Absolute measurement of thermal noise in a resonant short-range force experiment

H. Yan, E. A. Housworth, H. O. Meyer, G. Visser, E. Weisman, J. C. Long

Research output: Contribution to journalArticlepeer-review


Planar, double-torsional oscillators are especially suitable for short-range macroscopic force search experiments, since they can be operated at the limit of instrumental thermal noise. As a study of this limit, we report a measurement of the noise kinetic energy of a polycrystalline tungsten oscillator in thermal equilibrium at room temperature. The fluctuations of the oscillator in a high-Q torsional mode with a resonance frequency near 1 kHz are detected with capacitive transducers coupled to a sensitive differential amplifier. The electronic processing is calibrated by means of a known electrostatic force and input from a finite-element model. The measured average kinetic energy, Eexp = (2.0 ± 0.3) × 10-21 J, is in agreement with the expected value of 1/2kBT.

Original languageEnglish (US)
Article number205007
JournalClassical and Quantum Gravity
Issue number20
StatePublished - Oct 21 2014
Externally publishedYes


  • equipartition theorem
  • short-range tests of gravity
  • thermal noise measurements
  • torsional oscillators

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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