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A. Albrecht @ UCD 10/3/11 1
Inflation, infinity, equilibrium and the observable Universe
Andreas AlbrechtUC Davis
UCD ColloquiumOctober 3, 2011
A. Albrecht @ UCD 10/3/11 5
Cosmic Inflation:
Great phenomenology, but
Original goal of explaining why the cosmos is *likely* to take the form we observe has proven very difficult to realize.
A. Albrecht @ UCD 10/3/11 6
Cosmic Inflation:
Great phenomenology, but
Original goal of explaining why the cosmos is *likely* to take the form we observe has proven very difficult to realize.
This Talk
A. Albrecht @ UCD 10/3/11 7
Cosmic Inflation:
Great phenomenology, but
Original goal of explaining why the cosmos is *likely* to take the form we observe has proven very difficult to realize.
OR: Just be happy we have equations to solve?
A. Albrecht @ UCD 10/3/11 8
OUTLINE
1. Big Bang & inflation basics
2. Eternal inflation
3. de Sitter Equilibrium cosmology
4. Cosmic curvature from de Sitter Equilibrium cosmology
A. Albrecht @ UCD 10/3/11 9
OUTLINE
1. Big Bang & inflation basics
2. Eternal inflation
3. de Sitter Equilibrium cosmology
4. Cosmic curvature from de Sitter Equilibrium cosmology
A. Albrecht @ UCD 10/3/11 12
Friedmann Eqn.
2
2 8
3 k r m DE
aH G
a
CurvatureRelativistic Matter
2a4a
A. Albrecht @ UCD 10/3/11 13
Friedmann Eqn.
2
2 8
3 k r m DE
aH G
a
CurvatureRelativistic Matter
Non-relativistic Matter
2a
3a
4a
A. Albrecht @ UCD 10/3/11 14
Friedmann Eqn.
2
2 8
3 k r m DE
aH G
a
CurvatureRelativistic Matter
Non-relativistic Matter
Dark Energy
2a
3a
4a 0a
A. Albrecht @ UCD 10/3/11 18
-30 -20 -10 0 10-20
0
20
40
60
80
100
120
log(a/a0)
log( / c0 )
r
m
k
The curvature feature/“problem”
A. Albrecht @ UCD 10/3/11 19
-30 -20 -10 0 10-20
0
20
40
60
80
100
120
log(a/a0)
log( / c0 )
r
m
k
!
The curvature feature/“problem”
A. Albrecht @ UCD 10/3/11 20
-30 -20 -10 0 10-20
0
20
40
60
80
100
120
log(a/a0)
log( / c0 )
r
m
k
!
The curvature feature/“problem”
A. Albrecht @ UCD 10/3/11 21
-30 -20 -10 0 10-20
0
20
40
60
80
100
120
log(a/a0)
log( / c0 )
r
m
k
!
The curvature feature/“problem”
A. Albrecht @ UCD 10/3/11 22
-30 -20 -10 0 10-20
0
20
40
60
80
100
120
log(a/a0)
log( / c0 )
r
m
k
The curvature feature/“problem”
A. Albrecht @ UCD 10/3/11 23
-30 -20 -10 0 10-20
0
20
40
60
80
100
120
log(a/a0)
log( / c0 )
r
m
k
!
The curvature feature/“problem”
A. Albrecht @ UCD 10/3/11 24
-30 -20 -10 0 10-20
0
20
40
60
80
100
120
log(a/a0)
log( / c0 )
r
mMono
The monopole “problem”
A. Albrecht @ UCD 10/3/11 25
-30 -20 -10 0 10-20
0
20
40
60
80
100
120
log(a/a0)
log( / c0 )
r
mMono
!
The monopole “problem”
A. Albrecht @ UCD 10/3/11 26
Friedmann Eqn.
2
2 8
3 k r m DE
aH G
a
CurvatureRelativistic Matter
Non-relativistic Matter
Dark Energy
2a
3a
4a 0a
A. Albrecht @ UCD 10/3/11 27
Friedmann Eqn.
2
2 8
3 I k r m DE
aH G
a
CurvatureRelativistic Matter
Non-relativistic Matter
Dark Energy
2a
3a
4a 0a
Now add cosmic inflation
0a
Inflaton
A. Albrecht @ UCD 10/3/11 28
Friedmann Eqn.
