Short description: Several theories in particle physics and cosmology related to superstring theory and M-theory String theory Fundamental objects * String * Brane * D-brane Perturbative theory * Bosonic * Superstring * Type I * Type II (IIA / IIB) * Heterotic (SO(32) * E8×E8) Non-perturbative results * S-duality * T-duality * U-duality * M-theory * F-theory * AdS/CFT correspondence Phenomenology * Phenomenology * Cosmology * Landscape Mathematics * Mirror symmetry * Monstrous moonshine Related concepts * Theory of everything * Conformal field theory * Quantum gravity * Supersymmetry * Supergravity * Twistor string theory * N = 4 supersymmetric Yang–Mills theory * Kaluza–Klein theory * Multiverse * Holographic principle Theorists * Aganagić * Arkani-Hamed * Atiyah * Banks * Berenstein * Bousso * Cleaver * Curtright * Dijkgraaf * Distler * Douglas * Duff * Ferrara * Fischler * Friedan * Gates * Gliozzi * Gopakumar * Green * Greene * Gross * Gubser * Gukov * Guth * Hanson * Harvey * Hořava * Gibbons * Kachru * Kaku * Kallosh * Kaluza * Kapustin * Klebanov * Knizhnik * Kontsevich * Klein * Linde * Maldacena * Mandelstam * Marolf * Martinec * Minwalla * Moore * Motl * Mukhi * Myers * Nanopoulos * Naqvi * Năstase * Nekrasov * Neveu * Nielsen * van Nieuwenhuizen * Novikov * Olive * Ooguri * Ovrut * Polchinski * Polyakov * Rajaraman * Ramond * Randall * Randjbar-Daemi * Roček * Rohm * Scherk * Schwarz * Seiberg * Sen * Shenker * Siegel * Silverstein * Sơn * Staudacher * Steinhardt * Strominger * Sundrum * Susskind * 't Hooft * Townsend * Trivedi * Turok * Vafa * Veneziano * Verlinde * Verlinde * Wess * Witten * Yau * Yoneya * Zamolodchikov * Zamolodchikov * Zaslow * Zumino * Zwiebach * History * Glossary * v * t * e Part of a series on Physical cosmology * Big Bang · Universe * Age of the universe * Chronology of the universe Early universe * Planck epoch * Grand unification epoch * Electroweak epoch * Quark epoch * Hadron epoch * Lepton epoch * Photon epoch * Big Bang nucleosynthesis * Inflation * Dark Ages Backgrounds * Cosmic background radiation (CBR) * Gravitational wave background (GWB) * Cosmic microwave background (CMB) · Cosmic neutrino background (CNB) * Cosmic infrared background (INB) Expansion · Future * Hubble's law · Redshift * Expansion of the universe * Accelerating expansion of the universe * Comoving and proper distances * FLRW metric · Friedmann equations * Inhomogeneous cosmology * Future of an expanding universe * Ultimate fate of the universe * Heat death of the universe * Big Rip * Big Crunch * Big Bounce Components · Structure | Components * Lambda-CDM model * Baryonic matter * Energy * Radiation * Dark energy * Quintessence * Phantom energy * Dark matter * Cold dark matter * Warm dark matter * Hot dark matter * Dark radiation Structure * Shape of the universe * Reionization · Structure formation * Galaxy formation * Large-scale structure * Large quasar group * Galaxy filament * Supercluster * Galaxy cluster * Galaxy group * Local Group * Galaxy * Dark matter halo * Star cluster * Solar system * Planetary system * Void Experiments * BOOMERanG * Cosmic Background Explorer (COBE) * Dark Energy Survey * Euclid * Illustris project * Large Synoptic Survey Telescope * Planck space observatory * Sloan Digital Sky Survey (SDSS) * 2dF Galaxy Redshift Survey ("2dF") * UniverseMachine * Wilkinson Microwave Anisotropy Probe (WMAP) * Scientists * Aaronson * Alfvén * Alpher * Bharadwaj * Copernicus * de Sitter * Dicke * Eddington * Ehlers * Einstein * Ellis * Friedman * Galileo * Gamow * Guth * Hubble * Lemaître * Linde * Mather * Newton * Penzias * Rubin * Schmidt * Schwarzschild * Smoot * Starobinsky * Steinhardt * Suntzeff * Sunyaev * Tolman * Wilson * Zeldovich Subject history * Discovery of cosmic microwave background radiation * History of the Big Bang theory * Religious interpretations of the Big Bang theory * Timeline of cosmological theories * Category * v * t * e Brane cosmology refers to several theories in particle physics and cosmology related to string theory, superstring theory and M-theory. ## Contents * 1 Brane and bulk * 2 Why gravity is weak and the cosmological constant is small * 3 Models of brane cosmology * 4 Empirical tests * 5 See also * 6 References * 7 External links ## Brane and bulk Main page: Physics:Brane The central idea is that the visible, three-dimensional universe is restricted to a brane inside a higher-dimensional space, called the "bulk" (also known as "hyperspace"). If the additional dimensions are compact, then the observed universe contains the extra dimension, and then no reference to the bulk is appropriate. In the bulk model, at least some of the extra dimensions are extensive (possibly infinite), and other branes may be moving through this bulk. Interactions with the bulk, and possibly with other branes, can influence our brane and thus introduce effects not seen in more standard cosmological models. ## Why gravity is weak and the cosmological constant is small Some versions of brane cosmology, based on the large extra dimension idea, can explain the weakness of gravity relative to the other fundamental forces of nature, thus solving the hierarchy problem. In the brane picture, the electromagnetic, weak and strong nuclear force are localized on the brane, but gravity has no such constraint and propagates on the full spacetime, called bulk. Much of the gravitational attractive power "leaks" into the bulk. As a consequence, the force of gravity should appear significantly stronger on small (subatomic or at least sub-millimetre) scales, where less gravitational force has "leaked". Various experiments are currently under way to test this.[1] Extensions of the large extra dimension idea with supersymmetry in the bulk appears to be promising in addressing the so-called cosmological constant problem.[2][3][4] ## Models of brane cosmology One of the earliest documented attempts to apply brane cosmology as part of a conceptual theory is dated to 1983.[5] The authors discussed the possibility that the Universe has [math]\displaystyle{ (3+N)+1 }[/math] dimensions, but ordinary particles are confined in a potential well which is narrow along [math]\displaystyle{ N }[/math] spatial directions and flat along three others, and proposed a particular five-dimensional model. In 1998/99 Merab Gogberashvili published on arXiv a number of articles where he showed that if the Universe is considered as a thin shell (a mathematical synonym for "brane") expanding in 5-dimensional space then there is a possibility to obtain one scale for particle theory corresponding to the 5-dimensional cosmological constant and Universe thickness, and thus to solve the hierarchy problem.[6][7] Gogberashvili also showed that the four-dimensionality of the Universe is the result of the stability requirement found in mathematics since the extra component of the Einstein field equations giving the confined solution for matter fields coincides with one of the conditions of stability.[8] In 1999 there were proposed the closely related Randall–Sundrum scenarios, RS1 and RS2. (See Randall–Sundrum model for a nontechnical explanation of RS1). These particular models of brane cosmology have attracted a considerable amount of attention. For instance, the related Chung-Freese model, which has applications for spacetime metric engineering, followed in 2000.