We review the main features of the QCD phase diagram description, at finite temperature, baryon density and in the presence of a magnetic field, from the point of view of effective models, whose main ingredient is chiral symmetry. We concentrate our attention on two of these models: The linear sigma model with quarks and the Nambu–Jona-Lasinio model. We show that a main ingredient to understand the characteristics of the phase transitions is the inclusion of plasma screening effects that capture the physics of collective, long-wave modes, and thus describe a prime property of plasmas near transition lines, namely, long distance correlations. Inclusion of plasma screening makes possible to understand the inverse magnetic catalysis phenomenon even without the need to consider magnetic field-dependent coupling constants. Screening is also responsible for the emergence of a critical end point in the phase diagram even for small magnetic field strengths. Although versatile, the NJL model is also a more limited approach since, being a non-renormalizable model, a clear separation between pure vacuum and medium effects is not always possible. The model cannot describe inverse magnetic catalysis unless a magnetic field dependent coupling is included. The location of the critical end point strongly depends on the choice of the type of interaction and on the magnetic field dependence of the corresponding coupling. Overall, both models provide sensible tools to explore the properties of magnetized, strongly interacting matter. However, a cross talk among them as well as a consistent physical approach to determine the model parameters is much needed.

我们从有效模型的角度回顾了 QCD 相图描述的主要特征，在有限温度、重子密度和磁场存在下，其主要成分是手征对称性。我们将注意力集中在其中两个模型上：带有夸克的线性 sigma 模型和 Nambu-Jona-Lasinio 模型。我们表明，了解相变特征的一个主要因素是包含等离子体屏蔽效应，该效应捕获了集体长波模式的物理学，从而描述了过渡线附近等离子体的主要属性，即长距离相关性. 即使不需要考虑与磁场相关的耦合常数，包含等离子体筛选也可以理解逆磁催化现象。即使对于小的磁场强度，筛选也是导致相图中出现关键终点的原因。尽管用途广泛，但 NJL 模型也是一种更有限的方法，因为作为不可重整模型，纯真空和介质效应之间的明确分离并不总是可能的。除非包含依赖于磁场的耦合，否则该模型无法描述逆磁催化。临界终点的位置很大程度上取决于相互作用类型的选择和相应耦合的磁场依赖性。总体而言，这两种模型都为探索磁化、强相互作用物质的特性提供了明智的工具。然而，非常需要它们之间的串扰以及一致的物理方法来确定模型参数。