Atomic Clock Team at Harvard-Smithsonian Test Relativity Theory

Ronald Walsworth and colleagues at the Harvard-Smithsonian Center for Astrophysics recently reported their use of atomic hydrogen masers to perform the most stringent test to date of Lorentz symmetry of the proton. I.e., the researchers showed that the physics of the proton is symmetric under rotation. In a recently published paper, the authors present a new measurement constraining Lorentz and Charge-Parity-Time (CPT) symmetry violation of the proton using a hydrogen maser double resonance technique. A search for hydrogen Zeeman frequency variations with a period of the sidereal day (23.93 h) sets a limit on violation of Lorentz and CPT symmetry of the proton at the 10-27 GeV level, independent of nuclear model uncertainty, which improves significantly on previous bounds.

The paper reporting this test was published in Physical Review D, vol. 63, p. 111101 (2001).