A5114377644- Advanced Frequency and Time Standards
- Atomic and Subatomic Physics Research
- Scientific Measurement and Uncertainty Evaluation
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Fiber Laser Technologies
- Radioactive Decay and Measurement Techniques
- Spectroscopy and Laser Applications
- GNSS positioning and interference
- Geophysics and Sensor Technology
- Semiconductor Lasers and Optical Devices
- Cardiovascular Syncope and Autonomic Disorders
- Photonic and Optical Devices
- Advanced Fiber Optic Sensors
- Atmospheric Ozone and Climate
- Magnetic confinement fusion research
- Quantum optics and atomic interactions
- Molecular Spectroscopy and Structure
- Physics of Superconductivity and Magnetism
- Hemodynamic Monitoring and Therapy
- Advanced Electrical Measurement Techniques
- Network Time Synchronization Technologies
- Particle accelerators and beam dynamics
- Ionosphere and magnetosphere dynamics
- Mechanical and Optical Resonators
- Quantum Mechanics and Applications
Systèmes de Référence Temps-Espace
2012-2024
Université Paris Sciences et Lettres
2018-2024
Sorbonne Université
2011-2024
Centre National de la Recherche Scientifique
2011-2024
Observatoire de Paris
2011-2022
Istituto Nazionale di Ricerca Metrologica
2006-2015
Laboratoire National de Métrologie et d'Essais
2013
Torino e-district
2011
National Institute of Industrial Technology
2010
National Institute of Standards and Technology
2006-2009
Time has always had a special status in physics because of its fundamental role specifying the regularities nature and extraordinary precision with which it can be measured. This enables tests cosmology, as well practical applications such satellite navigation. Recently, regime operation for atomic clocks based on optical transitions become possible, promising even higher performance. We report frequency ratio two fractional uncertainty 5.2 × 10 –17 . The aluminum mercury single-ion clock...
Istituto Elettrotecnico Nazionale Galileo Ferraris (IEN), National Institute of Standards and Technology (NIST), Physical Laboratory (NPL), Laboratoire de Métrologie et d'Essais—Observatoire Paris/Systèmes Référence Temps Espace (OP) Physikalisch-Technische Bundesanstalt (PTB) operate cold-atom based primary frequency standards which are capable realizing the SI second with a relative uncertainty 1 × 10−15 or even below. These institutes performed an intense comparison campaign selected...
We report tests of local position invariance and the variation fundamental constants from measurements frequency ratio 282-nm $^{199}\mathrm{Hg}^{+}$ optical clock transition to ground state hyperfine splitting in $^{133}\mathrm{Cs}$. Analysis two clocks, extending over 6 yr at NIST, is used place a limit on its fractional $<5.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ per change normalized solar gravitational potential. The same also obtain 20-fold improvement previous...
We present a comprehensive study of the frequency shifts associated with lattice potential in Sr clock by comparing two such clocks stability reaching $5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}17}$ after 1 h integration time. put first experimental upper bound on multipolar $M1$ and $E2$ interactions, significantly smaller than recently predicted theoretical limit, give 30-fold improved limit effect hyperpolarizability. Finally, we report observation vector tensor clock....
We report on the observation of a dc Stark frequency shift at $10^{-13}$ level by comparing two strontium optical lattice clocks. This arises from presence electric charges trapped dielectric surfaces placed under vacuum close to atomic sample. show that these can be eliminated shining UV light surfaces, and characterize residual clock transition $10^{-18}$ applying an external field. study shows play important role in accuracy budget clocks, should duly taken into account.
The dissemination of atomic clocks with fiber-based techniques finds application in the fields metrology, fundamental physics, navigation, and spectroscopy but is a challenge terms reliability, maintenance, performance. Here, we describe realization 1023-km-long fiber link between metrological institutes Italy France that shares infrastructure Internet traffic exploits segmentation shorter, cascaded spans to fight optical losses exceeding 280 dB. With four months quasicontinuous operation...
In this paper we present an accuracy evaluation of the primary frequency standard IEN-CsF1 Italian 'Istituto Nazionale di Ricerca Metrologica'. particular, discuss major improvements applied to that have allowed us reach a total uncertainty 8 × 10−16 in measurement period 20 days 25 days. The full metrological chain links fountain International Atomic Time scale is described and characterized, with respect its noise performances.
