A5027284083- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Frequency and Time Standards
- Atomic and Subatomic Physics Research
- Scientific Measurement and Uncertainty Evaluation
- Geophysics and Gravity Measurements
- Geophysics and Sensor Technology
- Radioactive Decay and Measurement Techniques
- Quantum, superfluid, helium dynamics
- Mechanical and Optical Resonators
- Advanced Materials Characterization Techniques
- Spectroscopy and Laser Applications
- Renal function and acid-base balance
- Quantum Mechanics and Applications
- Experimental and Theoretical Physics Studies
- Iron oxide chemistry and applications
- Quantum Information and Cryptography
- Polymer Surface Interaction Studies
- Quantum optics and atomic interactions
- History and advancements in chemistry
- Ionosphere and magnetosphere dynamics
- Sensor Technology and Measurement Systems
- Inertial Sensor and Navigation
- Advanced Sensor Technologies Research
- Advanced Thermodynamics and Statistical Mechanics
- Solar and Space Plasma Dynamics
Centre National de la Recherche Scientifique
2015-2025
Systèmes de Référence Temps-Espace
2016-2025
Sorbonne Université
2016-2025
Université Paris Sciences et Lettres
2016-2025
Observatoire de Paris
2011-2024
Université Paris-Saclay
2023
Deleted Institution
2012-2021
Laboratoire National de Métrologie et d'Essais
2013-2020
Leibniz University Hannover
2018
Institut National des Sciences de l'Univers
2017
We have remeasured the absolute $1S$-$2S$ transition frequency ${\ensuremath{\nu}}_{\mathrm{H}}$ in atomic hydrogen. A comparison with result of previous measurement performed 1999 sets a limit $(\ensuremath{-}29\ifmmode\pm\else\textpm\fi{}57)\text{ }\mathrm{Hz}$ for drift respect to ground state hyperfine splitting ${\ensuremath{\nu}}_{\mathrm{Cs}}$ $^{133}\mathrm{Cs}$. Combining this recently published optical $^{199}\mathrm{Hg}^{+}$ against and microwave $^{87}\mathrm{Rb}$...
Over five years, we have compared the hyperfine frequencies of $^{133}\mathrm{C}\mathrm{s}$ and $^{87}\mathrm{R}\mathrm{b}$ atoms in their electronic ground state using several laser-cooled atomic fountains with an accuracy $\ensuremath{\sim}{10}^{\ensuremath{-}15}$. These measurements set a stringent upper bound to possible fractional time variation ratio between two frequencies:...
We have observed a Bose-Einstein condensate in dilute gas of 4He the (3)2S(1) metastable state. find critical temperature (4.7+/-0.5) microK and typical number atoms at threshold 8 x 10(6). The maximum our is about 5 10(5). An approximate value for scattering length = (16+/-8) nm measured. mean elastic collision rate then estimated to be 2 10(4) s(-1), indicating that we are deeply hydrodynamic regime. decay time s, which places an upper bound on constants two-body three-body inelastic collisions.
Limits on the long-term stability and accuracy of a second generation cold atom gravimeter are investigated. We demonstrate measurement protocol based four interleaved configurations, which allows rejection most systematic effects, but not those related to Coriolis acceleration wave-front distortions. Both transverse motion atomic cloud. Carrying out measurements with opposite orientations respect Earth's rotation vector direction us separate effects correct for shift. Finally, at different...
This paper describes advances in microwave frequency standards using laser-cooled atoms at BNM-SYRTE. First, recent improvements of the $^{133}$Cs and $^{87}$Rb atomic fountains are described. Thanks to routine use a cryogenic sapphire oscillator as an ultra-stable local reference, fountain instability $1.6\times 10^{-14}\tau^{-1/2}$ where $\tau $ is measurement time seconds measured. The second advance powerful method control shift due cold collisions. These two lead stability $2\times...
We present here an analysis of the sensitivity a time-domain atomic interferometer to phase noise lasers used manipulate wave-packets. The function is calculated in case three pulse Mach-Zehnder interferometer, which configuration two inertial sensors we are building at BNM-SYRTE. successfully compare this calculation experimental measurements. limited by lasers, as well residual vibrations. evaluate performance that could be obtained with state art quartz oscillators, impact phase-lock...
We report the direct comparison between stabilities of two mobile absolute gravimeters different technology: LNE-SYRTE Cold Atom Gravimeter and FG5X\#216 Universit\'e du Luxembourg. These instruments rely on principles operation: atomic optical interferometry. The took place in Walferdange Underground Laboratory for Geodynamics Luxembourg, at beginning last International Comparison Absolute Gravimeters, ICAG-2013. analyse a 2h10 duration common measurement, find that CAG shows better...
We report a comparison between two absolute gravimeters: the LNE-SYRTE cold atom gravimeter and FG5#220 of Leibniz Universität Hannover. They rely on different principles operation: atomic optical interferometry. Both are movable which enabled them to participate in last International Comparison Absolute Gravimeters (ICAG'09) at BIPM. Immediately after, their bilateral took place LNE watt balance laboratory showed an agreement (4.3 ± 6.4) µGal.
We demonstrate a hybrid accelerometer that benefits from the advantages of both conventional and atomic sensors in terms bandwidth (DC to 430 Hz) long term stability. First, use real time correction atom interferometer phase by signal classical enables run it at best performance without any isolation platform. Second, servo-lock DC component sensor output one realizes sensor. This method paves way for applications geophysics inertial navigation as overcomes main limitation accelerometers,...
