has inflation fulfilled its promise? the classical view the quantum view “ordering”...
TRANSCRIPT
Has inflation fulfilled its promise?
the classical view the quantum view
“ordering” “disordering”
• unpredictability problem
Linde, Linde, Mezhlumian, PRD 50, 2456 (1994)
• persistence of memory problem
• geodesic incompleteness
• entropy problem
• transplanckian problem
Either:
- solve these problems, or
- seek alternative models that avoid them
Observers & experimentalists will help:
- conduct tests that enable us to distinguishamong inflation and its alternatives
Hsmoothing > Hnormal >> Htoday
1) Inflation is fast
2) Quantum physics is random
Hsmoothing << HnormalSuppose
• Unpredictability
• Persistence of Memory
• Entropy Problem
• Singularity Problem
?
How do we go from small H to large H ?
)(4 pGH
a bounce
i.e., confront the singularity rather than ignore it
inflaton38
382
26
2
4
0
3
0
... ak
aaG
aG rmH
w ~ -1
Inflation: ultra-rapid expansion
)1(3/2~)( wtta
)1(3
0
38
a
G
w w >> 1
N.B. Do not need finely tuned initial conditions or inflation or dark energy …
ekpyrotic/cyclic: ultra-slow contraction
inflaton38
382
26
2
4
0
3
0
... ak
aaG
aG rmH
)1(3/2)(~)( wtta
Erickson, Wesley, PJS. TurokErickson, Gratton, PJS, Turok
)1(3
0
38
a
G
w w >> 1
… and avoid chaotic mixmaster behavior …
ekpyrotic/cyclic: slow contraction
inflaton38
382
26
2
4
0
3
0
... ak
aaG
aG rmH
Erickson, Wesley, PJS. TurokErickson, Gratton, PJS, Turok
)1(3
0
38
a
G
w w >> 1
… and makes scale-invariant perturbations of scalar fields …
ekpyrotic/cyclic: slow contraction
inflaton38
382
26
2
4
0
3
0
... ak
aaG
aG rmH
Erickson, Wesley, PJS. TurokErickson, Gratton, PJS, Turok
)1(3
0
38
a
G
w w >> 1
… without encountering transplanckian fluctuations.
ekpyrotic/cyclic: slow contraction
inflaton38
382
26
2
4
0
3
0
... ak
aaG
aG rmH
Erickson, Wesley, PJS. TurokErickson, Gratton, PJS, Turok
V
inflation
ekpyrotic/cyclic
V
1~)(
)(2
21
221
V
Vw
1)(
)(2
21
221
V
Vw
Khoury, PJS, Ovrut, TurokBuchbinder, Khoury, Ovrut
“bang”
radiation
matter
dark energy
“ekpyrotic”contraction
“crunch”
How do we convert scalar field fluctuationsinto curvature perturbations?
Entropic approach:two ordinary scalar fields and NO extra dimensions:
entropic curvature
Buchbinder, Khoury Ovrut,Creminelli and SenatoreKoyama, Mizumo, WandsWesley and Tolley,
Finelli & BrandenbergerLehners, McFadden, Turok, and PJS
AdS/CFT approach: (see Turok’s talk)
Turok, Craps, Hertog
• Gravitational waves?
• Non-gaussian fluctuations?
• Gravitational waves?
• Non-gaussian fluctuations?
Primordial amplitude proportional to Hsmoothing2
from Baumann, PJS, Takahashi, Ichikisee also Mollerach, Harari, Mattarese
Ananda, Clarkson, Wands
• Gravitational waves?
• Non-gaussian fluctuations?
Buchbinder, Khoury Ovrut, arXiv:0706.3903Creminelli and Senatore, hep-th/0702165
Koyama, Mizumo, Wands, to appear
wVfNL 3~''~
Entropic mechanism can producesignificant non-gaussianity:
36100 observedNLf (WMAP team)
27147 observedNLf (Yadav & Wandelt)
compatible for w < 30
conversionduring ekpyrotic
phase
J-L. Lehners & PJS
50200 NLf
Entropic mechanism can producesignificant non-gaussianity:
36100 observedNLf (WMAP team)
27147 observedNLf
conversionafter ekpyrotic
phase
compatible for w < 3000 and with tilt
(Yadav & Wandelt)
36100 observedNLf (WMAP team)
27147 observedNLf (Yadav & Wandelt)