Modified gravity Definition and 19 Threads

"What the theory of dark matter predicted is not what we see," said Case Western Reserve astrophysicist Stacy McGaugh, whose paper (12.11.24) describes structure formation in the early universe. McGaugh, professor and director of astronomy at Case Western Reserve, said instead of dark matter...

I am looking for examples of Modified Gravity theories that have been developed with the aim of dispensing dark matter, besides Milgrom's [MOND][1], Bekenstein's [TeVeS][2], and the recent relativistic version of MOND ([RMOND][3]) by Skordis and Zlosnik. Are there any other examples of similar...

Let ##\phi## be a scalar field and ##g_{\mu \nu} = \eta_{\mu \nu}+h_{\mu \nu}/M_p## where ##M_p## is the Planck mass (so we assume we deal with perturbations). Let ##\Lambda_2,\Lambda_3## be energy scales such that ##\Lambda_2 \gg \Lambda_3##. These are defined by ##\Lambda^2_2 = M_p H_0## and...

Does anyone have any good laypersons reads to get a good summary the dark matter versus modified gravity? Thanks

Hello everyone, I am currently finishing my Masters in Theoretical Physics and looking forward to continue in a PhD. I always thought I would love String Theory, and now that i am actually doing it I see that my feeling was correct. I do not know why but trying to understand its concepts...

One approach that has been proposed to replicate the description of dark matter phenomena in galaxies with a gravity modification that is set forth in a simplified manner in the phenomenological toy model theory MOND is to do so through a variation on Einstein's General Relativity known as...

There is a an encyclopaedia of all the different inflationary models. But I am wondering is there is a similar list of modified gravity models ?

In this paper (https://arxiv.org/abs/astro-ph/0603302) the authors derive the field equations for f(R) gravity considering a spherically symmetric and static metric. Now the Ricci scalar only depends on r so you could write f(R(r)) = g(r) for some g. However what it seems the authors have done...

Dark Matter was never found, what Modified Gravity theories should we check now?

Are they the same object?

Different things keep popping up in the literature that pose Dark matter and Dark energy are not needed to explain the universe, the latest MOG i have come across is this: http://arxiv.org/pdf/1510.07037.pdf What are the chances that a modified gravity theory will replace the standard model?

http://arxiv.org/abs/1508.04641 The body text of the paper ends up calling the "Hybrid metric-Palatini gravity theory" f(X) gravity. From the body text (citations and internal references omitted without notation): The paper closes by identifying many issues for further study and arguing...

What is the evidence for dark matter being new particles as opposed to some modified form of gravity?

I found a few curious arxiv papers by Alexandre Deur (via Twitter). Deur works in QCD. He explains QCD strings (flux line between quark and antiquark) as due to attraction between gluon field lines, ultimately due to gluon-gluon interactions. Phenomenologically this adds a linear term to the...

What are your personal opinions ??, Do you guys think gravity is just not fully understood that is why we can't explain certain events or DM is the probable answer to these discrepancies ? I personally don't think we need to create a somewhat imaginary matter (dark matter and dark energy) to...

what's the status of that? also why not just look for two systems that have the same visible distribution but with a different dark matter content?

Friends: I have been studying John Moffats Modified Gravity theory. I find it very interesting and I agree with him in that I think Dark Matter and Dark Energy are merely mediums to make our current equations work so we can predict the movements of the cosmos. However I am unclear on what...

http://arxiv.org/abs/astro-ph/0605278 Searching for modified gravity with baryon oscillations: from SDSS to WFMOS Authors: Kazuhiro Yamamoto, Bruce A. Bassett, Robert C. Nichol, Yasushi Suto, Kazuhiro Yahata Comments: 16 pages, submitted to PRD We discuss how the baryon acoustic...

http://arxiv.org/abs/astro-ph/0506692 Title: Cosmological expansion and the uniqueness of gravitational action Authors: T. Multamaki, I. Vilja Comments: 4 pages Modified theories of gravity have recently been studied by several authors as possibly viable alternatives to the cosmological...