The spin-polarized ferromagnetic state of a cold Fermi gas. (arXiv:2006.05247v2 [nucl-th] UPDATED)
<a href="http://arxiv.org/find/nucl-th/1/au:+Diener_J/0/1/0/all/0/1">J.P.W. Diener</a>, <a href="http://arxiv.org/find/nucl-th/1/au:+Scholtz_F/0/1/0/all/0/1">F.G. Scholtz</a>
The spin-polarized ferromagnetic state of a cold Fermi gas is investigated
for interacting and non-interacting charge-neutral and $beta$-equilibrated
gases. The standard minimal couplings between the magnetic field and the
fermions’ charges and magnetic dipole moments define the fermions’ interaction
with the magnetic field. Assuming a variable coupling strength between the
magnetic field and the fermion (baryon) dipole moments, it is shown that a
ferromagnetized state can be achieved that corresponds to a lower energy
spin-polarized state with a magnetic field entirely due to the gas’s magnetic
response. We find that, depending on the density, a very large increase in the
baryon dipole moments is needed to achieve this ferromagnetized state. While
the required increase seems unlikely, the induced magnetic field is of the
order $sim10^{17}$ gauss. Furthermore, while externally magnetized Fermi gases
have an anisotropic pressure, the pressure of the ferromagnetized gas is
completely isotropic and the thermodynamically preferred magnetized state.
The spin-polarized ferromagnetic state of a cold Fermi gas is investigated
for interacting and non-interacting charge-neutral and $beta$-equilibrated
gases. The standard minimal couplings between the magnetic field and the
fermions’ charges and magnetic dipole moments define the fermions’ interaction
with the magnetic field. Assuming a variable coupling strength between the
magnetic field and the fermion (baryon) dipole moments, it is shown that a
ferromagnetized state can be achieved that corresponds to a lower energy
spin-polarized state with a magnetic field entirely due to the gas’s magnetic
response. We find that, depending on the density, a very large increase in the
baryon dipole moments is needed to achieve this ferromagnetized state. While
the required increase seems unlikely, the induced magnetic field is of the
order $sim10^{17}$ gauss. Furthermore, while externally magnetized Fermi gases
have an anisotropic pressure, the pressure of the ferromagnetized gas is
completely isotropic and the thermodynamically preferred magnetized state.
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