Magnetic catalysis in nuclear matter

TL;DR

This paper investigates how strong magnetic fields influence nuclear matter properties, showing that magnetic catalysis increases nucleon mass and affects the transition to nuclear matter, with implications for dense matter in stars.

Contribution

It demonstrates the impact of magnetic catalysis on nuclear matter transition using relativistic models, incorporating the Dirac sea effects often neglected in astrophysics.

Findings

Magnetic fields increase nucleon mass and binding energy.

Nuclear matter formation becomes more energetically costly in strong magnetic fields.

Magnetic catalysis significantly affects dense nuclear matter in astrophysical objects.

Abstract

A strong magnetic field enhances the chiral condensate at low temperatures. This so-called magnetic catalysis thus seeks to increase the vacuum mass of nucleons. We employ two relativistic field-theoretical models for nuclear matter, the Walecka model and an extended linear sigma model, to discuss the resulting effect on the transition between vacuum and nuclear matter at zero temperature. In both models we find that the creation of nuclear matter in a sufficiently strong magnetic field becomes energetically more costly due to the heaviness of magnetized nucleons, even though it is also found that nuclear matter is more strongly bound in a magnetic field. Our results are potentially important for dense nuclear matter in compact stars, especially since previous studies in the astrophysical context have always ignored the contribution of the magnetized Dirac sea and thus the effect of magnetic catalysis.