An old factory where instead of machines there are atomic nuclei, and neutrino radiation seethes all around. When a massive star exhausts its fuel, its core compresses a hundredfold, and the temperature skyrockets to billions of degrees. At that moment, nuclear matter can abruptly rearrange itself (like water that instantly turns to ice under enormous pressure, but here what forms is not ice but quark matter: protons and neutrons break apart into their building blocks) quarks.
The authors created a new model of matter (equation of state) with a smooth change in the number of participating particles at high densities. In the calculations, this acted as a trigger: the core sharply contracts, then rebounds, and the shock wave tears the star apart. The main signature is a very long neutrino flash, lasting several times longer than in previous models with a sharp boundary between phases. If telescopes catch such a prolonged signal, we will for the first time witness the birth of a neutron star with a quark interior.
Thus, a dying supernova becomes a natural laboratory: by the duration of the neutrino 'cry' and the pattern of gravitational waves, we can peer into the densest matter in the universe without leaving Earth.
The neutrino flash from such an explosion can last several seconds — for comparison, a typical core collapse produces a signal ten times shorter, and this difference can be noticed even from a distance of thousands of light-years.
In Stanislaw Lem's novel 'Solaris', the planet's ocean behaves like a single quark structure — phase transitions within it produce mysterious phenomena similar to the neutrino signals described in the article.