Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1509.08098 · Physical Review Letters

Circumventing Heisenberg’s Uncertainty Principle in Atom Interferometry Tests of the Equivalence Principle

Albert Roura

Published Apr 17, 2017• 118 citations
arXivHTMLPDF

Abstract

Atom interferometry tests of universality of free fall based on the differential measurement of two different atomic species provide a useful complement to those based on macroscopic masses. However, when striving for the highest possible sensitivities, gravity gradients pose a serious challenge. Indeed, the relative initial position and velocity for the two species need to be controlled with extremely high accuracy, which can be rather demanding in practice and whose verification may require rather long integration times. Furthermore, in highly sensitive configurations gravity gradients lead to a drastic loss of contrast. These difficulties can be mitigated by employing wave packets with narrower position and momentum widths, but this is ultimately limited by Heisenberg's uncertainty principle. We present a promising scheme that overcomes these problems by compensating the effects of the gravity gradients and circumvents the fundamental limitations due to Heisenberg's uncertainty principle. Furthermore, it relaxes the experimental requirements on initial colocation by several orders of magnitude.

DOI
10.1103/physrevlett.118.160401

Related papers

Canceling the Gravity Gradient Phase Shift in Atom Interferometry

Giulio D'Amico, G. Rosi, S. Zhan +3 more

Gravity gradients represent a major obstacle in high-precision measurements by atom interferometry. Controlling their effects to the required stability and accuracy imposes very stringent requirements on the relative positioning of freely falling atomic clouds, as in the case of precise tests of Einstein's equivalence principle. We demonstrate a new method to exactly compensate the effects introduced by gravity gradients in a Raman-pulse atom interferometer. By shifting the frequency of the Raman lasers during the central π pulse, it is possible to cancel the initial position- and velocity-dependent phase shift produced by gravity gradients. We apply this technique to simultaneous interferometers positioned along the vertical direction and demonstrate a new method for measuring local gravity gradients that does not require precise knowledge of the relative position between the atomic clouds. Based on this method, we also propose an improved scheme to determine the Newtonian gravitational constant G towards the 10 ppm relative uncertainty.

Physical Review Letters•Dec 19, 2017•81 citations

Effective Inertial Frame in an Atom Interferometric Test of the Equivalence Principle

Chris Overstreet, Peter Asenbaum, Tim Kovachy +3 more

In an ideal test of the equivalence principle, the test masses fall in a common inertial frame. A real experiment is affected by gravity gradients, which introduce systematic errors by coupling to initial kinematic differences between the test masses. Here we demonstrate a method that reduces the sensitivity of a dual-species atom interferometer to initial kinematics by using a frequency shift of the mirror pulse to create an effective inertial frame for both atomic species. Using this method, we suppress the gravity-gradient-induced dependence of the differential phase on initial kinematic differences by 2 orders of magnitude and precisely measure these differences. We realize a relative precision of Δg/g≈6×10^{-11} per shot, which improves on the best previous result for a dual-species atom interferometer by more than 3 orders of magnitude. By reducing gravity gradient systematic errors to one part in 10^{13}, these results pave the way for an atomic test of the equivalence principle at an accuracy comparable with state-of-the-art classical tests.

