372 research outputs found
Electrical neutrality and -equilibrium conditions in dense quark matter: generation of charged pion condensation by chiral imbalance
The phase diagram of dense quark matter with chiral imbalance is considered
with the conditions of electric neutrality and -equilibrium. It has been
shown recently that chiral imbalance can generate charged pion condensation in
dense quark matter, so it was interesting to verify that this phenomenon takes
place in realistic physical scenarios such as electrically neutral matter in
-equilibrium, because a window of pion condensation at dense quark
matter phase diagram (without chiral imbalance) predicted earlier was closed by
the consideration of these conditions at the physical current quark mass. In
this paper it has been shown that the charged pion condensation is generated by
chiral imbalance in the dense electric neutral quark/baryonic matter in
-equilibrium, i. e. matter in neutron stars. It has been also
demonstrated that pion condensation is inevitable phenomenon in dense quark
matter with chiral imbalance if there is non-zero chiral imbalance in two
forms, chiral and chiral isospin one. It seems that in this case pion
condensation phase can be hardly avoided by any physical constraint on isopin
imbalance and that this conclusion can be probably generalized from neutron
star matter to the matter produced in heavy ion collisions or in neutron star
mergers. The chiral limit and the physical piont (physical pion mass) has been
considered and it was shown that the appearance of pion condensation is not
much affected by the consideration of non-zero current quark mass.Comment: 16 pages, 14 figure
Magnetic field instability in a neutron star driven by the electroweak electron-nucleon interaction versus the chiral magnetic effect
We show that the Standard Model electroweak interaction of ultrarelativistic
electrons with nucleons ( interaction) in a neutron star (NS) permeated by
a seed large-scale helical magnetic field provides its growth up to during a time comparable with the ages of young
magnetars . The magnetic field instability
originates from the parity violation in the interaction entering the
generalized Dirac equation for right and left massless electrons in an external
uniform magnetic field. We calculate the averaged electric current given by the
solution of the modified Dirac equation containing an extra current for right
and left electrons (positrons), which turns out to be directed along the
magnetic field. Such current includes both a changing chiral imbalance of
electrons and the potential given by a constant neutron density in NS.
Then we derive the system of the kinetic equations for the chiral imbalance and
the magnetic helicity which accounts for the interaction. By solving this
system, we show that a sizable chiral imbalance arising in a neutron protostar
due to the Urca-process diminishes
very rapidly because of a huge chirality flip rate. Thus the term prevails
the chiral effect providing a huge growth of the magnetic helicity and the
helical magnetic field.Comment: 6 pages in Revtex4.1, two columns, 2 eps figures; text was slightly
extended, multiple misprints were corrected, some references were added;
version published in Phys.Rev.D as a Rapid Communicatio
Dynamical evolution of the chiral magnetic effect: Applications to the quark-gluon plasma
We study the dynamical evolution of the so-called chiral magnetic effect in
an electromagnetic conductor. To this end, we consider the coupled set of
corresponding Maxwell and chiral anomaly equations, and we prove that these can
be derived from chiral kinetic theory. After integrating the chiral anomaly
equation over space in a closed volume, it leads to a quantum conservation law
of the total helicity of the system. A change in the magnetic helicity density
comes together with a modification of the chiral fermion density. We study in
Fourier space the coupled set of anomalous equations and we obtain the
dynamical evolution of the magnetic fields, magnetic helicity density, and
chiral fermion imbalance. Depending on the initial conditions we observe how
the helicity might be transferred from the fermions to the magnetic fields, or
vice versa, and find that the rate of this transfer also depends on the scale
of wavelengths of the gauge fields in consideration. We then focus our
attention on the quark-gluon plasma phase, and analyze the dynamical evolution
of the chiral magnetic effect in a very simple toy model. We conclude that an
existing chiral fermion imbalance in peripheral heavy ion collisions would
affect the magnetic field dynamics, and consequently, the charge dependent
correlations measured in these experiments.Comment: 41 pages, 14 figures, 3 appendices. Version 2: new global structure
(appendix added), more explanations and additional references. Version
accepted for publication in Physical Review D journa
- …