1. Observed Features of the Universe Universe is homogeneous and isotropic on lengths > 100 Mpc Universe expanding uniformly ordinary matter is more abundant than ordinary antimatter chemical composition is roughly 75% H, 25% He, + trace thermal background of radiation with T~3K nearly scale invariant spectrum of CMB fluctuations hierarchy of structure from 1 kpc to 1 Mpc scales matter is a minority (1/4x) of all energy ordinary matter is a minority (1/6x) of all matter universe is spatially flat expansion rate accelerating

2. Observed Features of the Universe Universe is homogeneous and isotropic on lengths > 100 Mpc Universe expanding uniformly ordinary matter is more abundant than ordinary antimatter chemical composition is roughly 75% H, 25% He, + trace thermal background of radiation with T~3K nearly scale invariant spectrum of CMB fluctuations hierarchy of structure from 1 kpc to 1 Mpc scales matter is a minority (1/4x) of all energy ordinary matter is a minority (1/6x) of all matter universe is spatially flat expansion rate accelerating

3. Why is the Universe homogeneous and isotropic? R obs (t 0 ) = radius of observable universe today ~ 1/H 0 ~ t 0 R obs (t) = size of same patch at time t

4. Why is the Universe homogeneous and isotropic? R obs (t 0 ) = radius of observable universe today ~ 1/H 0 ~ t 0 R obs (t) = size of same patch at time t

5. Why is the Universe homogeneous and isotropic? R obs (t 0 ) = radius of observable universe today ~ 1/H 0 ~ t 0 R obs (t) = size of same patch at time t >> 1 universe decelerating HORIZON PROBLEM

6. Why is the Universe so FLAT? Recall: >> 1 universe decelerating FLATNESS PROBLEM 

7. Why so few monopoles? MONOPOLE PROBLEM if monopoles are stable:

8. HORIZON PROBLEM MONOPOLE PROBLEM FLATNESS PROBLEM t

9. HORIZON PROBLEM MONOPOLE PROBLEM FLATNESS PROBLEM t accelerated expansion

10. INFLATION inflation = finite period of accelerated expansion

11. w < -1/3 means KE < V/2 Planck units

12. INFLATIONARY MENU ENTRANCE INFLATION EXIT phase transition “chaos” stochastic “tunneling from nothing” defect driven Slow roll flat potentials power-law potentials two or more fields tensor (R +  R 2 +…) fermi condensate KE driven oscillation extended scalar field decay bubble nucleation de Sitter fluct’s

13. Density Perturbations H nearly constant

14. Density Perturbations inflation ends, H -1 grows

15. for scalar field, B and E = 0 Newtonian gauge: 

16. k 

19. nearly scale invariant ! large x  oscillating small x  growing

20. large x  oscillating small x  growing

21. need this to be small More generally … w ~ -1: INFLATION w >> 1: EKPYROTIC/CYCLIC

22. AMPLITUDE Strategies 1) Evolve u -equation 2) famous trick 3) heuristic:

23. The Cyclic Universe w/Neil Turok with many important contributions from: Justin Khoury (Princeton), Burt Ovrut (Penn) and Nathan Seiberg (IAS)

24. Consensus (big bang + inflation) big bang

25. Consensus (big bang + inflation) big bang inflation

26. Consensus (big bang + inflation) big bang inflation radiation matter dark energy ?? ??? Cyclic PJS & Neil Turok “bang” radiation matter dark energy

27. Consensus (big bang + inflation) big bang inflation radiation matter dark energy ?? ??? Cyclic PJS & Neil Turok “bang” radiation matter dark energy V Y

28. Consensus (big bang + inflation) big bang inflation radiation matter dark energy ?? ??? Cyclic PJS & Neil Turok “bang” radiation matter dark energy V Y

29. Consensus (big bang + inflation) big bang inflation radiation matter dark energy ?? ??? Cyclic PJS & Neil Turok “bang” radiation matter dark energy V Y

30. Consensus (big bang + inflation) big bang inflation radiation matter dark energy ?? ??? Cyclic PJS & Neil Turok “bang” radiation matter dark energy V Y

31. Consensus (big bang + inflation) big bang inflation radiation matter dark energy ?? ??? Cyclic PJS & Neil Turok “bang” radiation matter dark energy “contraction” V Y

32. Consensus (big bang + inflation) big bang inflation radiation matter dark energy ?? ??? Cyclic PJS & Neil Turok “bang” radiation matter dark energy “contraction” “crunch” the “bounce”

33. Consensus (big bang + inflation) big bang inflation radiation matter dark energy ?? ??? Cyclic PJS & Neil Turok “bang” radiation matter dark energy “contraction” “crunch” the “bounce” Reproduces successful predictions

34. Consensus (big bang + inflation) big bang inflation radiation matter dark energy ?? ??? Cyclic PJS & Neil Turok “bang” radiation matter dark energy “contraction” “crunch” the “bounce” Fewer ingredients: no need for inflation

35. Consensus (big bang + inflation) big bang inflation radiation matter dark energy ?? ??? Cyclic PJS & Neil Turok “bang” radiation matter dark energy “contraction” “crunch” the “bounce” Dark energy given a purpose

36. Consensus (big bang + inflation) big bang inflation radiation matter dark energy ?? ??? Cyclic PJS & Neil Turok “bang” radiation matter dark energy “contraction” “crunch” the “bounce” Avoids infinities?

37. Consensus (big bang + inflation) big bang inflation radiation matter dark energy ?? ??? Cyclic PJS & Neil Turok “bang” radiation matter dark energy “contraction” “crunch” the “bounce” More complete theory of cosmic history

38. V Y Y M-theory Field-theory “branes” The Cyclic Universe

39. V Y THE BOUNCE