Description
Polar symmetric top molecules offer a multitude of interesting research opportunities as their permanent electric dipole moment makes them interact strongly and anisotropically and allows manipulating them already with moderate static electric fields. This, together with their wealth of internal states, permits studies and applications ranging from cold dipolar collisions to quantum information processing and quantum simulation. While their complexity is a blessing from an application perspective, it also renders trapping polyatomic molecules, achieving high densities and understanding as well as controlling collisions a challenging task.
By combining [1] a cryogenic buffer-gas cell with a centrifuge decelerator and an electrostatic trap [2], we can now confine up to $2\times10^7$ CH${_3}$F molecules at a temperature of $\sim350$ mK for several seconds, achieving densities of up to $10^7/$cm$^3$. Such high densities allow for the observation of collisions between the trapped molecules [3]. An ab-initio theory, taking into account both elastic and inelastic collisional loss channels, shows excellent agreement with our experiment and allows for the identification of dipolar relaxation as the major loss mechanism, accounting for $\sim95\%$ of the observed losses. We obtain inelastic rate constants below $4\times10^{-8}$cm$^3$/s and control and suppress the losses by tuning a homogeneous control field covering a large fraction of the volume of the trap. As understanding and suppression of these inelastic losses is imperative to proceed towards higher phase-space densities, our findings are immediately relevant for cold molecular collision studies and are an important step towards the observation of re-thermalisation between polyatomic molecules.
[1] X. Wu et al., Science 358, 645-648 (2017).
[2] B. G. U. Englert et al., Phys. Rev. Lett. 107, 263003 (2011).
[3] M. Koller et al., Phys. Rev. Lett. 128, 203401 (2022).
| Presenter name | Florian Jung |
|---|---|
| How will you attend ICAP-27? | I am planning on in-person attendance |
