Superfluidity in the absence of kinetics in spin-orbit-coupled optical lattices

TL;DR

This paper demonstrates that ultracold bosons in flat bands with quenched kinetic energy can form superfluid states driven solely by interactions, revealing a new condensation mechanism beyond traditional kinetic-energy-based paradigms.

Contribution

The study introduces and numerically analyzes interaction-only models in flat bands, uncovering a novel superfluidity mechanism without kinetic energy.

Findings

Superfluid states can emerge from interactions alone in flat bands.

Kinetic energy quenching leads to unconventional condensation mechanisms.

Results challenge traditional views on superfluidity dependence on kinetic energy.

Abstract

At low temperatures bosons typically condense to minimize their single-particle kinetic energy while interactions stabilize superfluidity. Optical lattices with artificial spin-orbit coupling challenge this paradigm because here kinetic energy can be quenched in an extreme regime where the single-particle band flattens. To probe the fate of superfluidity in the absence of kinetics we construct and numerically solve interaction-only tight-binding models in flat bands. We find that novel superfluid states arise entirely from interactions operating in quenched kinetic energy bands, thus revealing a distinct and unexpected condensation mechanism. Our results have important implications for the identification of quantum condensed phases of ultracold bosons beyond conventional paradigms.