Symmetry, Integrability and Geometry: Methods and Applications (SIGMA)

SIGMA 8 (2012), 027, 45 pages      arXiv:1110.0686
Contribution to the Special Issue “Loop Quantum Gravity and Cosmology”

Emergent Models for Gravity: an Overview of Microscopic Models

Lorenzo Sindoni
Max Planck Institute for Gravitational Physics, Albert Einstein Institute, Am Mühlenberg 1, 14467 Golm, Germany

Received October 02, 2011, in final form May 04, 2012; Published online May 12, 2012

We give a critical overview of various attempts to describe gravity as an emergent phenomenon, starting from examples of condensed matter physics, to arrive to more sophisticated pregeometric models. The common line of thought is to view the graviton as a composite particle/collective mode. However, we will describe many different ways in which this idea is realized in practice.

Key words: emergent gravity; quantum gravity.

pdf (678 kb)   tex (84 kb)


  1. Adler R., Bazin M., Schiffer M., Introduction to general relativity, McGraw-Hill Book Co., New York, 1965.
  2. Adler S.L., A formula for the induced gravitational constant, Phys. Lett. B 95 (1980), 241-243.
  3. Adler S.L., Einstein gravity as a symmetry-breaking effect in quantum field theory, Rev. Modern Phys. 54 (1982), 729-766, Erratum, Rev. Modern Phys. 55 (1983), 837.
  4. Aharony O., Gubser S.S., Maldacena J., Ooguri H., Oz Y., Large N field theories, string theory and gravity, Phys. Rep. 323 (2000), 183-386, hep-th/9905111.
  5. Akama K., An attempt at pregeometry. Gravity with composite metric, Progr. Theoret. Phys. 60 (1978), 1900-1909.
  6. Akama K., Pregeometry including fundamental gauge bosons, Phys. Rev. D 24 (1981), 3073-3081.
  7. Akama K., Chikashige Y., Matsuki T., Unified model of the Nambu-Jona-Lasinio type for the gravitational and electromagnetic forces, Progr. Theoret. Phys. 59 (1978), 653-655.
  8. Akama K., Chikashige Y., Matsuki T., Terazawa H., Gravity and electromagnetism as collective phenomena of fermion-antifermion pairs, Progr. Theoret. Phys. 60 (1978), 868-877.
  9. Alexander S.H.S., Calcagni G., Quantum gravity as a Fermi liquid, Found. Phys. 38 (2008), 1148-1184, arXiv:0807.0225.
  10. Alexander S.H.S., Calcagni G., Superconducting loop quantum gravity and the cosmological constant, Phys. Lett. B 672 (2009), 386-389, arXiv:0806.4382.
  11. Alfaro J., Morales-Técotl H.A., Urrutia L.F., Quantum gravity corrections to neutrino propagation, Phys. Rev. Lett. 84 (2000), 2318-2321, gr-qc/9909079.
  12. Amati D., Veneziano G., A unified gauge and gravity theory with only matter fields, Nuclear Phys. B 204 (1981), 451-476.
  13. Amati D., Veneziano G., Metric from matter, Phys. Lett. B 105 (1981), 358-362.
  14. Ambjørn J., Görlich A., Jurkiewicz J., Loll R., CDT - an entropic theory of quantum gravity, arXiv:1007.2560.
  15. Ambjørn J., Jurkiewicz J., Loll R., Causal dynamical triangulations and the quest for quantum gravity, arXiv:1004.0352.
  16. Ambjørn J., Jurkiewicz J., Loll R., Lattice quantum gravity - an update, PoS Proc. Sci. (2010), PoS(LATTICE2010), 014, 14 pages, arXiv:1105.5582.
  17. Ambjørn J., Jurkiewicz J., Loll R., Quantum gravity as sum over spacetimes, in New Paths Towards Quantum Gravity, Lecture Notes in Physics, Vol. 807, Springer, Berlin, 2010, 59-124, arXiv:0906.3947.
  18. Ambjørn J., Jurkiewicz J., Loll R., Quantum gravity, or the art of building spacetime, in Approaches to Quantum Gravity, Editor D. Oriti, Cambridge University Press, Cambridge, 2009, 341-359, hep-th/0604212.
  19. Amelino-Camelia G., Are we at the dawn of quantum-gravity phenomenology?, in Towards Quantum Gravity (Polanica, 1999), Lecture Notes in Phys., Vol. 541, Springer, Berlin, 2000, 1-49, gr-qc/9910089.
  20. Amelino-Camelia G., Quantum gravity phenomenology, arXiv:0806.0339.
  21. Anber M.M., Aydemir U., Donoghue J.F., Breaking diffeomorphism invariance and tests for the emergence of gravity, Phys. Rev. D 81 (2010), 084059, 12 pages, arXiv:0911.4123.
  22. Atkatz D., Dynamical method for generating the gravitational interaction, Phys. Rev. D 17 (1978), 1972-1976.
  23. Balasubramanian V., de Boer J., Jejjala V., Simón J., The library of Babel: on the origin of gravitational thermodynamics, J. High Energy Phys. 2005 (2005), no. 12, 006, 65 pages, hep-th/0508023.
  24. Balbinot R., Fagnocchi S., Fabbri A., Quantum effects in acoustic black holes: the backreaction, Phys. Rev. D 71 (2005), 064019, 12 pages, gr-qc/0405098.
  25. Balbinot R., Fagnocchi S., Fabbri A., Procopio G.P., Backreaction in acoustic black holes, Phys. Rev. Lett. 94 (2005), 161302, 4 pages, gr-qc/0405096.
