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Panda CD, Tao MJ, Ceja M, Khoury J, Tino GM, Müller H. Measuring gravitational attraction with a lattice atom interferometer. Nature 2024; 631:515-520. [PMID: 38926574 DOI: 10.1038/s41586-024-07561-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 05/13/2024] [Indexed: 06/28/2024]
Abstract
Despite being the dominant force of nature on large scales, gravity remains relatively elusive to precision laboratory experiments. Atom interferometers are powerful tools for investigating, for example, Earth's gravity1, the gravitational constant2, deviations from Newtonian gravity3-6 and general relativity7. However, using atoms in free fall limits measurement time to a few seconds8, and much less when measuring interactions with a small source mass2,5,6,9. Recently, interferometers with atoms suspended for 70 s in an optical-lattice mode filtered by an optical cavity have been demonstrated10-14. However, the optical lattice must balance Earth's gravity by applying forces that are a billionfold stronger than the putative signals, so even tiny imperfections may generate complex systematic effects. Thus, lattice interferometers have yet to be used for precision tests of gravity. Here we optimize the gravitational sensitivity of a lattice interferometer and use a system of signal inversions to suppress and quantify systematic effects. We measure the attraction of a miniature source mass to be amass = 33.3 ± 5.6stat ± 2.7syst nm s-2, consistent with Newtonian gravity, ruling out 'screened fifth force' theories3,15,16 over their natural parameter space. The overall accuracy of 6.2 nm s-2 surpasses by more than a factor of four the best similar measurements with atoms in free fall5,6. Improved atom cooling and tilt-noise suppression may further increase sensitivity for investigating forces at sub-millimetre ranges17,18, compact gravimetry19-22, measuring the gravitational Aharonov-Bohm effect9,23 and the gravitational constant2, and testing whether the gravitational field has quantum properties24.
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Affiliation(s)
- Cristian D Panda
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA.
| | - Matthew J Tao
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA
| | - Miguel Ceja
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA
| | - Justin Khoury
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, USA
| | - Guglielmo M Tino
- Dipartimento di Fisica e Astronomia, Università di Firenze, INFN, CNR-INO, Sesto Fiorentino, Italy
- European Laboratory for Non-Linear Spectroscopy (LENS), Sesto Fiorentino, Italy
| | - Holger Müller
- Department of Physics, University of California, Berkeley, Berkeley, CA, USA.
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2
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Bose S, Mazumdar A, Schut M, Toroš M. Entanglement Witness for the Weak Equivalence Principle. ENTROPY (BASEL, SWITZERLAND) 2023; 25:448. [PMID: 36981336 PMCID: PMC10047996 DOI: 10.3390/e25030448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 06/18/2023]
Abstract
The Einstein equivalence principle is based on the equality of gravitational and inertial mass, which has led to the universality of a free-fall concept. The principle has been extremely well tested so far and has been tested with a great precision. However, all these tests and the corresponding arguments are based on a classical setup where the notion of position and velocity of the mass is associated with a classical value as opposed to the quantum entities.Here, we provide a simple quantum protocol based on creating large spatial superposition states in a laboratory to test the quantum regime of the equivalence principle where both matter and gravity are treated at par as a quantum entity. The two gravitational masses of the two spatial superpositions source the gravitational potential for each other. We argue that such a quantum protocol is unique with regard to testing especially the generalisation of the weak equivalence principle by constraining the equality of gravitational and inertial mass via witnessing quantum entanglement.
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Affiliation(s)
- Sougato Bose
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
| | - Anupam Mazumdar
- Van Swinderen Institute, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Martine Schut
- Van Swinderen Institute, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Marko Toroš
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
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3
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Abstract
An atom interferometer measures the quantum phase due to gravitational time dilation.
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Affiliation(s)
- Albert Roura
- Institute of Quantum Technologies, German Aerospace Center (DLR), Ulm, Germany
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4
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Overstreet C, Asenbaum P, Curti J, Kim M, Kasevich MA. Observation of a gravitational Aharonov-Bohm effect. Science 2022; 375:226-229. [PMID: 35025635 DOI: 10.1126/science.abl7152] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Gravity curves space and time. This can lead to proper time differences between freely falling, nonlocal trajectories. A spatial superposition of a massive particle is predicted to be sensitive to this effect. We measure the gravitational phase shift induced in a matter-wave interferometer by a kilogram-scale source mass close to one of the wave packets. Deflections of each interferometer arm due to the source mass are independently measured. The phase shift deviates from the deflection-induced phase contribution, as predicted by quantum mechanics. In addition, the observed scaling of the phase shift is consistent with Heisenberg’s error-disturbance relation. These results show that gravity creates Aharonov-Bohm phase shifts analogous to those produced by electromagnetic interactions.
