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1. Observing Spin-Squeezed States under Spin-Exchange Collisions for a Second

Author: Meng-Zi Huang, Jose Alberto de la Paz, Tommaso Mazzoni, Konstantin Ott, Peter Rosenbusch, Alice Sinatra, Carlos L. Garrido Alzar, and Jakob Reichel
Subjects: Physics, QC1-999, Computer software, QA76.75-76.765
Abstract: Using the platform of a trapped-atom clock on a chip, we observe the time evolution of spin-squeezed hyperfine clock states in ultracold rubidium atoms on previously inaccessible time scales up to 1 s. The spin degree of freedom remains squeezed after 0.6 s, which is consistent with the limit imposed by particle loss and is compatible with typical Ramsey times in state-of-the-art microwave clocks. The results also reveal a surprising spin-exchange interaction effect that amplifies the cavity-based spin measurement via a correlation between spin and external degrees of freedom. These results open up perspectives for squeezing-enhanced atomic clocks in a metrologically relevant regime and highlight the importance of spin interactions in real-life applications of spin squeezing.
Published: 2023
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2. Spontaneous spin squeezing in a rubidium BEC

Author: Théo Laudat, Vincent Dugrain, Tommaso Mazzoni, Meng-Zi Huang, Carlos L Garrido Alzar, Alice Sinatra, Peter Rosenbusch, and Jakob Reichel
Subjects: spin squeezing, quantum metrology, atom chips, Bose–Einstein condensate, Science, Physics, QC1-999
Abstract: We describe an experiment where spin squeezing occurs spontaneously within a standard Ramsey sequence driving a two-component Bose–Einstein condensate (BEC) of ^87 Rb atoms trapped in an elongated magnetic trap. The squeezing is generated by state-dependent collisional interactions, despite the near-identical scattering lengths of the spin states in ^87 Rb. In our proof-of-principle experiment, we observe a metrological spin squeezing that reaches 1.3 ± 0.4 dB for 5000 atoms, with a contrast of 90 ± 1%. The method may be applied to realize spin-squeezed BEC sources for atom interferometry without the need for cavities, state-dependent potentials or Feshbach resonances.
Published: 2018
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3. Absolute Quantum Gravimeters and Gradiometers for Field Measurements.

Author: Laura Antoni-Micollier, Maxime Arnal, Romain Gautier, Camille Janvier, Vincent Ménoret, Jérémie Richard, Pierre Vermeulen, Peter Rosenbusch, Cédric Majek, and Bruno Desruelle
Published: 2024
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4. Reaching the Intrinsic Noise of an Absolute Quantum Gravimeter.

Author: Mayana Teloi, Mouhamad Haidar Lakkis, Anthony Amorosi, Laura Antoni-Micollier, Camille Janvier, Vincent Ménoret, Pierre Vermeulen, Peter Rosenbusch, and Christophe Collette
Published: 2024
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5. High-resolution hybrid atomic quantum gravimeter with real-time vibration compensation

Author: Anthony Amorosi, Mayana Teloi, Loïc Amez-Droz, Laura Faure, Vincent Ménoret, Peter Rosenbusch, Brieux Thibaut, and Christophe Collette
Abstract: Over the past decades, gravimeters based on different working principles have been developed, such as superconducting gravimeters, spring gravimeters or interferometric gravimeters. Their ability to measure local changes in gravitational acceleration with a very high level of sensitivity makes these instruments widely used in fundamental physics, inertial navigation and geophysics. Recently, quantum gravimeters based on cold atom interferometry have demonstrated some of the best resolution and stability. The atomic quantum gravimeter (AQG) from iXblue is a drift-free absolute gravimeter with a sensitivity of 750 nm/s^2 at 1 sec and a long-term stability that reaches 10 nm/s^2, currently standing as a top-class industry-standard instrument [1]. However, due to its cyclic operation principle, the sensor is subject to dead times and concentrates on low-frequency variations (DC – 1 Hz). In addition, ground vibrations often overshoot the atom interferometer dynamic range. These issues have been demonstrated to be overcome by combining the quantum gravimeter with a classical accelerometer that senses ground accelerations and decouples the atom interferometer from them, so creating a hybrid quantum-classical sensor [2]. We present the hybridization of an Atomic Quantum Gravimeter with a custom-made optical accelerometer. The accelerometer has been specifically designed to optimally reject ground vibrations in the sensitivity range of the atom interferometer in real time. It consists of a force-feedback interferometric inertial sensor with a bandwidth from 10 s to 100 Hz and sub-picometer resolution. The accelerometer mechanics features fused-silica flexures, allowing to reach a 2.8 Hz natural frequency and a mQ-product of 1100 kg in a compact, 10x10x10 cm3, design. The hybridization of the quantum gravimeter with the optical accelerometer is expected to push down the noise floor of both sensors, ultimately hitting the quantum projection noise of the Absolute Quantum Gravimeter, being 350 nm/s2 at 1 sec. This improvement would therefore open new perspectives for applications of the quantum gravimeter, such as Newtonian-Noise estimation or seismic isolation.[1] Ménoret et al, Gravity measurements below 10-9g with a transportable absolute quantum gravimeter, Scientific Reports 8, 12300 (2018)[2] Merlet et al, Operating an atom interferometer beyond its linear range, Mtrologia 46, 87 (2009)[3] Lautier et al, Hybridizing matter-wave and classical accelerometers, Applied Physics Letters 105, 144102 (2014)
Published: 2023
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6. Operational evaluation of an industrial differential quantum gravimeter

Author: Camille Janvier, Sebastien Merlet, Peter Rosenbusch, Vincent Ménoret, Arnaud Landragin, Franck Pereira dos Santos, and Bruno Desruelle
Abstract: We report on the recent progress on exail’s Differential Quantum Gravimeter (DQG). Developed by exail quantum sensors (formerly known as muquans). The DQG measures the acceleration due to gravity and the vertical gravity gradient simultaneously. It is an industry-grade demonstrator that has been operational for three years now and has achieved state-of-the-art sensitivity mainly limited by Quantum Projection Noise down to a noise floor at about 40E/sqrt(tau) and a long-term stability better than 1E [1]. For gravity measurements the performances are on par or better than exail’s AQG with a sensitivity of 600nm/s²/sqrt(tau) and a stability down to 5nm/s². Measuring the acceleration of the Earth gravity g and the gravity gradient simultaneously and at the same location promises enhanced information on the distribution of underground masses, especially at shallow depths [2].In addition to survey measurements, we report on the DQG evaluation at the the LNE-Trappes characterized gravimetry laboratory near Paris [3]. A comparison to the gravity reference value has shown good agreement. The vertical gravity gradient measurement also compared favorably to the determinations obtained using a spring relative gravimeter both in terms of performance and in terms of ease-of-use.Finally, we present on-going instrumental developments that will be key to the design of more compact instruments. Such instruments will be the basis for the Horizon Europe project FIQUgS which aims at realizing field compatible commercial gravimeters as well as data processing tools. [1] C. Janvier, et al., “A compact differential gravimeter at the quantum projection noise limit”, Phys. Rev. A 105, 022801 (2022)[2] G. Pajot, O. de Viron, M. M. Diament, M. F. Lequentrec-Lalancette, V. Mikhailov, Geo-Physics 73, 123 (2008).[3] S. Merlet, et al., “Micro-gravity investigations for the LNE watt balance project” Metrologia vol 45 265 (2008)
Published: 2023
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7. BNM-SYRTE fountains: recent results.

Author: Celine Vian, Peter Rosenbusch, Harold Marion, Sebastien Bize, Luigi Cacciapuoti, Shougang Zhang, Michel Abgrall, Damien Chambon, I. Maksimovic, Philippe Laurent, Giorgio Santarelli, André Clairon, Andre Nicholas Luiten, Michael E. Tobar, and Christophe Salomon
Published: 2005
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8. Wind speed reconstruction from mono-static wind lidar eliminating the effect of turbulence

Author: Peter Rosenbusch, Pierre Etienne Allain, Paul Mazoyer, Laurie Pontreau, and Jean-Pierre Cariou
Subjects: Wind power, Renewable Energy, Sustainability and the Environment, Turbulence, business.industry, Scalar (physics), Wind speed, Weighting, symbols.namesake, Lidar, Anemometer, symbols, Environmental science, business, Doppler effect, Remote sensing
Abstract: Light detection and ranging (lidar) is an attractive technique to measure wind speed via the Doppler effect, thanks to its flexibility. Although stand-alone deployment is growing, current standards for wind energy applications often require wind lidars to be verified against an in situ met mast with cup anemometers, which deliver point-like measurements. Analyzing 38 lidar-to-cup verification campaigns at eight accredited sites, we investigate the difference between these techniques during turbulence influenced atmospheric conditions. We demonstrate that strong turbulence results in the lidar 10-min scalar average wind speed overestimate the cup value, whereas the lidar vector average results in an underestimate. Although scalar and vector averaging provide acceptable measurements, we show that a linear combination, with appropriate weighting, reduces the lidar turbulence sensitivity by more than one order of magnitude. The resulting overall lidar-to-cup bias is within the one-standard-deviation comparison uncertainty at all sites. The resulting ensemble mean bias is [Formula: see text], where the uncertainty stems from variations between sites. We explain the experimental observations by a model derived from first principles. The developed hybrid averaging is implemented in the Leosphere WindCube v2.1 wind lidar.
Published: 2021
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9. UTC(OP) based on LNE-SYRTE atomic fountain primary frequency standards

