Talk:Scalar–tensor–vector gravity

Cry me a River

Truly discovering this article makes me want to weep. My GoogleQuery was 'Gravity Vector', inspired by a voice sample on the psy-trance stream I am working with. There seems to be a radical simplicity in this theory, perhaps infuriating to the established 'dark matter' order of this arm of Science.

I am an Artist, an econo-comic who dares to suggest that a unique kind of Chemistry play the part of the other Arm. My intention is to develop the boxed text into a progressively-complex presentation of these ideas, for children and their Mothers, primarily. Thank You Professor and WikiWorkers both.

I have long believed that recent insights ought to be taught first. Have a look at answers.com 'Gravity Vector'. It made me stupid and tired to think about those words. —Preceding unsigned comment added by Kapler42 (talk • contribs) 16:42, 3 May 2011 (UTC)

POV flag

Before some angry fan accuses me of Bekenstein bashing, I'd just like to point out that my undergraduate mentor was a fan back when it was generally thought (this was just before Hawking discovered Hawking radiation) that Bekenstein's proposals about black hole thermodynamics were rather wacky. So my Bekenstein fan club credentials are actually impeccable :-/ ---CH 10:46, 19 February 2006 (UTC)

Hm, this is a garbage article about a serious, although not very popular, theory. It really needs expert attention. –Joke 02:41, 23 February 2006 (UTC)

Cleanup

The histories of TeVeS and this article need to be merged. 132.205.46.157 02:30, 2 March 2006 (UTC)

STVG and TeVeS are distinct theories

Scalar-tensor-vector gravity (STVG) and TeVeS are two quite distinct theories. STVG was developed by John Moffat and TeVeS by Jacob Bekenstein. Both theories address the dark matter problem - providing fits to galaxy rotation curves - but beyond that there is little similarity. They should have separate Wikipedia pages. 64.231.137.148 19:26, 4 March 2006 (UTC)

Excised Text

Can an article be salvaged from this?

A modified gravity (MOG) has been published based on a symmetric pseudo-Riemannian metric and the Einstein-Hilbert action and an action formed from a skew symmetric third-rank tensor coupled to matter. This theory is called Metric-Skew-Tensor-Gravity (MSTG) [1]. A simpler version of this theory is based on an Einstein-Hilbert action and a second-rank skew symmetric tensor derived from the curl of a massive vector field called a phion field (particle). The gravitational "constant" G, the coupling "constant" and the effective mass of the phion field are described by spacetime dependent scalar fields in the action. This version of the theory is called Scalar-Vector-Tensor-Gravity (STVG) [2]. It can be proved that these theories are stable and are free from negative energy ghosts and tachyons (the Hamiltonian is bounded from below). The modified gravity theories are fully relativistic and generally covariant. The skew symmetric fields are interpreted as a "fifth force" in nature. The variation of the coupling constants and effective mass of the phion field can be understood in an asymptotically free quantum gravity scenario, using renormalization group (RG) flow techniques in which the constants are scale dependent and "run" with momentum and distance scale [3,1,2]. This scenario is analogous to the RG flow description of the running of coupling constants in the standard model of particle physics including quantum chromodynamics.

Both of these modified gravity theories lead to the same weak field consequences and determine the same modified acceleration law for weak gravitational fields. An extensive fitting to a large number of galaxy rotation curve data without exotic dark matter has been published [4]. When the photometric data describing the visible baryon matter disk, bulge and HI gas of galaxies is used, the fits only involve one free parameter -- the mass-to-light ratio <M/L>. An extensive fitting to x-ray galaxy clusters has also been published in which the fits to over 100 x-ray clusters is performed with effectively zero parameters without exotic dark matter [5]. The fits to the galaxy rotation curve data match closely the predictions of Milgrom's MOND formula [6] with a critical acceleration a_0. However, in contrast to STVG, MOND does not fit the x-ray cluster data without significant addition of dark matter. Moreover, the rotational velocity curves reduce at large distances from the galaxies (satellites) to their Kepler-Newtonian values. The modified gravity predicts lensing effects that agree with data without the need for unobserved dark matter. The theory can explain the Pioneer 10/11 anomalous acceleration data [7] if the anomaly has its origins in gravity. A fit to the available anomalous acceleration data for the Pioneer 10/11 spacecraft is obtained for a phenomenological representaion of the "running" constants and values of the associated parameters are shown to exist that are consistent with fifth force experimental bounds. An analysis of Kepler's third law for the varying gravitational constant, shows that the predicted anomalous acceleration is very small for the inner planets and grows to its observed value beyond Saturn's orbit. The predicted anomalous acceleration is consistent with all inner-planetary observations and with the JPL ephemerides data for the outer planets.

The cosmological consequences for MOG have been studied and the massive phion boson field is assumed to undergo a phase transition (spontaneous symmetry breaking) for a temperature below a critical value, T < T_c, generating an electrically neutral Bose-Einstein condensate (BEC) superfluid with zero viscosity and zero classical pressure [8]. This superfluid forms a second matter fluid in addition to the baryon-photon fluid before recombination. This allows for a fitting of the acoustic oscillation peaks observed in the cosmic microwave background (CMB) WMAP3 and combined world data. In particular, it predicts a third peak that cannot be obtained from only a baryon-photon fluid due to baryon drag. The BEC phion fluid produces a cosmological "dark" electrically neutral matter in addition to the visible baryons and photons. For the localized late-time galaxies and clusters of galaxies, the spontaneous symmetry breaking due to the non-vanishing vacuum expectation value of the phion field is relaxed and the BEC matter is dominated by visible baryon matter. The BEC matter only dominates over baryon and neutrino matter at large cosmological scales; in particular at the CMB surface of last scattering. In this way, the MOG describes a unified picture of the present data for the inner solar system, galaxies, clusters of galaxies and cosmology.

