Quantum degenerate two-species Fermi-Fermi mixture coexisting with a Bose-Einstein condensate

TL;DR

This paper reports the creation of a quantum degenerate mixture of two different fermionic atoms, Li-6 and K-40, coexisting with a Bose-Einstein condensate of Rb-87, enabling new studies of exotic quantum states.

Contribution

It demonstrates a novel method for sympathetically cooling a two-species Fermi-Fermi mixture using a Bose-Einstein condensate, with insights into enhanced cooling efficiency via catalytic effects.

Findings

Successful generation of a Li-6 K-40 Fermi-Fermi mixture

Enhanced sympathetic cooling efficiency due to K-40 presence

Potential for exploring new quantum matter states

Abstract

We report on the generation of a quantum degenerate Fermi-Fermi mixture of two different atomic species. The quantum degenerate mixture is realized employing sympathetic cooling of fermionic Li-6 and K-40 gases by an evaporatively cooled bosonic Rb-87 gas. We describe the combination of trapping and cooling methods that proved crucial to successfully cool the mixture. In particular, we study the last part of the cooling process and show that the efficiency of sympathetic cooling of the Li-6 gas by Rb-87 is increased by the presence of K-40 through catalytic cooling. Due to the differing physical properties of the two components, the quantum degenerate Li-6 K-40 Fermi-Fermi mixture is an excellent candidate for a stable, heteronuclear system allowing to study several so far unexplored types of quantum matter.