New Experimental Test of Coulomb's Law: A Laboratory Upper Limit on the Photon Rest Mass

Phys. Rev. Lett. 26, 721 – Published 22 March 1971
E. R. Williams, J. E. Faller, and H. A. Hill


A high-frequency test of Coulomb's law is described. The sensitivity of the experiment is given in terms of a finite photon rest mass using the Proca equations. The null result of our measurement expressed in the form of the photon rest mass squared is μ2=(1.04±1.2)×10-19 cm-2. Expressed as a deviation from Coulomb's law of the form 1r2+q, our experiment gives q=(2.7±3.1)×10-16. This result extends the validity of Coulomb's law by two orders of magnitude.


  • Received 22 January 1971
  • Published in the issue dated 22 March 1971

© 1971 The American Physical Society

Authors & Affiliations

E. R. Williams*, J. E. Faller, and H. A. Hill

  • Department of Physics, Wesleyan University, Middletoun, Connecticut 06457

  • *Present address: Physics Department, Williams College, Williamstown, Mass. 01267.

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