Physicists create a bizarre new quantum state called a fractional fermi sea

Physicists have uncovered a strange new form of quantum behavior in which particles organize themselves in ways that challenge established theories. Even more surprising, the particles maintain a remarkable hidden order despite being driven into an extremely energetic state.

In a study published in Physical Review Letters , researchers from the group led by Hanns-Christoph N gerl, working with theoretical physicist Alvise Bastianello of the CNRS and Universit Paris-Dauphine, describe how to engineer an exotic quantum state known as a "fractional Fermi sea."

The breakthrough involves pushing ultracold cesium atoms far beyond their normal conditions by repeatedly changing how strongly they attract or repel one another. Rather than simply becoming disordered, the particles rearrange themselves into an unusual configuration that behaves differently from the quantum systems scientists have traditionally studied.