  26. Banks T., Zaks A., Composite gauge bosons in 4-fermi theories, Nuclear Phys. B 184 (1981), 303-322.
  27. Bao D., Chern S.S., Shen Z., An introduction to Riemann-Finsler geometry, Graduate Texts in Mathematics, Vol. 200, Springer-Verlag, New York, 2000.
  28. Barbado L.C., Barceló C., Garay L.J., Jannes G., The trans-Planckian problem as a guiding principle, J. High Energy Phys. 2011 (2011), no. 11, 112, 18 pages, arXiv:1109.3593.
  29. Barceló C., Garay L.J., Jannes G., Sensitivity of Hawking radiation to superluminal dispersion relations, Phys. Rev. D 79 (2009), 024016, 13 pages, arXiv:0807.4147.
  30. Barceló C., Garay L.J., Jannes G., Two faces of quantum sound, Phys. Rev. D 82 (2010), 044042, 12 pages, arXiv:1006.0181.
  31. Barceló C., Jannes G., A real Lorentz-FitzGerald contraction, Found. Phys. 38 (2008), 191-199, arXiv:0705.4652.
  32. Barceló C., Liberati S., Visser M., Analogue gravity, Living Rev. Relativ. 14 (2011), 3, 159 pages, gr-qc/0505065.
  33. Barceló C., Liberati S., Visser M., Analogue gravity from Bose-Einstein condensates, Classical Quantum Gravity 18 (2001), 1137-1156, gr-qc/0011026.
  34. Barceló C., Liberati S., Visser M., Analogue models for FRW cosmologies, Internat. J. Modern Phys. D 12 (2003), 1641-1649, gr-qc/0305061.
  35. Barceló C., Liberati S., Visser M., Refringence, field theory and normal modes, Classical Quantum Gravity 19 (2002), 2961-2982, gr-qc/0111059.
  36. Barceló C., Visser M., Liberati S., Einstein gravity as an emergent phenomenon?, Internat. J. Modern Phys. D 10 (2001), 799-806, gr-qc/0106002.
  37. Bardeen J.M., Carter B., Hawking S.W., The four laws of black hole mechanics, Comm. Math. Phys. 31 (1973), 161-170.
  38. Bardeen J.M., Cooper L.N., Schrieffer J.R., Theory of superconductivity, Phys. Rev. 108 (1957), 1175-1204.
  39. Bekaert X., Boulanger N., Sundell P., How higher-spin gravity surpasses the spin two barrier: no-go theorems versus yes-go examples, arXiv:1007.0435.
  40. Bekenstein J.D., Black holes and entropy, Phys. Rev. D 7 (1973), 2333-2346.
  41. Belgiorno F., Cacciatori S.L., Clerici M., Gorini V., Ortenzi G., Rizzi L., Rubino E., Sala V.G., Hawking radiation from ultrashort laser pulse filaments, Phys. Rev. Lett. 105 (2010), 203901, 4 pages, arXiv:1009.4634.
  42. Benedetti D., Henson J., Imposing causality on a matrix model, Phys. Lett. B 678 (2009), 222-226, arXiv:0812.4261.
  43. Berenstein D., Large N BPS states and emergent quantum gravity, J. High Energy Phys. 2006 (2006), no. 1, 125, 58 pages, hep-th/0507203.
  44. Berezhiani Z., Kancheli O.V., Spontaneous breaking of Lorentz-invariance and gravitons as Goldstone particles, arXiv:0808.3181.
  45. Bettoni D., Liberati S., Sindoni L., Extended ΛCDM: generalized non-minimal coupling for dark matter fluids, J. Cosmol. Astropart. Phys. 2011 (2011), no. 11, 007, 17 pages, arXiv:1108.1728.
  46. Bialynicki-Birula I., Quantum electrodynamics without electromagnetic field, Phys. Rev. 130 (1963), 465-468.
  47. Bjorken J.D., A dynamical origin for the electromagnetic field, Ann. Physics 24 (1963), 174-187.
  48. Bjorken J.D., Emergent gauge bosons, hep-th/0111196.
  49. Bloch I., Dalibard J., Zwerger W., Many-body physics with ultracold gases, Rev. Modern Phys. 80 (2008), 885-964, arXiv:0704.3011.
  50. Bluhm R., Fung S.H., Kostelecký V.A., Spontaneous Lorentz and diffeomorphism violation, massive modes, and gravity, Phys. Rev. D 77 (2008), 065020, 28 pages, arXiv:0712.4119.
  51. Bluhm R., Kostelecký V.A., Spontaneous Lorentz violation, Nambu-Goldstone modes, and gravity, Phys. Rev. D 71 (2005), 065008, 17 pages, hep-th/0412320.
  52. Bombelli L., Henson J., Sorkin R.D., Discreteness without symmetry breaking: a theorem, Modern Phys. Lett. A 24 (2009), 2579-2587, gr-qc/0605006.
  53. Bombelli L., Lee J., Meyer D., Sorkin R.D., Space-time as a causal set, Phys. Rev. Lett. 59 (1987), 521-524.
  54. Born M., Wolf E., Principles of optics, Cambridge University Press, Cambridge, 1999.
  55. Brout R., Massar S., Parentani R., Spindel P., Hawking radiation without trans-Planckian frequencies, Phys. Rev. D 52 (1995), 4559-4568, hep-th/9506121.
  56. Buchbinder I.L., Odintsov S.D., Shapiro I.L., Effective action in quantum gravity, IOP Publishing Ltd., Bristol, 1992.
  57. Burgess C.P., Goldstone and pseudo-Goldstone bosons in nuclear, particle and condensed-matter physics, Phys. Rep. 330 (2000), 193-261, hep-th/9808176.
