UDC 530.1; 530.145 Fundamental Principles of Theoretical Physics and Concepts of Quasiaverages, Quantum Protectorate and Emergence A. L. Kuzemsky Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research, Dubna, Russia In the present paper we discuss the interrelation of the advanced interdisciplinary concepts of modern physics such as symmetry breaking, quantum protectorate, emergence and the Bogoliubov’s concept of quasiaverages in the context of modern theoretical physics, and, in particular, quantum and statistical physics. <...> The main aim of this analysis was to demonstrate the connection and interrelation of these conceptual advances of the many-particle physics and to try to show explicitly that those concepts, though different in details, have certain common features. <...> Some problems in the field of statistical physics of complex materials and systems e.g. foundation of the microscopic theory of magnetism and superconductivity were pointed in relation to these ideas. <...> The main suggestion is that the emphasis of symmetry breaking concept is on the symmetry itself, whereas the method of quasiaverages emphasizes the degeneracy of a system. <...> The concept of quantum protectorate reveals essential difference in the behavior of the complex many-body systems at the low-energy and high-energy scales. <...> Thus the notion of quantum protectorate might provide distinctive signatures and good criteria for a hierarchy of energy scales and the appropriate emergent behavior. <...> Key words and phrases: theoretical physics, quantum physics, quantum statistical mechanics, symmetry, broken symmetry, Bogoliubov’s quasiaverages, quantum protectorate, emergence, quantum theory of magnetism, microscopic theory of superconductivity. 1. <...> Moreover, the idea of symmetry is a useful and workable tool for many areas of quantum field theory [7], physics of elementary particles [6,10,11], statistical physics and condensed matter physics [12–15]. <...> It is known that when the Hamiltonian of a system is invariant under a symmetry The development of experimental techniques over the last decades opened the posoperation, but the ground state is not, the symmetry of the system can be spontaneously broken [16]. <...> Symmetries and breaking of symmetries play an important role in statistical physics, quantum field theory, physics of elementary particles, etc. [17–19] Received 11th June, 2012. 230 Bulletin of PFUR. <...> The intriguing mechanism of spontaneous symmetry breaking is a unifying concept that lie at the basis of most of the recent developments <...>