Generation of Motional Squeezed States for Neutral Atoms in Optical Tweezers.

Optical tweezers are a powerful tool for the precise positioning of a variety of small objects, including single neutral atoms. Once trapped, atoms can be cooled to the motional ground state of the tweezers. For a more advanced control of their spatial wave function, we report here a simple method to squeeze their motion, and the protocol to measure the squeezing factor based on momentum spreading estimation. We explore the limitations set by the technical imperfections of the tweezers, as well as the more fundamental limit set by their anharmonicity, and finally demonstrate a squeezing of 5.4 dB. The implementation of motional squeezing allows us to push back the limit set by the position quantum noise and thus to explore more extreme situations requiring atoms positioned with nanometric precision.