Precision measurement of ℏ/mCs based on photon recoil using laser-cooled atoms and atomic interferometry

D. S. Weiss, B. C. Young, S. Chu

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The recoil of an atom due to the absorption of up to 64 photons is measured, using laser-cooled cesium atoms which are made to interfere in an atomic fountain. Measurement of the photon recoil allows a determination of ℏ/mCs, and hence the fine-structure constant. The measurement is described and a detailed theoretical and experimental study of potential systematic errors is presented. A relative precision in the photon recoil measurement of 0.1 ppm is obtained in two hours of data collection. The measurement is currently 0.85 ppm below the accepted value of ℏ/mCs. We cannot now formally ascribe a systematic error, but suspect that the bulk of the discrepancy is due to imperfections of the interferometer beams used to induce the Raman transitions.

Original languageEnglish (US)
Pages (from-to)217-256
Number of pages40
JournalApplied Physics B Lasers and Optics
Issue number3
StatePublished - Sep 1 1994

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)
  • Physics and Astronomy(all)


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