  58. Cadoni M., Mignemi S., Acoustic analogues of black hole singularities, Phys. Rev. D 72 (2005), 084012, 9 pages, gr-qc/0504143.
  59. Calzetta E.A., Hu B.L., Early universe quantum processes in BEC Collapse Experiments, Internat. J. Theoret. Phys. 44 (2005), 1691-1704, cond-mat/0503367.
  60. Caravelli F., Hamma A., Markopoulou F., Riera A., Trapped surfaces and emergent curved space in the Bose-Hubbard model, Phys. Rev. D 85 (2012), 044046, 15 pages, arXiv:1108.2013.
  61. Caravelli F., Markopoulou F., Properties of quantum graphity at low temperature, Phys. Rev. D 84 (2011), 024002, 10 pages, arXiv:1008.1340.
  62. Carlini A., Greensite J., Square-root actions, metric signature, and the path integral of quantum gravity, Phys. Rev. D 52 (1995), 6947-6964, gr-qc/9502023.
  63. Carlini A., Greensite J., Why is spacetime Lorentzian?, Phys. Rev. D 49 (1994), 866-878, gr-qc/9308012.
  64. Carroll S.M., The cosmological constant, Living Rev. Relativ. 4 (2001), 1, 80 pages, astro-ph/0004075.
  65. Carroll S.M., Tam H., Wehus I.K., Lorentz violation in Goldstone gravity, Phys. Rev. D 80 (2009), 025020, 15 pages, arXiv:0904.4680.
  66. Case K.M., Gasiorowicz S.G., Can massless particles by charged?, Phys. Rev. 125 (1962), 1055-1058.
  67. Chirco G., Eling C., Liberati S., Reversible and irreversible spacetime thermodynamics for general Brans-Dicke theories, Phys. Rev. D 83 (2011), 024032, 12 pages, arXiv:1011.1405.
  68. Chirco G., Liberati S., Nonequilibrium thermodynamics of spacetime: the role of gravitational dissipation, Phys. Rev. D 81 (2010), 024016, 13 pages, arXiv:0909.4194.
  69. Chkareuli J.L., Froggatt C.D., Nielsen H.B., Deriving gauge symmetry and spontaneous Lorentz violation, Nuclear Phys. B 821 (2009), 65-73, hep-th/0610186.
  70. Chkareuli J.L., Froggatt C.D., Nielsen H.B., Lorentz invariance and origin of symmetries, Phys. Rev. Lett. 87 (2001), 091601, 4 pages, hep-ph/0106036.
  71. Chkareuli J.L., Froggatt C.D., Nielsen H.B., Spontaneously generated gauge invariance, Nuclear Phys. B 609 (2001), 46-60, hep-ph/0103222.
  72. Chkareuli J.L., Froggatt C.D., Nielsen H.B., Spontaneously generated tensor field gravity, Nuclear Phys. B 848 (2011), 498-522, arXiv:1102.5440.
  73. Chkareuli J.L., Jejelava J.G., Tatishvili G., Graviton as a Goldstone boson: nonlinear sigma model for tensor field gravity, Phys. Lett. B 696 (2011), 124-130, arXiv:1008.3707.
  74. Cho Y.M., Freund P.G.O., Non-Abelian gauge fields as Nambu-Goldstone fields, Phys. Rev. D 12 (1975), 1711-1720.
  75. Collins J., Perez A., Sudarsky D., Urrutia L., Vucetich H., Lorentz invariance and quantum gravity: an additional fine-tuning problem?, Phys. Rev. Lett. 93 (2004), 191301, 4 pages, gr-qc/0403053.
  76. Conrady F., Space as a low-temperature regime of graphs, J. Stat. Phys. 142 (2011), 898-917, arXiv:1009.3195.
  77. Corley S., Jacobson T., Hawking spectrum and high frequency dispersion, Phys. Rev. D 54 (1996), 1568-1586, hep-th/9601073.
  78. de Mello Koch R., Geometries from Young diagrams, J. High Energy Phys. 2008 (2008), no. 11, 061, 30 pages, arXiv:0806.0685.
  79. Denardo G., Spallucci E., Curvature and symmetry breaking: an induced-action approach, Nuovo Cimento A 71 (1982), 397-408.
  80. Denardo G., Spallucci E., Curvature and torsion from matter, Classical Quantum Gravity 4 (1987), 89-99.
  81. Denardo G., Spallucci E., Finite-temperature scalar pregeometry, Nuovo Cimento A 74 (1983), 450-460.
  82. Denardo G., Spallucci E., Finite temperature spinor pregeometry, Phys. Lett. B 130 (1983), 43-46.
  83. Denardo G., Spallucci E., Induced quantum gravity from heat kernel expansion, Nuovo Cimento A 69 (1982), 151-159.
  84. Deser S., Gravity from self-interaction redux, Gen. Relativity Gravitation 42 (2010), 641-646, arXiv:0910.2975.
  85. Di Francesco P., Ginsparg P., Zinn-Justin J., 2D gravity and random matrices, Phys. Rep. 254 (1995), 133, hep-th/9306153.
  86. Distler J., Garibaldi S., There is no "theory of everything" inside E8, Comm. Math. Phys. 298 (2010), 419-436, arXiv:0905.2658.
  87. Dittrich B., Eckert F.C., Martin-Benito M., Coarse graining methods for spin net and spin foam models, New J. Phys. 14 (2012), 035008, 43 pages, arXiv:1109.4927.
  88. Dreyer O., Emergent general relativity, in Approaches to Quantum Gravity, Editor D. Oriti, Cambridge University Press, Cambridge, 2009, 99-110, gr-qc/0604075.
