Quantum tornadoes in momentum space: First experimental proof of a new quantum phenomenon

Amazing stuff!

"... Scientists have long known that electrons can form vortices in quantum materials. What's new is the proof that these tiny particles create tornado-like structures in momentum space—a finding that has now been confirmed experimentally.  ...

Momentum space is a fundamental concept in physics that describes electron motion in terms of energy and direction, rather than their exact physical position. Position space (its "counterpart") is the realm where familiar phenomena like water vortices or hurricanes occur. Until now, even quantum vortices in materials had only been observed in position space. ..."

From the abstract:

"We report the experimental discovery of orbital vortex lines in the three-dimensional (3D) band structure of a topological semimetal. Combining linear and circular dichroism in soft x-ray angle-resolved photoemission (SX-ARPES) with first-principles theory, we image the winding of atomic orbital angular momentum, thereby revealing—and determining the location of—lines of vorticity in full 3D momentum space. We determine the core of the orbital angular momentum vortex to host an almost movable, twofold, spin-degenerate Weyl nodal line, a topological feature predicted to occur in certain nonsymmorphic crystals. These results establish bimodal dichroism in SX-ARPES as a robust approach to trace 3D orbital textures. Our findings constitute the first imaging of nontrivial quantum-phase winding at line nodes and may pave the way to new orbitronic phenomena in quantum materials."

Quantum tornadoes in momentum space: First experimental proof of a new quantum phenomenon

TU Dresden: Quantum tornadoes in momentum space – Würzburg-Dresden research team provides first proof of a new quantum phenomenon (original news release) "Electrons can form vortices in a quantum material. That alone is nothing new. However, the fact that the small particles form a tornado in momentum space has only now been proven experimentally. ... The proof of this quantum phenomenon marks a new milestone in the research of quantum materials."

Imaging Orbital Vortex Lines in Three-Dimensional Momentum Space (open access)

Fig. 4 Orbital vortex line in three-dimensional momentum space.