From microphysics to dynamics of magnetars

TL;DR

This paper examines how strong magnetic fields in magnetar interiors suppress neutron and proton pairing, affecting their rotational and thermal evolution, with a review of theoretical models and implications for magnetar behavior.

Contribution

It provides a detailed analysis of magnetic field effects on superfluid pairing in magnetars and discusses the resulting astrophysical implications.

Findings

Magnetic fields suppress neutron and proton pairing in magnetar interiors.

Suppression affects the rotational coupling between crust and core.

Impacts the cooling processes during magnetar evolution.

Abstract

MeV-scale magnetic fields in the interiors of magnetars suppress the pairing of neutrons and protons in the $S$-wave state. In the case of a neutron condensate the suppression is the consequence of the Pauli-paramagnetism of the neutron gas, i.e., the alignment of the neutron spins along the magnetic field. The proton $S$-wave pairing is suppressed because of the Landau diamagnetic currents of protons induced by the field. The Ginzburg-Landau and BCS theories of the critical magnetic fields for unpairing are reviewed. The macrophysical implications of the suppression (unpairing) of the condensates are discussed for the rotational crust-core coupling in magnetars and the neutrino-dominated cooling era of their thermal evolution.