Why in News?
Physicists from the University of Innsbruck and CNRS announced the discovery of a new quantum phase of matter called the fractional Fermi sea on June 29, 2026.
Key Points
Researchers created the state using ultracold cesium atoms confined to a one-dimensional (1D) environment.
The state was formed by cycling particles between repulsive and attractive interactions, pushing atoms into a highly excited yet organized configuration.
The discovery surpasses the Tomonaga-Luttinger liquid theory, the standard model for 1D quantum systems, and offers a new framework for quantum simulation beyond equilibrium.
The emergent quasiparticles in this state have been tentatively named super-Fermions.
Fermions are subatomic particles with half-integer spin that form the building blocks of ordinary matter. Examples:
Quarks: Elementary particles that combine to make protons and neutrons.
Leptons: Elementary particles that include electrons and neutrinos.
Composite Fermions: Particles like protons and neutrons made of an odd number of quarks
Exam Connect
Fermi Sea → concept in quantum mechanics where Fermions (e.g., electrons) fill available energy levels at absolute zero
Cesium (Cs) → alkali metal, atomic number 55 → used to define the second in atomic clocks