Superfluid Dynamics in Ultracold Quantum Mixtures*

Vortices play a significant role in the internal mechanisms of neutron stars, black holes, superconducting materials, and dilute-gas superfluids [1]. The comprehensive study of vortices in these systems could explain phenomena like energy transfer and dissipation [2]. The exceptional level of control attainable in ultracold atomic quantum gases provides an ideal environment to explore the fundamental behaviour of vortices under diverse conditions within the ultracold regime. In particular, the utilization of ultracold mixtures enables precise adjustment of interparticle interactions. Manipulation of intra- and interspecies interactions will facilitate the attainment of regimes where quantum fluctuations dominate over mean-field effects [3], regimes where exotic phenomena like entrainment and mutual friction might manifest. 

We report progress towards the construction of an ultracold rubidium-potassium experimental apparatus designed to study the dynamics of vortices and supercurrents in a binary superfluid. We will discuss potential applications of this apparatus to study the interactions between two superflows, conveyed through dissipationless drag or mutual friction. 

[1] E. B. Sonin, Dynamics of quantized vortices in superfluids, Cambridge University Press (2016) 

[2] J. H. Kim, et al., Phys. Rev. Lett. 127, 095302 (2021). 

[3] D. S. Petrov and G. E. Astrakharchik, Phys. Rev. Lett. 117, 100401 (2016).