I Has anyone done a PPN formalism on Dark Matter? Or other non-GR?

mollwollfumble
Messages
34
Reaction score
5
TL;DR Summary
Any signs of a factor of two difference between Dark Matter mass calculated using gravitational lensing vs calculated from the virial theorem?
This thought surprisingly came from thinking about the definition of temperature and the symmetry breaking that separated time from temperature. Which led to thoughts about symmetry breaking that separated QM from GR. Which led to to the symmetry breaking that separated dark energy from baryonic matter from dark matter. ie. the fine tuning there may be a result of symmetry breaking rather than just a statistical freak.

Although gravity between baryonic matter and baryonic matter has been confirmed using Parameterized post-Newtonian formalism to agree to high accuracy with General Relativity, I haven't seen evidence confirming that gravity between Dark Matter and baryonic matter acts using General Relativity.

Gravity between DM and baryonic matter could, for instance, act through gravitons in QM rather than through GR. If so, then the DM mass calculated from the virial theorem would differ by a factor of two from that calculated by gravitational lensing. Has this been tested? Any signs of a factor of two difference between Dark Matter mass calculated using different methods?
 
Physics news on Phys.org
Dark Matter is GR. So its PPN parameters are the same as GR's.
 
  • Like
Likes Demystifier
Vanadium 50 said:
Dark Matter is GR. So its PPN parameters are the same as GR's.
Dark matter theories, at the galaxy and galaxy cluster scale where a lot of the study of DM is being done, aren't really GR. They are really just straight up Newtonian gravity justified by the assumption that GR effects are negligible, which literature being discussing in a different PF thread right now, disputes.

I think what the OP is really asking is whether the improvements on unmodified Newtonian gravity used to approximate GR in most astronomy applications from the Post-Newtonian expansion (or equivalently, the PPN with GR parameters) could reproduce dark matter effects without resort to dark matter.

In other words, if considering some of the GR effects neglected in a purely Newtonian approximation, without using the mathematically intractable fully GR without any simplifying assumptions, as the post-Newtonian expansion and PPN with standard GR parameters do, could explain or partially explain phenomena usually attributed to dark matter.

The main non-Newtonian effects in GR which have been proposed to possibly account for phenomena in galaxies and galaxy clusters that are attributed dark matter have been gravitational field self-interactions and the GEM (gravitomagentic) effects that are both well recognized but have historically been discounted in weak field galaxy and galaxy cluster systems.

I'm not certain whether the PN expansion or PPN approach captures these GR specific effects in a way that would work for galaxy and galaxy cluster scale systems. But I think that this is what the OP wants to know.
 
  • Like
Likes Maarten Havinga
ohwilleke said:
I think what the OP is really asking
Then let him ask it. Answering questions he didn't ask rather than the one he did ask is unlikely to be helpful.
 
I seem to notice a buildup of papers like this: Detecting single gravitons with quantum sensing. (OK, old one.) Toward graviton detection via photon-graviton quantum state conversion Is this akin to “we’re soon gonna put string theory to the test”, or are these legit? Mind, I’m not expecting anyone to read the papers and explain them to me, but if one of you educated people already have an opinion I’d like to hear it. If not please ignore me. EDIT: I strongly suspect it’s bunk but...
I'm trying to understand the relationship between the Higgs mechanism and the concept of inertia. The Higgs field gives fundamental particles their rest mass, but it doesn't seem to directly explain why a massive object resists acceleration (inertia). My question is: How does the Standard Model account for inertia? Is it simply taken as a given property of mass, or is there a deeper connection to the vacuum structure? Furthermore, how does the Higgs mechanism relate to broader concepts like...
Back
Top