ohwilleke said:
I discuss this and some related ideas in a blog post at
http://dispatchesfromturtleisland.blogspot.com/2016/10/gravity-modification-from-quantum.html as there was too much to say in a comment.
in a toy model handwavy way Lee Smolin suggests Loop Quantum Gravity can give rise to MOND in the deep IR
other researchers argue LQG also gives rise to dark matter
so Loop Quantum Gravity theorists covers its bets, both MOND like modifications in deep IR + dark matter candidate
to me it makes sense that when gravity is very weak, the strength of gravity doesn't continue to zero continuously, but if gravity is quantized, the strength of gravity decreases in quantized levels, giving rise to MOND like effects.
Gravitational axial perturbations and quasinormal modes of loop quantum black holes
M.B. Cruz,
C.A.S. Silva,
F.A. Brito
(Submitted on 26 Nov 2015)
Gravitational waves can be used as a way to investigate the structure of spacetime. Loop Quantum Gravity is a theory that propose a way to model the behavior of spacetime in situations where its atomic characteristic arises. Among these situations, the spacetime behavior near the Big Bang or black hole's singularity. A recent prediction of loop quantum gravity is the existence of sub-Planckian black holes called loop quantum black holes (LQBH) or self-dual black holes which correspond to a quantized version of Schwarzschild black hole. In this work, we study the gravitational waves spectrum emitted by a LQBH through the analysis of its the quasinormal modes. From the results obtained, loop quantum black holes have been shown stable under axial gravitational perturbations.
Comments: 9 pages, 4 figures, 2 tables
Subjects: General Relativity and Quantum Cosmology (gr-qc)
Cite as:
arXiv:1511.08263 [gr-qc]
(or
arXiv:1511.08263v1 [gr-qc] for this version)
Self-dual Black Holes in LQG: Theory and Phenomenology
Leonardo Modesto,
Isabeau Prémont-Schwarz
(Submitted on 20 May 2009 (
v1), last revised 3 Jun 2009 (this version, v2))
In this paper we have recalled the semiclassical metric obtained from a classical analysis of the loop quantum black hole (LQBH). We show that the regular Reissner-Nordstrom-like metric is self-dual in the sense of T-duality: the form of the metric obtained in Loop quantum Gravity (LQG) is invariant under the exchange "r <-> a0/r" where "a0" is proportional to the minimum area in LQG and "r" is the standard Schwarzschild radial coordinate at asymptotic infinity. Of particular interest, the symmetry imposes that if an observer at "r" close to infinity sees a black hole of mass "m" an observer in the other asymptotic infinity beyond the horizon (at "r" close to "0") sees a dual mass "mp/m" ("mp" is the Planck mass). We then show that small LQBH are stable and could be a component of dark matter. Ultra-light LQBHs created shortly after the Big Bang would now have a mass of approximately "10^(-5) mp" and emit radiation with a typical energy of about 10^(13) - 10^(14) eV but they would also emit cosmic rays of much higher energies, albeit few of them. If these small LQBHs form a majority of the dark matter of the Milky Way's Halo, the production rate of ultra-high-energy-cosmic-rays (UHECR) by these ultra light black holes would be compatible with the observed rate of the Auger detector.
Comments: 18 pages, 32 figures. Extra Plot, Improved Numerical Results and Corrected typos
Subjects: High Energy Physics - Theory (hep-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
Journal reference: Phys.Rev.D80:064041,2009
DOI: http://arxiv.org/ct?url=http%3A%2F%2Fdx.doi.org%2F10%252E1103%2FPhysRevD%252E80%252E064041&v=3b61e8cb
Cite as:
arXiv:0905.3170 [hep-th]
(or
arXiv:0905.3170v2 [hep-th] for this version)
Emission spectra of self-dual black holes
Sabine Hossenfelder,
Leonardo Modesto,
Isabeau Prémont-Schwarz
(Submitted on 2 Feb 2012 (
v1), last revised 15 Feb 2012 (this version, v2))
We calculate the particle spectra of evaporating self-dual black holes that are potential dark matter candidates. We first estimate the relevant mass and temperature range and find that the masses are below the Planck mass, and the temperature of the black holes is small compared to their mass. In this limit, we then derive the number-density of the primary emission particles, and, by studying the wave-equation of a scalar field in the background metric of the black hole, show that we can use the low energy approximation for the greybody factors. We finally arrive at the expression for the spectrum of secondary particle emission from a dark matter halo constituted of self-dual black holes.
Comments: 15 pages, 6 figures, typos corrected, reference added
Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)
Cite as:
arXiv:1202.0412 [gr-qc]
(or
arXiv:1202.0412v2 [gr-qc] for this version)