Recent published papers have described an inhomogeneous cosmology based on a spherically symmetric set of Einstein's field equations. Exact solutions of these equations for a matter dominated universe are described by the Lemaitre-Tolman-Bondi solutions. A large scale inhomogeneous enhancement at late times in the expanding universe can for an off-centered observer explain the "axis of evil" and the observed asymmetry of the anisotropy in the northern and southern celestial hemispheres [9]. It has also been shown that an explanation of the accelerating expansion of the universe can be obtained from the late-time exact inhomogeneous solution provided a suitable spatial volume averaging is performed over the data and the expression for the deceleration parameter q [10]. This can explain the acceleration of the universe without a quintessence "dark" energy or a cosmological constant and avoid the fine-tuned "coincidence" problem.

A new quantum field theory (QFT) and interpretation of the vacuum energy has been published in which the zero-point vacuum energy in relativistic QFT is shown to cancel due to the invariance of the vauum state with respect to a generalized dynamical charge conjugation operator The QFT is partly based on the work of Carl Bender and collaborators on non-Hermitian Hamiltonians. It incorporates a para-statistical Pauli exclusion pinciple for negative energy bosons in the vacuum, which stabilizises the vacuum and resolved the cosmological constant problem [11].

[1] J. W. Moffat, JCAP 0505 (2005) 003, astro-ph/0412195.

[2] J. W. Moffat, JCAP 0603 (2006) 004, gr-qc/0506021.

[3] M. Reuter and H. Weyer, JCAP 0412 (2004) 001, hep-th/0410119.

[4] J. R. Brownstein and J. W. Moffat, Astrophys.J. 636 (2006) 721-741, astro-ph/0506370.

[5] J. R. Brownstein and J. W. Moffat, Mon.Not.Roy.Astron.Soc. 367 (2006) 527-540,astro-ph/0507222.

[6] M. Milgrom, Astroph. J. 270, 365 (1983).

[7] J. R. Brownstein and J. W. Moffat, Class. Quantum Grav. 23 (2006) 3427-3436, gr-qc/0511026.

[8] J. W. Moffat, astro-ph/0602607.

[9] J. W. Moffat, JCAP 0510 (2005) 012, astro-ph/0502110.

[10] J. W. Moffat, JCAP 05 (2006) 001, astro-ph/0505326.

[11] J. W. Moffat, Phys.Lett. B627 (2005) 9-17, hep-th/0507020.

—Preceding unsigned comment added by 132.205.45.148 (talk • contribs) 00:41, 15 July 2006

Why was this text excised in the first place? vttoth (talk) 13:59, 4 December 2008 (UTC)

Apparently, it was thought to be a text dump that replaced a usable stub, and perhaps an attempt at publishing a paper, from what I can discern from old talk pages, etc. 76.66.195.190 (talk) 14:12, 26 December 2008 (UTC)

TeVeS is not STVG!

Just thought I'd put this on top because people keep proposing that this article be merged with TeVeS. TeVeS is NOT STVG. Yes, they are both gravity theories. Yes, they both involve a vector field. Other than that, they have nothing to do with each other: TeVeS is a covariant theory that is designed to replicate MOND in the weak field approximation, while STVG is a theory that grew out of Moffat's NGT. vttoth (talk) 14:25, 4 April 2009 (UTC)

Big Blow to MOG

Announcements of dark matter have been made. Apparently, a dark matter string bridging two galaxies has been found. This does not bode well for Moffat's claim that his theory renders dark matter unnecessary. Can his theory account for the recent observations in Abell 222 and Abell 223, or does Einstein triumph once again? ☲Fireyair☲ (talk) 21:35, 11 July 2012 (UTC)

KK Theory?

I notice some similarities between this theory and Kaluza-Klein theory. In particular, there is a merger of gravitational and electromagnetic theories, and the creation of a fifth force. Is this more than skin-deep, or are there some non-trivial similarities here that the article can speak to? — Preceding unsigned comment added by 70.247.173.205 (talk) 01:16, 27 February 2016 (UTC)

LIGO Data

I’ve removed a new reference to an article claiming LIGO rules out MOG, since that conclusion is in tension with other published literature and appears unresolved as of yet. The authors claim MOG to be a two-metric theory, and therefore claim it predicts different propagation speeds for EM and Gravitational waves.

First, the removed article’s discussion of MOG hinges on the claim that MOG is a two-metric theory, which is incorrect—MOG uses a single metric, as reflected in this very article and its existing citations.

More directly, this Phys. Rev. B article claims that MOG does predict that gravitational and EM waves both propagate at the speed of light, which would be consistent with LIGO’s result, and again in direct contradiction the reference I’ve removed.

For the time being the claim that LIGO rules out MOG is controversial, on the grounds above.

UltraBird (talk) 04:17, 16 May 2018 (UTC)

References

Succeeds and Fails Section

I am aware that the section is a quote, even though it is not presented as such, but it comes across as misleading. That the theory only works 'where gravity is weak' implies that it only works in remote areas when in fact, it can account for everything save Neutron Stars and Black Holes and their surroundings. Although the gravity of everything else is weak in comparison to those two types of cosmological objects, it would be less confusing to state that the theory fails where gravity is extremely strong, since 'weak' implies the gravity of the Earth, even the Sun and other fusing stars is weak. — Preceding unsigned comment added by 65.28.183.104 (talk) 07:39, 29 November 2019 (UTC)