Progress in atomic fountains at LNE-SYRTE

Area of Science:

• Atomic, Molecular, and Optical Physics
• Metrology
• Quantum Physics

Background:

• The Laboratoire National de Métrologie et d'Essais-Systèmes de Référence Temps-Espace (LNE-SYRTE) operates a sophisticated ensemble of atomic fountains.
• Advancements in atomic clock technology are crucial for fundamental physics and timekeeping.

Purpose of the Study:

• To provide a comprehensive overview of the LNE-SYRTE fountain ensemble's work over the past five years.
• To detail advancements, systematic frequency shift studies, and applications of the atomic fountain clocks.

Main Methods:

• Description of the three fountain clocks (FO1, FO2, FOM) and their recent developments.
• Evaluation of systematic frequency shifts including distributed cavity phase shift and microwave lensing.
• Experimental work on controlling microwave leakage and spurious phase perturbations.

Main Results:

• Current accuracy budgets for the fountain clocks are presented.
• Systematic frequency shifts for FO1, FO2, and FOM fountains have been evaluated.
• Successful control of microwave leakage and spurious phase perturbations demonstrated.

Conclusions:

• The LNE-SYRTE fountain ensemble has achieved high accuracy in time and frequency metrology.
• The clocks are applied in international time scale calibrations, SI second representation, and fundamental physics tests.
• The FOM fountain was used to test the PHARAO cold atom space clock.