Author: G. D. Rovera, Ph. Laurent, M. Abgrall, Sébastien Bize, P. Uhrich, B. Chupin, J. Guéna, Peter Rosenbusch, Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace (LNE - SYRTE), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], Coordinated Universal Time, Computer science, business.industry, General Engineering, Electrical engineering, 01 natural sciences, Atomic fountain, 010309 optics, [SDU]Sciences of the Universe [physics], 0103 physical sciences, 010306 general physics, business, ComputingMilieux_MISCELLANEOUS
Abstract: UTC(OP), the French national realization of the international coordinated universal time, was redesigned and rebuilt. The first step was the implementation in October 2012 of a new algorithm based on a H-maser and on atomic fountain data. Thanks to the new implementation, the stability of UTC(OP) was dramatically improved and UTC(OP) competes with the best time scales available today. Then the hardware generation and distribution of the UTC(OP) physical signals were replaced. Part of the new hardware is composed of commercial devices, but the key elements were specifically developed. One of them is a special switch that allows the UTC(OP) signals to be derived from one of two time scales, based on two different H-masers, which are generated simultaneously. This insures the continuity of the UTC(OP) signal even when a change of the reference H-maser is required. With the new hardware implementation, UTC(OP) is made available through three coherent signals: 100 MHz, 10 MHz and 1 PPS. For more than 3 years, UTC(OP) remained well below 10 ns close to UTC, with a difference even less than 5 ns if we except a short period around MJD 56650.
Published: 2016
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10. First international comparison of fountain primary frequency standards via a long distance optical fiber link

Author: Heiner Denker, M. Lours, Sébastien Bize, Sebastian Koke, Gesine Grosche, Y. Le Coq, Anne Amy-Klein, Daniele Nicolodi, Christian Chardonnet, Burghard Lipphardt, Giorgio Santarelli, J. Guena, Paul-Eric Pottie, S. M. F. Raupach, M. Abgrall, Peter Rosenbusch, Nicolas Quintin, Christian Grebing, Stefan Weyers, F. Meynadier, R. Le Targat, Fabrice Wiotte, A. Kuhl, Nicola Chiodo, Emilie Camisard, Olivier Lopez, Vladislav Gerginov, Fabio Stefani, Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace (LNE - SYRTE), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Physikalisch-Technische Bundesanstalt [Braunschweig] (PTB), Institut für Erdmessung, Leibniz Universität Hannover=Leibniz University Hannover, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), GIP RENATER, RENATER, Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), Labex First-TF ANR-10-LABX-48-01, Equipex REFIMEVE+ ANR-11-EQPX-0039), Centre National d'Etudes Spatiales (CNES), Conseil Régional Ile-de-France (DIM Nano'K), CNRS with Action Spécifique GRAM, Deutsche Forschungsgemeinschaft (DFG) within the CRC 1128, ANR-11-BS04-0009,LIOM,Lien optique multiplexé pour la métrologie et la physique fondamentale(2011), European Project: SIB02, European Project: SIB55, European Project: 15SIB05, Leibniz Universität Hannover [Hannover] (LUH), and Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Dewey Decimal Classification::500 | Naturwissenschaften::550 | Geowissenschaften, Physics - Instrumentation and Detectors, Optical fiber, International Atomic Time, Frequency standards, Atomic Physics (physics.atom-ph), Optical link, Frequency standard, 01 natural sciences, Primary frequency standard, Physics - Atomic Physics, law.invention, Optical fiber frequency transfer, Optical frequency standard, Engineering (all), law, Transfer (computing), ddc:550, Atomic fountain clocks, International fountain clock comparison, Hyperfine structure, Clocks, Physics, primary standard, General Engineering, Redefinition of the seconds, time and frequency metrology, Instrumentation and Detectors (physics.ins-det), Physikalisch-technische bundesanstalt, Clock comparisons, optical fiber link, Fibers, Atomic physics, International atomic time (TAI), Standards, atomic clock, Atomic clocks, Frequency transfer, Ground state, Phase (waves), FOS: Physical sciences, Natural frequencies, 010309 optics, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], 0103 physical sciences, Optical fibers, 010306 general physics, Rubidium, Computational physics, Optical materials, Fountain, Satellite links
Abstract: We report on the first comparison of distant caesium fountain primary frequency standards (PFSs) via an optical fiber link. The 1415 km long optical link connects two PFSs at LNE-SYRTE (Laboratoire National de m\'{e}trologie et d'Essais - SYst\`{e}me de R\'{e}f\'{e}rences Temps-Espace) in Paris (France) with two at PTB (Physikalisch-Technische Bundesanstalt) in Braunschweig (Germany). For a long time, these PFSs have been major contributors to accuracy of the International Atomic Time (TAI), with stated accuracies of around $3\times 10^{-16}$. They have also been the references for a number of absolute measurements of clock transition frequencies in various optical frequency standards in view of a future redefinition of the second. The phase coherent optical frequency transfer via a stabilized telecom fiber link enables far better resolution than any other means of frequency transfer based on satellite links. The agreement for each pair of distant fountains compared is well within the combined uncertainty of a few 10$^{-16}$ for all the comparisons, which fully supports the stated PFSs' uncertainties. The comparison also includes a rubidium fountain frequency standard participating in the steering of TAI and enables a new absolute determination of the $^{87}$Rb ground state hyperfine transition frequency with an uncertainty of $3.1\times 10^{-16}$. This paper is dedicated to the memory of Andr\'{e} Clairon, who passed away on the 24$^{th}$ of December 2015, for his pioneering and long-lasting efforts in atomic fountains. He also pioneered optical links from as early as 1997.
Published: 2017
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11. Real-Time Realization of UTC at Observatoire de Paris

Author: Peter Rosenbusch, M. Abgrall, P. Uhrich, Ph. Laurent, G. D. Rovera, Sébastien Bize, J. Guéna, and B. Chupin
Subjects: Coordinated Universal Time, business.industry, Electrical engineering, Hydrogen maser, business, Telecommunications, Realization (systems), Atomic fountain
Abstract: UTC(OP), the French national realization of the international Coordinated Universal Time, was redesigned and rebuilt. The first step was the implementation in October 2012 of a new algorithm based on an H-maser and on atomic fountain data. Thanks to the new implementation, the stability of UTC(OP) was dramatically improved and UTC(OP) competes with the best time scales available today. Then the hardware generating and distributing the UTC(OP) physical signals was replaced. Part of the new hardware is composed of commercial devices, but the key elements were specifically developed. One of them is a special switch that allows the UTC(OP) signals be derived from one of two time scales, based on two different H-masers, which are generated simultaneously. This insures the continuity of the UTC(OP) signal even when a change of the reference H-maser is required. With the new hardware implementation, UTC(OP) is made available through three coherent signals: 100 MHz, 10 MHz, and 1 PPS. For more than 3 years, UTC(OP) remained well below 10 ns close to UTC, with a difference even less than 5 ns if we except a short period around MJD 56650.
Published: 2017
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12. Optical to microwave clock frequency ratios with a nearly continuous strontium optical lattice clock

Author: Daniele Nicolodi, E. Bookjans, Sébastien Bize, Jean-Luc Robyr, Yann Le Coq, J. Guena, S. Bilicki, Peter Rosenbusch, M. Abgrall, Rodolphe Le Targat, Gregoire Vallet, Chunyan Shi, Jérôme Lodewyck, Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace (LNE - SYRTE), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Time delay and integration, Physics, [PHYS]Physics [physics], Optical lattice, Strontium, business.industry, Atomic Physics (physics.atom-ph), Clock rate, General Engineering, chemistry.chemical_element, FOS: Physical sciences, 01 natural sciences, Metrology, Physics - Atomic Physics, 010309 optics, Computer Science::Hardware Architecture, Optics, Reliability (semiconductor), chemistry, 0103 physical sciences, 010306 general physics, business, Order of magnitude, Microwave, ComputingMilieux_MISCELLANEOUS
Abstract: Optical lattice clocks are at the forefront of frequency metrology. Both the instability and systematic uncertainty of these clocks have been reported to be two orders of magnitude smaller than the best microwave clocks. For this reason, a redefinition of the SI second based on optical clocks seems possible in the near future. However, the operation of optical lattice clocks has not yet reached the reliability that microwave clocks have achieved so far. In this paper, we report on the operation of a strontium optical lattice clock that spans several weeks, with more than 80% uptime. We make use of this long integration time to demonstrate a reproducible measurement of frequency ratios between the strontium clock transition and microwave Cs primary and Rb secondary frequency standards.
Published: 2016
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13. Time and frequency activities at LNE-SYRTE related to global navigation satellite systems