We report on the implementation of ultracold atoms as a source in state art atom gravimeter. perform gravity measurements with 10 nm s−2 statistical uncertainties so-far largely unexplored temperature range for such high accuracy sensor, down to 50 nK. This allows an improved characterization most limiting systematic effect, related wavefront aberrations light beamsplitters. A thorough model impact this effect onto measurement is developed and method proposed correct bias based extrapolation...
We study a space-based gravity gradiometer based on cold atom interferometry and its potential for the Earth's gravitational field mapping. The instrument architecture has been proposed in [Carraz et al., Microgravity Science Technology 26, 139 (2014)] enables high-sensitivity measurements of gradients by using interferometers differential accelerometer configuration. present design including subsystems analyze mission scenario, which we derive expected performances, requirements sensor key...
Atom interferometry offers new perspectives for geophysics and inertial sensing. We present the industrial prototype of a quantum-based instrument: compact, transportable, differential quantum gravimeter capable measuring simultaneously absolute values both gravitational acceleration $g$ its vertical gradient ${\mathrm{\ensuremath{\Gamma}}}_{zz}$. While sensitivity to is competitive with best gravimeters, on ${\mathrm{\ensuremath{\Gamma}}}_{zz}$ reaches limit set by projection...
In this Letter, we demonstrate a new scheme for Raman transitions which realize symmetric momentum-space splitting of $4\ensuremath{\hbar}k$, deflecting the atomic wave packets into same internal state. Combining advantages and Bragg diffraction, achieve three pulse state labeled an interferometer, intrinsically insensitive to main systematics applicable all kinds sources. This can be extended $4N\ensuremath{\hbar}k$ momentum transfer by multipulse sequence is implemented on...
We demonstrate a scheme for realizing compact cold atom gravimeter. The use of hollow pyramidal configuration allows to achieve all functions: trapping, interferometer and detection with unique laser beam leading drastic reduction in complexity volume. In particular, we relative sensitivity acceleration gravity (g) 1.7×10−7 at one second, moderate power 50 mW. This simple geometry combined such high opens wide perspectives practical applications.
In this paper, we show that an atom interferometer inertial sensor, when associated to the auxiliary measurement of external vibrations, can be operated beyond its linear range and still keep a high acceleration sensitivity.We propose compare two procedures (fringe fitting nonlinear lock) used extract mean phase fluctuations exceed 2π.Despite operating in urban environment inner Paris without any vibration isolation, use low noise seismometer for ground vibrations allows our gravimeter reach...
The 8th International Comparison of Absolute Gravimeters (ICAG2009) took place at the headquarters Bureau Weights and Measures (BIPM) from September to October 2009. It was first ICAG organized as a key comparison in framework CIPM Mutual Recognition Arrangement Committee for (CIPM MRA) 1999). ICAG2009 composed Key (KC) defined by MRA, Consultative Mass Related Quantities (CCM) designated CCM.G-K1. Participating gravimeters their operators came national metrology institutes (NMIs) or (DIs)...
A determination of the Planck constant h using LNE Kibble balance in air was carried out spring 2017. Substantial improvements since 2014, chiefly related to mass standard, mechanical alignments, voltage measurements and type evaluation uncertainties, leads a value 6.626 070 41(38) × 10–34 J · s, with relative standard uncertainty 5.7 10–8.
Recent developments in quantum technology have resulted a new generation of sensors for measuring inertial quantities, such as acceleration and rotation. These can exhibit unprecedented sensitivity accuracy when operated space, where the free-fall interrogation time be extended at will environment noise is minimal. European laboratories played leading role this field by developing concepts tools to operate these relevant environment, parabolic flights, towers, or sounding rockets. With...
A new Watt balance project is now in progress at the Bureau National de Metrologie (BNM), Paris, France. In this paper, general configuration and main parts of experimental setup currently development are presented. The aim to contribute international effort monitoring kilogram toward a definition mass unit with relative accuracy 10/sup -8/ or better.
We present a new method based on transfer of population by adiabatic passage that allows one to prepare cold atomic samples with well-defined ratio density and atom number. This is used perform measurement the collision frequency shift in laser cooled cesium clock at percent level, which makes evaluation fountain accuracy 10(-16) level realistic. With improvements, would allow measurements density-dependent phase shifts 10(-3) high precision experiments.
Recent improvements of Bureau National de Me/spl acute/trologie Syste/spl grave/mes Re/spl acute/fe/spl acute/rence Temps Espace (BNM-SYRTE) fountains FO1 and FO2 are described. Fractional frequency instabilities 2.9/spl times/10/sup -14//spl tau//sup -1/2/ for 1.6/spl have been demonstrated. A preliminary estimate the systematic shifts gives an uncertainty /spl plusmn/7.2/spl -16/ plusmn/6.5/spl FO2. Furthermore, we present a direct comparison between two fountains. When real-time...
We report on a micro-gravity survey of the laboratories where LNE's watt balance experiment is being conducted, including characterization Scintrex CG-5 relative gravimeter used for this study. The results are compared with model gravity field generated by local mass distribution. ultimate goal to transfer an absolute measurement g from one room another minimal uncertainty.
We study the influence of off-resonant two-photon transitions on high-precision measurements with atom interferometers based stimulated Raman transitions. These resonances induce a light shift resonant condition. The impact this effect is investigated in two highly sensitive experiments using gravimeter and gyroscope-accelerometer. show that it can lead to significant systematic phase shifts, which have be taken into account order achieve best performances terms accuracy stability.