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Rotation, the equivalence principle, and the Gravity Probe B experiment
1Shanghai United Center for Astrophysics (SUCA), Shanghai Normal University, Shanghai, China.
Abstract:
The ultraprecise Gravity Probe B experiment measured the frame-dragging effect and geodetic precession on four quartz gyros. We use this result to test WEP II (weak equivalence principle II) which includes rotation in the universal free-fall motion. The free-fall Eötvös parameter η for a rotating body is ≤10(-11) with a four-order improvement over previous results. The anomalous torque per unit angular momentum parameter λ is constrained to (-0.05±3.67)×10(-15) s(-1), (0.24±0.98)×10(-15) s(-1), and (0±3.6)×10(-13) s(-1), respectively, in the directions of geodetic effect, frame-dragging effect, and angular momentum axis; the dimensionless frequency-dependence parameter κ is constrained to (1.75±4.96)×10(-17), (1.80±1.34)×10(-17), and (0±3)×10(-14), respectively.
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