Hadron-Quark Phase Transition at Finite Density in the Presence of a Magnetic Field: Anisotropic Approach

TL;DR

This paper explores how a magnetic field affects the hadron-quark phase transition at finite density, revealing anisotropic effects, a new equilibrium condition, and magnetic monopole boundary phenomena relevant to neutron star physics.

Contribution

It introduces an anisotropic approach to the phase transition, deriving a new equilibrium condition and analyzing magnetic monopole boundary effects in the presence of a magnetic field.

Findings

Magnetic field causes anisotropic effects in the phase transition.

A new equilibrium condition governs the transition boundary.

Magnetic monopoles accumulate at the phase boundary.

Abstract

We investigate the hadron-quark phase transition at finite density in the presence of a magnetic field taking into account the anisotropy created by a uniform magnetic field in the system's equations of state. We find a new anisotropic equilibrium condition that will drive the first-order phase transition along the boundary between the two phases. Fixing the magnetic field in the hadronic phase, the phase transition is realized by increasing the baryonic chemical potential at zero temperature. It is shown that the magnetic field is mildly boosted after the system transitions from the hadronic to the quark phase. The magnetic-field discontinuity between the two phases is supported by a surface density of magnetic monopoles, which accumulate at the boundary separating the two phases. The mechanism responsible for the monopole charge density generation is discussed. Each phase is found to be paramagnetic with higher magnetic susceptibility in the quark phase. The connection with the physics of neutron stars is highlighted through out the paper.