Physicists have proposed a new candidate for cold dark matter: fermions that, through chiral symmetry breaking, form Cooper pairs and condense. In the hot early Universe, they behave like radiation, but then, similar to a freeze-out process, they abruptly lose energy, setting the current density. The key difference is that this condensate has nearly zero temperature and pressure, and its decay occurs slightly faster than in the standard model. This can be tested with data from the cosmic microwave background and the large-scale structure of the Universe.
Dark matter is the invisible scaffold of the cosmos, its existence betrayed by whirls of galaxies to Fritz Zwicky and Vera Rubin. What it is made of remained a mystery for half a century.
A new hypothesis paints an unusual picture. In the scorching early Universe, dark matter particles raced like light, but with expansion and cooling, they began to slow down and pair up — like dancers joining hands in a common round dance. Then, at a critical temperature, this dance froze instantly: the pairs condensed into a single quantum pattern, akin to a superconducting state. This transition explains why today dark matter is cold and motionless, and it yields a testable prediction: the distribution of matter in the Universe should be slightly sparser than previously thought.
The imprint of the frozen dance can be found by superimposing the map of ancient light (cosmic microwave background) onto the panorama of galaxy positions. If the anomaly is confirmed, we'll learn that dark matter is not a scattering of individual particles, but a unified quantum pair condensate that lies beyond the Standard Model of particle physics.
🎯 Dark matter wasn't always cold: in the first moments after the Big Bang, it behaved like radiation, then froze into a quantum condensate.