2
2 8
3 I k r m DE
aH G
a
CurvatureRelativistic Matter
Non-relativistic Matter
Dark Energy
Now add cosmic inflation
0a
Inflaton
A. Albrecht @ UCD 10/3/11 29
The inflaton:~Homogeneous scalar field obeying
3H V
2 01.
2I V V const a
All potentials have a “low roll” (overdamped) regime where
Cosmic damping Coupling to ordinary matter
V
A. Albrecht @ UCD 10/3/11 30
The inflaton:~Homogeneous scalar field obeying
3H V
2 01.
2I V V const a
All potentials have a “low roll” (overdamped) regime where
Cosmic damping Coupling to ordinary matter
V
A. Albrecht @ UCD 10/3/11 31
-60 -40 -20 0 20-20
0
20
40
60
80
100
120
log(a/a0)
log( / c0 )
I
r
m
Add a period of Inflation:
A. Albrecht @ UCD 10/3/11 32
-60 -40 -20 0 20-20
0
20
40
60
80
100
120
log(a/a0)
log( / c0 )
I
r
m
k
With inflation, initially large curvature is OK:
A. Albrecht @ UCD 10/3/11 33
-60 -40 -20 0 20-20
0
20
40
60
80
100
120
log(a/a0)
log( / c0 )
I
r
m
Mono
With inflation, early production of large amounts of non-relativistic matter (monopoles) is ok :
A. Albrecht @ UCD 10/3/11 34
Inflation detail:
-28.8 -28.6 -28.4 -28.2 -28 -27.8 -27.6-0.5
0
0.5
log(a/a0)
/M
P
-28.8 -28.6 -28.4 -28.2 -28 -27.8 -27.6100
105
110lo
g( / c0 )
KE
V
r
A. Albrecht @ UCD 10/3/11 35
-28.8 -28.6 -28.4 -28.2 -28 -27.8 -27.6-0.5
0
0.5
log(a/a0)
/M
P
-28.8 -28.6 -28.4 -28.2 -28 -27.8 -27.6100
105
110lo
g( / c0 )
KE
V
r
Inflation detail:
-2 0 20
1
2
3
/MP
V/M
GU
T4
2 21
2V m
A. Albrecht @ UCD 10/3/11 37
2
2 8 8
3 3I k r m DE Tot
aH G G
a
Hubble Length
1/2
1H
Tot
cR
H
(aka )c
A. Albrecht @ UCD 10/3/11 38
-60 -40 -20 0 20-20
0
20
40
60
80
100
120
log(a/a0)
log( / c0 )
I
r
m
Tot
A. Albrecht @ UCD 10/3/11 42
-60 -40 -20 0 20
-100
-50
0
50
100
log(a/a0)
log( / c0 )
Tot
1/21
HTot
cR
H
A. Albrecht @ UCD 10/3/11 43
-60 -40 -20 0 20
-100
-50
0
50
100
log(a/a0)
log(
(RH
/RH0
)2 )
RH2
1/21
HTot
cR
H
A. Albrecht @ UCD 10/3/11 44
-60 -40 -20 0 20
-100
-50
0
50
100
log(a/a0)
log(
RH
/RH0
)
RH
1/21
HTot
cR
H
A. Albrecht @ UCD 10/3/11 45
-60 -40 -20 0 20-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log(
RH
/RH0
)
RH
1/21
HTot
cR
H
A. Albrecht @ UCD 10/3/11 46
1/21i
Hi i
cR
H
-60 -40 -20 0 20-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log(
RH
/RH0
)
RHI
RHr
RHm
RH
A. Albrecht @ UCD 10/3/11 47
-60 -40 -20 0 20-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log(
RH
/RH0
)
RHI
RHr
RHm
RH
RHTot
1/21i
Hi i
cR
H
A. Albrecht @ UCD 10/3/11 48
-60 -40 -20 0 20-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log(
RH
/RH0
)
RH
1/21
HTot
cR
H
A. Albrecht @ UCD 10/3/11 49
-60 -50 -40 -30 -20 -10 0 10-70
-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log[
(RH/R
H0)-1
]
End of inflation
