A Theoretical status of hypothesized Generic Objects of Dark Energy

[PeterDonis]

TL;DR Summary

I am looking for input from experts on the current theoretical status of hypothesized Generic Objects of Dark Energy

I have come across some online references to Generic Objects of Dark Energy (GEODEs). They are briefly described in this Wikipedia article:

https://en.wikipedia.org/wiki/Generic_object_of_dark_energy

The only reference from that article that I have been able to find online is this paper:

https://arxiv.org/pdf/1904.03781v2.pdf
The paper refers to several previously proposed solutions, including the "de Sitter sphere" (Gliner 1966), which looks to me like a claimed spherical region of de Sitter space surrounded by a Schwarzschild vacuum, which seems obviously unstable to me (the surface area of the de Sitter region would not be constant in time), but I have been unable to find the original paper online or any other reference that shows the actual math of the solution.

I am wondering if any experts can give useful references concerning the current theoretical status of GEODEs or of any particular solutions in this area.

 

[mfb]

Are you looking for this specific model or is something similar okay as well? Mazur and Mottola have their mathematics here.

 

[PeterDonis]

Are you looking for this specific model

Any model of the general type.

Mazur and Mottola have their mathematics here.

Yes, thanks! I also found this paper by Visser and others that gives a more general model of which the Mazur-Mottola model is a special case:

https://arxiv.org/abs/gr-qc/0505137
This paper says that the key factor that allows such models to be stable is anisotropic pressure in a "crust" region that surrounds a region of negative pressure. The anisotropic pressure adds a term to the standard TOV equation that allows hydrostatic equilibrium.

All this suggests a possible, though highly speculative, route by which quantum effects could stop event horizons from ever forming, which is one of the ways to evade the black hole information paradox. Suppose that, whenever any object containing any kind of stress-energy got sufficiently compressed to be "close" to forming an event horizon, quantum field effects became strong enough to cause a phase transition which resulted in the general kind of stress-energy profile described in the Visser paper (a central core of "dark energy" type stuff, with pressure negative enough to violate the energy conditions, surrounded by a "crust" of anisotropic pressure providing stability, surrounded by a reasonably "normal" region that looks like the surface of a highly collapsed object)? This phase transition would either result in a stable object of the kind just described, or would cause a "bounce" that created an explosion and blew off enough mass to bring the remnant below the maximum mass limit for a neutron star or white dwarf.

 

[fresh_42]

I have found this: https://iopscience.iop.org/article/10.3847/1538-4357/ab32da

Abstract
We show that derivation of Friedmann's equations from the Einstein–Hilbert action, paying attention to the requirements of isotropy and homogeneity during the variation, leads to a different interpretation of pressure than what is typically adopted. Our derivation follows if we assume that the unapproximated metric and Einstein tensor have convergent perturbation series representations on a sufficiently large Robertson–Walker coordinate patch. We find the source necessarily averages all pressures, everywhere, including the interiors of compact objects. We demonstrate that our considerations apply (on appropriately restricted spacetime domains) to the Kerr solution, the Schwarzschild constant-density sphere, and the static de-Sitter sphere. From conservation of stress–energy, it follows that material contributing to the averaged pressure must shift locally in energy. We show that these cosmological energy shifts are entirely negligible for non-relativistic material. In relativistic material, however, the effect can be significant. We comment on the implications of this study for the dark energy problem.

 

[PeterDonis]

I have found this

I have already opened a separate thread on this paper in the Cosmology forum:

https://www.physicsforums.com/threa...y-and-pressure-in-friedmann-cosmology.977284/
I opened this thread for more general discussion of GEODEs, separate from specific discussion of that paper.

 

[.Scott]

Kevin Croker, an astrophysicist and Joel Weiner, a professor emeritus in mathematics - both at the University of Hawaii at Mānoa, describe objects of Dark energy similar to Black Holes.

Here are links to the original publication and to a story based on an interview.

Article in "Astrophysics Journal"
Article in "Life Science"

 

[PeterDonis]

Kevin Croker, an astrophysicist and Joel Weiner, a professor emeritus in mathematics - both at the University of Hawaii at Mānoa, describe objects of Dark energy similar to Black Holes.

This is the same paper @fresh_42 mentioned in post #4. See my response in post #5.