The work involves atoms cooled to a temperature of almost absolute zero, which behave as waves.
Done on board an Airbus A310 the experiment showed that potassium and rubidium atoms in free fall fell at the same speed in spite of a mass difference of a factor of two.
The objective was to verify Einstein’s equivalence principle [1] énoncé par Einstein.
These results prefigure future measurements made in space where, in spite of numerous technical problems, microgravity will enable the current precision of 10-13 to be considerably improved.
Even an infinitesimal difference would open the door to theories such as string theory which violate the principle of equivalence.
Reference
- Dual Matter-Wave Inertial Sensors in Weightlessness, Brynle Barrett,
Laura Antoni-Micollier, Laure Chichet, Baptiste Battelier, Thomas
Lévèque, Arnaud Landragin, Philippe Bouyer. Nature Communications,
12 décembre 2016. DOI : 10.1038/NCOMMS13786
[1] According to this principle, the inertial mass of a body (its resistance to a change in its mouvement) is equal to its gravitational mass (its reaction to gravity). To date, all measurements of these two quantities have shown them to be identical.