A pot of water always boils the same way: hit 100 degrees and bubbles start. Quantum fluids are different. When a cloud of atoms is cooled to near absolute zero, it can turn into a single matter wave — a Bose–Einstein condensate. But the transition itself, it turns out, can happen in three different ways.
The authors of the study showed that the scenario depends on a single number — an exponent that describes how many quantum states are available to particles at low energies. This exponent is set by the system's dimensionality and the shape of the confining field. If it's less than one, physical quantities like heat capacity change smoothly, like water spilling over a rim. If it equals one, they change but with a logarithmic correction. And if it's greater than one, only the characteristic length over which particles feel each other changes abruptly.
This approach works like a universal key that fits locks of all shapes. It applies to atomic condensates in magnetic traps, photons in microcavities, and magnons in thin films. Just know the trap's geometry, and you can predict how the system will approach the transition point.
In a two-dimensional trap, a Bose gas cannot condense at any finite temperature: you'd need infinitely strong cold. But in three dimensions, it happens at quite achievable temperatures.
In Peter Watts's novel Blindsight, an alien intelligence uses a Bose–Einstein condensate as a computational medium.