A classic lesson taught to us in school is that opposites attract and likes repel, and this is easily demonstrated with magnets. Unfortunately in science it is not always so simple. In superconductors we have like-charged electrons pairing together, in protons and nucleons we have quarks with three distinct charges (red, green, and blue), and now researchers at Kansas State University have discovered a quantum state that has three atoms bound together, even if two repel each other.
Three-atom quantum states have been found before, and the similar Efimov three-body state was first predicted in the 1970s. It took 30 years for it to be experimentally observed because it requires temperatures within a billionth of a degree above absolute zero. This new state also only exists at such a low temperature, but it has at least one crucial distinction from the Efimov state; its range. The Efimov state requires the atoms be very close to each other to interact. What KSU found operates at a greater distance, but is not quite long-range, which makes it very interesting.
For centuries researchers have been trying to understand three body problems, with the most obvious example being the Sun, Earth, and Moon. Unfortunately a perfect description of how these three classical bodies interact has not been discovered yet, because the system is too complex, even with just three bodies. In quantum mechanics though, the three body problem is (ironically) not as hard to work with. As this state exists on the cusp between short-range quantum mechanics and long-range classical mechanics, it may help create a link between the two realms. Also this discovery can further our understanding of particle physics as the researchers learn how different classes of particles behave in it.