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Affiliation(s)
- Chris Overstreet
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - Peter Asenbaum
- Department of Physics, Stanford University, Stanford, CA 94305, USA.,Institute for Quantum Optics and Quantum Information (IQOQI) Vienna, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna, Austria
| | - Joseph Curti
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - Minjeong Kim
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - Mark A Kasevich
- Department of Physics, Stanford University, Stanford, CA 94305, USA
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5
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Xu V, Jaffe M, Panda CD, Kristensen SL, Clark LW, Müller H. Probing gravity by holding atoms for 20 seconds. Science 2019; 366:745-749. [PMID: 31699937 DOI: 10.1126/science.aay6428] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 10/15/2019] [Indexed: 11/02/2022]
Abstract
Atom interferometers are powerful tools for both measurements in fundamental physics and inertial sensing applications. Their performance, however, has been limited by the available interrogation time of freely falling atoms in a gravitational field. By suspending the spatially separated atomic wave packets in a lattice formed by the mode of an optical cavity, we realize an interrogation time of 20 seconds. Our approach allows gravitational potentials to be measured by holding, rather than dropping, atoms. After seconds of hold time, gravitational potential energy differences from as little as micrometers of vertical separation generate megaradians of interferometer phase. This trapped geometry suppresses the phase variance due to vibrations by three to four orders of magnitude, overcoming the dominant noise source in atom-interferometric gravimeters.
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Affiliation(s)
- Victoria Xu
- Department of Physics, University of California, Berkeley, CA 94720, USA.
| | - Matt Jaffe
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Cristian D Panda
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Sofus L Kristensen
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Logan W Clark
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Holger Müller
- Department of Physics, University of California, Berkeley, CA 94720, USA.
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6
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Xin M, Leong WS, Chen Z, Lan SY. An atom interferometer inside a hollow-core photonic crystal fiber. SCIENCE ADVANCES 2018; 4:e1701723. [PMID: 29372180 PMCID: PMC5775024 DOI: 10.1126/sciadv.1701723] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 12/11/2017] [Indexed: 05/27/2023]
Abstract
Coherent interactions between electromagnetic and matter waves lie at the heart of quantum science and technology. However, the diffraction nature of light has limited the scalability of many atom-light-based quantum systems. We use the optical fields in a hollow-core photonic crystal fiber to spatially split, reflect, and recombine a coherent superposition state of free-falling 85Rb atoms to realize an inertia-sensitive atom interferometer. The interferometer operates over a diffraction-free distance, and the contrasts and phase shifts at different distances agree within one standard error. The integration of phase coherent photonic and quantum systems here shows great promise to advance the capability of atom interferometers in the field of precision measurement and quantum sensing with miniature design of apparatus and high efficiency of laser power consumption.
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Asenbaum P, Overstreet C, Kovachy T, Brown DD, Hogan JM, Kasevich MA. Phase Shift in an Atom Interferometer due to Spacetime Curvature across its Wave Function. PHYSICAL REVIEW LETTERS 2017; 118:183602. [PMID: 28524681 DOI: 10.1103/physrevlett.118.183602] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Indexed: 06/07/2023]
Abstract
Spacetime curvature induces tidal forces on the wave function of a single quantum system. Using a dual light-pulse atom interferometer, we measure a phase shift associated with such tidal forces. The macroscopic spatial superposition state in each interferometer (extending over 16 cm) acts as a nonlocal probe of the spacetime manifold. Additionally, we utilize the dual atom interferometer as a gradiometer for precise gravitational measurements.
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Affiliation(s)
- Peter Asenbaum
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Chris Overstreet
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Tim Kovachy
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Daniel D Brown
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Jason M Hogan
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Mark A Kasevich
- Department of Physics, Stanford University, Stanford, California 94305, USA
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8
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Quantum superposition at the half-metre scale. Nature 2016; 528:530-3. [PMID: 26701053 DOI: 10.1038/nature16155] [Citation(s) in RCA: 223] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 10/09/2015] [Indexed: 11/08/2022]
Abstract
The quantum superposition principle allows massive particles to be delocalized over distant positions. Though quantum mechanics has proved adept at describing the microscopic world, quantum superposition runs counter to intuitive conceptions of reality and locality when extended to the macroscopic scale, as exemplified by the thought experiment of Schrödinger's cat. Matter-wave interferometers, which split and recombine wave packets in order to observe interference, provide a way to probe the superposition principle on macroscopic scales and explore the transition to classical physics. In such experiments, large wave-packet separation is impeded by the need for long interaction times and large momentum beam splitters, which cause susceptibility to dephasing and decoherence. Here we use light-pulse atom interferometry to realize quantum interference with wave packets separated by up to 54 centimetres on a timescale of 1 second. These results push quantum superposition into a new macroscopic regime, demonstrating that quantum superposition remains possible at the distances and timescales of everyday life. The sub-nanokelvin temperatures of the atoms and a compensation of transverse optical forces enable a large separation while maintaining an interference contrast of 28 per cent. In addition to testing the superposition principle in a new regime, large quantum superposition states are vital to exploring gravity with atom interferometers in greater detail. We anticipate that these states could be used to increase sensitivity in tests of the equivalence principle, measure the gravitational Aharonov-Bohm effect, and eventually detect gravitational waves and phase shifts associated with general relativity.
