Ultracold atoms controlled by lasers realized a Laughlin state, a peculiar quantum liquid where each atom dances around its congeners. Credit: Nathan Goldman
The discovery of quantum Hall results throughout the 1980s unveiled new forms of matter described “Laughlin states”, called after the American Nobel laureate who successfully defined them in theory.
These unique states uniquely appear in two-dimensional products, under extremely cold conditions, and when subjected to an exceptionally strong magnetic field. In a Laughlin state, electrons make up an uncommon liquid, where each electron dances around its congeners while preventing them as much as possible.
Exciting such a quantum liquid produces collective states that physicists connect with fictitious particles, whose residential or commercial properties dramatically vary from electrons: these “anyons” bring a fractional charge (a portion of the elementary charge) and they surprisingly defy the standard classification of particles in terms of fermions or bosons.
For many years, physicists have actually checked out the possibility of recognizing Laughlin states in other types of systems than those provided by solid-state products, in view of more evaluating their strange residential or commercial properties. Nevertheless, the needed ingredients (the 2D nature of the system, the extreme magnetic field, the strong connections amongst the particles) showed very challenging.
Writing in Nature, a global team collected around the experimental group of Markus Greiner in Harvard report on the very first awareness of a Laughlin state using ultracold neutral atoms manipulated by lasers.
The experiment consists in trapping a couple of atoms in an optical box, and in carrying out the active ingredients needed for the creation of this exotic state: a strong synthetic electromagnetic field and strong repulsive interactions amongst the atoms.
In their Article, the authors reveal characteristic homes of the Laughlin state by imaging the atoms one by one through an effective quantum-gas microscope. They demonstrate the peculiar “dance” of the particles, which orbit around each other, in addition to the fractional nature of the recognized atomic Laughlin state.
This turning point opens the door to a large brand-new field of expedition of Laughlin states and their cousins (e.g. the so-called Moore-Read state) in quantum simulators. The possibility of producing, imaging, and manipulating anyons under a quantum-gas microscopic lense is especially appealing, in view of exploiting their unique residential or commercial properties in the lab.
Reference: “Realization of a fractional quantum Hall state with ultracold atoms” by Julian Léonard, Sooshin Kim, Joyce Kwan, Perrin Segura, Fabian Grusdt, Cécile Repellin, Nathan Goldman, and Markus Greiner, 21 June 2023, Nature.DOI: 10.1038/ s41586-023-06122-4.