Two-color QCD in a strong magnetic field: The role of the Polyakov loop

Abstract

We study two-color QCD in an external magnetic backround at finite temperature using the Polyakov-loop extended two-flavor two-color NJL model. At T=0, the chiral condensate is calculated and it is found to increase as a function of the magnetic field $B$. In the chiral limit the deconfinement transition lies below the chiral transition for nonzero magnetic fields $B$. At the physical point, the two transitions seem to coincide for field strengths up to $|qB|\approx 5m_{\pi}^2$ whereafter they split. The splitting between the two increases as a function of $B$ in both the chiral limit and at the physical point. In the range from zero magnetic field and $|qB|=20 m_{\pi}^2$, the transition temperature for the chiral transition increases by approximately 35 MeV, while the transition temperature for deconfinement is essentially constant.Comment: 11 pages and 8 figures. v2 matches published version in PR

Critical point in the QCD phase diagram for extremely strong background magnetic fields

“…Several attempts have been made recently to understand this behavior in effective approaches to QCD [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33], among others, by introducing new, B-dependent model parameters or by taking into account the running of the QCD coupling with the magnetic field. Several of these models exhibit a non-monotonous T c (B) dependence, with an initial reduction followed by an enhancement due to the magnetic field.…”

Pion pressure in a magnetic field

“…This is the path pursued by chiral perturbation theory (CHPT), and indeed, the low-temperature properties of QCD in a magnetic field have been explored within CHPT in many studies up to two-loop order [1][2][3][4][5][6][7][8][9][10][11][12]. Other approaches to finite-temperature QCD in magnetic fields include lattice QCD [13][14][15][16][17][18][19][20][21][22][23][24][25], Nambu-Jona-Lasinio model-based studies [26][27][28][29][30][31][32][33], and other techniques . Yet more references can be found in the review of Ref.…”

Phase diagram of two-color QCD matter at finite baryon and axial isospin densities *

“…We remark that in this simplified model, the back reaction on the electric-blind fields hasn't been taken into account. The coupling of the quark sector to the Polyakov loop is not enclosed and therefore it is not able to yield the (de)confinement effect [68,69]. Furthermore, a first principle calculation can be pursued by Dyson-Schwinger equations and/or functional renormalization group approaches.…”