This article describes a high-power and narrow-linewidth laser source at 399 nm useful for cooling trapping of ytterbium atoms. A continuous-wave titanium-sapphire 798 is frequency doubled using lithium triborate crystal in an enhancement cavity. Up to 1.0 W light has been obtained from 1.3 infrared light, with efficiency 80 % paper was published Applied Optics made available as electronic reprint the permission OSA. The can be found following URL on OSA website:...
In this paper, we propose an in-depth review of the vector and tensor polarizabilities two energy levels 87Sr clock transition whose measurement was reported in [P. G. Westergaard et al., Phys. Rev. Lett. 106, 210801 (2011)]. We conduct a theoretical calculation that reproduces measured coefficients. addition, detail experimental conditions used for their Sr optical lattice clocks, exhibit quadratic behaviour shifts with depth trapping potential evaluate impact on accuracy clock.
Abstract The recently concluded collaborative European project “Robust optical clocks for international timescales” (ROCIT) tackled some of the key challenges on roadmap towards a redefinition SI second. This paper gives an overview progress made improving robustness and automation verifying their uncertainty budgets through coordinated comparison campaigns. It also presents work incorporation into time scales, covering both use to steer local physical scales evaluations hydrogen masers...
In this paper, we review several aspects of the frequency stability optical lattice clocks. We describe a new ultra-stable cavity design with reduced thermal noise and record (below 10−15), as well non-destructive detection scheme for measuring clock transition probability. Given experimental parameters measured, simulate different sequence strategies optimizing stability. Finally, report on development second comparison strategies. particular, show by numerical method that low 2×10−16τ−1/2...
We used a Cs atomic fountain frequency standard to measure the Stark shift on ground state hyperfine transiton in cesium (9.2 GHz) due electric field generated by blackbody radiation. The measures relative at 300 K is -1.43(11)e-14 and agrees with our theoretical evaluation -1.49(07)e-14. This value differs from currently accepted one -1.69(04)e-14. difference has significant implication accuracy of standards, clocks comparison, variety high precision physics tests such as time stability...
We report the theoretical evaluations of static scalar polarizability $^{133}\mathrm{Cs}$ ground state and blackbody radiation shift induced on transition frequency between two hyperfine levels with ${m}_{F}=0$. This is fundamental importance in evaluation accuracy primary standards based atomic fountains employed realization SI second International Atomic Time scale at level $1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}15}$. Our computed value for...
In this paper we report the accuracy evaluation of Italian primary frequency standard IEN-CsF1. We discuss shifts is corrected for and procedure used evaluation. last section comparisons our fountain with those remote laboratories International Atomic Time.
This paper describes the new twin laser-cooled Cs fountain primary frequency standards NIST-F2 and ITCsF2, presents some of their design features. Most significant is a cryogenic microwave interrogation region which dramatically reduces blackbody radiation shift. We also present preliminary accuracy evaluation IT-CsF2.
The gravitational redshift is one of the main biases in comparison primary frequency standards; even if it not a limit for present accuracy microwave standards such as Cs beam or fountain clocks, could be challenge forthcoming generation atomic optical clocks. In this article we report evaluation with respect to Geoid reference at Istituto Nazionale di Ricerca Metrologica (INRIM) laboratories, an 1 × 10−17 terms relative frequency. based on GPS/levelling measurements and use both local...
We report frequency measurements for relatively weak H(2)O and (16)O(3) rotational transitions in the ground state nu(2) = 1 vibrationally excited state. obtained by using laboratory technique of tunable far-infrared spectroscopy with objective improving O(3) line parameters required modeling important atmospheric spectral window near 119 cm(-1). New sets molecular constants are calculated from data, improved values reported frequencies lines. The improvement simulations new results is...
We report a preliminary systematic shift uncertainty evaluation of our cesium fountain and the first comparison with NIST-F1 clock National Institute Standard Technology (NIST) two way satellite system. The stability time scale UTC (IEN), (generated commercial Cs beam) is insufficient to allow shifts by conventional techniques; therefore, accuracy was accomplished using mainly fast differential techniques, resulting in an overall 3/spl times/10/sup -15/.
A new collaborative European project "International timescales with optical clocks" (ITOC) aims to tackle the key challenges that must be addressed prior a redefinition of SI second. coordinated programme comparisons will carried out between clocks developed in five different laboratories, enabling their performance levels validated at an unprecedented level accuracy. Supporting work evaluate relativistic effects influence comparisons, including gravitational redshift clock transition...