We study dynamical chiral symmetry breaking for quarks in the fundamental representation of SU(N _c) for the N _f number of light quark flavors. We also investigate the phase diagram of quantum chromodynamics at finite temperature T and/or in the presence of a constant external magnetic field eB. The unified formalism for this analysis is provided by a symmetry-preserving Schwinger–Dyson equation treatment of a vector vector contact interaction model which encodes several well-established features of quantum chromodynamics to mimic the latter as closely as possible. Deconfinement and chiral symmetry restoration are triggered above a critical value of N _f at T = 0 = eB. On the other hand, increasing temperature itself screens strong interactions, thus ensuring that a smaller value of N _f is sufficient to restore chiral symmetry at higher temperatures. We also observe the well-known phenomenon of magnetic catalysis for a strong enough magnetic field. However, we note that if the effective coupling strength of the model decreases as a function of magnetic field, it can trigger inverse magnetic catalysis in a certain window of this functional dependence. Our model allows for the simultaneous onset of dynamical chiral symmetry breaking and confinement for each case. Qualitative as well as quantitative predictions of our simple but effective model are in reasonably satisfactory agreement with lattice results and other reliable and refined predictions based upon intricate continuum studies of quantum chromodynamics.

我们在SU ( N _c )的基本表示中研究了夸克的动力学手征对称性破缺，其中N _f数为轻夸克味。我们还研究了在有限温度T和/或存在恒定外部磁场eB的情况下量子色动力学的相图。这种分析的统一形式是由向量矢量接触相互作用模型的对称保持 Schwinger-Dyson 方程处理提供的，该模型编码了量子色动力学的几个完善的特征，以尽可能接近地模拟后者。在N _f的临界值以上触发解除约束和手性对称性恢复在T = 0 = eB。另一方面，升高温度本身会屏蔽强相互作用，从而确保较小的N _f值足以在较高温度下恢复手性对称性。对于足够强的磁场，我们还观察到了众所周知的磁催化现象。然而，我们注意到，如果模型的有效耦合强度随着磁场的变化而降低，它可以在这种函数依赖性的某个窗口内触发逆磁催化。我们的模型允许在每种情况下同时发生动态手征对称性破坏和限制。我们简单但有效的模型的定性和定量预测与基于量子色动力学的复杂连续研究的晶格结果和其他可靠和精确的预测相当令人满意。