2019/04/19 by Yurii A. Spirichev, Spirichev, Yurii A.
Earth and Planetary Sciences · Physics and Astronomy · #Classical Physics (physics.class-ph) #Crystallography and Radiation Phenomena #FOS: Physical sciences #High-pressure geophysics and materials #Quantum and Classical Electrodynamics #physics.class-ph
paper · pdf · doi:10.48550/arxiv.1904.10297
6 pages
arxiv created 2019/04/19 · openalex publication_date 2019/04/19 · arxiv updated 2019/04/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
It is shown that the necessary criterion for choosing the energy-momentum tensor of a physical system is the form of its linear invariant, which should be the lagrangian of this physical system. Examples of energy-momentum tensors that meet this criterion are given. For an electromagnetic field in vacuum, the linear invariant of the energy-momentum tensor must be the canonical lagrangian or the quadratic invariant of the electromagnetic field tensor. A mathematical method for obtaining the lagrangian that complements the Lagrange formalism is proposed.