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Test of the equivalence principle based on dual-species cold atom interferometers

Source: National Natural Science Foundation of China 

Grant No:91536221

Project: Test of the equivalence principle based on dual-species cold atom interferometers

Chief Specialist: Prof.Jin Wang

Abstract: The equivalence principle is one of the two basic assumptions of general relativity, but some new theories, which try to unify the gravity and the standard model, generally require violation of equivalence principle. The accuracy of equivalence principle test based on macroscopic objects is up to 10^[-13], while the best accuracy of atom interferometer based equivalence principle test is only 10^[-7]. We found that, the main factors limiting the accuracy of atom interferometer based equivalence principle test, are different error sources and the crosstalk between Raman lasers. To solve these problems, we propose and implement a four-wave double-diffraction Raman transition (4WDR) scheme, recently.We applied the 4WDR scheme in equivalence principle test experiment based on dual-species atom interferometer, and achieved preliminary progress. This project will carry out equivalence principle test with higher accuracy based on the  current progress, to further optimize the 4WDR dual-species atom interferometer scheme, to quantitatively analysis AC Stark shifts caused by multi-frequency Raman beams and their suppressing method, to extensively investigate the immune mechanism of phase noise due to Raman beams in the 4WDR scheme, to actively compensate the influence on experimental measurements due to Coriolis effect, and to accurately evaluate the systematic error and the measurement noise. The expected accuracy of atom interferometer based equivalence principle test in this project is better than 2 *10^[-8], which will exceed the best result in the world at present time.

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Wuhan Institute of Physics and Mathematics, CAS
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