Influence of chiral chemical potential μ5 on phase structure of the two-color quark matter

Abstract

In this paper the influence of chiral chemical potential $\mu_5$ on the phenomenon of diquark condensation and phase structure of dense quark matter altogether is contemplated in the framework of effective two-color and two-flavor Nambu--Jona-Lasinio model. We show that the duality relations, found $\mu_5=0$, are also valid for any value of $\mu_5\neq0$. Hence the dualities seem to be a real fundamental feature of the phase diagram of two color quark matter, and besides they are a very powerful tool of studying the phase structure. In terms of dualities and the influence on the phase diagram chiral imbalance $\mu_5$ stands alone from other chemical potentials. Two regimes in the phase diagram could be discerned, the first one, rather small or moderate values of chemical potentials $\mu_B$, $\mu_I$ and $\mu_{I5}$, where the picture is rather concise and elegant: each of the above phenomena is in one-to-one correspondence with some chemical potential ($\mu_{I5}$ induces chiral symmetry breaking, $\mu_I$ propels charged pion condensation and $\mu_B$ leads to diquark condensation). In this regime chiral chemical potential $\mu_5$ does not break this correspondence, it has a property of being universal catalyzer, i.e. it {\it catalyzes/enhances} all the phenomena on equal footing. The feature of chiral imbalance $\mu_5$ to catalyze chiral symmetry breaking phenomenon was known before but its catalytic properties appeared to be more universal and it can catalyze also diquark and charged pion condensation. These happen due to the dual properties. In the second regime, when several chemical potentials reach rather large values, one could observe a rather complicated and rich phase structure, and $\mu_5$ can be a factor that not so much catalyzes as {\it triggers} rather peculiar phases. For example, it can lead to the formation of diquark condensation at zero baryon chemical potential.