# Covariant formulation of non-equilibrium thermodynamics in General Relativity

@article{EspinosaPortals2021CovariantFO, title={Covariant formulation of non-equilibrium thermodynamics in General Relativity}, author={Llorenç Espinosa-Portal{\'e}s and Juan Garc{\'i}a-Bellido}, journal={Physics of the Dark Universe}, year={2021} }

We construct a generally-covariant formulation of non-equilibrium thermodynamics in General Relativity. We find covariant entropic forces arising from gradients of the entropy density, and a corresponding non-conservation of the energy momentum tensor in terms of these forces. We also provide a Hamiltonian formulation of General Relativity in the context of non-equilibrium phenomena and write the Raychaudhuri equations for a congruence of geodesics. We find that a fluid satisfying the strong…

## One Citation

Cosmic acceleration from first principles

- PhysicsPhysics of the Dark Universe
- 2021

General relativistic entropic acceleration theory may explain the present cosmic acceleration from first principles without the need of introducing a cosmological constant. Following the covariant…

## References

SHOWING 1-10 OF 40 REFERENCES

Theory of cosmological perturbations

- Physics
- 1992

We present in a manifestly gauge-invariant form the theory of classical linear gravitational perturbations in part I, and a quantum theory of cosmological perturbations in part II. Part I includes…

Thermodynamical aspects of gravity: new insights

- Physics
- 2010

The fact that one can associate thermodynamic properties with horizons brings together principles of quantum theory, gravitation and thermodynamics and possibly offers a window to the nature of…

A Variational Formulation of Nonequilibrium Thermodynamics for Discrete Open Systems with Mass and Heat Transfer

- Physics, MedicineEntropy
- 2018

We propose a variational formulation for the nonequilibrium thermodynamics of discrete open systems, i.e., discrete systems which can exchange mass and heat with the exterior. Our approach is based…

Gravitational collapse and spacetime singularities

- Physics
- 1965

accompanied by a violent release of energy, possible in the form of gravitational radiation. The detailed mathematical discussion of such situations is difficult since the full complexity of general…

Action Integrals and Partition Functions in Quantum Gravity

- Physics
- 1977

One can evaluate the action for a gravitational field on a section of the complexified spacetime which avoids the singularities. In this manner we obtain finite, purely imaginary values for the…

The singularities of gravitational collapse and cosmology

- PhysicsProceedings of the Royal Society of London. A. Mathematical and Physical Sciences
- 1970

A new theorem on space-time singularities is presented which largely incorporates and generalizes the previously known results. The theorem implies that space-time singularities are to be expected if…

Testing general relativity with present and future astrophysical observations

- Physics
- 2015

One century after its formulation, Einstein's general relativity (GR) has made remarkable predictions and turned out to be compatible with all experimental tests. Most of these tests probe the theory…

The four laws of black hole mechanics

- Physics
- 1973

Expressions are derived for the mass of a stationary axisymmetric solution of the Einstein equations containing a black hole surrounded by matter and for the difference in mass between two…

Embedding Black Holes and Other Inhomogeneities in the Universe in Various Theories of Gravity: A Short Review

- PhysicsUniverse
- 2018

Classic black hole mechanics and thermodynamics are formulated for stationary black holes with event horizons. Alternative theories of gravity of interest for cosmology contain a built-in…

ROLE OF CONFORMAL THREE-GEOMETRY IN THE DYNAMICS OF GRAVITATION.

- Physics
- 1972

The unconstrained dynamical degrees of freedom of the gravitational field are identi- fied with the conformally invariant three-geometries of spacelike hypersurfaces. New results concerning the…