  89. Dreyer O., Why things fall, PoS Proc. Sci. (2007), PoS(QG-Ph), 016, 12 pages, arXiv:0710.4350.
  90. Eguchi T., New approach to collective phenomena in superconductivity models, Phys. Rev. D 14 (1976), 2755-2763.
  91. Eguchi T., Sugawara H., Extended model of elementary particles based on an analogy with superconductivity, Phys. Rev. D 10 (1974), 4257-4262.
  92. Eling C., Guedens R., Jacobson T., Nonequilibrium thermodynamics of spacetime, Phys. Rev. Lett. 96 (2006), 121301, 4 pages, gr-qc/0602001.
  93. Elitzur S., Impossibility of spontaneously breaking local symmetries, Phys. Rev. D 12 (1975), 3978-3982.
  94. Elizalde E., Odintsov S.D., Romeo A., Dynamical determination of the metric signature in spacetime of nontrivial topology, Classical Quantum Gravity 11 (1994), L61-L67, hep-th/9312132.
  95. Finazzi S., Liberati S., Sindoni L., Cosmological constant: a Lesson from Bose-Einstein condensates, Phys. Rev. Lett. 108 (2012), 071101, 5 pages, arXiv:1103.4841.
  96. Finazzi S., Parentani R., Spectral properties of acoustic black hole radiation: broadening the horizon, Phys. Rev. D 83 (2011), 084010, 13 pages, arXiv:1012.1556.
  97. Floreanini R., Percacci R., Mean-field quantum gravity, Phys. Rev. D 46 (1992), 1566-1579.
  98. Floreanini R., Percacci R., Spallucci E., Coleman-Weinberg effect in quantum gravity, Classical Quantum Gravity 8 (1991), L193-L197.
  99. Freidel L., Group field theory: an overview, Internat. J. Theoret. Phys. 44 (2005), 1769-1783, hep-th/0505016.
  100. Gambini R., Pullin J., Nonstandard optics from quantum space-time, Phys. Rev. D 59 (1999), 124021, 4 pages, gr-qc/9809038.
  101. Garay L.J., Anglin J.R., Cirac J.I., Zoller P., Sonic analog of gravitational black holes in Bose-Einstein condensates, Phys. Rev. Lett. 85 (2000), 4643-4647, gr-qc/0002015.
  102. Garay L.J., Anglin J.R., Cirac J.I., Zoller P., Sonic black holes in dilute Bose-Einstein condensates, Phys. Rev. A 63 (2001), 023611, 13 pages, gr-qc/0005131.
  103. Gherghetta T., Peloso M., Poppitz E., Emergent gravity from a mass deformation in warped spacetime, Phys. Rev. D 72 (2005), 104003, 23 pages, hep-th/0507245.
  104. Giddings S.B., Black hole information, unitarity, and nonlocality, Phys. Rev. D 74 (2006), 106005, 15 pages, hep-th/0605196.
  105. Giddings S.B., (Non)perturbative gravity, nonlocality, and nice slices, Phys. Rev. D 74 (2006), 106009, 10 pages, hep-th/0606146.
  106. Giddings S.B., Lippert M., The information paradox and the locality bound, Phys. Rev. D 69 (2004), 124019, 9 pages, hep-th/0402073.
  107. Ginsparg P., Matrix models of 2d gravity, hep-th/9112013.
  108. Girelli F., Liberati S., Sindoni L., Emergence of Lorentzian signature and scalar gravity, Phys. Rev. D 79 (2009), 044019, 9 pages, arXiv:0806.4239.
  109. Girelli F., Liberati S., Sindoni L., Gravitational dynamics in Bose-Einstein condensates, Phys. Rev. D 78 (2008), 084013, 11 pages, arXiv:0807.4910.
  110. Girelli F., Liberati S., Sindoni L., Planck-scale modified dispersion relations and Finsler geometry, Phys. Rev. D 75 (2007), 064015, 9 pages, gr-qc/0611024.
  111. Girelli F., Livine E.R., A deformed Poincaré invariance for group field theories, Classical Quantum Gravity 27 (2010), 245018, 15 pages, arXiv:1001.2919.
  112. Girelli F., Livine E.R., Oriti D., Deformed special relativity as an effective flat limit of quantum gravity, Nuclear Phys. B 708 (2005), 411-433, gr-qc/0406100.
  113. Girelli F., Livine E.R., Oriti D., Four-dimensional deformed special relativity from group field theories, Phys. Rev. D 81 (2010), 024015, 14 pages, arXiv:0903.3475.
  114. Giulini D., Remarks on the notions of general covariance and background independence, in Approaches to Fundamental Physics, Lecture Notes in Phys., Vol. 721, Springer, Berlin, 2007, 105-120, gr-qc/0603087.
  115. Greensite J., Dynamical origin of the Lorentzian signature of spacetime, Phys. Lett. B 300 (1993), 34-37, gr-qc/9210008.
  116. Groot Nibbelink S., Pospelov M., Lorentz violation in supersymmetric field theories, Phys. Rev. Lett. 94 (2005), 081601, 4 pages, hep-ph/0404271.
