Effects of the quark-hadron phase transition on highly magnetized neutron stars

TL;DR

This paper investigates how quark-hadron phase transitions in highly magnetized, fast-spinning neutron stars can cause phenomena like spin-up and magnetic field enhancement, using advanced modeling of stellar structure.

Contribution

It introduces a comprehensive model combining relativistic mean field and MIT bag models to study phase transitions and their effects on neutron star rotation and magnetic fields.

Findings

Observation of backbending phenomenon in fast-spinning neutron stars.

Demonstration of magnetic field amplification during phase transition.

Identification of a potential 'magnetic-up era' in neutron star evolution.

Abstract

The presence of quark-hadron phase transitions in neutron stars can be related to several interesting phenomena. In particular, previous calculations have shown that fast rotating neutron stars, when subjected to a quark-hadron phase transition in their interiors, could give rise to the backbending phenomenon characterized by a spin-up era. In this work, we use an equation of state composed of two phases, containing nucleons (and leptons) and quarks. The hadronic phase is described in a relativistic mean field formalism that takes many-body forces into account, and the quark phase is described by the MIT bag model with a vector interaction. Stationary and axi-symmetric stellar models are obtained in a self-consistent way by solving numerically the Einstein-Maxwell equations by means of a pseudo-spectral method. As a result, we obtain the interesting backbending phenomenon for fast spinning neutron stars. More importantly, we show that a magnetic field, which is assumed to be axi-symmetric and poloidal, can also be enhanced due to the phase transition from normal hadronic matter to quark matter on highly magnetized neutron stars. Therefore, in parallel to the spin-up era, classes of neutron stars endowed with strong magnetic fields may go through a "magnetic-up era" in their lives.