Author: G. D. Rovera, M. Abgrall, Ph. Laurent, Peter Rosenbusch, Sébastien Bize, B. Chupin, J. Guéna, P. Uhrich, Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace (LNE - SYRTE), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], GNSS augmentation, Computer science, business.industry, Real-time computing, RINEX, 01 natural sciences, Synchronization, 010309 optics, Time to first fix, symbols.namesake, GNSS applications, 0103 physical sciences, Global Positioning System, Galileo (satellite navigation), symbols, Satellite navigation, business, 010301 acoustics, ComputingMilieux_MISCELLANEOUS, Remote sensing
Abstract: In modern navigation systems the distance measurements are based on the time spent by the information along the path between the emitter and the receiver. In all GNSS the user only receives signals broadcast from satellites, and the synchronization between all the clocks is crucial. The need of synchronization can be considered from two different point of view. In case of navigation the user must know in real time the time offset of each satellite with respect to a common time scale, like GPS system time or Galileo system time. In case of geodetic data analysis, made a-posteriori, the user will need a similar information but with a higher precision. One example are the data published by IGS that allow the estimation of the position at the millimeter level.
Published: 2016
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14. Demonstration of a dual alkali Rb/Cs fountain clock

Author: Peter Rosenbusch, D. Rovera, André Clairon, P. Laurent, S. Bize, Giorgio Santarelli, Michael E. Tobar, J. Guéna, and Michel Abgrall
Subjects: Physics, Acoustics and Ultrasonics, Electrical and Electronic Engineering, Atomic physics, Key features, Alkali metal, Fountain, Instrumentation, Hyperfine structure, Atomic fountain, Atomic clock, Dual (category theory)
Abstract: We report the operation of a dual Rb/Cs atomic fountain clock. (133)Cs and (87)Rb atoms are cooled, launched, and detected simultaneously in LNE-SYRTE's FO2 double fountain. The dual clock operation occurs with no degradation of either the stability or the accuracy. We describe the key features for achieving such a simultaneous operation. We also report on the results of the first Rb/Cs frequency measurement campaign performed with FO2 in this dual atom clock configuration, including a new determination of the absolute (87)Rb hyperfine frequency.
Published: 2010
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15. Le nouvel UTC(OP) fondé sur les fontaines atomiques du LNE-SYRTE

Author: S. Bize, P. Uhrich, B. Chupin, Ph. Laurent, Peter Rosenbusch, Michel Abgrall, J. Guéna, G.D. Rovera, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], General Medicine, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2016
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16. Millimeter-long fiber Fabry-Perot cavities

Author: Klemens Schüppert, Jakob Reichel, Ralf Kohlhaas, Sébastien Garcia, Konstantin Ott, Romain Long, Peter Rosenbusch, Laboratoire Kastler Brossel (LKB (Jussieu)), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace (LNE - SYRTE), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Universität Innsbruck [Innsbruck], Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Optical fiber, Atomic Physics (physics.atom-ph), Curved mirror, FOS: Physical sciences, 01 natural sciences, law.invention, Physics - Atomic Physics, 010309 optics, Finesse, Optics, law, 0103 physical sciences, Fiber, 010306 general physics, Mode volume, Quantum Physics, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], business.industry, Laser, Atomic and Molecular Physics, and Optics, Optoelectronics, Millimeter, business, Quantum Physics (quant-ph), Fabry–Pérot interferometer, Physics - Optics, Optics (physics.optics)
Abstract: International audience; We demonstrate fiber Fabry-Perot (FFP) cavities with concave mirrors that can be operated at cavity lengths as large as 1.5 mm without significant deterioration of the finesse. This is achieved by using a laser dot machining technique to shape spherical mirrors with ultralow roughness and employing single-mode fibers with large mode area for good mode matching to the cavity. Additionally, in contrast to previous FFPs, these cavities can be used over an octave-spanning frequency range with adequate coatings. We also show directly that shape deviations caused by the fiber's index profile lead to a finesse decrease as observed in earlier attempts to build long FFP cavities, and show a way to overcome this problem.
Published: 2016
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17. An optical lattice clock with spin-polarized 87Sr atoms

Author: X. Baillard, Pierre Lemonde, G. D. Rovera, Michel Abgrall, Peter Rosenbusch, Burghard Lipphardt, Rodolphe Le Targat, Harald Schnatz, Giorgio Santarelli, Mathilde Fouché, Philip G. Westergaard, Arnaud Lecallier, André Clairon, Gesine Grosche, F. Chapelet, Philippe Laurent, Sébastien Bize, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Physikalisch-Technische Bundesanstalt [Braunschweig] (PTB), Métrologie des fréquences optiques, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Références micro-ondes et échelles de temps, Laboratoire Collisions Agrégats Réactivité (LCAR), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), and Physikalisch-Technische Bundesanstalt (PTB)
Subjects: Physics, Optical lattice, [PHYS.PHYS.PHYS-ATOM-PH]Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], Atomic Physics (physics.atom-ph), FOS: Physical sciences, 01 natural sciences, Atomic and Molecular Physics, and Optics, Frequency difference, Physics - Atomic Physics, 010309 optics, 0103 physical sciences, Clock transition, Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010306 general physics, Spin-½
Abstract: International audience; We present a new evaluation of an 87Sr optical lattice clock using spin polarized atoms. The frequency of the 1S0-->3P0 clock transition is found to be 429 228 004 229 873.6 Hz with a fractional uncertainty of 2.6×10-15, a value that is comparable to the frequency difference between the various primary standards throughout the world. This measurement is in excellent agreement with a previous one of similar accuracy [Phys. Rev. Lett. 98, 083002 (2007)].
Published: 2007
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18. Long high finesse ﬁber Fabry-Perot resonators

Author: Sébastien Garcia, Peter Rosenbusch, Ralf Kohlhaas, Jakob Reichel, and Konstantin Ott
Subjects: Fabrication, Materials science, business.industry, Laser, law.invention, Resonator, Light intensity, Finesse, Optics, law, Optoelectronics, Millimeter, business, Free spectral range, Fabry–Pérot interferometer
Abstract: We present the realization of millimeter long ber coupled open Fabry-Perot resonators with a nesse of 46.000.Deterioration of the nesse with increasing resonator length observed in previous experiments could be suppressedby advances in the CO 2 laser-based fabrication process of the ber micro mirrors. In this way, resonator lengthsup to 1.4 mm could be realized, corresponding to a free spectral range of 107 GHz and linewidths of 2.2 MHz.Keywords: long ber Fabry-Perot resonator, high nesse, micro cavity, CO2 machining 1. INTRODUCTION Fabry-Perot resonators are widely spread in research and technology. The two main features of such a res-onator, the enhancement of the light intensity and the excellent wavelength selectivity lead to applications inspectroscopy, 1,2 lasers, 3 telecommunications 4 and sensing. 5 Many of these applications bene t from integration of Fabry-Perot resonators in optical bers, which leadsto a reduction of the apparatus size, an increased stability and the advantage of being directly ber coupled.Established examples are ber Fabry-Perot tunable lters (FFP-TF)
Published: 2015
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19. Stability of a trapped-atom clock on a chip

Author: Vincent Dugrain, R. Szmuk, W. Maineult, Peter Rosenbusch, Jakob Reichel, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Kastler Brossel (LKB (Jussieu)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Kastler Brossel (LKB (Lhomond)), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Atomic Physics (physics.atom-ph), Atom chip, FOS: Physical sciences, Metrology, 7. Clean energy, Physics - Atomic Physics, 67.85.-d, Computer Science::Hardware Architecture, Ultracold atom, Time and frequency, Physics::Atomic and Molecular Clusters, Physics::Atomic Physics, 06.30.Ft, [PHYS]Physics [physics], Condensed Matter::Quantum Gases, Physics, Quantum Physics, 37.10.Gh, Ultracold gases trapped gases, Chip, Atomic and Molecular Physics, and Optics, Atomic clock, Atom traps and guides, 06.20.-f, Atomic physics, Quantum Physics (quant-ph), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We present a compact atomic clock interrogating ultracold 87Rb magnetically trapped on an atom chip. Very long coherence times sustained by spin self-rephasing allow us to interrogate the atomic transition with 85% contrast at 5 s Ramsey time. The clock exhibits a fractional frequency stability of $5.8\times 10^{-13}$ at 1 s and is likely to integrate into the $1\times10^{-15}$ range in less than a day. A detailed analysis of 7 noise sources explains the measured frequency stability. Fluctuations in the atom temperature (0.4 nK shot-to-shot) and in the offset magnetic field ($5\times10^{-6}$ relative fluctuations shot-to-shot) are the main noise sources together with the local oscillator, which is degraded by the 30% duty cycle. The analysis suggests technical improvements to be implemented in a future second generation set-up. The results demonstrate the remarkable degree of technical control that can be reached in an atom chip experiment., 12 pages, 11 figures
Published: 2015
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20. Symmetric microwave potentials for interferometry with thermal atoms on a chip

