During the first two years of the project, my team and I designed, built, and developed a new setup required to tackle the objectives of 2DDip. This new setup now routinely produces degenerate quantum gases of dysprosium atoms in tailorable trap geometries and is soon to be further upgraded to access the quasi-2D regime.
More precisely, during the first year of 2DDip, we designed and implemented a new and high-performance cold dysprosium source based on an innovative scheme. The source has been fully operational since the end of 2022 and its novelty is detailed in the team's first experimental publication (PRA 108, 023719 (2023)).
In the second year of 2DDip, we continue to develop our experimental platform towards the desired tunability and control. We implemented a 3D optical trapping potential based on two crossed laser beams of 1064 nm wavelength with tunable shape. In this trap, we implemented an evaporative cooling scheme which led to the achievement of quantum degeneracy of the 3D Bose gas of dysprosium atoms within 1.5 years after the start of the project. Under optimised conditions, we were able to produce Bose-Einstein condensates of 150,000 atoms with more than 75% condensed fraction, which is amongst the best performance in the state of the art.
We then gained control over the uniform bias magnetic field applied to the atoms, both in terms of its magnitude and direction, and observed the first signatures of interaction tuning. We have implemented a high-resolution imaging objective and have observed uniform superfluid and density-modulated states both in time of flight and in situ through this objective.
We are currently implementing a dedicated trap to reach the quasi-2D regime, a so-called 'accordion lattice trap', and a fully tailorable in-plane trap based on a digital micromirror device setup. Both setups have been designed and thoroughly tested. With the implementation of these traps, we expect to have a fully operational experimental setup to produce, address, and probe ultracold quasi-2D dipolar gases within the next few months. This will serve as the core for 2DDip investigations in the coming years.
On the other hand, we have also carried out preliminary theoretical work on several aspects related to the 2DDip core research, ranging from the exploration of the phase diagram, the investigation of the nature of the underlying phase transition, the role and interplay of topological defects in solid and superfluid orders, as well as the more practical effect of potential defects on the underlying physics.
Based on this preliminary work and experimental advances, we will now begin our central investigation into the special ordering features of quasi-2D quantum gases of dipolar atoms.
