L'application de l'approche des ensembles causaux au problème de la gravitation quantique est basée sur l'hypothèse que l'espace-temps est fondamentalement discret. Le caractère discret de l'espace-temps ouvre la voie à de nouveaux types de lois dynamiques pour la cosmologie, et les modèles de croissance séquentielle classique (CSG) de Rideout et Sorkin constituent une classe intéressante de lois de ce type. Il a été démontré qu'une renormalisation des paramètres dynamiques du modèle CSG survient à chaque fois que l'univers subit un rebond de Big Crunch–Big Bang. Nous proposons dans cet article un moyen de modéliser la création d'un nouvel univers après la singularité d'un trou noir. Nous montrons que la renormalisation des paramètres dynamiques se produit dans un modèle CSG après un tel événement de création. Nous spéculons sur le fait que cela pourrait réaliser certains aspects de la sélection naturelle cosmologique proposée par Smolin.
The causal set approach to the problem of quantum gravity is based on the hypothesis that spacetime is fundamentally discrete. Spacetime discreteness opens the door to novel types of dynamical law for cosmology and the Classical Sequential Growth (CSG) models of Rideout and Sorkin form an interesting class of such laws. It has been shown that a renormalisation of the dynamical parameters of a CSG model occurs whenever the universe undergoes a Big Crunch–Big Bang bounce. In this paper we propose a way to model the creation of a new universe after the singularity of a black hole. We show that renormalisation of dynamical parameters occurs in a CSG model after such a creation event. We speculate that this could realise aspects of Smolin's Cosmological Natural Selection proposal.
Mot clés : Gravitation quantique, Ensembles causaux, Cosmologie
Fay Dowker 1 ; Stav Zalel 1
@article{CRPHYS_2017__18_3-4_246_0, author = {Fay Dowker and Stav Zalel}, title = {Evolution of universes in causal set cosmology}, journal = {Comptes Rendus. Physique}, pages = {246--253}, publisher = {Elsevier}, volume = {18}, number = {3-4}, year = {2017}, doi = {10.1016/j.crhy.2017.03.002}, language = {en}, }
Fay Dowker; Stav Zalel. Evolution of universes in causal set cosmology. Comptes Rendus. Physique, Volume 18 (2017) no. 3-4, pp. 246-253. doi : 10.1016/j.crhy.2017.03.002. https://comptes-rendus.academie-sciences.fr/physique/articles/10.1016/j.crhy.2017.03.002/
[1] Rūmī: Poet and Mystic (1207–1273), George Allen and Unwin Ltd., London, 1950
[2] Space–time as a causal set, Phys. Rev. Lett., Volume 59 (1987), p. 521 http://inspirehep.net/record/21718
[3] First steps with causal sets, Capri, Italy, September 1990 (R. Cianci; R. de Ritis; M. Francaviglia; G. Marmo; C. Rubano; P. Scudellaro, eds.), World Scientific, Singapore (1991), pp. 68-90 www.perimeterinstitute.ca/personal/rsorkin/some.papers/65.capri.pdf
[4] Space-time and causal sets, Cocoyoc, Mexico, December 1990 (J.C. D'Olivo; E. Nahmad-Achar; M. Rosenbaum; M.P. Ryan; L.F. Urrutia; F. Zertuche, eds.), World Scientific, Singapore (1991), pp. 150-173 www.perimeterinstitute.ca/personal/rsorkin/some.papers/66.cocoyoc.pdf
[5] Techniques of Differential Topology in Relativity, SIAM, Philadelphia, PA, USA, 1972
[6] A new topology for curved space–time which incorporates the causal, differential, and conformal structures, J. Math. Phys., Volume 17 (1976), pp. 174-181
[7] The Large Scale Structure of Space–Time, Cambridge University Press, Cambridge, UK, 1973
[8] Evidence for a continuum limit in causal set dynamics, Phys. Rev. D, Volume 63 (2001) | arXiv | DOI
[9] J. Myrheim, Statistical geometry, CERN preprint TH-2538, 1978.
[10] Quantum gravity: a fundamental problem and some radical ideas (M. Levy; S. Deser, eds.), Recent Developments in Gravitation, Proceedings of the 1978 Cargese Summer Institute, Plenum, New York, 1979
[11] Discrete quantum gravity and causal sets, Can. J. Phys., Volume 79 (2001), pp. 1-16
[12] Causal sets as discrete spacetime, Contemp. Phys., Volume 47 (2006) no. 1, pp. 1-9
[13] Forks in the road, on the way to quantum gravity, Int. J. Theor. Phys., Volume 36 (1997), pp. 2759-2781 | arXiv
[14] Everpresent lambda, Phys. Rev. D, Volume 69 (2004) | arXiv
[15] Everpresent lambda – II: structural stability, Phys. Rev. D, Volume 87 (2013) | arXiv | DOI
[16] A strong constraint on ever-present lambda, Phys. Rev. D, Volume 75 (2007) | arXiv | DOI
[17] The cosmic microwave background in a causal set universe, Phys. Rev. D, Volume 77 (2008) | arXiv | DOI
[18] et al. Quasar-Lyman α forest cross-correlation from BOSS DR11: baryon acoustic oscillations, J. Cosmol. Astropart. Phys., Volume 1405 (2014) | arXiv | DOI
[19] et al. Baryon acoustic oscillations in the forest of BOSS DR11 quasars, Astron. Astrophys., Volume 574 (2015) | arXiv | DOI
[20] Did the universe evolve?, Class. Quantum Gravity, Volume 9 (1992) no. 1, pp. 173-191
[21] Causal Sets: Discrete Gravity (Notes for the Valdivia summer school) | arXiv
[22] Classical sequential growth dynamics for causal sets, Phys. Rev. D, Volume 61 (1999)
[23] Indications of causal set cosmology, Int. J. Theor. Phys., Volume 39 (2000), pp. 1731-1736 | arXiv | DOI
[24] Linear extensions of a random partial order, Ann. Appl. Probab., Volume 4 (1994) no. 1, pp. 108-123
[25] G. Brightwell, Talk at ‘Causets at DIAS II,’ Dublin Institute for Advanced Study, Dublin, Ireland, 14–18 December 2009.
[26] On the ‘renormalization’ transformations induced by cycles of expansion and contraction in causal set cosmology, Phys. Rev. D, Volume 63 (2001) | arXiv
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