Author: Jérôme Estève, Christine Guerlin, Landry Huet, Jakob Reichel, Mahdi Ammar, Matthieu Dupont-Nivet, Jean-Paul Pocholle, Sylvain Schwartz, Isabelle Bouchoule, Peter Rosenbusch, Christoph I Westbrook, Thales Research and Technology [Palaiseau], THALES, Laboratoire Charles Fabry / Optique atomique, Laboratoire Charles Fabry (LCF), Université Paris-Sud - Paris 11 (UP11)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace (LNE - SYRTE), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Kastler Brossel (LKB (Lhomond)), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), ANR-09-NANO-0039,CATS,Capteur atomique intégré sur puce(2009), THALES [France], Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Atom interferometer, Coherence time, Atomic Physics (physics.atom-ph), FOS: Physical sciences, 7. Clean energy, Physics - Atomic Physics, Optics, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], Astronomical interferometer, 03.75.Dg,37.10.Gh,37.25.+k, Adiabatic process, Condensed Matter::Quantum Gases, Physics, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Interferometric visibility, [PHYS.PHYS.PHYS-ATOM-PH]Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], 37.10.Gh, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, Atomic and Molecular Physics, and Optics, Symmetry (physics), Interferometry, Atom traps and guides, 37.25.+k, atom interferometry, 03.75.Dg, Atomic physics, business, Atom interferometry techniques, Microwave
Abstract: International audience; A trapped atom interferometer involving state-selective adiabatic potentials with two microwave frequencies on a chip is proposed. We show that this configuration provides a way to achieve a high degree of symmetry between the two arms of the interferometer, which is necessary for coherent splitting and recombination of thermal (i.e., noncondensed) atoms. The resulting interferometer holds promise to achieve high contrast and long coherence time, while avoiding the mean-field interaction issues of interferometers based on trapped Bose-Einstein condensates.
Published: 2015
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21. Stability analysis of the French timescale UTC(OP)

Author: Michel Abgrall, B. Chupin, Ph. Laurent, G. D. Rovera, Sébastien Bize, Peter Rosenbusch, J. Guena, P. Uhrich, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Références micro-ondes et échelles de temps, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, business.industry, Electrical engineering, Statistical analysis, Hydrogen maser, Geodesy, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Stability (probability), Atomic clock
Abstract: This paper presents the current results obtained with the new version of the French timescale UTC(OP) in operation since more than two years now. The time scale is based on an hydrogen maser steered by one of the SYRTE atomic fountains. Thanks to this technique, UTC(OP) is one of the best real time realization of UTC. A statistical analysis of different UTC - UTC(k) comparisons is presented.
Published: 2015
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22. Interference-filter-stabilized external-cavity diode lasers

Author: Peter Rosenbusch, Pierre Lemonde, Ph. Laurent, Sébastien Bize, André Clairon, A. Gauguet, X. Baillard, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Métrologie des fréquences optiques, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Interférométrie Atomique et Capteurs Inertiels, and Références micro-ondes et échelles de temps
Subjects: Materials science, FOS: Physical sciences, Physics::Optics, Semiconductor laser theory, law.invention, Physics - General Physics, Optics, law, Physics::Atomic Physics, Electrical and Electronic Engineering, Physical and Theoretical Chemistry, Diffraction grating, Interference filter, Distributed feedback laser, business.industry, Injection seeder, Laser, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, General Physics (physics.gen-ph), Filter (video), Optoelectronics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], business, Tunable laser, Physics - Optics, Optics (physics.optics)
Abstract: We have developed external-cavity diode lasers, where the wavelength selection is assured by a low loss interference filter instead of the common diffraction grating. The filter allows a linear cavity design reducing the sensitivity of the wavelength and the external cavity feedback against misalignment. By separating the feedback and wavelength selection functions, both can be optimized independently leading to an increased tunability of the laser. The design is employed for the generation of laser light at 698, 780 and 852 nm. Its characteristics make it a well suited candidate for space-born lasers., Comment: 12 pages, 5 figures
Published: 2006
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23. BNM-SYRTE Fountains: Recent Results

Author: C. Vian, Giorgio Santarelli, Michael E. Tobar, J. Grünert, Sébastien Bize, F. Narbonneau, L. Cacciapuotti, Ph. Laurent, I. Maksimovic, André Clairon, D. Chambon, Peter Rosenbusch, Christophe Salomon, Michel Abgrall, F.P. Dos Santos, Andre N. Luiten, and H. Marion
Subjects: Physics, Nuclear magnetic resonance, Electrical and Electronic Engineering, Microwave oscillators, Instrumentation, Atomic collisions, Frequency difference
Abstract: Recent improvements of Bureau National de Me/spl acute/trologie Syste/spl grave/mes de Re/spl acute/fe/spl acute/rence Temps Espace (BNM-SYRTE) fountains FO1 and FO2 are described. Fractional frequency instabilities of 2.9/spl times/10/sup -14//spl tau//sup -1/2/ for FO1 and 1.6/spl times/10/sup -14//spl tau//sup -1/2/ for FO2 have been demonstrated. A preliminary estimate of the systematic frequency shifts gives an uncertainty of /spl plusmn/7.2/spl times/10/sup -16/ for FO1 and /spl plusmn/6.5/spl times/10/sup -16/ for FO2. Furthermore, we present a direct comparison between the two fountains. When a real-time measurement of the collisional shift is included, we observe a stability of the comparison of 5.0/spl times/10/sup -14//spl tau//sup -1/2/ and a frequency difference of /spl delta/=4/spl times/10/sup -16/, well within the combined uncertainties.
Published: 2005
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24. Advances in atomic fountains

Author: P. Laurent, Christophe Salomon, André Clairon, Patrick D. Wolf, Michael E. Tobar, J. Grünert, F. Pereira Dos Santos, C. Vian, I. Maksimovic, Peter Rosenbusch, Michel Abgrall, Luigi Cacciapuoti, Giorgio Santarelli, Sébastien Bize, H. Marion, Pierre Lemonde, Andre N. Luiten, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Références micro-ondes et échelles de temps, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Théorie et métrologie, School of Physics, University of Western Australia, Laboratoire Kastler Brossel (LKB (Lhomond)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Field (physics), business.industry, General Engineering, Energy Engineering and Power Technology, Stability (probability), Atomic clock, Theory of relativity, Optics, Ultracold atom, International Space Station, Aerospace engineering, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], business, Order of magnitude, Physical law
Abstract: International audience; This article describes the work performed at BNM-SYRTE (Observatoire de Paris) in the past few years, toward the improvement and the use of microwave frequency standards using laser-cooled atoms. First, recent improvements of the 133Cs and 87Rb atomic fountains are described. An important advance is the achievement of a fractional frequency instability of 1.6×10tau where tau is the measurement time in seconds, thanks to the routine use of a cryogenic sapphire oscillator as an ultra-stable local frequency reference. The second advance is a powerful method to control the frequency shift due to cold collisions. These two advances lead to a fractional frequency in stability of 2×10 at 50 000 s between two independent primary standards. In addition, these clocks realize the SI second with an accuracy of 7×10, one order of magnitude below that of uncooled devices. Tests of fundamental physical laws constitute an important field of application for highly accurate atomic clocks. In a second part, we describe tests of possible variations of fundamental constants using 87Rb and 133Cs fountains. The third part is an update on the cold atom space clock PHARAO developed in collaboration with CNES. This clock is one of the main instruments of the ACES/ESA mission which will fly on board the International Space Station in 2007-2008, enabling a new generation of relativity tests. To cite this article: S. Bize et al., C. R. Physique 5 (2004).
Published: 2004
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25. Dynamics of a single vortex line in a Bose Einstein condensate

