Generalized unimodular gravity as a form of k-essence
arXiv:2011.06521 · doi:10.1103/PhysRevD.103.064035
Abstract
We consider modifications of general relativity characterized by a special noncovariant constraint on metric coefficients, which effectively generates a perfect-fluid type of matter stress tensor in Einstein equations. Such class of modified gravity models includes recently suggested generalized unimodular gravity (GUMG) theory and its simplest version -- unimodular gravity (UMG). We make these gravity models covariant by introducing four Stueckelberg fields and show that in the case of generalized unimodular gravity three out of these fields dynamically decouple. This means that the covariant form of generalized unimodular gravity is dynamically equivalent to k-essence theory with a specific Lagrangian which can be reconstructed from the parameters of GUMG theory. We provide the examples, where such reconstruction can be done explicitly, and briefly discuss theories beyond GUMG, related to self-gravitating media models. Also we compare GUMG k-inflation with cuscuton models of dynamically inert k-essence field and discuss motivation for GUMG coming from effective field theory.
arXiv comment15 pages, 1 figure
References in corpus (42)
- 4D Gravity on a Brane in 5D Minkowski Space
- Quantum Gravity at a Lifshitz Point
- The Dynamics of General Relativity
- k-Inflation
- Massive Gravity
- Perturbations in k-inflation
- Relativistic Fluid Dynamics: Physics for Many Different Scales
- Null energy condition and superluminal propagation
- Infrared-modified gravities and massive gravitons
- On the Extra Mode and Inconsistency of Horava Gravity
- Phases of massive gravity
- Prospects and Problems of Tachyon Matter Cosmology
- Solid Inflation
- Cuscuton: A Causal Field Theory with an Infinite Speed of Sound
- The Gelaton Scenario: Equilateral non-Gaussianity from multi-field dynamics
- Unifying framework for scalar-tensor theories of gravity
- Renormalization of Horava Gravity
- Enhancing the tensor-to-scalar ratio in simple inflation
- Low-Energy Quantum Effective Action for Relativistic Superfluids
- Relativistic fluid dynamics: physics for many different scales
- Escaping from the black hole?
- A Class of Minimally Modified Gravity Theories
- Hydrodynamics of relativisic systems with broken continuous symmetries
- Elastic Inflation
- Comparing selfinteracting scalar fields and R + R^3 cosmological models
- Darkness without dark matter and energy -- generalized unimodular gravity
- Caustic free completion of pressureless perfect fluid and k-essence
- Formation of caustics in k-essence and Horndeski theory
- New Weyl-invariant vector-tensor theory for the cosmological constant
- Recovering P(X) from a canonical complex field
- Effective perfect fluids in cosmology
- Thermodynamics of k-essence
- Massive and modified gravity as self-gravitating media
- Dynamics of the generalized unimodular gravity theory
- Thermodynamics of Dark Energy
- Axionic cosmological constant
- A note on unfree gauge symmetry
- Inflation in generalized unimodular gravity
- Unfree gauge symmetry in the BV formalism
- Looking beyond the horizon
- Einstein-Aether Theory
- A Positive Energy Theorem for P(X,phi) Theories
Cited by in corpus (8)
- Losing the trace to find dynamical Newton or Planck constants
- Inflation and the cosmological (not-so) constant in unimodular gravity
- A clarification on prevailing misconceptions in unimodular gravity
- An effective field theory of holographic dark energy
- New Dynamical Degrees of Freedom from Invertible Transformations
- Thawing k-essence dark energy in the PAge space
- Reconstruction of inflationary scenarios in non-conservative unimodular gravity
- Charged thin shells in unimodular gravity