arXiv:1711.09986•Physical Review Letters•May 4, 2018•133 citations

Atom interferometry for tests of general relativity

Loriani Fard

The search for a fundamental, self-consistent theoretical framework to cover phenomena over all energy scales is possibly the most challenging quest of contemporary physics. Approaches to reconcile quantum mechanics and general relativity entail the modification of their foundations such as the equivalence principle. This corner stone of general relativity is suspected to be violated in various scenarios and is therefore under close scrutiny. Experiments based on the manipulation of cold atoms are excellently suited to challenge its different facets. Freely falling atoms constitute ideal test masses for tests of the universality of free fall in interferometric setups. Moreover, the superposition of internal energy eigenstates provides the notion of a clock, which allows to perform tests of the gravitational redshift. Furthermore, as atom interferometers constitute outstanding phasemeters, they hold the promise to detect gravitational waves, another integral aspect of general relativity. In recent years, atom interferometers have developed into versatile sensors with excellent accuracy and stability, and allow to probe physics at the interface of quantum mechanics and general relativity without classical analog. In this thesis, various aspects regarding tests of general relativity with atom interferometry have been theoretically investigated. This includes the analysis of fundamental effects as well as feasibility studies of experimental configurations. The work is partially focussed on a space-borne mission scenario for a dedicated quantum test of the universality of free fall beyond state-of-the-art by dropping matter waves of different elements. To enable the target accuracy at the level of 10^(−17), a compensation scheme has been developed and discussed, mitigating the detrimental effects of imperfect test mass co-location upon release and relaxing the requirements on the source preparation by several orders of magnitude. In addition, it was demonstrated that the careful design of quantum degenerate sources is indispensable for these experiments, requiring tailored schemes to prepare miscible binary sources. The possibility to test the gravitational redshift with atom interferometers has also been examined in this thesis and connected to the ideas of clock interferometry. With the proof that closed light pulse atom interferometers without transitions between internal internal states are not sensitive to gravitational time dilation, an ongoing scientific debate has been resolved. Instead, certain configurations were shown to implement a quantum version of the special-relativistic twin paradox, for which an experiment has been proposed. Finally, requirements on atomic sources and atom optics for scenarios of gravitational wave detection on ground and in space have been investigated.

•Jan 1, 2020•0 citations

Resolution of the colocation problem in satellite quantum tests of the universality of free fall

Sina Loriani, Christian Schubert, Dennis Schlippert +5 more

A major challenge common to all Galilean drop tests of the universality of free fall (UFF) is the required control over the initial kinematics of the two test masses upon release due to coupling to gravity gradients and rotations. In this work, we consider a space-borne test of the UFF based on atom interferometry and show that this detrimental effect can be mitigated at the ${10}^{\ensuremath{-}18}$ level given an initial differential position (velocity) uncertainty in the order of $\ensuremath{\mu}\mathrm{m}$ ($\ensuremath{\mu}\mathrm{m}/\mathrm{s}$) of the test masses. This corresponds to a relaxation of the source control by several orders of magnitude with respect to comparable mission scenarios, such as the STE-QUEST mission proposal reported in [D. N. Aguilera et al., Classical Quantum Gravity 31, 115010 (2014)]. Our twofold mitigation strategy extends a compensation mechanism that is already established in terrestrial experiments to satellite missions with varying gravity gradients and exploits the spectral distribution of the systematics. We assess the experimental feasibility and find that the moderate parameters of the proposed scheme are in line with technological capabilities. The described attenuation of the gravity-gradient-induced uncertainty removes one major obstacle in quantum tests of the UFF and allows us to consider mission scenarios with target accuracies beyond the state of the art.

arXiv:2006.08729•Physical review. D/Physical review. D.•Dec 18, 2020•23 citations

Improved frequency-shift gravity-gradient compensation on canceling the Raman-pulse-duration effect in atomic gravimeters

Yajie Wang, Xiao-Yu Lu, Yu-Jie Tan +2 more

Although frequency-shift gravity-gradient compensation is currently the technique with the most potential to test the weak equivalence principle with atom interferometry at high precision, it faces an unavoidable obstacle on how to cancel the coupling between the Raman-pulse-duration effect and the gravity gradient related to the atomic initial kinematics. According to the Einstein equivalence principle, we develop a method to calculate this coupling effect in a space-stretching free-falling frame, based on which an improved frequency-shift gravity-gradient compensation technique is put forward to make high-accuracy weak-equivalence-principle tests with the microscopic particles, such as at the level of ${10}^{\ensuremath{-}14}$, more possible.