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9
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Hamilton P, Jaffe M, Haslinger P, Simmons Q, Müller H, Khoury J. Atom-interferometry constraints on dark energy. Science 2015; 349:849-51. [DOI: 10.1126/science.aaa8883] [Citation(s) in RCA: 185] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- P. Hamilton
- Department of Physics, 366 Le Conte Hall MS 7300, University of California–Berkeley, Berkeley, CA 94720, USA
| | - M. Jaffe
- Department of Physics, 366 Le Conte Hall MS 7300, University of California–Berkeley, Berkeley, CA 94720, USA
| | - P. Haslinger
- Department of Physics, 366 Le Conte Hall MS 7300, University of California–Berkeley, Berkeley, CA 94720, USA
| | - Q. Simmons
- Department of Physics, 366 Le Conte Hall MS 7300, University of California–Berkeley, Berkeley, CA 94720, USA
| | - H. Müller
- Department of Physics, 366 Le Conte Hall MS 7300, University of California–Berkeley, Berkeley, CA 94720, USA
- Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA
| | - J. Khoury
- Center for Particle Cosmology, Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
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10
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Estey B, Yu C, Müller H, Kuan PC, Lan SY. High-Resolution Atom Interferometers with Suppressed Diffraction Phases. PHYSICAL REVIEW LETTERS 2015; 115:083002. [PMID: 26340186 DOI: 10.1103/physrevlett.115.083002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Indexed: 06/05/2023]
Abstract
We experimentally and theoretically study the diffraction phase of large-momentum transfer beam splitters in atom interferometers based on Bragg diffraction. We null the diffraction phase and increase the sensitivity of the interferometer by combining Bragg diffraction with Bloch oscillations. We demonstrate agreement between experiment and theory, and a 1500-fold reduction of the diffraction phase, limited by measurement noise. In addition to reduced systematic effects, our interferometer has high contrast with up to 4.4×10(6) radians of phase difference, and a resolution in the fine structure constant of δα/α=0.25 ppb in 25 h of integration time.
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Affiliation(s)
- Brian Estey
- Department of Physics, 366 Le Conte Hall MS 7300, University of California, Berkeley, California 94720, USA
| | - Chenghui Yu
- Department of Physics, 366 Le Conte Hall MS 7300, University of California, Berkeley, California 94720, USA
| | - Holger Müller
- Department of Physics, 366 Le Conte Hall MS 7300, University of California, Berkeley, California 94720, USA
| | - Pei-Chen Kuan
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Shau-Yu Lan
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
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11
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Photonic Aharonov-Bohm effect in photon-phonon interactions. Nat Commun 2015; 5:3225. [PMID: 24476790 PMCID: PMC3916835 DOI: 10.1038/ncomms4225] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 01/09/2014] [Indexed: 11/25/2022] Open
Abstract
The Aharonov–Bohm effect is one of the most intriguing phenomena in both classical and quantum physics, and associates with a number of important and fundamental issues in quantum mechanics. The Aharonov–Bohm effects of charged particles have been experimentally demonstrated and found applications in various fields. Recently, attention has also focused on the Aharonov–Bohm effect for neutral particles, such as photons. Here we propose to utilize the photon–phonon interactions to demonstrate that photonic Aharonov–Bohm effects do exist for photons. By introducing nonreciprocal phases for photons, we observe experimentally a gauge potential for photons in the visible range based on the photon–phonon interactions in acousto-optic crystals, and demonstrate the photonic Aharonov–Bohm effect. The results presented here point to new possibilities to control and manipulate photons by designing an effective gauge potential. The Aharonov–Bohm effect describes the influence of an electromagnetic vector potential on the phase of a charged particle. Here, Li et al. demonstrate that photon–phonon interactions can lead to the Aharonov–Bohm effect also for the electrically neutral photons.
