Download - Observed Features of the Universe
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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
![Page 2: Observed Features of the Universe](https://reader030.vdocuments.mx/reader030/viewer/2022032805/5681324d550346895d98c44f/html5/thumbnails/2.jpg)
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
![Page 3: Observed Features of the Universe](https://reader030.vdocuments.mx/reader030/viewer/2022032805/5681324d550346895d98c44f/html5/thumbnails/3.jpg)
Why is the Universe homogeneous and isotropic?
Robs (t0) = radius of observable universe today ~ 1/H0 ~ t0
Robs (t) = size of same patch at time t
o
eo
o
eoobseobs a
at
a
atRtR )()(
pp
e
tppe
teecausal
ttt
ta
dttatR
e
e
110
1
0 )()()(
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Why is the Universe homogeneous and isotropic?
Robs (t0) = radius of observable universe today ~ 1/H0 ~ t0
Robs (t) = size of same patch at time t
o
ep
e
o
o
ep
ecausal
eobs
a
a
t
t
a
a
tR
tR
)1()1( ~)(
)(
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Why is the Universe homogeneous and isotropic?
Robs (t0) = radius of observable universe today ~ 1/H0 ~ t0
Robs (t) = size of same patch at time t
o
e
ecausal
eobs
a
a
tR
tR
~)(
)(>> 1
universe decelerating
HORIZON PROBLEM
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Why is the Universe so FLAT?
Recall:
>> 1
universe decelerating
FLATNESS PROBLEM
22
3
8
a
kGH
221
Ha
ktot
222
111
aHatot
2
2
1
1
o
e
etot
otot
a
a
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Why so few monopoles?
MONOPOLE PROBLEM
)(~
3ecausal tR
gM3
3 )(~
o
e
eobsa
a
tR
gM
if monopolesare stable:
3
3 )(~
o
e
oobsa
a
tR
gM
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3
3 )(~
e
e
oobsmono a
a
tL
gM
o
ep
ecausal
eobs
a
a
tR
tR
)1(~)(
)(
HORIZON PROBLEM
MONOPOLE PROBLEM
2
2
1
1
o
e
etot
otot
a
a
FLATNESS PROBLEM a
t
ea
oa
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3
3 )(~
e
e
oobsmono a
a
tL
gM
o
ep
ecausal
eobs
a
a
tR
tR
)1(~)(
)(
HORIZON PROBLEM
MONOPOLE PROBLEM
2
2
1
1
o
e
etot
otot
a
a
FLATNESS PROBLEM a
t
ea
oa
initiala
accelerated expansion
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INFLATION
inflation = finite period of accelerated expansion
apG
a )3(3
4
31
31
p
worp
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V
V
V
V
p
p
pT
221
221
221
221
V
Vpw
221
221
w < -1/3 means KE < V/2
'3 VH 1'
V
V
Planck units
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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 + R2 +…)
fermi condensate
KE driven
oscillation
extended
scalar field decay
bubble nucleation
de Sitter fluct’s
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Density Perturbations
H nearly constant
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Density Perturbations
inflation ends, H-1 grows
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ijiji
iS
EB
Bg
;;
;)(
2
2
for scalar field, B and E = 0 Newtonian gauge:
])21()21()[( 2222 dxdads
0
ij
T
hg
0
00)(
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0)( 2 kk uUku
k
ku
)(2
kkk uua
)"2( 2
2'2'82212 VVaU VHV
ddprime /dtddot /
ka
eikk
2
2/3
~k
ieu
ik
k
k
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0)( 2 kk uUku
k
ku
)(2
kkk uua
)"2( 2
2'2'82212 VVaU VHV
ddprime /dtddot /
1'
2
21
V
V
'3 VH 1
"
V
V]26[22 HaU
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0)( 2 kk uUku
k
ku
)(2
kk uua
)"2( 2
2'2'82212 VVaU VHV
ddprime /dtddot /
0)( 222
22 k
k uUxxd
udx kx
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0)( 222
22 k
k uUxxd
udx kx
Unwithku nk
2212
1
~ nearly scaleinvariant !