Author: Vincent Bretin, Peter Rosenbusch, and Jean Dalibard
Subjects: Condensed Matter::Quantum Gases, Physics, Angular momentum, Physics and Astronomy (miscellaneous), Oscillation, Dynamics (mechanics), Harmonic potential, Mechanics, Atomic and Molecular Physics, and Optics, Vortex, Condensed Matter::Superconductivity, Quadrupole, Particle, Line (formation)
Abstract: We study experimentally the line of a single vortex in a rotating prolate Bose-Einstein condensate confined in a harmonic potential. In agreement with predictions, we find that the vortex line is in most cases curved at the ends. We also present measurements of the quadrupole oscillation of the condensate in presence of a single vortex. A theoretical treatment to account for the short time and long time behaviors of these modes is developed. Finally, we use these measurements to infer the angular momentum per particle and relate it to the shape of the vortex line.
Published: 2003
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26. Performances of UTC(OP) based on LNE-SYRTE atomic fountains

Author: G. D. Rovera, Michel Abgrall, J. Guena, B. Chupin, Ph. Laurent, Peter Rosenbusch, P. Uhrich, Sébastien Bize, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Références micro-ondes et échelles de temps, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Scale (ratio), Computer science, business.industry, Calibration, Electrical engineering, Telecommunications, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Realization (systems), Atomic clock, Remote sensing
Abstract: International audience; We present the current realization of UTC(OP) generated at LNE-SYRTE, Observatoire de Paris (OP), Paris, France, which is also the source of French legal time. UTC(OP) is based on a H-maser standard steered on the atomic fountains developed by LNE-SYRTE. The steering algorithm and the prediction of UTC(OP) departure from UTC are described, together with the results of the first year of operation. Since October 2012, the departure of UTC(OP) from UTC remained well below 10 ns.
Published: 2014
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27. Alkali vapor pressure modulation on the 100 ms scale in a single-cell vacuum system for cold atom experiments

Author: Jakob Reichel, Vincent Dugrain, Peter Rosenbusch, Laboratoire Kastler Brossel (LKB (Jussieu)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace (LNE - SYRTE), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Kastler Brossel (LKB (Lhomond)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics - Instrumentation and Detectors, Materials science, Atomic Physics (physics.atom-ph), Vapor pressure, FOS: Physical sciences, Heat sink, 7. Clean energy, Physics - Atomic Physics, Trap (computing), Ultracold atom, Physics::Atomic Physics, Instrumentation, ComputingMilieux_MISCELLANEOUS, Condensed Matter::Quantum Gases, [PHYS]Physics [physics], Quantum Physics, Instrumentation and Detectors (physics.ins-det), Thermal conduction, Alkali metal, Pressure sensor, Quantum Gases (cond-mat.quant-gas), Modulation, Atomic physics, Condensed Matter - Quantum Gases, Quantum Physics (quant-ph), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We describe and characterize a device for alkali vapor pressure modulation on the 100ms timescale in a single-cell cold atom experiment. Its mechanism is based on optimized heat conduction between a current-modulated alkali dispenser and a heat sink at room temperature. We have studied both the short-term behavior during individual pulses and the long-term pressure evolution in the cell. The device combines fast trap loading and relatively long trap lifetime, enabling high repetition rates in a very simple setup. These features make it particularly suitable for portable atomic sensors., Comment: One reference added, one corrected
Published: 2014
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28. TESTING PERIODIC LOCAL POSITION INVARIANCE USING LONG-TERM COMPARISON OF THE SYRTE ATOMIC FOUNTAINS AND H-MASERS

Author: Michel Abgrall, John J. McFerran, Giorgio Santarelli, Ph. Laurent, Daniele Rovera, Paul L. Stanwix, J. Guena, Michael E. Tobar, Sébastien Bize, Peter Rosenbusch, and André Clairon
Subjects: Physics, law, Position (vector), Quantum electrodynamics, Maser, Term (time), law.invention
Published: 2014
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29. Magnetisation reversal in thin Cu/Ni/Cu/Si(0 0 1) films

Author: J. A. C. Bland, Peter Rosenbusch, G. Lauhoff, and Jaeyong Lee
Subjects: Reflection high-energy electron diffraction, Materials science, Condensed matter physics, Magnetometer, Relaxation (NMR), Nucleation, Coercivity, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, law.invention, Overlayer, Magnetization, Hysteresis, law
Abstract: A step wedged structure of the form 30 A Cu/50 A Ni/ h A Cu/Si(0 0 1) ( h = 600, 1000, 1500, 2000 A ) grown by MBE has been characterised by in situ RHEED and ex situ polar MOKE magnetometry and MOKE microscopy. The magnetisation reversal process was investigated through measurements of hysteresis loops, magnetisation relaxation and domain images. The sample exhibits a strong magnetic aftereffect and the macroscopic relaxation measurements were fitted by a model which assumes thermally activated magnetisation reversal through domain nucleation and domain-wall propagation. Magnetic imaging confirms that domain-wall propagation dominates over domain nucleation at all Cu buffer layer thicknesses. For the 600 A Cu buffer layer, strong domain-wall pinning occurs on a micron scale, whereas for the 2000 A Cu a domain-wall can propagate freely over hundreds of microns. The reduced pinning causes the coercive field to decrease as the Cu buffer thickness increases. The Barkhausen length deduced from fits to the relaxation data increases with Cu buffer thickness. The correlation length at the Cu buffer and Ni overlayer surface as obtained from the width of the RHEED streaks also increases, suggesting an interdependence between the crystallographic properties of the buffer and overlayer and the magnetic properties.
Published: 1997
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30. Atom chips for quantum sensing with cold thermal atoms

Author: Jakob Reichel, M. Ammar, M. Dupont-Nivet, Sylvain Schwartz, C. Westbrook, I. Bouchoule, L. Huet, C. Guerlin, Peter Rosenbusch, J.-P. Pocholle, Thales Research and Technology [Palaiseau], THALES [France], Laboratoire Charles Fabry / Optique atomique, Laboratoire Charles Fabry (LCF), Université Paris-Sud - Paris 11 (UP11)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Kastler Brossel (LKB (Lhomond)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), THALES, Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Condensed Matter::Quantum Gases, Physics, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Atom interferometer, Quantum sensor, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Interferometry, Chemical species, 0103 physical sciences, Atom, Astronomical interferometer, Physics::Atomic Physics, Matter wave, Atomic physics, 010306 general physics, 0210 nano-technology, Coherence (physics)
Abstract: International audience; We discuss the possibility of building a matter wave interferometer using thermal (i.e. non condensed) cold atoms trapped in the vicinity of an atom chip for quantum sensing of acceleration and gravity fields with reduced mean-field effects. To maintain a satisfactory level of coherence, a high degree of symmetry is required between the two arms of such an interferometer. We discuss this point quantitatively, and describe the experimental protocol we are developing for this purpose, based on internal state labeling and on the use of two parallel coplanar waveguides deposited on top of the atom chip to selectively address the potential of each internal state through microwave dressing. We also report our recent experimental work demonstrating the possibility of achieving a magneto-optical trap with some of the beams passing through the chip.
Published: 2013
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31. Correction: Corrigendum: Experimental realization of an optical second with strontium lattice clocks

Author: R. Gartman, Michel Abgrall, Jérôme Lodewyck, D. Rovera, Giorgio Santarelli, M. Lours, J. Guéna, Bartlomiej Nagorny, R. Le Targat, Philip G. Westergaard, Michal Zawada, Mikhail Gurov, P. Laurent, Pierre Lemonde, Michael E. Tobar, Y. Le Coq, S. Bize, Luca Lorini, Peter Rosenbusch, and André Clairon
Subjects: 010302 applied physics, Physics, Strontium, Multidisciplinary, Clock rate, General Physics and Astronomy, chemistry.chemical_element, General Chemistry, 01 natural sciences, General Biochemistry, Genetics and Molecular Biology, Theoretical physics, chemistry, Quantum mechanics, Lattice (order), 0103 physical sciences, 010306 general physics
Abstract: Nature Communications 4: Article number: 2109 (2013); Published: 9 July 2013; Updated: 31 October 2013. In the legend to Fig. 4c in this Article, references 47 and 48 were incorrectly included in a list of sources for 87Sr clock frequency measurements. The correct sources are Hong et al.49 and Yamaguchi et al.
Published: 2013
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32. Experimental realization of an optical second with strontium lattice clocks

