Application of laser cooling to the time and frequency metrology

Chetan Vishwakarma

F. Strumia

N. Beverini, F. Strumia

Hélène Perrin, P. Lemonde, Franck Pereira dos Santos +4 more

In this review, we discuss the impact of the development of lasers on ultra-cold atoms and molecules and their applications. After a brief historical review of laser cooling and Bose–Einstein condensation, we present important applications of ultra-cold atoms, including time and frequency metrology, atom interferometry and inertial sensors, atom lasers, simulation of condensed matter systems, production and study of strongly correlated systems, and production of ultra-cold molecules.

Nikita Poljakov, J. Schaper, Julia A. Coenders +5 more

Abstract Sympathetic laser cooling is a key concept in precision spectroscopy and quantum state control of charged particles. Significant challenges arise in the metrologically relevant case where the effective interaction between the particles is weak and the particle to be cooled exhibits significant initial motional energy. Here we specifically address the most generally applicable case where the laser-cooled ion and the particle of interest are confined to two spatially separate potential wells with equal motional frequency for resonant enhancement of the cooling dynamics. We analyze the latter through numerical simulations and find that anharmonicities of the potential wells can prevent maintaining the resonance condition throughout the cooling process and thus inhibit a significant reduction in motional energy. We propose a cooling scheme that sweeps the trapping frequency of the potential wells. We show that this scheme enables efficient cooling from cryogenic temperatures all the way to the quantum regime of motion. As a specific application scenario, we analyze the sympathetic cooling of (anti-)protons into the quantum regime of motion for quantum logic spectroscopy-based tests of charge-parity-time invariance at the quantum limit in Penning traps. Nevertheless, our results and cooling strategies are generally applicable to other laser-inaccessible ion species.

Julio R. Gea-Banacloche, Marlan O. Scully, Dana Z. Anderson