tensor–vector–scalar gravity

tensor–vector–scalar gravity
Name	Tensor–vector–scalar gravity
Other names	TeVeS
Field	Physics
Introduced	2004
Proponents	Jacob Bekenstein
Related	Modified Newtonian Dynamics, General relativity

tensor–vector–scalar gravity

Tensor–vector–scalar gravity is a relativistic modification of General relativity proposed to reproduce Modified Newtonian Dynamics phenomenology while remaining compatible with relativistic requirements. It was formulated to address anomalous rotation curves around Milky Way, Andromeda Galaxy, and galaxy clusters such as the Coma Cluster without invoking nonbaryonic Cold Dark Matter as postulated by the Lambda-CDM model. The theory introduces additional dynamical fields to the tensorial metric of Albert Einstein’s framework and has been applied in contexts ranging from the Cosmic microwave background analyses to gravitational lensing in systems like the Bullet Cluster.

Introduction

TeVeS was developed by Jacob Bekenstein in 2004 to provide a covariant completion of ideas originating with Mordehai Milgrom’s Modified Newtonian Dynamics, aiming to reconcile rotation curve successes with relativistic phenomena such as gravitational lensing and cosmology studied by collaborations like Planck Collaboration and WMAP. The proposal augments the Einstein field equations with a unit timelike vector field and a dynamical scalar field in addition to the metric tensor, engaging with observational programs led by institutions such as European Southern Observatory and National Aeronautics and Space Administration. Its formulation interacts with tests performed by projects including Sloan Digital Sky Survey, Hubble Space Telescope, and the Very Large Telescope.

Theoretical formulation

The TeVeS action couples a tensor field akin to the Schwarzschild metric’s metric tensor, a timelike vector field similar in role to fields studied by John Wheeler and a scalar field with a noncanonical kinetic term, invoking variational principles used by Richard Feynman and Lev Landau. The vector sector enforces a unit constraint analogous to constructions in work by Willie Misner, with Lagrange multipliers resembling methods of Noether-type analyses. Field equations generalize the Einstein field equations and incorporate free functions that mimic Milgrom acceleration constant behavior; such free functions have been parametrized in studies by groups at Max Planck Institute for Astrophysics and Perimeter Institute for Theoretical Physics. The coupling to matter follows the minimal coupling prescription similar to treatments in textbooks by Misner, Thorne, and Wheeler and employs metrics related by disformal transformations studied by John Moffat and others.

Cosmological implications

In cosmology, TeVeS modifies the evolution of perturbations relevant to the Cosmic microwave background anisotropies measured by Planck Collaboration and WMAP. Structure formation under TeVeS has been modeled to compare with large-scale surveys such as Sloan Digital Sky Survey and 2dF Galaxy Redshift Survey, often requiring additional components analogous to hot or sterile species considered in Particle Data Group analyses. Predictions for the matter power spectrum and baryon acoustic oscillations have been contrasted with data analyzed by teams at University of Cambridge, Harvard–Smithsonian Center for Astrophysics, and Jet Propulsion Laboratory. TeVeS cosmologies can produce accelerated expansion scenarios discussed in contexts studied by Supernova Cosmology Project and High-Z Supernova Search Team but face tension with precise parameter fits from the Planck Collaboration.

Phenomenology and astrophysical tests

TeVeS has been applied to galactic rotation curves in systems observed by the Very Large Array and Arecibo Observatory and to strong lensing in galaxy clusters targeted by Subaru Telescope and the Hubble Space Telescope. The theory can reproduce flat rotation curves in low-surface-brightness galaxies cataloged in works from University of Groningen and University of California, Santa Cruz, and offers alternative explanations for the Tully–Fisher relation studied by researchers at Space Telescope Science Institute. Gravitational lensing predictions have been confronted with observations of merging clusters such as the Bullet Cluster and systems analyzed by teams at Harvard University and McGill University; these comparisons leverage weak-lensing surveys from projects like CFHTLenS and DES.

Comparisons with dark matter and alternative theories

TeVeS competes with the Lambda-CDM model and particle dark matter candidates pursued by collaborations such as ATLAS experiment and CMS experiment at CERN. It is often compared to alternatives including MOdified Gravity proposals by John Moffat (MOG), relativistic MOND extensions, and scalar–tensor theories like those developed by Brans–Dicke and explored at institutions such as Stanford University and Princeton University. Phenomenologically it aims to reproduce successes of collisionless Cold Dark Matter simulations conducted by groups at Millennium Simulation and Illustris project while avoiding invoking weakly interacting massive particles sought by experiments at LUX-ZEPLIN and XENON collaborations.

Experimental constraints and observational status

Constraints on TeVeS arise from solar-system tests conducted by missions like Cassini and laboratory bounds related to tests finalized at Cavendish Laboratory. Binary pulsar timing measured for systems such as PSR B1913+16 and Double Pulsar place limits on preferred-frame effects analogous to analyses by Hulse–Taylor and teams at Max Planck Institute for Radio Astronomy. Cosmological constraints derive from Planck Collaboration data and large-scale structure surveys like Sloan Digital Sky Survey and Dark Energy Survey, while gravitational-wave observations reported by LIGO Scientific Collaboration and VIRGO Collaboration further restrict propagation speeds and polarization content of additional fields.

Criticisms and theoretical challenges

Criticisms of TeVeS include fine-tuning of free functions noted by theorists at Perimeter Institute for Theoretical Physics and challenges matching cluster-scale lensing in the Bullet Cluster and Train Wreck Cluster discussed by observers at Harvard–Smithsonian Center for Astrophysics. Stability analyses and superluminality issues have been raised in papers involving researchers from University of Cambridge, University of Oxford, and Princeton University, and embedding TeVeS into high-energy frameworks such as string-theoretic approaches developed at Institute for Advanced Study has proved difficult. The need to reconcile TeVeS with nonbaryonic relic constraints from Big Bang nucleosynthesis and neutrino-sector bounds compiled by the Particle Data Group remains an outstanding problem.

Category:Gravity theories