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12
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Hamilton P, Jaffe M, Brown JM, Maisenbacher L, Estey B, Müller H. Atom interferometry in an optical cavity. PHYSICAL REVIEW LETTERS 2015; 114:100405. [PMID: 25815912 DOI: 10.1103/physrevlett.114.100405] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Indexed: 06/04/2023]
Abstract
We propose and demonstrate a new scheme for atom interferometry, using light pulses inside an optical cavity as matter wave beam splitters. The cavity provides power enhancement, spatial filtering, and a precise beam geometry, enabling new techniques such as low power beam splitters (<100 μW), large momentum transfer beam splitters with modest power, or new self-aligned interferometer geometries utilizing the transverse modes of the optical cavity. As a first demonstration, we obtain Ramsey-Raman fringes with >75% contrast and measure the acceleration due to gravity, g, to 60 μg/sqrt[Hz] resolution in a Mach-Zehnder geometry. We use >10(7) cesium atoms in the compact mode volume (600 μm 1/e(2) waist) of the cavity and show trapping of atoms in higher transverse modes. This work paves the way toward compact, high sensitivity, multiaxis interferometry.
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Affiliation(s)
- Paul Hamilton
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Matt Jaffe
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Justin M Brown
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Lothar Maisenbacher
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Brian Estey
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Holger Müller
- Department of Physics, University of California, Berkeley, California 94720, USA
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13
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Hamilton P, Zhmoginov A, Robicheaux F, Fajans J, Wurtele JS, Müller H. Antimatter interferometry for gravity measurements. PHYSICAL REVIEW LETTERS 2014; 112:121102. [PMID: 24724644 DOI: 10.1103/physrevlett.112.121102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Indexed: 06/03/2023]
Abstract
We describe a light-pulse atom interferometer that is suitable for any species of atom and even for electrons and protons as well as their antiparticles, in particular, for testing the Einstein equivalence principle with antihydrogen. The design obviates the need for resonant lasers through far-off resonant Bragg beam splitters and makes efficient use of scarce atoms by magnetic confinement and atom recycling. We expect to reach an initial accuracy of better than 1% for the acceleration of the free fall of antihydrogen, which can be improved to the part-per million level.
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Affiliation(s)
- Paul Hamilton
- Physics Department, University of California, Berkeley, California 94720, USA
| | - Andrey Zhmoginov
- Physics Department, University of California, Berkeley, California 94720, USA
| | | | - Joel Fajans
- Physics Department, University of California, Berkeley, California 94720, USA
| | - Jonathan S Wurtele
- Physics Department, University of California, Berkeley, California 94720, USA
| | - Holger Müller
- Physics Department, University of California, Berkeley, California 94720, USA
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14
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Lan SY, Kuan PC, Estey B, English D, Brown JM, Hohensee MA, Müller H. A Clock Directly Linking Time to a Particle's Mass. Science 2013; 339:554-7. [DOI: 10.1126/science.1230767] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Historically, time measurements have been based on oscillation frequencies in systems of particles, from the motion of celestial bodies to atomic transitions. Relativity and quantum mechanics show that even a single particle of mass m determines a Compton frequency ω0 = mc2/ℏ, where c is the speed of light and ℏ is Planck's constant h divided by 2π. A clock referenced to ω0 would enable high-precision mass measurements and a fundamental definition of the second. We demonstrate such a clock using an optical frequency comb to self-reference a Ramsey-Bordé atom interferometer and synchronize an oscillator at a subharmonic of ω0. This directly demonstrates the connection between time and mass. It allows measurement of microscopic masses with 4 × 10−9 accuracy in the proposed revision to SI units. Together with the Avogadro project, it yields calibrated kilograms.
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15
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Schleich WP, Greenberger DM, Rasel EM. Redshift controversy in atom interferometry: representation dependence of the origin of phase shift. PHYSICAL REVIEW LETTERS 2013; 110:010401. [PMID: 23383761 DOI: 10.1103/physrevlett.110.010401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 10/22/2012] [Indexed: 06/01/2023]
Abstract
Motivated by the recent debate on whether the Kasevich-Chu atom interferometer can measure the gravitational redshift, we show that in different representations of quantum mechanics chosen for the calculation, the observed phase shift appears as though it originates from different physical phenomena. In particular, we demonstrate that the decomposition of the total phase shift into three dynamical phases, which emerges in a semiclassical approach and is at the very heart of the redshift controversy, does not appear in an exact treatment based on a representation-free analysis. Here only two phenomena determine the phase shift: the difference of the laser phases and the acceleration of the atom. Hence, the Kasevich-Chu interferometer is an accelerometer or gravimeter.
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Affiliation(s)
- Wolfgang P Schleich
- Institut für Quantenphysik and Center for Integrated Quantum Science and Technology, Universität Ulm, D-89069 Ulm, Germany
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