Physicists Photograph Three Kinds of Atom, One Atom at a Time

A team of physicists has extended single-atom imaging to a lattice gas built from three kinds of atom rather than the usual two, reading off both the site each atom occupied and which kind it was. In that mixture, the team reports signs of atoms of one kind settling in place while the others keep moving.

Jirayu Mongkolkiattichai of the University of Virginia, Peter Schauss of the University of Virginia and Universitat Hamburg, and colleagues published the measurement Nov. 5, 2026, in Science. The authors describe Hubbard systems, the family of models the experiment builds out of real atoms, as textbook cases of matter whose particles interact too strongly to be treated one at a time. They write that adding a further kind of particle breaks a symmetry of the standard two-kind model and "leads to a wide variety of new exotic quantum phases."

Physicists call each kind of atom a flavor. The team mapped the phase diagram of the three-flavor model, meaning which states the mixture settles into at different densities and interaction strengths, and "found signatures of flavor-selective localization and selective pairing at temperatures down to the tunneling energy scale." The pairing is selective in the sense that pairs form between some flavors and not others.

The measurements were then compared with numerical calculations of the same model. The paper's reference list points to Zenodo deposits of the experimental data, the numerical data and the code behind the calculations.

The authors write that a gas pushed to a higher phase space density, in effect colder and more tightly packed, may put a further phase of the system within reach and may open a path toward studies of color superfluidity, an idea borrowed from the theory of the strong nuclear force.

The paper lists funding from the National Science Foundation, the German Research Foundation, the Robert A. Welch Foundation, the Keck Foundation, the Jefferson Trust and the Jeffress Memorial Trust.