Some argue that the particular models proposed by Sakharov and others have been proven impossible by the Weinberg–Witten theorem. However, models with emergent gravity are possible as long as other things, such as spacetime dimensions, emerge together with gravity. Developments in AdS/CFT correspondence after 1997 suggest that the microphysical degrees of freedom in induced gravity might be radically different. The bulk spacetime arises as an emergent phenomenon of the quantum degrees of freedom that are entangled and live in the boundary of the spacetime. According to some prominent researchers in emergent gravity (such as Mark Van Raamsdonk) spacetime is built up of quantum entanglement.[2] This implies that quantum entanglement is the fundamental property that gives rise to spacetime. In 1995, Jacobson showed that the Einstein field equations can be derived from the first law of thermodynamics applied at local Rindler horizons.[3]Thanu Padmanabhan and Erik Verlinde explore links between gravity and entropy, Verlinde being known for an entropic gravity proposal.[4][5] The Einstein equation for gravity can emerge from the entanglement first law.[6][7][8] In the "quantum graphity" proposal of Konopka, Markopoulu-Kalamara, Severini and Smolin, the fundamental degrees of freedom exist on a dynamical graph that is initially complete, and an effective spatial lattice structure emerges in the low-temperature limit.[9][10]
^H. Kleinert (1987). "Gravity as Theory of Defects in a Crystal with Only Second-Gradient Elasticity". Annalen der Physik. 44 (2): 117. Bibcode:1987AnP...499..117K. doi:10.1002/andp.19874990206.
^Van Raamsdonk, Mark (19 June 2010). "Building up spacetime with quantum entanglement". General Relativity and Gravitation. 42 (10): 2323–2329. arXiv:1005.3035. Bibcode:2010GReGr..42.2323V. doi:10.1007/s10714-010-1034-0.
^Jacobson, Ted (1995-08-14). "Thermodynamics of Spacetime: The Einstein Equation of State". Physical Review Letters. 75 (7): 1260–1263. arXiv:gr-qc/9504004. Bibcode:1995PhRvL..75.1260J. doi:10.1103/PhysRevLett.75.1260. PMID 10060248. S2CID 13223728.
^Padmanabhan, T. (2010-04-01). "Thermodynamical Aspects of Gravity: New insights". Reports on Progress in Physics. 73 (4): 046901. arXiv:0911.5004. Bibcode:2010RPPh...73d6901P. doi:10.1088/0034-4885/73/4/046901. ISSN 0034-4885. S2CID 209835245.
^Verlinde, Erik (2011). "On the origin of gravity and the laws of Newton". Journal of High Energy Physics. 2011 (4): 29. arXiv:1001.0785. Bibcode:2011JHEP...04..029V. doi:10.1007/jhep04(2011)029. ISSN 1029-8479. S2CID 3597565.
^Lee, Jae-Weon; Kim, Hyeong-Chan; Lee, Jungjai (2013). "Gravity from quantum information". Journal of the Korean Physical Society. 63 (5): 1094–1098. arXiv:1001.5445. Bibcode:2013JKPS...63.1094L. doi:10.3938/jkps.63.1094. ISSN 0374-4884. S2CID 118494859.
^Swingle, Brian; Van Raamsdonk, Mark (2014). "Universality of Gravity from Entanglement". arXiv:1405.2933 [hep-th].
^Oh, Eunseok; Park, I. Y.; Sin, Sang-Jin (2018-07-13). "Complete Einstein equations from the generalized First Law of Entanglement". Physical Review D. 98 (2): 026020. arXiv:1709.05752. Bibcode:2018PhRvD..98b6020O. doi:10.1103/PhysRevD.98.026020. S2CID 119084958.
D. Berenstein, Emergent Gravity from CFT, online lecture.
C. J. Hogan Quantum Indeterminacy of Emergent Spacetime, preprint
A.D. Sakharov, Vacuum Quantum Fluctuations in Curved Space and the Theory of Gravitation, 1967.
Matt Visser, Sakharov's induced gravity: a modern perspective, 2002.
H. Kleinert, Multivalued Fields in Condensed Matter, Electrodynamics, and Gravitation, 2008.
M. Brouwer et al., First test of Verlinde's theory of Emergent Gravity using Weak Gravitational Lensing measurements, 2016.
