Holography and strong interactions: Some summaries

Holographic models make it possible to relate the properties of strongly interacting systems to the properties of strongly gravitating bodies in spaces with additional dimensions. The holographic description in quantum chromodynamics has been obtained only in the infrared limit. Holography is applicable both at zero temperature $T=0$ and in the deconfinement phase at $T>T_c$. The phenomenological point of view for $T>T_c$ considers the properties of a quark-gluon or simply gluon plasma. Holographic models provide a number of qualitative predictions which are in good agreement with the experiment and sometimes have no alternative explanations. In particular, the phase transition to deconfinement is described as the “dimensional reduction” of the four-dimensional description to the three-dimensional one. The dimensional reduction in the standard field-theory formulation appears only in the limit $T\to\infty$ of very high temperatures.