Three Flavours Instead of Two: A Quantum Microscope Sees Every Atom in a New State of Matter
Some of the hardest problems in physics come from a model so simple you can write it on the back of an envelope — and so hard to solve that theorists have struggled with it for decades. Now researchers have built a new version of it in the laboratory, with a twist nobody had managed before: a third kind of particle. And they can photograph every single atom.
The work, published in the journal Science on 6 November 2026, was led by Peter Schauss at the University of Hamburg, with collaborators in Germany, Thailand, India, China and the United States, including Rice University.
A model of electrons, built from atoms
The Hubbard model describes particles hopping between sites on a lattice, like pieces on a chessboard, and repelling each other when they meet. It is one of the most important models for describing how electrons behave in solids, and understanding it is considered a promising route to explaining high-temperature superconductivity — materials that carry electricity with no resistance at temperatures far above absolute zero.
The trouble is that the model is easy to write down and extremely hard to solve. So physicists build it instead: they cool atoms to near absolute zero, trap them in a lattice made of laser light, and let the atoms stand in for electrons. Until now, these systems have used two kinds of atom, standing in for the two spin states of an electron — spin-up and spin-down.
The new experiment adds a third. By using atoms in three different internal states, the team created the first tunable three-component Hubbard system, in which the interactions between each pair of kinds can be dialled up and down separately. A quantum gas microscope — a camera that can detect each individual atom — made the atoms visible one by one.
A Mott state, and magnets pulling both ways
One of the first things the team looked for was a so-called Mott state, in which strong interactions stop particles from moving freely between sites, turning the system into an insulator. It is near Mott states, paradoxically, that high-temperature superconductivity emerges. They found it — and the system proved surprisingly stable, despite fears that three-body collisions would quickly destroy it.
They also found richer behaviour than two-component systems show: in the same system, ferromagnetic correlations between two of the states and antiferromagnetic correlations between two others could occur at once — the atoms lining up in some pairings and opposing in others. A new method for counting lattice sites occupied by three atoms at once agreed with numerical calculations done by collaborators at Rice.
Theorist Kaden Hazzard of Rice University, a co-author, put the value of the third component plainly: "Although the Hubbard model is important and simple to write down, it isn't easy to solve. Theorists have been banging our heads on the two-component Hubbard model for decades, yet there are still major open questions. Adding a third tunable component lets us see how the two-component model reacts to it, potentially helping us answer these major questions."
There is a deeper echo, too. A system with three kinds of particle resembles nuclear physics, where quarks come in three "colours". The team plans to refine the interactions further so the system can be used to study models of quantum chromodynamics — the theory of the strong force — in the laboratory.
For students, it is a wonderful example of how physicists learn: when the maths is too hard to solve on paper, build a small, controllable copy of the problem out of atoms and light, and watch what it does.
If your child finds physics fascinating but hard to picture — atoms, forces, and why materials behave the way they do — a first lesson in physics can make the invisible visible. Book your first lesson
Sources:
- Phys.org, "Quantum gas microscope reveals individual atoms in first tunable three-component Hubbard system", 6 November 2026: https://phys.org/news/2026-11-quantum-gas-microscope-reveals-individual.html
- Jirayu Mongkolkiattichai et al., "Quantum gas microscopy of three-flavor Hubbard systems", Science (2026), DOI: 10.1126/science.adv1247
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