ALCALINF

This project will achieve a major leap in matter-wave interferometry by devising very long baseline atom interferometers operating with alkali-earth atomic species. This new generation of atom interferometers will use a single photon optical transition to split, deflect and project the atomic wavefunction. Since the very same radiation emitted by a single laser interacts with the atomic ensemble, or with multiple atomic ensembles in a gravity gradiometer configuration, this scheme will be immune to the laser frequency and phase noise that arises in 2-photon beam splitters for large wavepackets/atomic ensembles separations. Thanks to this new approach, we will explore atom interferometry in an unprecedented parameter range. Hence, the evolution of a largely delocalized wavepackets coherent superposition raises unanswered questions about the relativistic correction arising from the light travel time between the wavepackets during the atom-light interaction. Our 6-meter tall experiment will allow for tackling this open problem. It will also allow addressing other topics such as the investigation of coherence and decoherence of largely delocalized macroscopic waves, the demonstration of correlation metrology for very long baseline atom interferometry and, more ambitiously, the exploration of a new type of matter-wave interferometer where the delocalized wavepackets coherent superposition is kept for seconds in a lattice configuration. Finally, this project can lead to future improvement of gravitational antennas, with applications ranging from geophysics to gravitational wave detection. This project is an international collaboration with Marco Prevedelli, invited professor at Bordeaux from Bologna univervisy, David Wilkowski from the internation laboratory Majulab in Singapore, and Mark Kasevich, Jason Hogan and Peter Graham from Stanford University, in the frame of the recent “Laboratoire International Associé” BSAIL between Bordeaux and Stanford.