We report an improved test of the weak equivalence principle by using a simultaneous $^{85}\mathrm{Rb}\text{\ensuremath{-}}^{87}\mathrm{Rb}$ dual-species atom interferometer. We propose and implement a four-wave double-diffraction Raman transition scheme for the interferometer, and demonstrate its ability in suppressing common-mode phase noise of Raman lasers after their frequencies and intensity ratios are optimized. The statistical uncertainty of the experimental data for E\"otv\"os parameter $\ensuremath{\eta}$ is $0.8\ifmmode\times\else\texttimes\fi{}1{0}^{\ensuremath{-}8}$ at 3200 s. With various systematic errors corrected, the final value is $\ensuremath{\eta}=(2.8\ifmmode\pm\else\textpm\fi{}3.0)\ifmmode\times\else\texttimes\fi{}1{0}^{\ensuremath{-}8}$. The major uncertainty is attributed to the Coriolis effect.
We report an improved test of the weak equivalence principle by using a simultaneous 85Rb\ensuremath-87Rb dual-species atom interferometer. We propose and implement a four-wave double-diffraction Raman transition scheme for the interferometer, and demonstrate its ability in suppressing common-mode phase noise of Raman lasers after their frequencies and intensity ratios are optimized. The statistical uncertainty of the experimental data for E"otv"os parameter \ensuremathη is 0.8\ifmmode×\else\texttimes\fi10\ensuremath−8 at 3200 s. With various systematic errors corrected, the final value is \ensuremathη=(2.8\ifmmode±\else\textpm\fi3.0)\ifmmode×\else\texttimes\fi10\ensuremath−8. The major uncertainty is attributed to the Coriolis effect.
Coriolis effect is an important error source in the weak equivalence principle (WEP) test using atom interferometer. In this paper, the problem of Coriolis error in WEP test is studied theoretically and experimentally. In theoretical simulation, the Coriolis effect is analyzed by establishing an error model. The measurement errors of Eötvös coefficient (η) in WEP test related to experimental parameters, such as horizontal-velocity difference and horizontal-position difference of atomic clouds, horizontal-position difference of detectors, and rotation compensation of Raman laser’s mirror are calculated. In experimental investigation, the position difference between 85Rb and 87Rb atomic clouds is reduced to 0.1 mm by optimizing the experimental parameters, an alternating detection method is used to suppress the error caused by detection position difference, thus the Coriolis error related to the atomic clouds and detectors is reduced to 1.1× 10−9. This Coriolis error is further corrected by compensating the rotation of Raman laser’s mirror, and the total uncertainty of η measurement related to the Coriolis effect is reduced as δη = 4.4 × 10−11.
We use rubidium atoms with specified mass and internal energy to carry out a joint mass-energy test of the equivalence principle (EP). We improve the four-wave double-diffraction Raman transition method (4WDR) we proposed before to select atoms with a certain mass and angular momentum state, and form a dual-species atom interferometer. By using the extended 4WDR to 85Rb and 87Rb atoms with different angular momenta, we measure their differential gravitational acceleration, and we determine the value of the E\"otv\"os parameter, $\ensuremath{\eta}$, which measures the strength of the violation of EP. The E\"otv\"os parameters of the four paired combinations $^{85}\mathrm{Rb}|F=2\ensuremath{\rangle}\text{\ensuremath{-}}^{87}\mathrm{Rb}|F=1\ensuremath{\rangle}$, $^{85}\mathrm{Rb}|F=2\ensuremath{\rangle}\text{\ensuremath{-}}^{87}\mathrm{Rb}|F=2\ensuremath{\rangle}$, $^{85}\mathrm{Rb}|F=3\ensuremath{\rangle}\text{\ensuremath{-}}^{87}\mathrm{Rb}|F=1\ensuremath{\rangle}$, and $^{85}\mathrm{Rb}|F=3\ensuremath{\rangle}\text{\ensuremath{-}}^{87}\mathrm{Rb}|F=2\ensuremath{\rangle}$ were measured to be ${\ensuremath{\eta}}_{1}=(1.5\ifmmode\pm\else\textpm\fi{}3.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$, ${\ensuremath{\eta}}_{2}=(\ensuremath{-}0.6\ifmmode\pm\else\textpm\fi{}3.7)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$, ${\ensuremath{\eta}}_{3}=(\ensuremath{-}2.5\ifmmode\pm\else\textpm\fi{}4.1)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$, and ${\ensuremath{\eta}}_{4}=(\ensuremath{-}2.7\ifmmode\pm\else\textpm\fi{}3.6)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$, respectively. The violation parameter of mass is constrained to ${\ensuremath{\eta}}_{0}=(\ensuremath{-}0.8\ifmmode\pm\else\textpm\fi{}1.4)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$, and that of internal energy to ${\ensuremath{\eta}}_{E}=(0.0\ifmmode\pm\else\textpm\fi{}0.4)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$ per reduced energy ratio a ($a=h{\ensuremath{\nu}}_{0}/{m}_{i}^{85}{c}^{2}$, and ${\ensuremath{\nu}}_{0}=1$ GHz). This work opens a door for joint tests of two attributes beyond the traditional pure mass or energy tests of EP with quantum systems.
