Experimental Investigation Of Weak Equivalence Principle Test Using A ⁸⁵Rb-⁸⁷Rb Dual-species Cold Atom Interferometer

The equivalence principle including the weak equivalence principle(WEP),also known as the universality of free fall,is one of the two assumptions of Einstein's general relativity.The-ories which try to unify gravity and the standard model,generally require violation of WEP.To explore the applicable extent of WEP and to help the birth of new quantum gravity theories,it is very important to precisely test WEP both with macro-objects and with microscopic particles.The test with atoms relies on atom interferometry which has been developed for over 20 years and has been widely used in measurements of gravity and its gradient,rotation,the New-tonian gravitational constant and so on.It is possible to test WEP using atom interferometers in microscopic particles domain.In this thesis,experimental investigation of WEP test using a 85Rb-87Rb dual-species cold atom interferometer was carried out.We had achieved the following innovative perspectives and results.1.We proposed and implemented a four-wave double-diffraction Raman transition(4WDR)scheme for the interferometer,and demonstrated its ability in suppressing common-mode phase noise of Raman lasers after their frequencies and intensity ratios were optimized.2.We had builded a 85Rb-87Rb dual-species atom interferometer,and realised simultane-ous differential gravity acceleration measurements.3.We reported an improved test of WEP by using a simultaneous 85Rb-87Rb dual-species atom interferometer.The statistical uncertainty of the experimental data for Eotvos parameter ? was 0.8 × 10-8 at 3200 s.With various systematic errors corrected the final value was ? =(2.8 ±3.0)× 10-8.4.After the dual-species atom fountain source had been improved,the resolution of ? was increased to 3.0×10-9 after 3200 s of integration time.To further reduce the systematic uncertainty,the Coriolis effect should be compensated.We performed the compensation of Coriolis effect by rotating a tip-tilt mirror reflecting Raman beams.Experimental data showed that Coriolis effect was efficiently suppressed,the fractional uncertainty due to residual rotation effect was 5.8×10-9.