A. Albrecht @ UCD 10/3/11 50
-60 -50 -40 -30 -20 -10 0 10-70
-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log[
(RH/R
H0)-1
]
End of reheating
A. Albrecht @ UCD 10/3/11 51
-60 -50 -40 -30 -20 -10 0 10-70
-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log[
(RH/R
H0)-1
]
Weak Scale
A. Albrecht @ UCD 10/3/11 52
-60 -50 -40 -30 -20 -10 0 10-70
-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log[
(RH/R
H0)-1
]
BBN
A. Albrecht @ UCD 10/3/11 53
-60 -50 -40 -30 -20 -10 0 10-70
-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log[
(RH/R
H0)-1
]
Radiation-Matter equality
A. Albrecht @ UCD 10/3/11 54
-60 -50 -40 -30 -20 -10 0 10-70
-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log[
(RH/R
H0)-1
]
Today
A. Albrecht @ UCD 10/3/11 55
-60 -50 -40 -30 -20 -10 0 10-70
-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log(
RH/R
H0)
Perturbations from inflation
comoving
A. Albrecht @ UCD 10/3/11 56
-60 -50 -40 -30 -20 -10 0 10-70
-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log(
RH/R
H0)
Here
Perturbations from inflation
comoving
A. Albrecht @ UCD 10/3/11 57
-60 -50 -40 -30 -20 -10 0 10-70
-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log(
RH/R
H0)
Here
Here
Perturbations from inflation
comoving
2
2
H
A. Albrecht @ UCD 10/3/11 58
-60 -50 -40 -30 -20 -10 0 10-70
-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log(
RH/R
H0)
Here
Here
comoving
2
2
H
A. Albrecht @ UCD 10/3/11 59
-60 -50 -40 -30 -20 -10 0 10-70
-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log(
RH/R
H0)
Here
Here
comoving
2
2
H
A. Albrecht @ UCD 10/3/11 60
-28.8 -28.6 -28.4 -28.2 -28 -27.8 -27.6-0.5
0
0.5
log(a/a0)
/M
P
-28.8 -28.6 -28.4 -28.2 -28 -27.8 -27.6100
105
110lo
g( / c0 )
KE
V
r
Inflation detail:
-2 0 20
1
2
3
/MP
V/M
GU
T4
2 21
2V m
A. Albrecht @ UCD 10/3/11 61
-28.8 -28.6 -28.4 -28.2 -28 -27.8 -27.6-0.5
0
0.5
log(a/a0)
/M
P
-28.8 -28.6 -28.4 -28.2 -28 -27.8 -27.6100
105
110lo
g( / c0 )
KE
V
r
Inflation detail:
-2 0 20
1
2
3
/MP
V/M
GU
T4
2 21
2V m
128 10m GeV
to give
510
A. Albrecht @ UCD 10/3/11 62
-60 -50 -40 -30 -20 -10 0 10-70
-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log(
RH/R
H0)
Here
Here
comoving
2
2
H
A. Albrecht @ UCD 10/3/11 67
OUTLINE
1. Big Bang & inflation basics
2. Eternal inflation
3. de Sitter Equilibrium cosmology
4. Cosmic curvature from de Sitter Equilibrium cosmology
A. Albrecht @ UCD 10/3/11 68
OUTLINE
1. Big Bang & inflation basics
2. Eternal inflation
3. de Sitter Equilibrium cosmology
4. Cosmic curvature from de Sitter Equilibrium cosmology
A. Albrecht @ UCD 10/3/11 69
Does inflation make the SBB natural?
How easy is it to get inflation to start?
What happened before inflation?