  117. Gu Z.C., Wen X.G., A lattice bosonic model as a quantum theory of gravity, gr-qc/0606100.
  118. Gu Z.C., Wen X.G., Emergence of helicity ±2 modes (gravitons) from qubit models, arXiv:0907.1203.
  119. Guralnik G.S., Photon as a symmetry-breaking solution to field theory. I, Phys. Rev. 136 (1964), B1404-B1416.
  120. Guralnik G.S., Photon as a symmetry-breaking solution to field theory. II, Phys. Rev. 136 (1964), B1417-B1422.
  121. Gurau R., Ryan J.P., Colored tensor models - a review, SIGMA 8 (2012), 020, 78 pages, arXiv:1109.4812.
  122. Hamma A., Markopoulou F., Lloyd S., Caravelli F., Severini S., Markstrom K., Quantum Bose-Hubbard model with an evolving graph as a toy model for emergent spacetime, Phys. Rev. D 81 (2010), 104032, 22 pages, arXiv:0911.5075.
  123. Hayward S.A., Complex lapse, complex action, and path integrals, Phys. Rev. D 53 (1996), 5664-5669, gr-qc/9511007.
  124. Hebecker A., Wetterich C., Spinor gravity, Phys. Lett. B 574 (2003), 269-275, hep-th/0307109.
  125. Hehl F.W., Obukhov Y.N., Spacetime metric from local and linear electrodynamics: a new axiomatic scheme, in Special Relativity, Lecture Notes in Physics, Vol. 702, Springer, Berlin, 2006, 163-187, gr-qc/0508024.
  126. Henson J., The causal set approach to quantum gravity, in Approaches to Quantum Gravity, Editor D. Oriti, Cambridge University Press, Cambridge, 2009, 393-413, gr-qc/0601121.
  127. Hojman S.A., Kuchar K., Teitelboim C., Geometrodynamics regained, Ann. Physics 96 (1976), 88-135.
  128. Horava P., Quantum gravity at a Lifshitz point, Phys. Rev. D 79 (2009), 084008, 15 pages, arXiv:0901.3775.
  129. Horava P., Stability of fermi surfaces and K theory, Phys. Rev. Lett. 95 (2005), 016405, 4 pages, hep-th/0503006.
  130. Horowitz G.T., Polchinski J., Gauge/gravity duality, in Approaches to Quantum Gravity, Editor D. Oriti, Cambridge University Press, Cambridge, 2009, 169-186, gr-qc/0602037.
  131. Hossenfelder S., Experimental search for quantum gravity, in Classical and Quantum Gravity: Theory, Analysis and Applications, Editor V.R. Frignanni, Nova Publishers, New York, 2011, Chapter 5, arXiv:1010.3420.
  132. Hu B.L., Can spacetime be a condensate?, Internat. J. Theoret. Phys. 44 (2005), 1785-1806, gr-qc/0503067.
  133. Hu B.L., Emergent/quantum gravity: macro/micro structures of spacetime, J. Phys. Conf. Ser. 174 (2009), 012015, 16 pages, arXiv:0903.0878.
  134. Hu B.L., General relativity as geometrohydrodynamics, gr-qc/9607070.
  135. Hu B.L., Gravity and nonequilibrium thermodynamics of classical matter, Internat. J. Modern Phys. D 20 (2011), 697-716, arXiv:1010.5837.
  136. Hubeny V.E., Minwalla S., Rangamani M., The fluid/gravity correspondence, arXiv:1107.5780.
  137. Iengo R., Russo J.G., Serone M., Renormalization group in Lifshitz-type theories, J. High Energy Phys. 2009 (2009), no. 11, 020, 25 pages, arXiv:0906.3477.
  138. Jacobson T., Thermodynamics of spacetime: the Einstein equation of state, Phys. Rev. Lett. 75 (1995), 1260-1263, gr-qc/9504004.
  139. Jannes G., Emergent gravity: the BEC paradigm, Ph.D. thesis, Universidad Complutense de Madrid, 2009, arXiv:0907.2839.
  140. Jannes G., Volovik G.E., The cosmological constant: a lesson from topological Weyl media, arXiv:1108.5086.
  141. Jenkins A., Constraints on emergent gravity, Internat. J. Modern Phys. D 18 (2009), 2249-2255, arXiv:0904.0453.
  142. Jenkins A., Topics in particle physics and cosmology beyond the standard model, Ph.D. thesis, California Institute of Technology, 2006, hep-th/0607239.
  143. Konopka T., Statistical mechanics of graphity models, Phys. Rev. D 78 (2008), 044032, 17 pages, arXiv:0805.2283.
  144. Konopka T., Markopoulou F., Severini S., Quantum graphity: a model of emergent locality, Phys. Rev. D 77 (2008), 104029, 15 pages, arXiv:0801.0861.
  145. Konopka T., Markopoulou F., Smolin L., Quantum graphity, hep-th/0611197.
  146. Kostelecký V.A., Potting R., Gravity from spontaneous Lorentz violation, Phys. Rev. D 79 (2009), 065018, 21 pages, arXiv:0901.0662.
  147. Kostelecký V.A., Tasson J.D., Matter-gravity couplings and Lorentz violation, Phys. Rev. D 83 (2011), 016013, 59 pages, arXiv:1006.4106.
  148. Kraus P., Tomboulis E.T., Photons and gravitons as Goldstone bosons and the cosmological constant, Phys. Rev. D 66 (2002), 045015, 10 pages, hep-th/0203221.
  149. Lahav O., Itah A., Blumkin A., Gordon C., Steinhauer J., Numerical observation of Hawking radiation from acoustic black holes in atomic Bose-Einstein condensates, New J. Phys. 10 (2008), 103001, 15 pages, arXiv:0803.0507.
  150. Lahav O., Itah A., Blumkin A., Gordon C., Steinhauer J., Realization of a sonic black hole analog in a Bose-Einstein condensate, Phys. Rev. Lett. 105 (2010), 240401, 4 pages, arXiv:0906.1337.
  151. Landau L.D., Lifshitz E.M., Course of theoretical physics, Vol. 7. Theory of elasticity, Pergamon Press, London, 1959.
