Saurabh was the driving force behind this. He believed that this paper could go far and made sure that these great results get the attention it deserves. The effort paid of — thanks and congratulations to the whole team!
In this Letter, we demonstrate magnetogravitational matter-wave lensing as a novel tool in atom-optics in atomtronic waveguides. We collimate and focus matter waves originating from Bose-Einstein condensates and ultracold thermal atoms in ring-shaped time-averaged adiabatic potentials. We demonstrate “delta-kick cooling” of Bose-Einstein condensates, reducing their expansion energies by a factor of 46 down to 800 pK. The atomtronic waveguide ring has a diameter of less than one millimeter, compared to other state- of-the-art experiments requiring zero gravity or free-flight distances of ten meters and more. This level of control with extremely reduced spatial requirements is an important step toward atomtronic quantum sensors.