412 n
))()()()((~ 21 xJkCxJkCxu nnk
large x oscillating2/3
~k
ieu
ik
k
small x growing
21 CiC
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0)( 222
22 k
k uUxxd
udx kx
412 n
))()()()((~ 21 xJkCxJkCxu nnk
large x oscillating2/3
~k
ieu
ik
k
small x growing
)26(~~ 21 kku n
k
21 CiC
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0)( 222
22 k
k uUxxd
udx kx
412 n
2)32(
)1(6
w
w
need this to
be small
More generally …
w ~ -1: INFLATION
w >> 1: EKPYROTIC/CYCLIC
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AMPLITUDE Strategies
1) Evolve u -equation
2) famous trick '
2 /)1(3
2~
aH
u
awk
k
3) heuristic:
'~~~~~
/1
/~
2/32
2/1
2/3
V
VHHtH
t
t
t
tt
T
T
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The Cyclic Universe
w/Neil Turok
with many important contributions from:Justin Khoury (Princeton), Burt Ovrut (Penn)
and Nathan Seiberg (IAS)
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Consensus(big bang + inflation)
big bang
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Consensus(big bang + inflation)
big bang
inflation
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Consensus(big bang + inflation)
big bang
inflation
radiation
matter
dark energy ??
???
CyclicPJS & Neil Turok
“bang”
radiation
matter
dark energy
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Consensus(big bang + inflation)
big bang
inflation
radiation
matter
dark energy ??
???
CyclicPJS & Neil Turok
“bang”
radiation
matter
dark energy
V
Y
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Consensus(big bang + inflation)
big bang
inflation
radiation
matter
dark energy ??
???
CyclicPJS & Neil Turok
“bang”
radiation
matter
dark energy
V
Y
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Consensus(big bang + inflation)
big bang
inflation
radiation
matter
dark energy ??
???
CyclicPJS & Neil Turok
“bang”
radiation
matter
dark energy
V
Y
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Consensus(big bang + inflation)
big bang
inflation
radiation
matter
dark energy ??
???
CyclicPJS & Neil Turok
“bang”
radiation
matter
dark energy
V
Y
![Page 31: Observed Features of the Universe](https://reader030.vdocuments.mx/reader030/viewer/2022032805/5681324d550346895d98c44f/html5/thumbnails/31.jpg)
Consensus(big bang + inflation)
big bang
inflation
radiation
matter
dark energy ??
???
CyclicPJS & Neil Turok
“bang”
radiation
matter
dark energy
“contraction”V
Y
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Consensus(big bang + inflation)
big bang
inflation
radiation
matter
dark energy ??
???
CyclicPJS & Neil Turok
“bang”
radiation
matter
dark energy
“contraction”
“crunch”
the “b
ou
nce
”
![Page 33: Observed Features of the Universe](https://reader030.vdocuments.mx/reader030/viewer/2022032805/5681324d550346895d98c44f/html5/thumbnails/33.jpg)
Consensus(big bang + inflation)
big bang
inflation
radiation
matter
dark energy ??
???
CyclicPJS & Neil Turok
“bang”
radiation
matter
dark energy
“contraction”
“crunch”
the “b
ou
nce
”
Reproduces successful predictions
![Page 34: Observed Features of the Universe](https://reader030.vdocuments.mx/reader030/viewer/2022032805/5681324d550346895d98c44f/html5/thumbnails/34.jpg)
Consensus(big bang + inflation)
big bang
inflation
radiation
matter
dark energy ??
???
CyclicPJS & Neil Turok
“bang”
radiation
matter
dark energy
“contraction”
“crunch”
the “b
ou
nce
”
Fewer ingredients: no need for inflation
![Page 35: Observed Features of the Universe](https://reader030.vdocuments.mx/reader030/viewer/2022032805/5681324d550346895d98c44f/html5/thumbnails/35.jpg)
Consensus(big bang + inflation)
big bang
inflation
radiation
matter
dark energy ??
???
CyclicPJS & Neil Turok
“bang”
radiation
matter
dark energy
“contraction”
“crunch”
the “b
ou
nce
”
Dark energy given a purpose
![Page 36: Observed Features of the Universe](https://reader030.vdocuments.mx/reader030/viewer/2022032805/5681324d550346895d98c44f/html5/thumbnails/36.jpg)
Consensus(big bang + inflation)
big bang
inflation
radiation
matter
dark energy ??
???
CyclicPJS & Neil Turok
“bang”
radiation
matter
dark energy
“contraction”
“crunch”
the “b
ou
nce
”
Avoids infinities?
![Page 37: Observed Features of the Universe](https://reader030.vdocuments.mx/reader030/viewer/2022032805/5681324d550346895d98c44f/html5/thumbnails/37.jpg)
Consensus(big bang + inflation)
big bang
inflation
radiation
matter
dark energy ??
???
CyclicPJS & Neil Turok
“bang”
radiation
matter
dark energy
“contraction”
“crunch”
the “b
ou
nce
”
More complete theory of cosmic history
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V
Y
Y
M-theoryField-theory
“branes”
The Cyclic Universe
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V
Y
The Cyclic Universe
THE BOUNCE