Buenos Aires

338 views

Published on

Published in: Technology, Travel
  • Be the first to comment

  • Be the first to like this

Buenos Aires

  1. 1. A Stringy Proposal for Early Time Cosmology: The Cosmological Slingshot Scenario Germani, NEG, Kehagias, hep-th/0611246 Germani, NEG, Kehagias, arXiv:0706.0023 Germani, Ligouri, arXiv:0706.0025
  2. 2. Standard cosmology It is nearly It is nearly homogeneous isotropic 4d metric What do we The vacuum know about theenergy density is universe? The space is very small almost flat It is expanding It is accelerating The perturbations around homogeneity have a flat WMAP collaboration (slightly red) spectrum astro-ph/0603449
  3. 3. Standard cosmology It is nearly It is nearly homogeneous isotropic 4d metric The vacuumenergy density is Einstein equation Hubble equations The space is very small almost flat It is expanding Energy Curvature It is accelerating density term The perturbations around homogeneity have a flat (slightly red) spectrum
  4. 4. Standard cosmology It is nearly Solution It is nearly homogeneous isotropic 4d metric Plank a The vacuumenergy density is Hubble equation The space is very small almost flat Big Bang It is expanding  It is accelerating t tPlank to The perturbations around homogeneity have a flat (slightly red) spectrum
  5. 5. Standard cosmology It is nearly It is nearly homogeneous isotropic  is constant in the observable The vacuum region of 1028 cmenergy density is The space is very small almost flat Causally disconnected regions are It is expanding in equilibrium! It is accelerating t tPlank to The perturbations around homogeneity have a flat (slightly red) spectrum
  6. 6. Standard cosmology It is nearly It is nearly homogeneous isotropic Isotropic solutions form a subset of The vacuum measure zero on the set of all energy density is The space is Bianchi solutions almost flat very small Perturbations around isotropy dominate at early time, like a -6 , It is expanding giving rise to chaotic behavior! It is accelerating The perturbations aroundBelinsky, Khalatnikov, Lifshitz, homogeneity have a flat Collins, Hawking Adv. Phys. 19, 525 (1970) (slightly red) spectrum Astr.Jour.180, (1973)
  7. 7. Standard cosmology It is nearly It is nearly homogeneous isotropic (10-8 at Nuc.) The vacuumenergy density is The space is very small almost flat It is a growing function It is expanding Since it is small today, it was even It is accelerating smaller at earlier time! The perturbations around homogeneity have a flat (slightly red) spectrum
  8. 8. Standard cosmology It is nearly It is nearly homogeneous isotropic What created perturbations? If they were created by primordial The vacuum quantum fluctuations, its resultingenergy density is The space is very small spectrum for normal matter is not flat almost flat Their existence is necessary for the formation of structure (clusters, It is expanding galaxies) It is accelerating The perturbations around homogeneity have a flat (slightly red) spectrum
  9. 9. Guth, PRD 23, 347 (1981) Linde, PLB 108, 389 (1982) Standard cosmology It is nearly It is nearly homogeneous isotropic Inflation Solving to the problems Plank a The vacuumenergy density is The space is very small almost flat Big Bang It is expanding  It is accelerating t tPlank tearlier < tNuc to The perturbations around homogeneity have a flat (slightly red) spectrum
  10. 10. Standard cosmology It is nearly It is nearly homogeneous isotropic Bounce Plank a The vacuum The space is Quantum regimeenergy density is very small almost flat It is expanding  It is accelerating t tearlier< tNuc to The perturbations around homogeneity have a flat (slightly red) spectrum
  11. 11. Standard cosmology It is nearly It is nearly homogeneous isotropic Bounce Inflation Plank the bounce be classical? a The vacuum The space is Can Quantum regimeenergy density is very small almost flat It is expanding  It is accelerating t tearlier< tNuc to The perturbations around homogeneity have a flat (slightly red) spectrum
  12. 12. Kehagias, Kiritsis hep-th/9910174Mirage cosmology Plank a  t tearlier to Cosmological Higher dimensional evolution bulk Warping factor
  13. 13. Mirage cosmology Plank aIncreasing Monotonous warping motion Big Bang Expanding Universe  t tPlank tearlier to How can we obtain a bounce? A minimum in the warping factor Solve Einstein A turning point equations in the motion Solve equations of motion
  14. 14. Germani, NEG, Kehagias hep-th/0611246Slingshot cosmology Plank a  x|| t tearlier to 10d bulk Cosmological IIB SUGRA solution expansion Warping factor Xa
  15. 15. Slingshot cosmology RR field Plank a Dilaton field Induced metric  x|| t Xa Bounce tearlier to Burgess, Quevedo, Rabadan, Turning Tasinato, Zavala, hep-th/0310122 point Xa
  16. 16. Slingshot cosmology 6d flat euclidean metric Transverse metric Plank a Free particle AdS5xS5 space  Bounce t Xa tearlier to  Turning point Warping Non-vanishing angular impact factor momentum l parameter Xa Burgess, Martineau , Quevedo, Heavy source Rabadan, hep-th/0303170 Stack of branes Burgess, NEG, F. Quevedo, Rabadan, hep-th/0310010
  17. 17. Slingshot cosmology 6d flat Euclidean metric Plank a There is no space Free particle curvature AdS5xS5 space  t Xa tearlier to Non-vanishing angular momentum l Xa Heavy source Stack of branes
  18. 18. Slingshot cosmology Plank a There is no space curvature  t tearlier to Flatness problem Can we solve the flatness problem? is solved Constraint in parameter space
  19. 19. Slingshot cosmology All the higher orders in r´ Plank a What about Isotropy problem isotropy? is solved  t tearlier to Dominates at early time, avoiding chaotic behaviour
  20. 20. Slingshot cosmology Plank a And about perturbations?  t tearlier to
  21. 21. Germani, NEG, Kehagias arXiv:0706.0023Slingshot cosmology Boehm, Steer, hep-th/0206147 Plank a Scalaroscillator Bardeen Induced scalar Harmonic about And field potential perturbations?  t tearlier to Growing modes Frozen modes Decaying modes Oscilating modes Frozen modes survive up to late times Decaying modes do not survive
  22. 22. Slingshot cosmology Plank a  t tearlier to Frozen modes Power spectrum Created by quantum perturbations =< > h*
  23. 23. Slingshot cosmology Plank l > lc Classical mode a l < lc Quantum mode r *= lkL / lc l= c Creation of the mode Creation of the mode  t l = k /a = kL / r tearlier to We get a flat spectrum Power spectrum Hollands, Wald h* gr-qc/0205058
  24. 24. Slingshot cosmology Plank aGravity is ten dimensional AdS Late time a CY spaceCompactification throat in cosmology Formation of structure Mirage Kepler laws Local gravity domination in domination in  Real life! the throat the top t tearlier to The transition is out of our control Mirage Local 4d gravity dominated dominated era era backreaction AdS throat Top of the CY
  25. 25. Slingshot cosmology It is nearly homogeneous Nice Results Open Points It is nearly isotropic The price we paid is an unknown Klevanov-Strassler geometry gives transition region spectral index, and a slightly red between local in The vacuum mirage gravitywith WMAP agreement (reheating)energy density is The space is very small Problems with Hollands and Wald almost flat There is no effective 4D theory proposal are avoided in the Slingshot scenario Back-reaction effects should be studied An effective 4D action can be It is expanding It is accelerating found The perturbations around homogeneity have a flat spectrum

×