**Preface to "Quantum Information and Symmetry"**

Quantum information theory (QIT) and its applications have become one of the most relevant fields in contemporary research related to both physical and technical sciences. We have approached the point in which novel quantum technologies are starting to play a crucial role in our world. Due to achievements in the field of QIT and its applications, we are living in the second quantum revolution era. As the broadly understood symmetries play a significant role in physics, they will also point to new research directions in the field of QIT.

The Special Issue is devoted to this overlapping of the ideas of QIT and methods and models in which various kinds of symmetries are applied. The published articles not only focus on theoretical concepts related to information theory but also discuss physical models that could be implemented in future designs of QIT devices. These devices could be built, for instance, as an implementation of models describing superconductivity phenomena, which are also discussed in the Special Issue. The broad range of other topics related to the symmetries and quantum information are presented and discussed. For instance, quantum correlations (including quantum entanglement), solitonic attractors, single-quit radiation fields, models of bosonic systems, PT-symmetry, Kerr-type nonlinearities, and others are the subjects of the articles presented in the Issue.