January 01, 1970
induced, gravity, emergent, gravity, idea, quantum, gravity, that, spacetime, curvature, dynamics, emerge, mean, field, approximation, underlying, microscopic, degrees, freedom, similar, fluid, mechanics, approximation, bose, einstein, condensates, concept, or. Induced gravity or emergent gravity is an idea in quantum gravity that spacetime curvature and its dynamics emerge as a mean field approximation of underlying microscopic degrees of freedom similar to the fluid mechanics approximation of Bose Einstein condensates The concept was originally proposed by Andrei Sakharov in 1967 Contents 1 Overview 2 See also 3 References 4 External linksOverview editSakharov observed that many condensed matter systems give rise to emergent phenomena that are analogous to general relativity For example crystal defects can look like curvature and torsion in an Einstein Cartan spacetime This allows one to create a theory of gravity with torsion from a world crystal model of spacetime in which the lattice spacing is of the order of a Planck length 1 Sakharov s idea was to start with an arbitrary background pseudo Riemannian manifold in modern treatments possibly with torsion and introduce quantum fields matter on it but not introduce any gravitational dynamics explicitly This gives rise to an effective action which to one loop order contains the Einstein Hilbert action with a cosmological constant In other words general relativity arises as an emergent property of matter fields and is not put in by hand On the other hand such models typically predict huge cosmological constants Some argue that the particular models proposed by Sakharov and others have been proven impossible by the Weinberg Witten theorem However models with emergent gravity are possible as long as other things such as spacetime dimensions emerge together with gravity Developments in AdS CFT correspondence after 1997 suggest that the microphysical degrees of freedom in induced gravity might be radically different The bulk spacetime arises as an emergent phenomenon of the quantum degrees of freedom that are entangled and live in the boundary of the spacetime According to some prominent researchers in emergent gravity such as Mark Van Raamsdonk spacetime is built up of quantum entanglement 2 This implies that quantum entanglement is the fundamental property that gives rise to spacetime In 1995 Jacobson showed that the Einstein field equations can be derived from the first law of thermodynamics applied at local Rindler horizons 3 Thanu Padmanabhan and Erik Verlinde explore links between gravity and entropy Verlinde being known for an entropic gravity proposal 4 5 The Einstein equation for gravity can emerge from the entanglement first law 6 7 8 In the quantum graphity proposal of Konopka Markopoulu Kalamara Severini and Smolin the fundamental degrees of freedom exist on a dynamical graph that is initially complete and an effective spatial lattice structure emerges in the low temperature limit 9 10 See also editBlack hole thermodynamics Entropic force List of quantum gravity researchers Superfluid vacuum theory Einstein Cartan theoryReferences edit H Kleinert 1987 Gravity as Theory of Defects in a Crystal with Only Second Gradient Elasticity Annalen der Physik 44 2 117 Bibcode 1987AnP 499 117K doi 10 1002 andp 19874990206 Van Raamsdonk Mark 19 June 2010 Building up spacetime with quantum entanglement General Relativity and Gravitation 42 10 2323 2329 arXiv 1005 3035 Bibcode 2010GReGr 42 2323V doi 10 1007 s10714 010 1034 0 Jacobson Ted 1995 08 14 Thermodynamics of Spacetime The Einstein Equation of State Physical Review Letters 75 7 1260 1263 arXiv gr qc 9504004 Bibcode 1995PhRvL 75 1260J doi 10 1103 PhysRevLett 75 1260 PMID 10060248 S2CID 13223728 Padmanabhan T 2010 04 01 Thermodynamical Aspects of Gravity New insights Reports on Progress in Physics 73 4 046901 arXiv 0911 5004 Bibcode 2010RPPh 73d6901P doi 10 1088 0034 4885 73 4 046901 ISSN 0034 4885 S2CID 209835245 Verlinde Erik 2011 On the origin of gravity and the laws of Newton Journal of High Energy Physics 2011 4 29 arXiv 1001 0785 Bibcode 2011JHEP 04 029V doi 10 1007 jhep04 2011 029 ISSN 1029 8479 S2CID 3597565 Lee Jae Weon Kim Hyeong Chan Lee Jungjai 2013 Gravity from quantum information Journal of the Korean Physical Society 63 5 1094 1098 arXiv 1001 5445 Bibcode 2013JKPS 63 1094L doi 10 3938 jkps 63 1094 ISSN 0374 4884 S2CID 118494859 Swingle Brian Van Raamsdonk Mark 2014 Universality of Gravity from Entanglement arXiv 1405 2933 hep th Oh Eunseok Park I Y Sin Sang Jin 2018 07 13 Complete Einstein equations from the generalized First Law of Entanglement Physical Review D 98 2 026020 arXiv 1709 05752 Bibcode 2018PhRvD 98b6020O doi 10 1103 PhysRevD 98 026020 S2CID 119084958 Konopka Tomasz Markopoulou Fotini Smolin Lee 2006 11 17 Quantum Graphity arXiv hep th 0611197 Konopka Tomasz Markopoulou Fotini Severini Simone 2008 05 27 Quantum graphity A model of emergent locality Physical Review D 77 10 104029 arXiv 0801 0861 Bibcode 2008PhRvD 77j4029K doi 10 1103 PhysRevD 77 104029 ISSN 1550 7998 S2CID 6959359 External links editCarlos Barcelo Stefano Liberati Matt Visser Living Rev Rel 8 12 2005 D Berenstein Emergent Gravity from CFT online lecture C J Hogan Quantum Indeterminacy of Emergent Spacetime preprint A D Sakharov Vacuum Quantum Fluctuations in Curved Space and the Theory of Gravitation 1967 Matt Visser Sakharov s induced gravity a modern perspective 2002 H Kleinert Multivalued Fields in Condensed Matter Electrodynamics and Gravitation 2008 M Brouwer et al First test of Verlinde s theory of Emergent Gravity using Weak Gravitational Lensing measurements 2016 Retrieved from https en wikipedia org w index php title Induced gravity amp oldid 1172222458, wikipedia, wiki, book, books, library,