We present here the performance of a simultaneous dual-species matter-wave accelerometer for measuring the differential acceleration between two different atomic species (87Rb and 85Rb). We study the expression and the extraction of the differential phase from the interferometer output. The differential accelerometer reaches a short-term sensitivity of $1.23\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}g/\sqrt{\mathrm{Hz}}$ limited by the detection noise and a resolution of $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}g$ after 11 000 s, a very high sensitivity using a dual-species atom interferometer. Thanks to the simultaneous measurement, such resolution levels can still be achieved even with vibration levels up to $3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}g$, corresponding to a common-mode vibration noise rejection ratio of 94 dB (rejection factor of 50 000). These results prove the ability of such atom sensors for realizing a quantum-based test of the weak equivalence principle at a level of $\ensuremath{\eta}\ensuremath{\sim}{10}^{\ensuremath{-}9}$ even with high vibration levels and a compact sensor.
The wave-front aberration of Raman beams induces phase noise in atom interferometers and thus limits the performance of atom interferometers. We theoretically analyze the wave-front-aberration phase noise in weak-equivalence-principle tests using dual-species atom interferometers, and propose an expansion-rate-selection method to suppress the wave-front-aberration phase noise in both isotopic and nonisotopic atom interferometers. The suppression ratio is about 10 at the expense of half the number of atoms. The simulation based on appropriate experimental parameters shows that the wave-front aberration caused standard deviations to the E\"otv\"os coefficient in weak-equivalence-principle tests using $^{85}\mathrm{Rb}\text{\ensuremath{-}}^{87}\mathrm{Rb}$ and $^{41}\mathrm{K}\text{\ensuremath{-}}^{87}\mathrm{Rb}$ are $1.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}$ and $3.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13}$. Better results can be obtained by improving the wave-front quality and utilizing atom cloud with lower temperature. The analysis and suppression of wave-front-aberration phase noise will be useful for the design of high-precision atom interferometer--based weak-equivalence-principle tests both on ground and in space.
We use a dual-species atom interferometer with 2 s of free-fall time to measure the relative acceleration between 85Rb and 87Rb wave packets in the Earth's gravitational field. Systematic errors arising from kinematic differences between the isotopes are suppressed by calibrating the angles and frequencies of the interferometry beams. We find an E\"otv\"os parameter of $\ensuremath{\eta}=[1.6\ifmmode\pm\else\textpm\fi{}1.8(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}3.4(\mathrm{syst})]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12}$, consistent with zero violation of the equivalence principle. With a resolution of up to $1.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}\text{ }\text{ }\mathrm{g}$ per shot, we demonstrate a sensitivity to $\ensuremath{\eta}$ of $5.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}/\sqrt{\mathrm{Hz}}$.
This article develops an expanded critical–propositional analysis of Lin Zhou and collaborators’ 2015 experiment, “Test of Equivalence Principle at 10−8 Level by a Dual-Species Double-Diffraction Raman Atom Interferometer,” published in Physical Review Letters, in systematic dialogue with the Theory of Objectivity (TO) formulated by Vidamor Cabannas and Denivaldo Silva. Zhou et al. implemented a simultaneous 85Rb– 87Rb atom interferometer employ- ing a four-wave double-diffraction Raman transition scheme and obtained an Eötvös parameter η = (2.8 ± 3.0) × 10−8 , finding no violation of the Weak Equivalence Principle within the sensitivity of the experiment (Zhou et al. 2015). The experiment is especially significant for the Theory of Objectivity because it combines elemental differentiation, fields, frequencies, radiation, phase evolution, relational measurement, information generation, and gravity within a single controlled physical architecture. The analysis distinguishes four epistemological categories that must not be conflated: direct empirical confirmation, indirect empirical corroboration, structural compatibility, and merely analogical correspondence. Zhou et al. do not test the primordial Logical Nothingness proposed by the First Absolute Truth of TO, nor do they directly demonstrate the ontological existence of a unique field belonging to every element, as asserted by the Second Absolute Truth. Likewise, the experiment does not establish that logical existence itself requires the relational observation described by the Fifth Absolute Truth. Nevertheless, the experiment offers significant operational bridges. The two rubidium isotopes remain physically distinguishable while participating in a common gravitational regularity; their interferometric information is produced through relations involving atoms, radiation, frequencies, momentum transfer, phase, and detection; and the measured equality of free-fall acceleration imposes a quantitative constraint on any TO-derived gravitational model in which elemental individuality or proper fields could generate composition-dependent acceleration. Particular attention is given to the TO conception of the transcendent element as knowledge or information generated in atomic relations and associated with atomic radiation. The interferometer provides a concrete physical chain in which interactions are converted into relative phase, populations, radiation-mediated detection, and finally experimentally accessible information. This does not establish the full ontological interpretation proposed by TO, but it supplies an unusually clear operational analogue. The article further articulates Zhou et al. with the foundational TO literature, the 2025–2026 reformulation of its modal and empirical program, and supporting or dialogical literature including Einstein, Heisenberg, Bohm, Prigogine, Penrose, Kuhn, Aspect, Planck, and gravitational-wave observations. A formal bridge is proposed in which a TO-specific field contribution Φi generates a potential differential acceleration δg(Φi). The Zhou result then becomes an empirical restriction on the magnitude of such a contribution. The central conclusion is therefore deliberately limited but scientifically pro- ductive: Zhou et al. do not confirm the Theory of Objectivity as a whole, but their experiment constitutes an important empirical constraint and a viable platform for converting selected TO propositions into quantitatively testable predictions. Keywords: Theory of Objectivity; Weak Equivalence Principle; atom interferometry; rubidium isotopes; gravity; modal ontology; information; Raman transitions; Eötvös parameter; empirical testability.