Author: Michel Abgrall, B. Nagorny, Michal Zawada, R. Gartman, Jérôme Lodewyck, Giorgio Santarelli, M. Lours, D. Rovera, Philip G. Westergaard, Pierre Lemonde, Mikhail Gurov, Y. Le Coq, P. Laurent, Michael E. Tobar, André Clairon, J. Guéna, R. Le Targat, Peter Rosenbusch, S. Bize, Luca Lorini, Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace (LNE - SYRTE), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Spectroscopie Hertzienne de l'ENS (LSH-ENS), École normale supérieure - Paris (ENS-PSL), Laboratoire Kastler Brossel (LKB (Lhomond)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), The University of Western Australia (UWA), École normale supérieure - Paris (ENS Paris), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, [PHYS]Physics [physics], Strontium, Optical lattice, Multidisciplinary, business.industry, Theoretical models, General Physics and Astronomy, chemistry.chemical_element, General Chemistry, 01 natural sciences, General Biochemistry, Genetics and Molecular Biology, Atomic clock, Computational physics, 010309 optics, Optics, chemistry, Caesium, Lattice (order), 0103 physical sciences, Fundamental physics, 010306 general physics, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Microwave
Abstract: International audience; Progress in realizing the SI second had multiple technological impacts and enabled further constraint of theoretical models in fundamental physics. Caesium microwave fountains, realizing best the second according to its current definition with a relative uncertainty of 2-4 Â 10 À 16 , have already been overtaken by atomic clocks referenced to an optical transition, which are both more stable and more accurate. Here we present an important step in the direction of a possible new definition of the second. Our system of five clocks connects with an unprecedented consistency the optical and the microwave worlds. For the first time, two state-of-the-art strontium optical lattice clocks are proven to agree within their accuracy budget, with a total uncertainty of 1.5 Â 10 À 16. Their comparison with three independent caesium fountains shows a degree of accuracy now only limited by the best realizations of the microwave-defined second, at the level of 3.1 Â 10 À 16 .
Published: 2013
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33. The new UTC(OP) based on LNE-SYRTE atomic fountains

Author: Peter Rosenbusch, Ph. Laurent, M. Abgrall, G. D. Rovera, S. Bize, P. Uhrich, J. Guena, B. Chupin, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Références micro-ondes et échelles de temps, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Engineering, business.industry, Electrical engineering, Electronic engineering, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Realization (systems), Atomic clock
Abstract: International audience; The new realization of UTC(OP) is described. The steering algorithm and the prediction of UTC(OP) are presented in details. The results of the first semester of operation are reported.
Published: 2013
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34. Splitting of trapped thermal atoms for atom-chip based interferometry

Author: Jérôme Estève, Chris Westbrook, Jakob Reichel, Mahdi Ammar, Jean-Paul Pocholle, Landry Huet, Christine Guerlin, Sylvain Schwartz, Isabelle Bouchoule, and Peter Rosenbusch
Subjects: Condensed Matter::Quantum Gases, Physics, Atom interferometer, White light interferometry, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, Physics::Optics, Chip, Molecular physics, Interferometry, Radiation pressure, Splitter, Thermal, Optoelectronics, Physics::Atomic Physics, business, Microwave
Abstract: We present a design of an atom interferometer using thermal atoms trapped on a chip. We point-out that such an interferometer requires highly symmetrical potentials, and we propose a splitter based on microwave potentials with two coplanar waveguides to achieve this goal.
Published: 2013
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35. Towards an interferometer with thermal atoms trapped on a chip

Author: Christine Guerlin, Christoph I Westbrook, M. Dupont-Nivet, Isabelle Bouchoule, Jakob Reichel, L. Huet, Sylvain Schwartz, Peter Rosenbusch, and M. Ammar
Subjects: Condensed Matter::Quantum Gases, Physics, Quantum optics, Atom interferometer, Coherence time, media_common.quotation_subject, Phase (waves), Degree of coherence, Asymmetry, Interferometry, Atom, Physics::Atomic Physics, Atomic physics, media_common
Abstract: Summary form only given. Atom chips [1] have shown to be very successful for trapping and manipulating cold atoms. Atom interferometry in the vicinity of an atom chip has been recently achieved by coherently splitting a Bose-Einstein condensate with radiofrequency [2] and microwave [3] dressing. However, some limitations on the precision of the phase measurement occur in this case due to the phase diffusion process resulting from mean field interactions in the Bose-Einstein condensate.In this communication, we will discuss the possibility of using a thermal (i.e. non-condensed) ensemble of ultra-cold atoms trapped on an atom chip in order to create a trapped-atom interferometer with much weaker atomic interactions. In such a scheme (which can be seen as the atomic equivalent of a white light interferometer in optics), the coherence time will strongly depend on the level of symmetry that can be achieved between the potentials forming the two arms of the interferometer. For example, in a simple model of two harmonic potentials, it can be shown that a slight relative frequency difference Δω/ω can be associated with a limitation on the coherence time T given by the following expression: T≈ 2π1ιω kΘ Δω where Θ is the temperature of the atomic ensemble and k the Boltzmann constant (the latter expression being valid only for kΘ >> ! ω). For example, a relative asymmetry of 10-3 will result, for a temperature of about 1μK, to a limitation on the coherence time of 40ms, which favourably compares to what has been achieved experimentally with Bose-Einstein condensates [2]. We will then discuss how we plan to achieve, with the on-going experiment at Thales TRT [4], a splitting of the atomic cloud with the highest possible level of symmetry. The basic idea is to use internal state labelling on the so-called “clock states” of the 87Rb atom and microwave dressing [3] with two independent coplanar waveguides, each waveguide being preferentially resonant with one of the two internal states involved in the process. This way, we expect to have quasi-independent control over the two arms of the interferometer and thus to be able to achieve a coherent splitting as much symmetrical as possible.We will finally discuss the potential applications of this technique in terms of acceleration and gravity measurement with cold atoms on a chip, which could be of great interest in the future if combined, for example, with high bandwidth microelectromechanical sensors.
Published: 2013
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36. Comparison of Sr Optical Lattice Clocks at the 10-16 Level

Author: Michel Abgrall, Ph. Laurent, Peter Rosenbusch, G. G. Rovera, Jérôme Lodewyck, Chunyan Shi, J. Guena, Sébastien Bize, Yann Le Coq, M. Gurov, R. Le Targat, Ulrich Eismann, and J. L. Robyr
Subjects: Optical lattice, Strontium, Chemistry, Laser cooling, Caesium, chemistry.chemical_element, High resolution, Atomic physics, Microwave
Abstract: We present a comprehensive set of high resolution comparisons between strontium optical lattice clocks in agreement at the 10-16 level and three microwave cesium fountains. The microwave to optical comparison reaches a total uncertainty of 3.1×10-16.
Published: 2013
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37. Testing local position and fundamental constant invariance due to periodic gravitation and boost using long-term comparison of the SYRTE atomic fountains and H-masers

Author: P. Laurent, Michael E. Tobar, Michel Abgrall, J. Guéna, Peter Rosenbusch, D. Rovera, John J. McFerran, André Clairon, Paul L. Stanwix, S. Bize, Giorgio Santarelli, The University of Western Australia (UWA), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Spectroscopie Hertzienne de l'ENS (LSH-ENS), École normale supérieure - Paris (ENS-PSL), Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace (LNE - SYRTE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Institut des Biomolécules Max Mousseron [Pôle Chimie Balard] (IBMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Kastler Brossel (LKB (Lhomond)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], Quark, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Cosmic microwave background, Cosmic background radiation, FOS: Physical sciences, Fine-structure constant, Electron, General Relativity and Quantum Cosmology (gr-qc), Rest frame, 01 natural sciences, General Relativity and Quantum Cosmology, Gravitational potential, Quantum mechanics, 0103 physical sciences, Beta (velocity), Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010306 general physics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics
Abstract: The frequencies of three separate Cs fountain clocks and one Rb fountain clock have been compared to various hydrogen masers to search for periodic changes correlated with the changing solar gravitational potential at the Earth and boost with respect to the Cosmic Microwave Background (CMB) rest frame. The data sets span over more than eight years. The main sources of long-term noise in such experiments are the offsets and linear drifts associated with the various H-masers. The drift can vary from nearly immeasurable to as high as 1.3*10^-15 per day. To circumvent these effects we apply a numerical derivative to the data, which significantly reduces the standard error when searching for periodic signals. We determine a standard error for the putative Local Position Invariance (LPI) coefficient with respect to gravity for a Cs-Fountain H-maser comparison of 4.8*10^-6 and 10^-5 for a Rb-Fountain H-maser comparison. From the same data the putative boost LPI coefficients were measured to a precision of up to parts in 10^11 with respect to the CMB rest frame. By combining these boost invariance experiments to a Cryogenic Sapphire Oscillator versus H-maser comparison, independent limits on all nine coefficients of the boost violation vector with respect to fundamental constant invariance (fine structure constant, electron mass and quark mass respectively), were determined to a precision of parts up to 10^10., Comment: accepted for publication in Phys Rev D
Published: 2013
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38. Improved Tests of Local Position Invariance UsingRb87andCs133Fountains