A. Albrecht @ UCD 10/3/11 70
HR
Quantum fluctuations during slow roll:
A region of one field coherence length ( ) gets a new quantum contribution to the field value from an uncorrelated commoving mode of size in a time leading to a (random) quantum rate of change:
Thus
measures the importance of quantum fluctuations in the field evolution
HR
H 1t H
2Q H
2Q H
t
A. Albrecht @ UCD 10/3/11 71
HR
Quantum fluctuations during slow roll:
A region of one field coherence length ( ) gets a new quantum contribution to the field value from an uncorrelated commoving mode of size in a time leading to a (random) quantum rate of change:
Thus
measures the importance of quantum fluctuations in the field evolution
HR
H 1t H
2Q H
( )
510
2Q H
t
A. Albrecht @ UCD 10/3/11 72
HR
Quantum fluctuations during slow roll:
A region of one field coherence length ( ) gets a new quantum contribution to the field value from an uncorrelated commoving mode of size in a time leading to a (random) quantum rate of change:
Thus
measures the importance of quantum fluctuations in the field evolution
HR
H 1t H
2Q H
t
2Q H
( )
510
For realistic perturbations the evolution is very classical
A. Albrecht @ UCD 10/3/11 73
-2 -1 0 1 20
0.5
1
1.5
2
2.5
/MP
V/M
GU
T4
If this region “produced our observable universe”…
A. Albrecht @ UCD 10/3/11 74
-2 -1 0 1 20
0.5
1
1.5
2
2.5
/MP
V/M
GU
T4
It seems reasonable to assume the field was rolling up here beforehand (classical extrapolation)
A. Albrecht @ UCD 10/3/11 75
-60 -50 -40 -30 -20 -10 0-80
-70
-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log[
(RH/R
H0)]
A. Albrecht @ UCD 10/3/11 76
-150 -100 -50 0
-200
-150
-100
-50
0
50
100
150
log(a/a0)
log[
(RH/R
H0)]
410
A. Albrecht @ UCD 10/3/11 77
-600 -500 -400 -300 -200 -100 0
-600
-400
-200
0
200
400
600
log(a/a0)
log[
(RH/R
H0)]
410
A. Albrecht @ UCD 10/3/11 78
-1500 -1000 -500 0-2000
-1500
-1000
-500
0
500
1000
1500
2000
log(a/a0)
log[
(RH/R
H0)]
410
310
A. Albrecht @ UCD 10/3/11 79
-6000 -5000 -4000 -3000 -2000 -1000 0
-6000
-4000
-2000
0
2000
4000
6000
log(a/a0)
log[
(RH/R
H0)]
310
A. Albrecht @ UCD 10/3/11 80
-15000 -10000 -5000 0-2
-1.5
-1
-0.5
0
0.5
1
1.5
2x 10
4
log(a/a0)
log[
(RH/R
H0)]
310
210
A. Albrecht @ UCD 10/3/11 81
-6 -5 -4 -3 -2 -1 0
x 104
-6
-4
-2
0
2
4
6
x 104
log(a/a0)
log[
(RH/R
H0)]
210
A. Albrecht @ UCD 10/3/11 82
-12 -10 -8 -6 -4 -2 0 2
x 104
-1
-0.5
0
0.5
1
x 105
log(a/a0)
log[
(RH/R
H0)]
210
110
A. Albrecht @ UCD 10/3/11 83
-4 -3 -2 -1 0
x 105
-6
-4
-2
0
2
4
6
x 105
log(a/a0)
log[
(RH/R
H0)]
1
110
A. Albrecht @ UCD 10/3/11 84
-4 -3 -2 -1 0
x 105
-6
-4
-2
0
2
4
6
x 105
log(a/a0)
log[
(RH/R
H0)]
1 Q
110
A. Albrecht @ UCD 10/3/11 85
-4 -3 -2 -1 0
x 105
-6
-4
-2
0
2
4
6
x 105
log(a/a0)
log[
(RH/R
H0)]
1 Q
110
Not at all classical!
