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Test of Cosmic Spatial Isotropy for Polarized Electrons Using a Rotatable Torsion Balance

Li-Shing Hou·Wei-Tou Ni·Yu-Chu M. Li
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Abstract

To test the cosmic spatial isotropy, we use a rotatable torsion balance carrying a transversely spin-polarized ferrimagnetic Dy_{6}Fe_{23} mass. With a rotation period of one hour, the period of anisotropy signal is reduced from one sidereal day by about 24 times, and hence the 1/f noise is greatly reduced. Our present experimental results constrain the cosmic anisotropy Hamiltonian H = C_{1} sigma_{1} + C_{2} sigma_{2} + C_{3} sigma_{3} (sigma_{3} is in the axis of earth rotation) to (C_{1}^{2} +C_{2}^{2})^{1/2} = (1.8 +- 5.3) X 10^{-21} eV and | C_{3} | = (1.2 +- 3.5) X 10^{-19} eV. This improves the previous limits on (C_{1},C_{2}) by 120 times and C_{3} by a factor of 800.

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Li-Shing Hou, Wei-Tou Ni, Yu-Chu M. Li. 2000-09-04. Test of Cosmic Spatial Isotropy for Polarized Electrons Using a Rotatable Torsion Balance. https://doi.org/10.1103/physrevlett.90.201101

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