  152. Landau L.D., Lifshitz E.M., Course of theoretical physics, Vol. 8. Electrodynamics of continuous media, Pergamon Press, Oxford, 1960.
  153. Laugwitz D., Differential and Riemannian geometry, Academic Press, New York, 1965.
  154. Levin M., Wen X.G., Colloquium: Photons and electrons as emergent phenomena, Rev. Modern Phys. 77 (2005), 871-879, cond-mat/0407140.
  155. Levin M., Wen X.G., Fermions, strings, and gauge fields in lattice spin models, Phys. Rev. B 67 (2003), 245316, 10 pages, cond-mat/0302460.
  156. Levin M., Wen X.G., Quantum ether: photons and electrons from a rotor model, Phys. Rev. B 73 (2006), 035122, 10 pages, hep-th/0507118.
  157. Lewenstein M., Sanpera A., Ahufinger V., Damski B., Sen De A., Sen U., Ultracold atomic gases in optical lattices: mimicking condensed matter physics and beyond, Adv. Phys. 56 (2007), 243-379, cond-mat/0606771.
  158. Liberati S., Maccione L., Quantum gravity phenomenology: achievements and challenges, J. Phys. Conf. Ser. 314 (2011), 012007, 10 pages, arXiv:1105.6234.
  159. Liberati S., Sindoni L., Sonego S., Linking the trans-Planckian and information loss problems in black hole physics, Gen. Relativity Gravitation 42 (2010), 1139-1152, arXiv:0904.0815.
  160. Liberati S., Visser M., Weinfurtner S., Analogue quantum gravity phenomenology from a two-component Bose-Einstein condensate, Classical Quantum Gravity 23 (2006), 3129-3154, gr-qc/0510125.
  161. Lin H., Lunin O., Maldacena J., Bubbling AdS space and 1/2 BPS geometries, J. High Energy Phys. 2004 (2004), no. 10, 025, 68 pages, hep-th/0409174.
  162. Loebbert F., The Weinberg-Witten theorem on massless particles: an essay, Ann. Phys. 17 (2008), 803-829.
  163. Markopoulou F., Smolin L., Disordered locality in loop quantum gravity states, Classical Quantum Gravity 24 (2007), 3813-3823, gr-qc/0702044.
  164. Mathur S.D., The information paradox: a pedagogical introduction, Classical Quantum Gravity 26 (2009), 224001, 31 pages, arXiv:0909.1038.
  165. Mattingly D., Have we tested Lorentz invariance enough?, PoS Proc. Sci. (2007), PoS(QG-Ph), 026, 17 pages, arXiv:0802.1561.
  166. Nambu Y., Jona-Lasinio G., Dynamical model of elementary particles based on an analogy with superconductivity. I, Phys. Rev. 122 (1961), 345-358.
  167. Nambu Y., Jona-Lasinio G., Dynamical model of elementary particles based on an analogy with superconductivity. II, Phys. Rev. 124 (1961), 246-254.
  168. >Ohanian H.C., Gravitons as Goldstone bosons, Phys. Rev. 184 (1969), 1305-1312.
  169. O'Raifeartaigh L., Hidden gauge symmetry, Rep. Progr. Phys. 42 (1979), 159-223.
  170. Oriti D., Group field theory as the microscopic description of the quantum spacetime fluid: a new perspective on the continuum in quantum gravity, PoS Proc. Sci. (2007), PoS(QG-Ph), 030, 38 pages, arXiv:0710.3276.
  171. Oriti D., On the depth of quantum space, arXiv:1107.4534.
  172. Oriti D., The group field theory approach to quantum gravity, in Approaches to Quantum Gravity, Editor D. Oriti, Cambridge University Press, Cambridge, 2009, 310-331, gr-qc/0607032.
  173. Oriti D., The microscopic dynamics of quantum space as a group field theory, arXiv:1110.5606.
  174. Oriti D., Sindoni L., Towards classical geometrodynamics from group field theory hydrodynamics, New J. Phys. 13 (2011), 025006, 44 pages, arXiv:1010.5149.
  175. Padmanabhan T., Cosmological constant - the weight of the vacuum, Phys. Rep. 380 (2003), 235-320, hep-th/0212290.
  176. Padmanabhan T., Gravity and the thermodynamics of horizons, Phys. Rep. 406 (2005), 49-125, gr-qc/0311036.
  177. Padmanabhan T., Thermodynamical aspects of gravity: new insights, Rep. Progr. Phys. 73 (2010), 046901, 44 pages, arXiv:0911.5004.
  178. Padmanabhan T., Vacuum fluctuations of energy density can lead to the observed cosmological constant, Classical Quantum Gravity 22 (2005), L107-L112, hep-th/0406060.
  179. Percacci R., The Higgs phenomenon in quantum gravity, Nuclear Phys. B 353 (1991), 271-290, arXiv:0712.3545.
  180. Percacci R., Vacca G.P., Asymptotic safety, emergence and minimal length, Classical Quantum Gravity 27 (2010), 245026, 16 pages, arXiv:1008.3621.
  181. Perez A., Spin foam models for quantum gravity, Classical Quantum Gravity 20 (2003), R43-R104, gr-qc/0301113.
  182. Pethick C.J., Smith H., Bose-Einstein condensation in dilute gases, 2nd ed., Cambridge University Press, Cambridge, 2008.
  183. Phillips P.R., Is the graviton a Goldstone boson?, Phys. Rev. 166 (1964), 966-973.
  184. Polchinski J., String theory. Vol. I. An introduction to the bosonic string, Cambridge Monographs on Mathematical Physics, Cambridge University Press, Cambridge, 1998.
