Muquans, the first quantum gravimeter
Résif funded the development of the world’s first commercial quantum gravimeter. This compact and transportable gravimeter is commercialized by the start-up Muquans, founded in association with researchers from CNRS, the Institut d’optique Graduate School and Paris Observatory.
Quantum technologies are putting themselves to the test in the field: the Absolute Quantum Gravimeter (AQG) enables the acceleration of gravity to be measured with great precision and thus to evaluate changes in mass below the ground surface.
Until the advent of quantum technologies, the best method of absolute gravimetry was to measure by laser interferometry the acceleration experienced by a cube corner reflector in free fall in vacuum. The absolute quantum gravimeter is based on the principle of a free-fall measurement, but this time characterizing the fall of a cloud of atoms at very low temperatures. Rubidium atoms, trapped by lasers, are cooled to a temperature close to absolute zero. Left in free fall, their vertical acceleration is then measured by a matter-wave interferometry technique that exploits the quantum properties of matter, making it possible to evaluate the acceleration of gravity with an uncertainty 1 billion times smaller than the value of 9.80 m/s2.
The two parts of the instrument – the sensor head and the electronic control device – have been developed to be easily transportable, to be adapted to field conditions (vibrations…), and to be easily implemented thanks to a software that allows a fully automatic operation of the instrument. The latest version of the instrument, even more compact and robust, was presented at the Rencontres Scientifiques et Techniques Résif in November 2019.
The first results  obtained during joint experiments between Résif and Muquans open wide perspectives for scientific or industrial applications, in particular in the field of geophysics, for the study of the internal structure of the globe and natural resources, for reservoir monitoring or in metrology.
This instrument is the result of technology transfer from two French academic laboratories, SYRTE (Systèmes de Références Temps-Espace, UMR 8630 CNRS – Observatoire de Paris – Université Pierre et Marie Curie) and LP2N (Laboratoire Photonique Numérique et Nanosciences, UMR 5298 CNRS – Institut d’Optique – Université de Bordeaux).Thanks to its expertise in field gravimetry, RESIF helped define the technical specifications for this instrument.
 “Gravity measurements below 10−9 g with a transportable absolute quantum gravimeter” – Vincent Ménoret, Pierre Vermeulen, Nicolas Le Moigne, Sylvain Bonvalot, Philippe Bouyer, Arnaud Landragin & Bruno Desruelle. Nature Scientific Reports, 2018, 8:12300 | DOI:10.1038/s41598-018-30608-1
Bruno Desruelle – Président de Muquans – bruno.desruelle[at]muquans.com