Phase diagram of hot magnetized two-flavor color-superconducting quark matter

Abstract

A two-flavor color superconducting (2SC) Nambu-Jona-Lasinio (NJL) model is introduced at finite temperature T , chemical potential µ and in the presence of a constant magnetic fieldẽB. The effect of (T, µ,ẽB) on the formation of chiral and color symmetry breaking condensates is studied. The complete phase portrait of the model in T − µ, µ −ẽB, and T −ẽB phase spaces for various fixedẽB, T , and µ is explored. A threshold magnetic field eB t ≃ 0.5 GeV 2 is found above which the dynamics of the system is solely dominated by the lowest Landau level (LLL) and the effects of T and µ are partly compensated byẽB.

Chiral and deconfinement transitions in a magnetic background using the functional renormalization group with the Polyakov loop

“…The qualitative behavior of the transition temperature for physical quark masses is in disagreement with model calculations using either the (Polyakov-loop extended) Nambu-Jona-Lasinio ((P)NJL) model or the (Polyakov-loop extended) quarkmeson model ((P)QM); in these models, the critical temperature is an increasing function of the magnetic field, see e.g. [10][11][12][13][14][15][16][17][18][19][20]. Possible resolutions to the disagreement have been suggested [21][22][23][24][25][26][27][28] and we will discuss these at the end of the paper.…”

Magnetized color superconducting quark matter under compact star conditions: Phase structure within the SU(2)f NJL model

“…When effective quark-quark interactions are added, quarks can form Cooper pairs that give rise to a variety of color superconducting phases [19,20]. In this context, the effect of a constant magnetic field has been analyzed by several authors [21][22][23][24][25][26][27][28]. At this point, it is important to remark that the local character of the interactions considered in the NJL-type models leads to divergences in the momentum integrals.…”

“…Moreover, when the magnetic field is introduced, the vacuum energy acquires a Landau level (LL) structure and additional care is required in the treatment of the divergences. Many of the existing calculations of the properties of magnetized superconducting quark matter within this type of models remove these divergences by introducing some type of regulator function for each LL separately [24][25][26][27][28]. This procedure, however, might in general introduce unphysical oscillations.…”

Chiral transition in a magnetic field and at finite baryon density

“…The effects of external magnetic fields on the chiral transition have been studied in detail using the NJL model [41][42][43][44][45][46][47][48][49][50], the Polyakov-loop extended NJL model [51][52][53], the QM model [49,50,54], the (P)QM model [55], and the instanton-liquid model [56]. Similarly, the effects of strong magnetic field on the various color superconducting phases have been studied using the NJL model [57][58][59][60][61].…”