Papers
Topics
Authors
Recent
Gemini 2.5 Flash
Gemini 2.5 Flash
173 tokens/sec
GPT-4o
7 tokens/sec
Gemini 2.5 Pro Pro
46 tokens/sec
o3 Pro
4 tokens/sec
GPT-4.1 Pro
38 tokens/sec
DeepSeek R1 via Azure Pro
28 tokens/sec
2000 character limit reached

Emergent Modified Gravity (2404.06375v1)

Published 9 Apr 2024 in gr-qc, astro-ph.CO, and hep-th

Abstract: A complete canonical formulation of general covariance makes it possible to construct new modified theories of gravity that are not of higher-curvature form, as shown here in a spherically symmetric setting. The usual uniqueness theorems are evaded by using a crucial and novel ingredient, allowing for fundamental fields of gravity distinct from an emergent space-time metric that provides a geometrical structure to all solutions. As specific examples, there are new expansion-shear couplings in cosmological models, a form of modified Newtonian dynamics (MOND) can appear in a space-time covariant theory without introducing extra fields, and related effects help to make effective models of canonical quantum gravity fully consistent with general covariance.

Definition Search Book Streamline Icon: https://streamlinehq.com
References (37)
  1. P. A. M. Dirac, The theory of gravitation in Hamiltonian form, Proc. Roy. Soc. A 246 (1958) 333–343
  2. J. Katz, Les crochets de Poisson des contraintes du champ gravitationne, Comptes Rendus Acad. Sci. Paris 254 (1962) 1386–1387
  3. The Dynamics of General Relativity, In L. Witten, editor, Gravitation: An Introduction to Current Research, Wiley, New York, 1962, Reprinted in [37]
  4. Geometrodynamics Regained, Ann. Phys. (New York) 96 (1976) 88–135
  5. A new type of large-scale signature change in emergent modified gravity, Phys. Rev. D 109 (2024) 084001, [arXiv:2312.09217]
  6. An effective model for the quantum Schwarzschild black hole, Phys. Lett. B 829 (2022) 137075, [arXiv:2112.12110]
  7. Nonsingular spherically symmetric black-hole model with holonomy corrections, Phys. Rev. D 106 (2022) 024035, [arXiv:2205.02098]
  8. A Lie-Rinehart algebra in general relativity, [arXiv:2201.02883]
  9. Covariance in models of loop quantum gravity: Spherical symmetry, Phys. Rev. D 92 (2015) 045043, [arXiv:1507.00329]
  10. M. Bojowald and S. Brahma, Covariance in models of loop quantum gravity: Gowdy systems, Phys. Rev. D 92 (2015) 065002, [arXiv:1507.00679]
  11. Effective line elements and black-hole models in canonical (loop) quantum gravity, Phys. Rev. D 98 (2018) 046015, [arXiv:1803.01119]
  12. A. Alonso-Bardají and D. Brizuela, Holonomy and inverse-triad corrections in spherical models coupled to matter, Eur. Phys. J. C 81 (2021) 283, [arXiv:2010.14437]
  13. A. Alonso-Bardají and D. Brizuela, Anomaly-free deformations of spherical general relativity coupled to matter, Phys. Rev. D 104 (2021) 084064, [arXiv:2106.07595]
  14. R. Tibrewala, Inhomogeneities, loop quantum gravity corrections, constraint algebra and general covariance, Class. Quantum Grav. 31 (2014) 055010, [arXiv:1311.1297]
  15. M. Bojowald and R. Swiderski, Spherically Symmetric Quantum Geometry: Hamiltonian Constraint, Class. Quantum Grav. 23 (2006) 2129–2154, [gr-qc/0511108]
  16. M. Bojowald and E. I. Duque, Emergent modified gravity: Covariance regained, Phys. Rev. D 108 (2023) 084066, [arXiv:2310.06798]
  17. V. Mukhanov and R. Brandenberger, A nonsingular universe, Phys. Rev. Lett. 68 (1992) 1969–1972
  18. M. Bojowald, Non-covariance of “covariant polymerization” in models of loop quantum gravity, Phys. Rev. D 103 (2021) 126025, [arXiv:2102.11130]
  19. A covariant polymerized scalar field in loop quantum gravity, Universe 8 (2022) 526, [arXiv:2102.09501]
  20. J. D. Reyes, Spherically Symmetric Loop Quantum Gravity: Connections to 2-Dimensional Models and Applications to Gravitational Collapse, PhD thesis, The Pennsylvania State University, 2009
  21. G. W. Horndeski, Second-order scalar-tensor field equations in a four-dimensional space, Int. J. Theor. Phys. 10 (1974) 363–384
  22. T. Kobayashi, Horndeski theory and beyond: a review, Rept. Prog. Phys. 82 (2019) 086901, [arXiv:1901.07183]
  23. D. Langlois and K. Noui, Degenerate higher derivative theories beyond Horndeski: evading the Ostrogradski instability, JCAP 02 (2016) 034, [arXiv:1510.06930]
  24. K. Takahashi and T. Kobayashi, Generalized 2D dilaton gravity and KGB, Class. Quant. Grav. 36 (2019) 095003, [arXiv:1812.08847]
  25. M. Bojowald and G. M. Paily, Deformed General Relativity and Effective Actions from Loop Quantum Gravity, Phys. Rev. D 86 (2012) 104018, [arXiv:1112.1899]
  26. P. Hořava, Quantum gravity at a Lifshitz point, Phys. Rev. D 79 (2009) 084008, [arXiv:0901.3775]
  27. M. Bojowald, The BKL scenario, infrared renormalization, and quantum cosmology, JCAP 01 (2019) 026, [arXiv:1810.00238]
  28. M. Bojowald and E. I. Duque, MONDified gravity, Phys. Lett. B 847 (2023) 138279, [arXiv:2310.19894]
  29. M. Milgrom, A modification of the Newtonian dynamics-Implications for galaxies, Ap. J. 270 (1983) 371–383
  30. S. S. McGaugh and W. De Blok, Testing the hypothesis of modified dynamics with low surface brightness galaxies and other evidence, Ap. J. 499 (1998) 66
  31. Quasiclassical solutions for static quantum black holes, Phys. Rev. D 109 (2024) 024006, [arXiv:2012.07649]
  32. J. D. Bekenstein, Relativistic gravitation theory for the modified Newtonian dynamics paradigm, Phys. Rev. D 70 (2004) 083509, [astro-ph/0403694]
  33. J. W. Moffat, Scalar–tensor–vector gravity theory, JCAP 2006 (2006) 004, [gr-qc/0506021]
  34. A. Alonso-Bardají and D. Brizuela, Spacetime geometry from canonical spherical gravity, [arXiv:2310.12951]
  35. M. Bojowald and E. I. Duque, Emergent modified gravity coupled to scalar matter, Phys. Rev. D 109 (2024) 084006, [arXiv:2311.10693]
  36. E. I. Duque, Emergent modified gravity: The perfect fluid and gravitational collapse, Phys. Rev. D 109 (2024) 044014, [arXiv:2311.08616]
  37. The Dynamics of General Relativity, Gen. Rel. Grav. 40 (2008) 1997–2027
Citations (5)
View on Semantic Scholar

Summary

We haven't generated a summary for this paper yet.

Ai Sparkles Streamline Icon: https://streamlinehq.com Summarize Now