  185. Prain A., Fagnocchi S., Liberati S., Analogue cosmological particle creation: quantum correlations in expanding Bose-Einstein condensates, Phys. Rev. D 82 (2010), 105018, 18 pages, arXiv:1009.0647.
  186. Prescod-Weinstein C., Smolin L., Disordered locality as an explanation for the dark energy, Phys. Rev. D 80 (2009), 063505, 5 pages, arXiv:0903.5303.
  187. Punzi R., Schuller F.P., Wohlfarth M.N.R., Area metric gravity and accelerating cosmology, J. High Energy Phys. 2007 (2007), no. 2, 030, 44 pages, hep-th/0612141.
  188. Punzi R., Schuller F.P., Wohlfarth M.N.R., Massive motion in area metric spacetimes, Phys. Rev. D 79 (2009), 124025, 8 pages.
  189. Rätzel D., Rivera S., Schuller F.P., Geometry of physical dispersion relations, Phys. Rev. D 83 (2011), 044047, 23 pages, arXiv:1010.1369.
  190. Rey A.M., Hu B.L., Calzetta E., Roura A., Clark C.W., Nonequilibrium dynamics of optical-lattice-loaded Bose-Einstein-condensate atoms: beyond the Hartree-Fock-Bogoliubov approximation, Phys. Rev. A 69 (2004), 033610, 21 pages, cond-mat/0308305.
  191. Rovelli C., Quantum gravity, Cambridge Monographs on Mathematical Physics, Cambridge University Press, Cambridge, 2004.
  192. Rund H., The differential geometry of Finsler spaces, Die Grundlehren der Mathematischen Wissenschaften, Bd. 101, Springer-Verlag, Berlin, 1959.
  193. Sakharov A.D., Vacuum quantum fluctuations in curved space and the theory of gravitation, Gen. Relativity Gravitation 32 (2000), 365-367 (Translated from Dokl. Akad. Nauk 1 (1967), no. 1, 70-71).
  194. Schrödinger E., Space-time structure, Cambridge University Press, Cambridge, 1950.
  195. Seiberg N., Emergent spacetime, hep-th/0601234.
  196. Sindoni L., Emergent gravitational dynamics from multi-Bose-Einstein-condensate hydrodynamics?, Phys. Rev. D 83 (2011), 024022, 18 pages, arXiv:1011.4411.
  197. Sindoni L., Emergent gravity: the analogue models perspective, Ph.D. thesis, SISSA, Trieste, Italy, 2009.
  198. Sindoni L., Gravity as an emergent phenomenon: a GFT perspective, arXiv:1105.5687.
  199. Sindoni L., Girelli F., Liberati S., Emergent gravitational dynamics in Bose-Einstein condensates, AIP Conf. Proc. 1196 (2009), 258-265, arXiv:0909.5391.
  200. Skákala J., Aspects of general relativity: pseudo-Finsler extensions, quasi-normal frequencies and multiplication of tensorial distributions, Ph.D. thesis, Victoria University of Wellington, 2011, arXiv:1107.2978.
  201. Skákala J., Visser M., Bi-metric pseudo-Finslerian spacetimes, J. Geom. Phys. 61 (2011), 1396-1400, arXiv:1008.0689.
  202. Skákala J., Visser M., Birefringence in pseudo-Finsler spacetimes, J. Phys. Conf. Ser. 189 (2009), 012037, 8 pages, arXiv:0810.4376.
  203. Skákala J., Visser M., Pseudo-Finslerian space-times and multirefringence, Internat. J. Modern Phys. D 19 (2010), 1119-1146, arXiv:0806.0950.
  204. Skákala J., Visser M., The causal structure of spacetime is a parameterized Randers geometry, Classical Quantum Gravity 28 (2011), 065007, 7 pages, arXiv:1012.4467.
  205. Sorkin R.D., Does locality fail at intermediate length-scales, in Approaches to Quantum Gravity, Editor D. Oriti, Cambridge University Press, Cambridge, 2009, 26-43, gr-qc/0703099.
  206. Sorkin R.D., Is the cosmological "constant" a nonlocal quantum residue of discreteness of the causal set type?, AIP Conf. Proc. 957 (2007), 142-153, arXiv:0710.1675.
  207. Steinacker H., Non-commutative geometry and matrix models, arXiv:1109.5521.
  208. Struyve W., Gauge invariant accounts of the Higgs mechanism, Stud. Hist. Philos. Sci. B Stud. Hist. Philos. Modern Phys. 42 (2011), 226-236, arXiv:1102.0468.
  209. Szpak N., Schutzhold R., Optical lattice quantum simulator for quantum electrodynamics in strong external fields: spontaneous pair creation and the Sauter–-Schwinger effect, New J. Phys. 14 (2012), 035001, 23 pages, arXiv:1109.2426.
  210. Szpak N., Schutzhold R., Quantum simulator for the Schwinger effect with atoms in bichromatic optical lattices, Phys. Rev. A 84 (2011), 050101(R), 4 pages, arXiv:1103.0541.
  211. Terazawa H., Various actions for pregeometry, Progr. Theoret. Phys. 86 (1991), 337-342.
  212. Terazawa H., Akama K., Dynamical subquark model of pregauge and pregeometric interactions, Phys. Lett. B 96 (1980), 276–-278.
  213. Terazawa H., Akama K., Chikashige Y., What are the gauge bosons made of?, Progr. Theoret. Phys. 56 (1976), 1935-1938.
  214. Terazawa H., Chikashige Y., Akama K., Unified model of the Nambu-Jona-Lasinio type for all elementary particle forces, Phys. Rev. D 15 (1977), 480-487.
