Applications of the Theory of Groups in Mechanics and Physics

1. Elements of General Theory of Groups.- 1 Basic notions.- 1.1 Introduction of the notion of group.- 1.2 Basic definitions and theorems.- 1.3 Representations of groups.- 1.4 The S3 group.- 2 Topological groups.- 2.1 Definitions. Generalities. Lie groups.- 2.2 Lie algebras. Unitary representations.- 3 Particular Abelian groups.- 3.1 The group of real numbers.- 3.2 The group of discrete translations.- 3.3 The SO(2) and Cn, groups.- 2. Lie Groups.- 1 The SO(3) group.- 1.1 Rotations.- 1.2 Parametrization of SO(3) and O(3).- 1.3 Functions defined on O(3). Infinitesimal generators.- 2 The SU(2) group.- 2.1 Parametrization of SU(2).- 2.2 Functions defined on SU(2). Infinitesimal generators.- 3 The SU(3) and GL(n, ?) groups.- 3.1 SU(3) Lie algebra.- 3.2 Infinitesimal generators. Parametrization of SU(3).- 3.3 The GL(n, ?) and SU(n) groups.- 4 The Lorentz group.- 4.1 Lorentz transformations.- 4.2 Parametrization and infinitesimal generators.- 3. Symmetry Groups of Differential Equations.- 1 Differential operators.- 1.1 The SO(3) and SO(n) groups.- 1.2 The SU(2) and SU(3) groups.- 2 Invariants and differential equations.- 2.1 Preliminary considerations.- 2.2 Invariant differential operators.- 3 Symmetry groups of certain differential equations.- 3.1 Central functions. Characters.- 3.2 The SO(3), SU(2), and SU(3) groups.- 3.3 Direct products of irreducible representations.- 4 Methods of study of certain differential equations.- 4.1 Ordinary differential equations.- 4.2 The linear equivalence method.- 4.3 Partial differential equations.- 4. Applications in Mechanics.- 1 Classical models of mechanics.- 1.1 Lagrangian formulation of classical mechanics.- 1.2 Hamiltonian formulation of classical mechanics.- 1.3 Invariance of the Lagrange and Hamilton equations.- 1.4 Noether\'s theorem and its reciprocal.- 2 Symmetry laws and applications.- 2.1 Lie groups with one parameter and with m parameters.- 2.2 The Symplectic and Euclidean groups.- 3 Space-time symmetries. Conservation laws.- 3.1 Particular groups. Noether\'s theorem.- 3.2 The reciprocal of Noether\'s theorem.- 3.3 The Hamilton-Jacobi equation for a free particle.- 4 Applications in the theory of vibrations.- 4.1 General considerations.- 4.2 Transformations of normal coordinates.- 5. Applications in the Theory of Relativity and Theory of Classical Fields.- 1 Theory of Special Relativity.- 1.1 Preliminary considerations.- 1.2 Applications in the theory of Special Relativity.- 2 Theory of electromagnetic field.- 2.1 Noether\'s theorem for the electromagnetic field.- 2.2 Conformal transformations in four dimensions.- 3 Theory of gravitational field.- 3.1 General equations.- 3.2 Conservation laws in the Riemann space.- 6. Applications in Quantum Mechanics and Physics of Elementary Particles.- 1 Non-relativistic quantum mechanics.- 1.1 Invariance properties of quantum systems.- 1.2 The angular momentum. The spin.- 2 Internal symmetries of elementary particles.- 2.1 The isospin and the SU(2) group.- 2.2 The unitary spin and the SU(3) group.- 3 Relativistic quantum mechanics.- 3.1 Basic equations. Symmetry groups.- 3.2 Elementary particle interactions.- References.