A very excited dipolar quantum droplet

In this preprint, we present together with collaborators from the University of Otago the excitation spectrum of Erbium at the crossover from a Bose-Einstein condensate to a trapped macrodroplet. The measurements coincide well with the predictions and confirm the peculiar features of this spectrum: a strong upward shift in energy at low momentum and the appearance of multiple excitation branches at higher momentum. It turns out that these features can be explained by the tendency of the excitations to avoid the central dense part of the droplet and by becoming more like ripples moving over the surface of a droplet!

See the pre-print here: arXiv:2308.00003.

Erbium in optical tweezers!

In the T-REQS lab we have now loaded our first Er atoms into optical tweezers! This is an significant step towards our goal of producing arrays of single atoms within tweezers which we will use to study the interactions of Rydberg atoms.

Supersolids go round!

In recent years a new state of matter has appeared on the scene: the supersolid. This has both the crystal structure of a solid and the properties of a superfluid, a quantum fluid that can flow without friction. We show that an established method for forming supersolids in a one-dimensional crystal–by tuning how the particles interact with one another–fails to reach supersolidity in two dimensions. However, by developing a new theoretical technique we demonstrate that cooling a gas of magnetic atoms directly into the supersolid regime is a viable method for creating two-dimensional supersolids in round, pancake-shaped traps. This leads us to the experimental observation of the first supersolid in a round trap, and opens the door to future theoretical studies of the crystal growth.

You can find out more about this in our paper.