Author: Michael E. Tobar, Sébastien Bize, J. Guena, Ph. Laurent, Michel Abgrall, Peter Rosenbusch, André Clairon, and Daniele Rovera
Subjects: Physics, Quark, General Physics and Astronomy, 01 natural sciences, Redshift, Atomic fountain, 010305 fluids & plasmas, Gravitational potential, Position (vector), Quantum mechanics, 0103 physical sciences, Limit (mathematics), Atomic physics, 010306 general physics, Ground state, Hyperfine structure
Abstract: We report tests of local position invariance based on measurements of the ratio of the ground state hyperfine frequencies of 133Cs and 87Rb in laser-cooled atomic fountain clocks. Measurements extending over 14 years set a stringent limit to a possible variation with time of this ratio: d ln(ν(Rb)/ν(Cs))/dt=(-1.39±0.91)×10(-16) yr(-1). This improves by a factor of 7.7 over our previous report [H. Marion et al., Phys. Rev. Lett. 90, 150801 (2003)]. Our measurements also set the first limit to a fractional variation of the Rb/Cs frequency ratio with gravitational potential at the level of c(2)d ln(ν(Rb)/ν(Cs))/dU=(0.11±1.04)×10(-6), providing a new stringent differential redshift test. The above limits equivalently apply to the fractional variation of the quantity α(-0.49)(g(Rb)/g(Cs)), which involves the fine-structure constant α and the ratio of the nuclear g-factors of the two alkalis. The link with variations of the light quark mass is also presented together with a global analysis combining other available highly accurate clock comparisons.
Published: 2012
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39. Testing for periodic changes in fundamental constants using long-term comparison of the SYRTE Cs fountains and H-masers

Author: M. Abgrall, A. Clairon, Peter Wolf, D. Rovera, S. Bize, Paul L. Stanwix, Giorgio Santarelli, Ph. Laurent, J. Guena, Michael E. Tobar, Peter Rosenbusch, The University of Western Australia (UWA), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Références micro-ondes et échelles de temps, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Théorie et métrologie
Subjects: Physics, Julian day, Cosmic microwave background, Noise (electronics), Atomic clock, Computational physics, Term (time), law.invention, Gravitational potential, law, Quantum mechanics, Sensitivity (control systems), Maser, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; We analyze data sets from three separate Cs Fountains compared to various Hydrogen Masers to search for periodic changes correlated with the changing gravitational potential and boost with respect to the Cosmic Microwave Background. Data sets begin at a Modified Julian Day of 52822 (July 2nd 2003) and continue to November 2nd 2011. The main source of long-term noise in such experiments is the offsets associated with the various H-masers used in the comparison combined with the linear drift. The drift can vary to nearly immeasurable to as high as 1.3×10^-15 per day. To circumvent this problem we use the derivative technique. This technique significantly reduces the standard error when searching for periodic signals from such data. Results determine a standard error of the LPI coefficient of 4.8×10^-6 , while boost sensitivity of fundamental constants was measured down to a precision in parts in 10^-11 .
Published: 2012
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40. Progress in atomic fountains at LNE-SYRTE

Author: Ph. Laurent, D. Rovera, A. Clairon, S. Bize, Giorgio Santarelli, M. Lours, J. Guena, M. Abgrall, Michael E. Tobar, Ruoxin Li, B. Chupin, Peter Rosenbusch, and Kurt Gibble
Subjects: Physics, Acoustics and Ultrasonics, International Atomic Time, Atomic Physics (physics.atom-ph), business.industry, FOS: Physical sciences, Atomic fountain, Atomic clock, Physics - Atomic Physics, law.invention, Metrology, Optics, law, Black-body radiation, Electrical and Electronic Engineering, Maser, Fountain, business, Instrumentation, Microwave
Abstract: We give an overview of the work done with the Laboratoire National de M\'etrologie et d'Essais-Syst\`emes de R\'ef\'erence Temps-Espace (LNE-SYRTE) fountain ensemble during the last five years. After a description of the clock ensemble, comprising three fountains, FO1, FO2, and FOM, and the newest developments, we review recent studies of several systematic frequency shifts. This includes the distributed cavity phase shift, which we evaluate for the FO1 and FOM fountains, applying the techniques of our recent work on FO2. We also report calculations of the microwave lensing frequency shift for the three fountains, review the status of the blackbody radiation shift, and summarize recent experimental work to control microwave leakage and spurious phase perturbations. We give current accuracy budgets. We also describe several applications in time and frequency metrology: fountain comparisons, calibrations of the international atomic time, secondary representation of the SI second based on the 87Rb hyperfine frequency, absolute measurements of optical frequencies, tests of the T2L2 satellite laser link, and review fundamental physics applications of the LNE-SYRTE fountain ensemble. Finally, we give a summary of the tests of the PHARAO cold atom space clock performed using the FOM transportable fountain., Comment: 19 pages, 12 figures, 5 tables, 126 references
Published: 2012

41. Spin waves and Collisional Frequency Shifts of a Trapped-Atom Clock

Author: Christian Deutsch, Wilfried Maineult, Jakob Reichel, Peter Rosenbusch, Kurt Gibble, Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace (LNE - SYRTE), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, [PHYS]Physics [physics], Optical lattice, Quantum Physics, Atomic Physics (physics.atom-ph), General Physics and Astronomy, FOS: Physical sciences, Fermion, 01 natural sciences, Atomic clock, 010305 fluids & plasmas, Pulse (physics), Physics - Atomic Physics, Spin wave, 0103 physical sciences, Atomic physics, 010306 general physics, Quantum statistical mechanics, Quantum Physics (quant-ph), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Hyperfine structure, ComputingMilieux_MISCELLANEOUS, Spin-½
Abstract: We excite spin-waves with spatially inhomogeneous pulses and study the resulting frequency shifts of a chip-scale atomic clock of trapped $^{87}$Rb. The density-dependent frequency shifts of the hyperfine transition simulate the s-wave collisional frequency shifts of fermions, including those of optical lattice clocks. As the spin polarizations oscillate in the trap, the frequency shift reverses and it depends on the area of the second Ramsey pulse, exhibiting a predicted beyond mean-field frequency shift. Numerical and analytic models illustrate the observed behaviors., Will appear soon in Physical Review Letters - Typos corrected
Published: 2012
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42. Comparison of two Strontium optical lattice clocks in agreement at the 10−16 level

Author: Rodolphe Le Targat, Luca Lorini, Bartek Nagórny, Mikhail Gurov, Jérôme Lodewyck, Yann Le Coq, Michel Abgrall, Jocelyne Guéna, Sébastien Bize, Peter Rosenbusch, Daniele Rovera, Philippe Laurent, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Métrologie des fréquences optiques, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Nicolaus Copernicus University [Toruń]
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience
Published: 2012

43. Evidence of a fermionic collisional shift

Author: Christian Deutsch, Jakob Reichel, Wilfried Maineult, Peter Rosenbusch, and Kurt Gibble
Subjects: Physics, Radiation pressure, Quantum mechanics, Atom optics, Collision, Atomic clock
Abstract: We present here experimental result showing that an collisional shift that cannot be explained by mean-field effects. We demonstrate that the latter results from subtle interaction scheme in our cold atomic cloud, mathematically equivalent to a fermionic collisional shift. We show agreement between theory and experiment, and extract the relevant energy scales implied in the collision process.
Published: 2011
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44. Recent atomic fountain clock comparisons at LNE-SYRTE

Author: Sébastien Bize, Giorgio Santarelli, Ph. Laurent, André Clairon, Michael E. Tobar, Michel Abgrall, Peter Rosenbusch, J. Guena, Michel Lours, B. Chupin, and Daniele Rovera
Subjects: Physics, Electronic engineering, Atomic physics, Fountain, Atomic fountain, Atomic clock
Abstract: We report on the current status of the LNE-SYRTE fountain clock ensemble composed of three fully operational fountain, one of which is a dual Cs/Rb clock. We focus on the comparisons between them and their impact as primary frequency standards contributing to the accuracy of TAI.
Published: 2011
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45. Extended coherence time on the clock transition of optically trapped Rubidium

