A magnetar is a neutron star with a magnetic field hundreds of millions of times stronger than Earth's. If you brought an ordinary magnet near such a field, it would instantly lose its magnetism, and atoms would stretch into thin filaments. Under these conditions, light and electrons interact in unusual ways: the familiar rules of quantum electrodynamics break down, and calculations need to be rethought.

Scientists applied a method previously used for hot quark-gluon plasma to describe light scattering in a superstrong field. For the first time, they systematically accounted for the fact that excited electron levels (Landau levels) do not live forever but decay over a finite time. It's like calculating the bounce of a ball off a wall and taking into account that the wall gives a little rather than being perfectly rigid.

The results showed that accounting for the finite lifetime of levels noticeably changes scattering cross sections: that is, the probability of how light gets deflected or changes energy. This is important for understanding how energy is transported in a magnetar's atmosphere and why its radiation has an unusual spectrum. All calculations are available in an open Python package so other researchers can use them in their models.