Abstract
By analyzing a gedanken experiment designed to measure the distance l between two spatially separated points, we find that this distance cannot be measured with uncertainty less than (ll2 P)1/3, considerably larger than the Planck scale lP (or the string scale in string theories), the conventional-wisdom uncertainty in distance measurements. This limitation to space-time measurements is interpreted as resulting from quantum fluctuations of space-time itself. Thus, at very short distance scales, space-time is “foamy.” This intrinsic foaminess of space-time provides another source of noise in the interferometers. The LIGO/VIRGO and LISA generations of gravity-wave interferometers, through future refinements, are expected to reach displacement noise levels low enough to test our proposed degree of foaminess in the structure of space-time.
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Ng, Y.J., van Dam, H. Measuring the Foaminess of Space-Time with Gravity-Wave Interferometers. Foundations of Physics 30, 795–805 (2000). https://doi.org/10.1023/A:1003745212871
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DOI: https://doi.org/10.1023/A:1003745212871