Physical Review A•Nov 5, 2018•8 citations

Overcoming loss of contrast in atom interferometry due to gravity gradients

Albert Roura, Wolfgang Zeller, Wolfgang P. Schleich

Long-time atom interferometry is instrumental to various high-precision measurements of fundamental physical properties, including tests of the equivalence principle.Due to rotations and gravity gradients, the classical trajectories characterizing the motion of the wave packets for the two branches of the interferometer do not close in phase space, an effect which increases significantly with the interferometer time.The relative displacement between the interfering wave packets in such open interferometers leads to a fringe pattern in the density profile at each exit port and a loss of contrast in the oscillations of the integrated particle number as a function of the phase shift.Paying particular attention to gravity gradients, we present a simple mitigation strategy involving small changes in the timing of the laser pulses which is very easy to implement.A useful representation-free description of the state evolution in an atom interferometer is introduced and employed to analyze the loss of contrast and mitigation strategy in the general case.(As a by-product, a remarkably compact derivation of the phaseshift in a general light-pulse atom interferometer is provided.)Furthermore, exact results are obtained for (pure and mixed) Gaussian states which allow a simple interpretation in terms of the alignment of Wigner functions in phase-space.Analytical results are also obtained for expanding Bose-Einstein condensates within the time-dependent Thomas-Fermi approximation.Finally, a combined strategy for rotations and nonaligned gravity gradients is considered as well.

