Radiative Inflation and Dark Energy

1. Alexander Merle Royal Institute of Technology (KTH) Stockholm Radiative Inflation and Dark Energy Based on: 1010.5726 [hep-ph] (Di Bari, King, Luhn, AM, Schmidt-May) “TheReturn of de Sitter“ 2011 March 16

2. Contents: • Introduction • Theprincipalidea • Inflation • Dark Energy • An out of thisworld RIDE scenario • Conclusions

3. 1. Introduction

4. 1. Introduction http://wmap.gsfc.nasa.gov/

5. 1. Introduction (well?) known... http://wmap.gsfc.nasa.gov/

6. 1. Introduction (well?) known... Neutralino, KK, gravitino,... http://wmap.gsfc.nasa.gov/

7. 1. Introduction (well?) known... Constant? Quintessence?? Neutralino, KK, gravitino,... http://wmap.gsfc.nasa.gov/

8. 1. Introduction • Werequire an explanationforthemysteriousDark Energy in theUniverse:

9. 1. Introduction • Werequire an explanationforthemysteriousDark Energy in theUniverse: • Vacuumenergy: famousmismatch of 120 ordersof magnitude... Wrong?!?

10. 1. Introduction • Werequire an explanationforthemysteriousDark Energy in theUniverse: • Vacuumenergy: famousmismatch of 120 ordersof magnitude... Wrong?!? • Dynamicalscalarfieldcould also explaindarkenergyQuintessence

11. 1. Introduction • Werequire an explanationforthemysteriousDark Energy in theUniverse: • Vacuumenergy: famousmismatch of 120 ordersof magnitude... Wrong?!? • Dynamicalscalarfieldcould also explaindarkenergyQuintessence BUT:origin of thisscalarfieldunclear

12. 1. Introduction • Werequire an explanationforthemysteriousDark Energy in theUniverse: • Vacuumenergy: famousmismatch of 120 ordersof magnitude... Wrong?!? • Dynamicalscalarfieldcould also explaindarkenergyQuintessence BUT:origin of thisscalarfieldunclear Suggests a connection to particlephysics

13. 1. Introduction Furtherissues:

14. 1. Introduction Furtherissues: • Flatnessproblem: Whyis k=0? • Horizonproblem: Whyis (ΔT/T)l>1 ~ 10-5?

15. 1. Introduction Furtherissues: • Flatnessproblem: Whyis k=0? • Horizonproblem: Whyis (ΔT/T)l>1 ~ 10-5? http://wmap.gsfc.nasa.gov/

16. 1. Introduction Inflationcansolvetheseproblems:

17. 1. Introduction Inflationcansolvetheseproblems: • exponential expansion of theearlyUniverse

18. 1. Introduction Inflationcansolvetheseproblems: • exponential expansion of theearlyUniverse • can also bedescribedby a scalarfield

19. 1. Introduction Inflationcansolvetheseproblems: • exponential expansion of theearlyUniverse • can also bedescribedby a scalarfield soundssimilar to Quintessence

20. 1. Introduction Inflationcansolvetheseproblems: • exponential expansion of theearlyUniverse • can also bedescribedby a scalarfield soundssimilar to Quintessence typically, particlephysicistslike to unifythings...

21. 1. Introduction Inflationcansolvetheseproblems: • exponential expansion of theearlyUniverse • can also bedescribedby a scalarfield soundssimilar to Quintessence typically, particlephysicistslike to unifythings... Thisiswhatwetried to do!!

22. 2. Thegeneralidea

23. 2. Thegeneralidea Goal:wewant to unify Inflation & Quintessence

24. 2. Thegeneralidea Goal:wewant to unify Inflation & Quintessence Particularly simple modelthatdoesthe job: • Rosenfeld & Frieman JCAP 0509 (2005) 003

25. 2. Thegeneralidea Goal:wewant to unify Inflation & Quintessence Particularly simple modelthatdoesthe job: • Rosenfeld & Frieman JCAP 0509 (2005) 003 • complexscalarfield:

26. 2. Thegeneralidea Goal:wewant to unify Inflation & Quintessence Particularly simple modelthatdoesthe job: • Rosenfeld & Frieman JCAP 0509 (2005) 003 • complexscalarfield: • Inflaton potential:

27. 2. Thegeneralidea Goal:wewant to unify Inflation & Quintessence Particularly simple modelthatdoesthe job: • Rosenfeld & Frieman JCAP 0509 (2005) 003 • complexscalarfield: • Inflaton potential: Mexican hat potential:

28. 2. Thegeneralidea (WikimediaCommons)

