Optical lattice clocks : black-body enhanced environment

LNE-SYRTE, the national time-frequency metrology laboratory located at Paris Observatory, develops some of the most accurate atomic clocks in the world. The caesium microwave fountains at LNESYRTE realise the second, the unit of time of the international system of units and contribute to the steering of TAI (Temps Atomique International), the basis of UTC. In parallel, LNE-SYRTE is developing a new generation of atomic clocks, optical clocks, based on transitions of strontium or mercury atoms in the optical domain. These clocks use ultra-cold atoms trapped in an array of dipole traps, probed by a laser whose frequency is ultra-stable.

These clocks now reach an accuracy of the order of 10-17, with prospects of a gain of several orders of magnitude in the coming years. In 2017, LNESYRTE’s optical clocks demonstrated the first contribution of an optical clock to TAI. In this context of improving the accuracy and stability of clocks, the clocks of LNE-SYRTE take part to clock comparisons, both locally and internationally via satellite links and a fiber optic network linking European metrology institutes. These comparisons have many applications, both to demonstrate the reproducibility of clocks and to carry out fundamental physics tests. Finally, the demonstration of quantum entanglement effects between atoms can be used to improve the frequency stability of clocks.

The internship project aims at implementing a new vacuum vessel for one of the Sr optical lattice clocks. The purpose is to demonstrate an environment with temperature inhomogeneities smaller than 100 mK in order to precisely estimate the systematic frequency shift due to the interaction between the cold atoms and the ambient black body radiation. The vacuum system is currently assembled and pumped. The candidate will characterized it (temperature, injection of the optical lattice, eddy current), and transfer it to the clock system in order to perform the spectroscopy of the clock transition and measure systematic effects.

Jérôme Lodewyck
LNE-SYRTE, Observatoire de Paris
77, avenue Denfert Rochereau
75014 Paris Tél: 01 40 51 22 24