible by squeezed-light quantum noise reduction techniques added in subsequent LIGO upgrades.
The smallest fractional change in length (strain) detectable by Advanced LIGO's laser interferometer, over its 4-kilometer arm length, at its most sensitive operating frequency band.
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Limits Registry. LR-MOST-SENSITIVE-GRAVITATIONAL-WAVE-STRAIN-MEASUREMENT. Smallest length change ever measured by a scientific instrument. 2026.