Surface tension of highly magnetized degenerate quark matter

TL;DR

This paper investigates how strong magnetic fields influence the surface tension of degenerate quark matter, revealing anisotropic effects and the dominant role of strange quarks, with implications for astrophysical phenomena.

Contribution

It provides the first detailed calculation of anisotropic surface tension in highly magnetized quark matter using the multiple reflection expansion formalism.

Findings

Surface tension ranges from 2 to 20 MeV/fm^2 at relevant densities.

Strange quarks contribute the most to surface tension.

Magnetic fields above 5×10^{-3} GeV^2 significantly alter surface tension anisotropy.

Abstract

We study the surface tension of highly magnetized three flavor quark matter within the formalism of multiple reflection expansion (MRE). Quark matter is described as a mixture of free Fermi gases composed by quarks $u$, $d$, $s$ and electrons, in chemical equilibrium under weak interactions. Due to the presence of strong magnetic fields the particles' transverse motion is quantized into Landau levels, and the surface tension has a different value in the parallel and transverse directions with respect to the magnetic field. We calculate the transverse and longitudinal surface tension for different values of the magnetic field and for quark matter drops with different sizes, from a few fm to the bulk limit. For baryon number densities between $2-10$ times the nuclear saturation density, the surface tension falls in the range $2 - 20$ MeV /fm$^{2}$. The largest contribution comes from strange quarks which have a surface tension an order of magnitude larger than the one for $u$ or $d$ quarks and more than two orders of magnitude larger than for electrons. Our results show that the total surface tension is quite insensitive to the size of the drop. We also find that the surface tensions in the transverse and parallel directions are almost unaffected by the magnetic field if $eB$ is below $\sim 5 \times 10^{-3} $ GeV$^2$. Nevertheless, for higher values of $eB$, there is a significant increase in the parallel surface tension and a significant decrease in the transverse one with respect to the unmagnetized case.