Water boils at 100 degrees Celsius, but if you squeeze it hard enough, it behaves differently. Similarly, quarks and gluons, the building blocks of protons and neutrons, change their properties in a strong magnetic field. Such fields arise in heavy-ion collisions at accelerators and can reveal how matter behaved in the first moments after the Big Bang.

Using supercomputer simulations, the scientists modeled the behavior of quarks and gluons (described by quantum chromodynamics) at different temperatures and magnetic field strengths. They focused on a quantity that measures how strongly baryon charge (the number of heavy particles) is correlated with electric charge. Under normal conditions, this correlation is weak, but in a strong magnetic field it increases by more than a factor of two. It's as if the magnetic field switches on a spotlight, making the hidden threads between particles visible.

To compare their calculations with real experiments at the STAR and ALICE detectors, the authors built a simple model, like a translator from the language of theory to the language of measurements. They accounted for the fact that detectors do not see all particles, only those emitted at certain angles. It turned out that even with these limitations, the detectors retain about 80% of the sensitivity to the magnetic field. That's good news: it means the effect can be tested experimentally.

The calculations also showed that as the magnetic field and temperature change, some curves intersect and swap places, like two roads that sometimes converge and sometimes diverge. This behavior points to a complex interplay of thermal and magnetic effects. Understanding these patterns brings us closer to unraveling how matter behaved in the very first moments of the Universe's existence.