29. 2. Thegeneralidea • dependsonly on theinflaton η • at theminimum, an (accidental) U(1)PQsymmetry of the potential will bebrokenNambu-Goldstoneboson φ (WikimediaCommons)

30. 2. Thegeneralidea • dependsonly on theinflaton η • at theminimum, an (accidental) U(1)PQsymmetry of the potential will bebrokenNambu-Goldstoneboson φ (WikimediaCommons)

31. 2. Thegeneralidea • dependsonly on theinflaton η • at theminimum, an (accidental) U(1)PQsymmetry of the potential will bebrokenNambu-Goldstoneboson φ (WikimediaCommons) ifthis GB obtains a small potential, itcanserve as Quintessencefield

32. 2. Thegeneralidea onepossibility: axion-like potential due to non-perturbativegravitationaleffects (“gravitationalinstantons“: Kallosh et al., PR D52 (1995) 912)

33. 2. Thegeneralidea onepossibility: axion-like potential due to non-perturbativegravitationaleffects (“gravitationalinstantons“: Kallosh et al., PR D52 (1995) 912) important: m4mustnecessarilybesmall (meV)4

34. 2. Thegeneralidea onepossibility: axion-like potential due to non-perturbativegravitationaleffects (“gravitationalinstantons“: Kallosh et al., PR D52 (1995) 912) important: m4mustnecessarilybesmall (meV)4 Thismodeliseasy and nice!

35. 2. Thegeneralidea onepossibility: axion-like potential due to non-perturbativegravitationaleffects (“gravitationalinstantons“: Kallosh et al., PR D52 (1995) 912) important: m4mustnecessarilybesmall (meV)4 Thismodeliseasy and nice! BUT:it has TWO problems...

36. 2. Thegeneralidea

37. 2. Thegeneralidea

38. 2. Thegeneralidea • nearlyφ4-Inflation • practicallyruled out by WMAP3/WMAP5

39. 2. Thegeneralidea • nearlyφ4-Inflation • practicallyruled out by WMAP3/WMAP5 • Quintessencescale & fieldmassstronglyconstrain f • f > 0.5 MP (Dutta & Sorbo, PR D75 (2007) 063520) • very high, maybetrans-Planckian... • HENCE: wehave to overcometheseproblems

40. 2. Thegeneralidea • nearlyφ4-Inflation • practicallyruled out by WMAP3/WMAP5 • Quintessencescale & fieldmassstronglyconstrain f • f > 0.5 MP (Dutta & Sorbo, PR D75 (2007) 063520) • very high, maybetrans-Planckian... • HENCE: wehave to overcometheseproblems

41. 2. Thegeneralidea • WAY OUT: RIDE

42. 2. Thegeneralidea • WAY OUT: RIDE • φ2- instead of φ4-Inflation:

43. 2. Thegeneralidea • WAY OUT: RIDE • φ2- instead of φ4-Inflation: •  okay withcurrentdata

44. 2. Thegeneralidea • WAY OUT: RIDE • φ2- instead of φ4-Inflation: •  okay withcurrentdata • connection to Quintessenceonlybyradiativecorrections (like MSSM Higgsmass):

45. 2. Thegeneralidea • WAY OUT: RIDE • φ2- instead of φ4-Inflation: •  okay withcurrentdata • connection to Quintessenceonlybyradiativecorrections (like MSSM Higgsmass): • disentanglesthetightconnectionbetweenthe Inflation and Dark Energy scales (onlylog-dependence)

46. 2. Thegeneralidea • Tasks to beaddressed:

47. 2. Thegeneralidea • Tasks to beaddressed: • testInflation: calculate nS and r •  will turn out to be okay with WMAP7

48. 2. Thegeneralidea • Tasks to beaddressed: • testInflation: calculate nS and r •  will turn out to be okay with WMAP7 • test Dark Energy: alreadydone (pNGBquintessence, e.g. Dutta & Sorbo, PR D75 (2007) 063520)

49. 2. Thegeneralidea • Tasks to beaddressed: • testInflation: calculate nS and r •  will turn out to be okay with WMAP7 • test Dark Energy: alreadydone (pNGBquintessence, e.g. Dutta & Sorbo, PR D75 (2007) 063520) • try to find a frameworkwithinparticlephysicswherethismodelcanberealized • supersymmetricsequesteredscenario

50. 2. Thegeneralidea • Tasks to beaddressed: • testInflation: calculate nS and r •  will turn out to be okay with WMAP7 • test Dark Energy: alreadydone (pNGBquintessence, e.g. Dutta & Sorbo, PR D75 (2007) 063520) • try to find a frameworkwithinparticlephysicswherethismodelcanberealized • supersymmetricsequesteredscenario Let ‘s do that!!!