arXiv:1401.7699•New Journal of Physics•Dec 8, 2014•77 citations
Atom interferometry tests of universality of free fall based on the differential measurement of two different atomic species provide a useful complement to those based on macroscopic masses. However, when striving for the highest possible sensitivities, gravity gradients pose a serious challenge. Indeed, the relative initial position and velocity for the two species need to be controlled with extremely high accuracy, which can be rather demanding in practice and whose verification may require rather long integration times. Furthermore, in highly sensitive configurations gravity gradients lead to a drastic loss of contrast. These difficulties can be mitigated by employing wave packets with narrower position and momentum widths, but this is ultimately limited by Heisenberg's uncertainty principle. We present a promising scheme that overcomes these problems by compensating the effects of the gravity gradients and circumvents the fundamental limitations due to Heisenberg's uncertainty principle. Furthermore, it relaxes the experimental requirements on initial colocation by several orders of magnitude.
Gravity gradients represent a major obstacle in high-precision measurements by atom interferometry. Controlling their effects to the required stability and accuracy imposes very stringent requirements on the relative positioning of freely falling atomic clouds, as in the case of precise tests of Einstein's equivalence principle. We demonstrate a new method to exactly compensate the effects introduced by gravity gradients in a Raman-pulse atom interferometer. By shifting the frequency of the Raman lasers during the central π pulse, it is possible to cancel the initial position- and velocity-dependent phase shift produced by gravity gradients. We apply this technique to simultaneous interferometers positioned along the vertical direction and demonstrate a new method for measuring local gravity gradients that does not require precise knowledge of the relative position between the atomic clouds. Based on this method, we also propose an improved scheme to determine the Newtonian gravitational constant G towards the 10 ppm relative uncertainty.
In an ideal test of the equivalence principle, the test masses fall in a common inertial frame. A real experiment is affected by gravity gradients, which introduce systematic errors by coupling to initial kinematic differences between the test masses. Here we demonstrate a method that reduces the sensitivity of a dual-species atom interferometer to initial kinematics by using a frequency shift of the mirror pulse to create an effective inertial frame for both atomic species. Using this method, we suppress the gravity-gradient-induced dependence of the differential phase on initial kinematic differences by 2 orders of magnitude and precisely measure these differences. We realize a relative precision of Δg/g≈6×10^{-11} per shot, which improves on the best previous result for a dual-species atom interferometer by more than 3 orders of magnitude. By reducing gravity gradient systematic errors to one part in 10^{13}, these results pave the way for an atomic test of the equivalence principle at an accuracy comparable with state-of-the-art classical tests.
The search for a fundamental, self-consistent theoretical framework to cover phenomena over all energy scales is possibly the most challenging quest of contemporary physics. Approaches to reconcile quantum mechanics and general relativity entail the modification of their foundations such as the equivalence principle. This corner stone of general relativity is suspected to be violated in various scenarios and is therefore under close scrutiny. Experiments based on the manipulation of cold atoms are excellently suited to challenge its different facets. Freely falling atoms constitute ideal test masses for tests of the universality of free fall in interferometric setups. Moreover, the superposition of internal energy eigenstates provides the notion of a clock, which allows to perform tests of the gravitational redshift. Furthermore, as atom interferometers constitute outstanding phasemeters, they hold the promise to detect gravitational waves, another integral aspect of general relativity. In recent years, atom interferometers have developed into versatile sensors with excellent accuracy and stability, and allow to probe physics at the interface of quantum mechanics and general relativity without classical analog. In this thesis, various aspects regarding tests of general relativity with atom interferometry have been theoretically investigated. This includes the analysis of fundamental effects as well as feasibility studies of experimental configurations. The work is partially focussed on a space-borne mission scenario for a dedicated quantum test of the universality of free fall beyond state-of-the-art by dropping matter waves of different elements. To enable the target accuracy at the level of 10^(−17), a compensation scheme has been developed and discussed, mitigating the detrimental effects of imperfect test mass co-location upon release and relaxing the requirements on the source preparation by several orders of magnitude. In addition, it was demonstrated that the careful design of quantum degenerate sources is indispensable for these experiments, requiring tailored schemes to prepare miscible binary sources. The possibility to test the gravitational redshift with atom interferometers has also been examined in this thesis and connected to the ideas of clock interferometry. With the proof that closed light pulse atom interferometers without transitions between internal internal states are not sensitive to gravitational time dilation, an ongoing scientific debate has been resolved. Instead, certain configurations were shown to implement a quantum version of the special-relativistic twin paradox, for which an experiment has been proposed. Finally, requirements on atomic sources and atom optics for scenarios of gravitational wave detection on ground and in space have been investigated.
A major challenge common to all Galilean drop tests of the universality of free fall (UFF) is the required control over the initial kinematics of the two test masses upon release due to coupling to gravity gradients and rotations. In this work, we consider a space-borne test of the UFF based on atom interferometry and show that this detrimental effect can be mitigated at the ${10}^{\ensuremath{-}18}$ level given an initial differential position (velocity) uncertainty in the order of $\ensuremath{\mu}\mathrm{m}$ ($\ensuremath{\mu}\mathrm{m}/\mathrm{s}$) of the test masses. This corresponds to a relaxation of the source control by several orders of magnitude with respect to comparable mission scenarios, such as the STE-QUEST mission proposal reported in [D. N. Aguilera et al., Classical Quantum Gravity 31, 115010 (2014)]. Our twofold mitigation strategy extends a compensation mechanism that is already established in terrestrial experiments to satellite missions with varying gravity gradients and exploits the spectral distribution of the systematics. We assess the experimental feasibility and find that the moderate parameters of the proposed scheme are in line with technological capabilities. The described attenuation of the gravity-gradient-induced uncertainty removes one major obstacle in quantum tests of the UFF and allows us to consider mission scenarios with target accuracies beyond the state of the art.
Although frequency-shift gravity-gradient compensation is currently the technique with the most potential to test the weak equivalence principle with atom interferometry at high precision, it faces an unavoidable obstacle on how to cancel the coupling between the Raman-pulse-duration effect and the gravity gradient related to the atomic initial kinematics. According to the Einstein equivalence principle, we develop a method to calculate this coupling effect in a space-stretching free-falling frame, based on which an improved frequency-shift gravity-gradient compensation technique is put forward to make high-accuracy weak-equivalence-principle tests with the microscopic particles, such as at the level of ${10}^{\ensuremath{-}14}$, more possible.
Long-time atom interferometry is instrumental to various high-precision measurements of fundamental physical properties, including tests of the equivalence principle.Due to rotations and gravity gradients, the classical trajectories characterizing the motion of the wave packets for the two branches of the interferometer do not close in phase space, an effect which increases significantly with the interferometer time.The relative displacement between the interfering wave packets in such open interferometers leads to a fringe pattern in the density profile at each exit port and a loss of contrast in the oscillations of the integrated particle number as a function of the phase shift.Paying particular attention to gravity gradients, we present a simple mitigation strategy involving small changes in the timing of the laser pulses which is very easy to implement.A useful representation-free description of the state evolution in an atom interferometer is introduced and employed to analyze the loss of contrast and mitigation strategy in the general case.(As a by-product, a remarkably compact derivation of the phaseshift in a general light-pulse atom interferometer is provided.)Furthermore, exact results are obtained for (pure and mixed) Gaussian states which allow a simple interpretation in terms of the alignment of Wigner functions in phase-space.Analytical results are also obtained for expanding Bose-Einstein condensates within the time-dependent Thomas-Fermi approximation.Finally, a combined strategy for rotations and nonaligned gravity gradients is considered as well.