In a significant advancement at the intersection of physics and art, researchers have achieved the first direct observation of the quantum Kelvin-Helmholtz instability (KHI) within quantum fluids. The study, a collaboration between teams at Osaka Metropolitan University and the Korea Advanced Institute of Science and Technology, has revealed novel vortex patterns termed eccentric fractional skyrmions (EFSs). These topological defects, characterized by their crescent shapes, bear a visual resemblance to elements in Vincent van Gogh's renowned painting, 'The Starry Night.' The Kelvin-Helmholtz instability, a known phenomenon in classical fluid dynamics, typically generates waves and vortices at the boundary between fluids moving at different speeds.
The experimental breakthrough involved cooling lithium gases to temperatures near absolute zero, creating a multi-component Bose-Einstein condensate, a quantum superfluid. By directing two streams of this superfluid to flow at differing velocities, researchers observed the emergence of a wavy pattern at their interface, which subsequently generated quantum-governed vortices identified as EFSs. These EFSs are distinguished by their crescent-like form and embedded singularities, points where the spin structure breaks down, causing sharp distortions. The visual parallel to Van Gogh's painting has garnered attention from both scientific and artistic communities. Skyrmions, originally discovered in magnetic materials, are of considerable interest for their potential applications in spintronics and advanced memory devices due to their stability, compact size, and unique dynamic properties.
The discovery of EFSs in a superfluid environment not only expands fundamental understanding of quantum systems but also opens new avenues for technological innovation. Published on August 8, 2025, in Nature Physics, the research validates decades-old theoretical predictions concerning KHI-driven interface waves and their wavelengths. Future experiments by the research team will focus on refining measurements and further investigating the properties of EFSs to rigorously test theoretical predictions regarding KHI-driven interface waves' wavelength and frequency. The broader theoretical implications are substantial, as EFSs challenge existing topological classifications, prompting exploration into whether similar structures exist in other quantum systems. This advancement promises to deepen comprehension of quantum vortices, the structural characteristics of multi-component fluids, and the boundaries of topological classification in physics.