  215. Ueda M., Kawaguchi Y., Spinor Bose-Einstein condensates, arXiv:1001.2072.
  216. Unruh W.G., Experimental black-hole evaporation?, Phys. Rev. Lett. 46 (1981), 1351-1353.
  217. Unruh W.G., Sonic analogue of black holes and the effects of high frequencies on black hole evaporation, Phys. Rev. D 51 (1995), 2827-2838.
  218. Unruh W.G., Schützhold R., Universality of the Hawking effect, Phys. Rev. D 71 (2005), 024028, 11 pages, gr-qc/0408009.
  219. Vacaru S., Stavrinos P., Gaburov E., Gon ta D., Clifford and Riemann-Finsler structures in geometric mechanics and gravity, DGDS. Differential Geometry - Dynamical Systems. Monographs, Vol. 7, Geometry Balkan Press, Bucharest, 2006, gr-qc/0508023.
  220. Verlinde E., On the origin of gravity and the laws of Newton, J. High Energy Phys. 2011 (2011), no. 4, 029, 27 pages, arXiv:1001.0785.
  221. Visser M., Acoustic propagation in fluids: an unexpected example of Lorentzian geometry, gr-qc/9311028.
  222. Visser M., Sakharov's induced gravity: a modern perspective, Modern Phys. Lett. A 17 (2002), 977-991, gr-qc/0204062.
  223. Visser M., Barceló C., Liberati S., Analogue models of and for gravity, Gen. Relativity Gravitation 34 (2002), 1719-1734, gr-qc/0111111.
  224. Volovik G.E., Cosmological constant and vacuum energy, Ann. Phys. 14 (2005), 165-176, gr-qc/0405012.
  225. Volovik G.E., Emergent physics: Fermi-point scenario, Philos. Trans. R. Soc. Lond. Ser. A Math. Phys. Eng. Sci. 366 (2008), 2935-2951, arXiv:0801.0724.
  226. Volovik G.E., Emergent physics on vacuum energy and cosmological constant, AIP Conf. Proc. 850 (2006), 26-33, cond-mat/0507454.
  227. Volovik G.E., Quantum phase transitions from topology in momentum space, in Quantum Analogues: from Phase Transitions to Black Holes and Cosmology, Lecture Notes in Phys., Vol. 718, Springer, Berlin, 2007, 31-73, cond-mat/0601372.
  228. Volovik G.E., Superfluid analogies of cosmological phenomena, Phys. Rep. 351 (2001), 195-348, gr-qc/0005091.
  229. Volovik G.E., The universe in a helium droplet, International Series of Monographs on Physics, Vol. 117, The Clarendon Press, Oxford University Press, New York, 2003.
  230. Volovik G.E., Vacuum energy: quantum hydrodynamics versus quantum gravity, JETP Lett. 82 (2005), 319-324, gr-qc/0505104.
  231. Weinberg S., Photons and gravitons in S-matrix theory: derivation of charge conservation and equality of gravitational and inertial mass, Phys. Rev. 135 (1964), B1049-B1056.
  232. Weinberg S., The cosmological constant problem, Rev. Modern Phys. 61 (1989), 1-23.
  233. Weinberg S., The quantum theory of fields. Vol. 1. Foundations, Cambridge University Press, Cambridge, 1995.
  234. Weinberg S., Witten E., Limits of massless particles, Phys. Lett. B 96 (1980), 59-62.
  235. Weinfurtner S., Jain P., Visser M., Gardiner C.W., Cosmological particle production in emergent rainbow spacetimes, Classical Quantum Gravity 26 (2009), 065012, 49 pages, arXiv:0801.2673.
  236. Weinfurtner S., Liberati S., Visser M., Analogue space-time based on 2-component Bose-Einstein condensates, in Quantum Analogues: from Phase Transitions to Black Holes and Cosmology, Lecture Notes in Phys., Vol. 718, Springer, Berlin, 2007, 115-163, gr-qc/0605121.
  237. Weinfurtner S., Tedford E.W., Penrice M.C.J., Unruh W.G., Lawrence G.A., Measurement of stimulated Hawking emission in an analogue system, Phys. Rev. Lett. 106 (2011), 021302, 4 pages, arXiv:1008.1911.
  238. Weinfurtner S., White A., Visser M., Trans-Planckian physics and signature change events in Bose gas hydrodynamics, Phys. Rev. D 76 (2007), 124008, 19 pages, gr-qc/0703117.
  239. Wen X.G., Quantum field theory of many-body systems: from the origin of sound to an origin of light and electrons, Oxford University Press, Oxford, 2004.
  240. Wen X.G., Quantum order from string-net condensations and the origin of light and massless fermions, Phys. Rev. D 68 (2003), 065003, 25 pages, hep-th/0302201.
  241. Wetterich C., Gravity from spinors, Phys. Rev. D 70 (2004), 105004, 21 pages, hep-th/0307145.
  242. Wetterich C., Lattice spinor gravity, Phys. Lett. B 704 (2011), 612-619, arXiv:1108.1313.
  243. Wetterich C., Spontaneous symmetry breaking origin for the difference between time and space, Phys. Rev. Lett. 94 (2005), 011602, 4 pages.
  244. Yoshimoto S., Spinor pregeometry at finite temperature, Progr. Theoret. Phys. 78 (1987), 435-439.
  245. Zee A., Broken-symmetric theory of gravity, Phys. Rev. Lett. 42 (1979), 417–-421.
  246. Zee A., Spontaneously generated gravity, Phys. Rev. D 23 (1981), 858-866.

Previous article  Next article   Contents of Volume 8 (2012)