Author: F. Piéchon, Jan J. Arlt, Ernst M. Rasel, Carsten Klempt, Peter Rosenbusch, J. Will, F. Ramirez-Martinez, Wolfgang Ertmer, G. Kleine Büning, Institut für Quantenoptik, Leibniz Universität Hannover, QUANTOP, Institut for Fysik og Astronomi, Aarhus Universitet, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Métrologie des fréquences optiques, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Interférométrie Atomique et Capteurs Inertiels, Références micro-ondes et échelles de temps, Laboratoire de Physique des Solides (LPS), and Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Coherence time, Quantum decoherence, Atomic Physics (physics.atom-ph), Dephasing, FOS: Physical sciences, General Physics and Astronomy, Technical improvement, Frequency shift, General nature, Frequency standard, New mechanisms, Electromagnetic radiation, Frequency measurements, Physics - Atomic Physics, Quantum mechanics, Atom, Quantum memories, ddc:530, A-stability, Quantum, Spin-½, Light shift, Physics, Systematic investigations, Quantum Physics, Inhomogeneous density, Integration time, Clock transition, Noise contributions, Quantum Gases (cond-mat.quant-gas), Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik, Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Quantum Physics (quant-ph), entanglement, Condensed Matter - Quantum Gases
Abstract: Optically trapped ensembles are of crucial importance for frequency measurements and quantum memories, but generally suffer from strong dephasing due to inhomogeneous density and light shifts. We demonstrate a drastic increase of the coherence time to 21 s on the magnetic field insensitive clock transition of Rb-87 by applying the recently discovered spin self-rephasing. This result confirms the general nature of this new mechanism and thus shows its applicability in atom clocks and quantum memories. A systematic investigation of all relevant frequency shifts and noise contributions yields a stability of 2.4E-11 x tau^(-1/2), where tau is the integration time in seconds. Based on a set of technical improvements, the presented frequency standard is predicted to rival the stability of microwave fountain clocks in a potentially much more compact setup., 5 pages, 4 figures
Published: 2011
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46. Compact frequency standard using atoms trapped on a chip

Author: Jakob Reichel, Christian Deutsch, T. Schneider, Friedemann Reinhard, F. Ramirez-Martinez, Clément Lacroûte, Peter Rosenbusch, Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Métrologie des fréquences optiques, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Interférométrie Atomique et Capteurs Inertiels, Références micro-ondes et échelles de temps, Laboratoire Kastler Brossel (LKB (Lhomond)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Heinrich Heine Universität Düsseldorf = Heinrich Heine University [Düsseldorf]
Subjects: Physics, Atmospheric Science, Photon, business.industry, Coplanar waveguide, Aerospace Engineering, Astronomy and Astrophysics, Frequency standard, Atomic clock, Magnetic field, law.invention, Geophysics, Optics, Space and Planetary Science, law, Ultracold atom, General Earth and Planetary Sciences, Maser, Atomic physics, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Microwave
Abstract: International audience; We present a compact atomic frequency standard based on the interrogation of magnetically trapped 87Rb atoms. Two photons, in the microwave and radiofrequency domain excite the atomic transition. At a magnetic field of 3.23 G this transition from |F = 1, mF = -1> to |F = 2, mF = 1> is 1st order insensitive to magnetic field variations. Long Ramsey interrogation times can thus be achieved, leading to a projected stability in the low 10-13 at 1 s. This makes this device a viable alternative to LITE and HORACE as a good candidate for replacing or complementing the rubidium frequency standards and passive hydrogen masers already on board of the GPS, GLONASS, and GALILEO satellites. Here we present preliminary results. We use an atom chip to cool and trap the atoms. A coplanar waveguide is integrated to the chip to carry the Ramsey interrogation signal, making the physics package potentially as small as (5 cm)3. We describe the experimental apparatus and show preliminary Ramsey fringes of 1.25 Hz linewidth. We also show a preliminary frequency stability sigmay = 1.5 × 10-12tau-1/2 for 10 < tau < 103 s. This represents one order of magnitude improvement with respect to previous experiments.
Published: 2011
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47. Spin self-rephasing and very long coherence times in trapped atomic ensembles

Author: Peter Rosenbusch
Subjects: Physics, Exchange interaction, Atom optics, Optical polarization, Knudsen number, Atomic physics, Ground state, Spectroscopy, Quantum statistical mechanics, Coherence (physics)
Abstract: We perform Ramsey spectroscopy on the ground state of ultra-cold 87Rb atoms magnetically trapped on a chip in the Knudsen regime. Field inhomogeneities over the sample should limit the 1/e contrast decay time to about 3 s, while decay times of 58 ± 12 s are actually observed. We explain this surprising result by a spin self-rephasing mechanism induced by the identical spin rotation effect originating from the exchange interaction. We propose a theory of this synchronization mechanism and obtain good agreement with the experimental observations. The effect is general and may appear in other physical systems.
Published: 2011
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48. Characterization of the distributed cavity phase shift in FO2 for improving the accuracy of SYRTE fountain clocks

Author: M. Abgrall, Ph. Laurent, D. Rovera, Peter Rosenbusch, Giorgio Santarelli, A. Clairon, J. Guena, Kurt Gibble, S. Bize, Ruoxin Li, and Michael E. Tobar
Subjects: Physics, business.industry, Phase (waves), Stability (probability), Atomic clock, Atomic fountain, Computational physics, Optics, Ultracold atom, Position (vector), Measurement uncertainty, Physics::Atomic Physics, business, Microwave
Abstract: The distributed cavity phase (DCP) shift is a significant source of uncertainty in the accuracy budget of several atomic fountains (see for instance [1 2]). This effect arises when the moving cold atom cloud interacts with the imperfectly stationary microwave field inside the Ramsey cavity. The effect depends on several parameters: The cavity geometry which determines the phase distribution in the cavity, the atomic cloud position and velocity distributions, the microwave power, the overall fountain geometry and the detection parameters which modify the effective velocity distribution of detected atoms. Due to this large number of parameters, there is no straightforward method to measure the distributed cavity phase shift in atomic fountains. So far, the related uncertainty has typically been estimated based on one of several available models for the phase distribution [3 6], on measurements of the atomic cloud parameters and their stability in time and on worst case calculations of the clock shift.
Published: 2010
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49. Spin self-rephasing and very long coherence times in a trapped atomic ensemble

Author: F. Piéchon, Peter Rosenbusch, T. Schneider, Clément Lacroûte, Friedemann Reinhard, Franck Laloë, F. Ramirez-Martinez, Jean-Noël Fuchs, Jakob Reichel, Christian Deutsch, Laboratoire Kastler Brossel (LKB (Lhomond)), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Solides (LPS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Interférométrie Atomique et Capteurs Inertiels, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Références micro-ondes et échelles de temps, Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laloë, Franck, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Atomic Physics (physics.atom-ph), General Physics and Astronomy, FOS: Physical sciences, 01 natural sciences, Particle identification, 010305 fluids & plasmas, Physics - Atomic Physics, Particle decay, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], 0103 physical sciences, effet de rotation des spins identiques, [PHYS.PHYS.PHYS-ATOM-PH] Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], 010306 general physics, Spectroscopy, Quantum statistical mechanics, puces à atomes, ondes de spin, [PHYS.QPHY] Physics [physics]/Quantum Physics [quant-ph], Physics, Quantum Physics, [PHYS.PHYS.PHYS-ATOM-PH]Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], 3. Good health, Magnetic field, horloges atomiques, Knudsen number, Atomic physics, Ground state, Quantum Physics (quant-ph), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Coherence (physics)
Abstract: We perform Ramsey spectroscopy on the ground state of ultra-cold 87Rb atoms magnetically trapped on a chip in the Knudsen regime. Field inhomogeneities over the sample should limit the 1/e contrast decay time to about 3 s, while decay times of 58 s are actually observed. We explain this surprising result by a spin self-rephasing mechanism induced by the identical spin rotation effect originating from particle indistinguishability. We propose a theory of this synchronization mechanism and obtain good agreement with the experimental observations. The effect is general and susceptible to appear in other physical systems., Comment: Revised version; improved description of the theoretical treatment
Published: 2010
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50. Switching atomic fountain clock microwave interrogation signal and high-resolution phase measurements

Author: F. Chapelet, Michael E. Tobar, T. Potier, S. Bize, Guido Governatori, A. Clairon, Giorgio Santarelli, D. Chambon, Ph. Laurent, M. Lours, J. Guena, and Peter Rosenbusch
Subjects: Spectrum analyzer, Engineering, Signal processing, Acoustics and Ultrasonics, business.industry, Atomic clock, Atomic fountain, Optics, Phase noise, Electronic engineering, Physics::Atomic Physics, Electrical and Electronic Engineering, business, Instrumentation, Frequency modulation, Microwave, Microwave cavity
Abstract: This paper focuses on the development of tools aiming to solve several problems related to the microwave interrogation signal in atomic fountains. We first consider the problem related to cycle synchronous phase transients caused by the sequential operation of the atomic fountain. To search for such systematic phase variations deeply buried in the microwave synthesizer phase noise, we have developed a novel triggered-phase transient analyzer capable of processing the microwave signal to extract the phase in a synchronous manner even in the presence of frequency modulation. With this device we check in vivo the LNE-SYRTE fountain's interrogation signals with a resolution approaching 1 microradian. In addition, using this device, we investigate an innovative approach to solve a second problem, namely, the shift caused by microwave leakage in the fountain. Our approach consists of switching off the fountain microwave interrogation signal when atoms are outside the microwave cavity. To do that, we have developed a switch that is almost free of phase transients and is thus able to eliminate the frequency shift caused by microwave leakage without inducing significant phase transients on the interrogation signal.
Published: 2009

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