N. V. Gubina | Searcharxiv

arXiv2012

Inhomogeneous charged pion condensation phenomenon in the NJL$_2$ model with quark number and isospin chemical potentials

The properties of two-flavored massive Nambu--Jona-Lasinio model in (1+1)-dimensional spacetime are investigated in the presence of isospin and quark number chemical potentials. The consideration is performed in the large-$N_c$ limit, where $N_c$ is the number of colored quarks. It is shown in the framework of this model that charged pion condensation phenomenon of dense quark/hadron isotopically asymmetric matter is rather a spatially inhomogeneous than a homogeneous one.

hep-ph↗

arXiv2011

Chiral density waves in the NJL$_2$ model with quark number and isospin chemical potentials

We investigate the phase portrait of the (1+1)-dimensional massless two-flavored NJL$_2$ model containing a quark number chemical potential $μ$ and an isospin chemical potential $μ_I$ in the limit of a large number of colors $N_c\to\infty$. Particular attention is paid to the question to what extent the inclusion of an isospin asymmetry affects chiral condensates to have a spatial inhomogeneity in the form of the so-called chiral density waves (CDW) (chiral spirals). It is shown that at zero temperature and comparatively small values of $μ$, i.e. at $μ<μ_c\approx 0.68M_0$ ($M_0$ is the dynamical quark mass in the vacuum) only the homogeneous charged pion condensation phase is realized for arbitrary nonzero values of $μ_I$. Contrary to this, for large values of $μ>μ_c$, two CDW phases appear in the $(μ_I,μ)$-phase diagram of the model. In the first phase, CDWs are clockwise twisted chiral spirals and in the second phase they are counterclockwise. The influence of nonzero temperature on the formation of the CDW phases is also investigated.

hep-ph↗