The Possibility of a Non-Lagrangian Theory of Gravity

Abstract

General Relativity resembles a very elegant crystal glass: If we touch its principles, that is, its Lagrangian, there is a risk of breaking everything. Or, if we will, it is like a short blanket: Curing some problems creates new problems. This paper is devoted to bring to light the reasons why we pursue the possibility of a non-Lagrangian theory of gravity under the hypothesis of an extension of the original general relativity with an ansatz inspired in the fundamental principles of classical and quantum physics.

6 pages, 1 figure. Version accepted in Universe MDPI

References in corpus (9)

• Cosmology Intertwined II: The Hubble Constant Tension
• Cosmology Intertwined III: $f{\sigma }_8$ and $S_8$
• The Parameterized Post-Friedmann Framework for Theories of Modified Gravity: Concepts, Formalism and Examples
• Nonlinear growth in modified gravity theories of dark energy
• Palatini $f(R)$ gravity in the solar system: post-Newtonian equations of motion and complete PPN parameters
• Testing gravity at the Second post-Newtonian level through gravitational deflection of massive particles
• Lovelock's theorem revisited
• Five-dimensional PPN formalism and experimental test of Kaluza-Klein theory
• Cosmological Constant Implementing Mach Principle in General Relativity