Initial atomic coherences and Ramsey frequency pulling in fountain clocks

Gerginov, Vladislav; Nemitz, Nils; Weyers, S.

doi:10.1103/physreva.90.033829

Cited by 11 publications

(13 citation statements)

References 31 publications

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“…The Ramsey fringe is obtained by scanning the microwave frequency detuning. The contrast of the Ramsey fringe is limited by the purity of the quantization axis (C-field) [21]. In the atomic fountain experiment, the C-filed is generated by a long solenoid, which is driven by a high precision current source.…”

Section: Resultsmentioning

confidence: 99%

Optimization of Operation Parameters in a Cesium Atomic Fountain Clock Using Monte Carlo Method

Yang

et al. 2021

IEEE Access

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The number of atoms detected and the contrast of Ramsey fringe are critical operating parameters in an atomic fountain clock. To optimize these operating parameters, a Monte Carlo method is used to simulate the evolution of the atomic cloud. It is found that the physical variables, including atomic temperature, the launching direction of the atomic cloud, and the initial position of the atomic cloud, have a large influence on the ratio of the falling-back atoms to the launching atoms, and consequently on the detected atomic number, and that the atomic temperature affects the pattern of the Ramsey fringe. In the experiment, these relevant physical variables are optimized and a falling-back ratio as high as 8.6%±0.4% is obtained for a cesium atomic fountain with a launch height of 1 m. Moreover, the Ramsey fringe is experimentally optimized and the contrast of the central Ramsey fringe reaches 90%. This optimization method is also applicable to similar experiments with cold atoms. INDEX TERMSCesium atomic fountain clock, Monte Carlo simulation, ratio of the falling-back atoms, launching direction of atomic cloud

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Section: Resultsmentioning

confidence: 99%

Optimization of Operation Parameters in a Cesium Atomic Fountain Clock Using Monte Carlo Method

Yang

et al. 2021

IEEE Access

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“…Finally, the caesium atoms would eventually transit non-adiabatically to the superposition states of all the Zeeman sublevels. In summary, Majorana transition frequency shift occurs when the atomic states coupled with adjacent energy levels through Majorana transition are affected by Ramsey frequency pulling, [18] thus inducing a clock transition frequency shift. According to Ref.…”

Section: Mechanism Of the Majorana Transition Frequency Shift In Caes...mentioning

confidence: 99%

“…The periodic oscillation meant that the Majorana transition frequency shift was largely, but not completely, inhibited, and the changes in current mainly affected the phase of the atomic state. [18,24] Only if the current increases to a certain value can the magnetic field satisfy the atomic adiabatic transition condition and the frequency shift vanish. However, the current should not be too high as this would change the magnitude of the second-order Zeeman frequency shift.…”

Section: Numerical Simulation Of the Majorana Transition Frequency Shiftmentioning

confidence: 99%

Measurements of Majorana transition frequency shift in caesium atomic fountain clocks

Shi¹,

Wang²,

Yang³

et al. 2023

Chinese Phys. B

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Caesium atomic fountain clock is a primary frequency standard. During its operation, Majorana transition frequency shift will occur once a magnetic field at some special locations along the atomic trajectory is singular. In this study, by developing a physical model, we analysed the magnetic field requirements for atomic adiabatic transition, and calculated the influence of the Majorana atomic transition on the atomic state via a quantum method. Based on the simulation results of the magnetic field in the fountain clock, we applied the Monte Carlo method to simulate the relationship between the Majorana transition frequency shift and magnetic field at the entrance of magnetic shieldings, as well as the initial atomic population. The measurement of the Majorana transition frequency shift was realized by state-selecting asymmetrically populated atoms. The relationship between the Majorana transition frequency shift and axial magnetic field at the entrance of magnetic shieldings was obtained. The measured results were essentially consistent with the calculated results. Thus, the magnetic field at the entrance of magnetic shield was configured, and the Majorana transition frequency shift of the fountain clock was calculated to be 4.57×10-18.

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“…This coefficient is a figure of merit of the orientation of the H field along the quantization axis. A high orientation factor (ξ close to 1) minimizes the excitation of the σ-transitions (∆F = 1, ∆m F = ±1), that can cause unwanted linepulling on the clock transition [28]. For completeness, we also report the filling factor, which is mostly important for active oscillators (or POP clocks with microwave detection [29]), expressing the degree of coupling between the microwave field and the atomic sample:…”

Section: A Finite Element Analysis (Fea)mentioning

confidence: 99%

Loaded Microwave Cavity for Compact Vapor-Cell Clocks

Gozzelino

Micalizio

Calosso

et al. 2021

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Vapor-cell devices based on microwave interrogation provide a stable frequency reference with a compact and robust setup. Further miniaturization must focus on optimizing the physics package, containing the microwave cavity and atomic reservoir. In this paper, we present a compact cavity-cell assembly based on a dielectric-loaded cylindrical resonator. The loaded cavity resonating at 6.83 GHz has an external volume of only 35 cm 3 and accommodates a vapor cell with 0.9 cm 3 inner volume. The proposed design aims at strongly reducing the core of the atomic clock, maintaining at the same time high-performing short-term stability (σy(τ ) ≤ 5 × 10 −13 τ −1/2 standard Allan deviation). The proposed structure is characterized in terms of microwave field uniformity and atom-field coupling with the aid of finite-elements calculations. The thermal sensitivity is also analyzed and experimentally characterized. We present preliminary spectroscopy results by integrating the compact cavity within a rubidium clock setup based on the pulsed optically pumping technique. The obtained clock signals are compatible with the targeted performances. The loaded-cavity approach is thus a viable design option for miniaturized microwave clocks.

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Initial atomic coherences and Ramsey frequency pulling in fountain clocks

Cited by 11 publications

References 31 publications

Optimization of Operation Parameters in a Cesium Atomic Fountain Clock Using Monte Carlo Method

Optimization of Operation Parameters in a Cesium Atomic Fountain Clock Using Monte Carlo Method

Measurements of Majorana transition frequency shift in caesium atomic fountain clocks

Loaded Microwave Cavity for Compact Vapor-Cell Clocks

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