Unconventional Superfluids in Quantum Gases with Competing Interactions

Unconventional superfluids, where frictionless flow appears combined with features such as topological excitations or crystalline order, are some of the most surprising collective quantum phases of matter.

Although the corresponding topological superfluids and supersolids were originally predicted in condensed matter, ultracold quantum gases provide a more controlled experimental approach to these phases, and promise microscopic access to their exotic properties.

A key mechanism towards unconventional superfluidity is the competition in the same system of interactions of different origins, a situation naturally addressed by multicomponent gases. When these interactions have opposite signs, new and surprising phases emerge.

A prime example is the ultradilute quantum liquid phase recently observed by my group in a mixture of Bose-Einstein condensates, which is most likely only the first item in a long list of new unconventional phases.The goal of SuperComp is to exploit the full potential of quantum gases with competing interactions to unlock the observation of unconventional superfluid phases that have until now defied experimental realization.

To this end, I will explore three distinct mechanisms resulting in unconventional superfluid behavior: quantum fluctuations, engineered dispersion relations, and interactions with non-zero orbital angular momentum.

Exploiting combinations of bosonic and fermionic potassium atoms, I will realize novel types of ultradilute quantum liquids, supersolid-like gases and liquids, density-dependent artificial gauge fields, elastic multi-body interactions, and investigate a new approach towards the long-sought px+ipy topological superfluid phase of 2D Fermi gases.

These experiments will deepen our understanding of the mechanisms responsible for unconventional superfluidity, and impact not only the field of quantum gases, but also the much broader range of disciplines where unconventional superfluids or superconductors play a key role.