[9] Later, the pre-big bang, ekpyrotic and cyclic proposals appeared. The ekpyrotic theory hypothesizes that the origin of the observable universe occurred when two parallel branes collided.[10] ## Empirical tests As of now, no experimental or observational evidence of large extra dimensions, as required by the Randall–Sundrum models, has been reported. An analysis of results from the Large Hadron Collider in December 2010 severely constrains the black holes produced in theories with large extra dimensions.[11] The recent multi-messenger gravitational wave event GW170817 has also been used to put weak limits on large extra dimensions.[12][13] ## See also * Kaluza–Klein theory * Loop quantum cosmology ## References 1. ↑ "Session D9 - Experimental Tests of Short Range Gravitation.". https://flux.aps.org/meetings/YR04/APR04/baps/abs/S690.html. 2. ↑ Aghababaie, Y.; Burgess, C.P.; Parameswaran, S.L.; Quevedo, F. (March 2004). "Towards a naturally small cosmological constant from branes in 6-D supergravity". Nucl. Phys. B 680 (1–3): 389–414. doi:10.1016/j.nuclphysb.2003.12.015. Bibcode: 2004NuPhB.680..389A. 3. ↑ Burgess, C.P.; Leo van Nierop (March 2013). "Technically Natural Cosmological Constant From Supersymmetric 6D Brane Backreaction". Phys. Dark Univ. 2 (1): 1–16. doi:10.1016/j.dark.2012.10.001. Bibcode: 2013PDU.....2....1B. 4. ↑ P. Burgess, C.; van Nierop, L.; Parameswaran, S.; Salvio, A.; Williams, M. (February 2013). "Accidental SUSY: Enhanced Bulk Supersymmetry from Brane Back-reaction". JHEP 2013 (2): 120. doi:10.1007/JHEP02(2013)120. Bibcode: 2013JHEP...02..120B. http://inspirehep.net/record/1191922. 5. ↑ Rubakov, V. A.; Shaposhnikov, M. E. (1983). "Do we live inside a domain wall?". Physics Letters. B 125 (2–3): 136–138. doi:10.1016/0370-2693(83)91253-4. Bibcode: 1983PhLB..125..136R. 6. ↑ Gogberashvili, M. (1998). "Hierarchy problem in the shell universe model". International Journal of Modern Physics D 11 (10): 1635–1638. doi:10.1142/S0218271802002992. 7. ↑ Gogberashvili, M. (2000). "Our world as an expanding shell". Europhysics Letters 49 (3): 396–399. doi:10.1209/epl/i2000-00162-1. Bibcode: 2000EL.....49..396G. 8. ↑ Gogberashvili, M. (1999). "Four dimensionality in noncompact Kaluza–Klein model". Modern Physics Letters A 14 (29): 2025–2031. doi:10.1142/S021773239900208X. Bibcode: 1999MPLA...14.2025G. 9. ↑ Chung, Daniel J. H.; Freese, Katherine (2000-08-25). "Can geodesics in extra dimensions solve the cosmological horizon problem?". Physical Review D 62 (6): 063513. doi:10.1103/physrevd.62.063513. ISSN 0556-2821. Bibcode: 2000PhRvD..62f3513C. 10. ↑ Musser, George; Minkel, JR (2002-02-11). "A Recycled Universe: Crashing branes and cosmic acceleration may power an infinite cycle in which our universe is but a phase". Scientific American Inc.. http://www.sciam.com/article.cfm?id=a-recycled-universe. 11. ↑ Khachatryan, V. et al. (2011). "Search for Microscopic Black Hole Signatures at the Large Hadron Collider". Physics Letters B 697 (5): 434–453. doi:10.1016/j.physletb.2011.02.032. Bibcode: 2011PhLB..697..434C. 12. ↑ Visinelli, Luca; Nadia Bolis; Sunny Vagnozzi (March 2018). "Brane-world extra dimensions in light of GW170817". Phys. Rev. D 97 (6): 064039. doi:10.1103/PhysRevD.97.064039. Bibcode: 2018PhRvD..97f4039V. 13. ↑ Freeland, Emily (2018-09-21). "Hunting for extra dimensions with gravitational waves". The Oskar Klein Centre for Cosmoparticle Physics blog. https://ssl.fysik.su.se/okc/internal/blog/hunting-for-extra-dimensions-with-gravitational-waves/. ## External links * Brane cosmology on arxiv.org * Brax, Philippe; van de Bruck, Carsten (2003). "Cosmology and Brane Worlds: A Review". Classical and Quantum Gravity 20 (9): R201–R232. doi:10.1088/0264-9381/20/9/202. Bibcode: 2003CQGra..20R.201B. – Cosmological consequences of the brane world scenario are reviewed in a pedagogical manner. * Dimensional Shortcuts - evidence for sterile neutrino; (August 2007; Scientific American) * Langlois, David (2003). "Brane cosmology: an introduction". Progress of Theoretical Physics Supplement 148: 181–212. doi:10.1143/PTPS.148.181. Bibcode: 2002PThPS.148..181L. – These notes (32 pages) give an introductory review on brane cosmology. * Papantonopoulos, Eleftherios (2002). "Brane Cosmology". Cosmological Crossroads. Lecture Notes in Physics. 