1 / 22

STANDARD COSMOLOGY; PROBLEMS AND THEIR SOLUTIONS

KUMAR ATMJEET (UNIV. OF DELHI) SUPERVISOR: T. SOURADEEP IUCAA, PUNE (May-July, 2006). STANDARD COSMOLOGY; PROBLEMS AND THEIR SOLUTIONS. CONTENTS. STANDARD MODEL Assumptions Geometrical Description Successes

barid
Télécharger la présentation

STANDARD COSMOLOGY; PROBLEMS AND THEIR SOLUTIONS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. KUMAR ATMJEET (UNIV. OF DELHI) SUPERVISOR: T. SOURADEEP IUCAA, PUNE (May-July, 2006) STANDARD COSMOLOGY; PROBLEMS AND THEIR SOLUTIONS

  2. CONTENTS • STANDARD MODEL • Assumptions • Geometrical Description • Successes • PROBLEMS WITH THE STANDARD MODEL . Horizon problem • Flatness problem • Inhomogeneity problem • Monopole problem • INFLATIONARY UNIVERSE • Inflation • Chaotic model of inflation • As a solution to cosmological problems • INTRODUCTION TO CMBR • MY WORK

  3. STANDARD MODEL • INTRODUCTION • Assumptions : • homogeneous • isotropic • perfect fluid • hot dense fireball

  4. Geometrical Description(FRW*- model) 1

  5. Friedmann's equations: 2 3 4 5 6

  6. Successes of Standard model • Observed universe is homogenious and isotropic • Expansion follows a linear V-r law (Hubble's Law) • Explains the origin of light elements • Prediction of CMB • Planckian nature of spectrum • Cmb isotropy • Oldest steller system are no older than the inferred age of • universe

  7. PROBLEMS WITH THE STANDARD MODEL • Horizon problem • Flatness problem (fine tunning problem) • Inhomogeneity problem ( large scale structures formation) • Monopole problem Is there any solution to these problems?

  8. INFLATIONARY UNIVERSE • Definition: 7 8 9 10

  9. Horizon problem: Flatness problem

  10. to lp(t) t(rec) t(R) xp lp(t) ti

  11. lnflationary model

  12. Solution to the cosmological problems to lp(t) t(rec) t(R) xp lp(t) a(t)=exp(Ht) ti

  13. log() start of inflation end of inflation present day future

  14. Rolling Slowly • Chaotic model of inflation Vacuum Energy

  15. Inflation field dynamics • single scalar field (Φ) • consists of a self interacting potential V(Φ) • field is initially in a false vacuum state • initial chaos causes the field to roll down towards true vacuum • state

  16. Lagrangian for a scalar field: 11 12 13(a) 13(b)

  17. field dynamics continued.... 14 15 16 17 (a), (b,c), (d)

  18. “Slow roll aprrox.(SRA)” condition for inflation parameters: SR Aprroximation 18(a)] 18(b) 19(a) 19(b) slow roll condition 20

  19. References:

  20. THANKS! 07-09-06 THURSDAY

More Related