592. pp. 458–477. doi:10.1007/3-540-48025-0_15. ISBN 978-3-540-43778-9. Bibcode: 2002LNP...592..458P. – Lectures (24 pages) presented at the First Aegean Summer School on Cosmology, Samos, September 2001. * v * t * e String theory Background| * Strings * History of string theory * First superstring revolution * Second superstring revolution * String theory landscape Theory| * Nambu–Goto action * Polyakov action * Bosonic string theory * Superstring theory * Type I string * Type II string * Type IIA string * Type IIB string * Heterotic string * N=2 superstring * F-theory * String field theory * Matrix string theory * Non-critical string theory * Non-linear sigma model * Tachyon condensation * RNS formalism * GS formalism String duality| * T-duality * S-duality * U-duality * Montonen–Olive duality Particles and fields| * Graviton * Dilaton * Tachyon * Ramond–Ramond field * Kalb–Ramond field * Magnetic monopole * Dual graviton * Dual photon Branes| * D-brane * NS5-brane * M2-brane * M5-brane * S-brane * Black brane * Black holes * Black string * Brane cosmology * Quiver diagram * Hanany–Witten transition Conformal field theory| * Virasoro algebra * Mirror symmetry * Conformal anomaly * Conformal algebra * Superconformal algebra * Vertex operator algebra * Loop algebra * Kac–Moody algebra * Wess–Zumino–Witten model Gauge theory| * Anomalies * Instantons * Chern–Simons form * Bogomol'nyi–Prasad–Sommerfield bound * Exceptional Lie groups (G2, F4, E6, E7, E8) * ADE classification * Dirac string * p-form electrodynamics Geometry| * Kaluza–Klein theory * Compactification * Why 10 dimensions? * Kähler manifold * Ricci-flat manifold * Calabi–Yau manifold * Hyperkähler manifold * K3 surface * G2 manifold * Spin(7)-manifold * Generalized complex manifold * Orbifold * Conifold * Orientifold * Moduli space * Hořava–Witten domain wall * K-theory * Twisted K-theory Supersymmetry| * Supergravity * Superspace * Lie superalgebra * Lie supergroup Holography| * Holographic principle * AdS/CFT correspondence M-theory| * Matrix theory * Introduction to M-theory String theorists| * Aganagić * Arkani-Hamed * Atiyah * Banks * Berenstein * Bousso * Cleaver * Curtright * Dijkgraaf * Distler * Douglas * Duff * Ferrara * Fischler * Friedan * Gates * Gliozzi * Gopakumar * Green * Greene * Gross * Gubser * Gukov * Guth * Hanson * Harvey * Hořava * Gibbons * Kachru * Kaku * Kallosh * Kaluza * Kapustin * Klebanov * Knizhnik * Kontsevich * Klein * Linde * Maldacena * Mandelstam * Marolf * Martinec * Minwalla * Moore * Motl * Mukhi * Myers * Nanopoulos * Naqvi * Năstase * Nekrasov * Neveu * Nielsen * van Nieuwenhuizen * Novikov * Olive * Ooguri * Ovrut * Polchinski * Polyakov * Rajaraman * Ramond * Randall * Randjbar-Daemi * Roček * Rohm * Scherk * Schwarz * Seiberg * Sen * Shenker * Siegel * Silverstein * Sơn * Staudacher * Steinhardt * Strominger * Sundrum * Susskind * 't Hooft * Townsend * Trivedi * Turok * Vafa * Veneziano * Verlinde * Verlinde * Wess * Witten * Yau * Yoneya * Zamolodchikov * Zamolodchikov * Zaslow * Zumino * Zwiebach 0.00 (0 votes) Original source: https://en.wikipedia.org/wiki/Brane cosmology. 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