A. Albrecht @ UCD 10/3/11 86
-4 -3 -2 -1 0
x 105
-6
-4
-2
0
2
4
6
x 105
log(a/a0)
log[
(RH/R
H0)]
110
Self-reproduction regime
Substantial probability of fluctuating up the potential and continuing the inflationary expansion “Eternal Inflation”
1 Q
Linde 1986 and (then) many others
A. Albrecht @ UCD 10/3/11 87
-4 -3 -2 -1 0
x 105
-6
-4
-2
0
2
4
6
x 105
log(a/a0)
log[
(RH/R
H0)]
110
Self-reproduction regime
Substantial probability of fluctuating up the potential and continuing the inflationary expansion “Eternal Inflation”
1 Q
A. Albrecht @ UCD 10/3/11 88
-4 -3 -2 -1 0
x 105
-6
-4
-2
0
2
4
6
x 105
log(a/a0)
log[
(RH/R
H0)]
110
Self-reproduction regime
Substantial probability of fluctuating up the potential and continuing the inflationary expansion “Eternal Inflation”
1 Q
Observable Universe
A. Albrecht @ UCD 10/3/11 89
-4 -3 -2 -1 0
x 105
-6
-4
-2
0
2
4
6
x 105
log(a/a0)
log[
(RH/R
H0)]
1Q
110
4.410 310 Pl
A. Albrecht @ UCD 10/3/11 90
-60 -50 -40 -30 -20 -10 0-80
-70
-60
-50
-40
-30
-20
-10
0
10
log(a/a0)
log[
(RH/R
H0)]
10 Pl
A. Albrecht @ UCD 10/3/11 91
-4 -3 -2 -1 0
x 105
-6
-4
-2
0
2
4
6
x 105
log(a/a0)
log[
(RH/R
H0)]
110
Self-reproduction regime
Substantial probability of fluctuating up the potential and continuing the inflationary expansion “Eternal Inflation”
1 Q
A. Albrecht @ UCD 10/3/11 92
-200 -100 0 100 2000
0.5
1
1.5
2
2.5x 10
4
/MP
V/M
GU
T4
In self-reproduction regime, quantum fluctuations compete with classical rolling
Q
A. Albrecht @ UCD 10/3/11 93
Self-reproduction is a generic feature of any inflaton potential:
3H V During inflation
3H V
3
V
H
2 3 3/2
Q H H V
V V
A. Albrecht @ UCD 10/3/11 94
Self-reproduction is a generic feature of any inflaton potential:
3H V During inflation
3H V
3
V
H
2 3 3/2
Q H H V
V V
1 for self- reproduction
A. Albrecht @ UCD 10/3/11 95
-200 -100 0 100 2000
0.5
1
1.5
2
2.5x 10
4
/MP
V/M
GU
T4
In self-reproduction regime, quantum fluctuations compete with classical rolling
Q
Linde & Linde
A. Albrecht @ UCD 10/3/11 97
2 5 SHd e R
2 /SHt R c
New pocket (elsewhere)
t
Classically Rolling
Classically Rolling
Self-reproduction regime
A. Albrecht @ UCD 10/3/11 98
3 5 SHd e R
3 /SHt R c
New pocket (elsewhere)
t
Classically Rolling
Self-reproduction regime
A. Albrecht @ UCD 10/3/11 99
500 5 SHd e R
500 /SHt R c
New pocket (elsewhere)
t
502r e d
Classically Rolling
Self-reproduction regime
A. Albrecht @ UCD 10/3/11 100
1000 5 SHd e R
1000 /SHt R c
New pocket (elsewhere)
1002r e d
t
Classically Rolling
Self-reproduction regime
A. Albrecht @ UCD 10/3/11 101
1400 5 SHd e R
1400 /SHt R c
New pocket (elsewhere)
1402r e d
t
Self-reproduction regime
A. Albrecht @ UCD 10/3/11 102
1395 5 SHd e R
1400 /SHt R c
New pocket (elsewhere)
1393r e d
t
Classically Rolling
Self-reproduction regime
A. Albrecht @ UCD 10/3/11 103
1991 5 SHd e R
2000 /SHt R c
New pocket (elsewhere)
1989r e d
t
Classically Rolling
Self-reproduction regime
A. Albrecht @ UCD 10/3/11 104
534395 5 S IendH Hd e R R
602,785 /SHt R c
New pocket (elsewhere)
534393r e d
t
Classically Rolling
Self-reproduction regime
A. Albrecht @ UCD 10/3/11 105
534395 5 S IendH Hd e R R
New pocket (elsewhere)
534393r e d
2 /IendHt R c
t
Reheating
Self-reproduction regime
A. Albrecht @ UCD 10/3/11 106
534395 5 S IendH Hd e R R
New pocket (elsewhere)
534393r e d
3.2 /IendHt R c
t
Radiation Era
Self-reproduction regime
A. Albrecht @ UCD 10/3/11 108
Eternal inflation features
• Most of the Universe is always inflating• Leads to infinite Universe, infinitely many pocket universes. The
self-reproduction phase lasts forever.
A. Albrecht @ UCD 10/3/11 109
Eternal inflation features
• Most of the Universe is always inflating• Leads to infinite Universe, infinitely many pocket universes. The
self-reproduction phase lasts forever (globally).
A. Albrecht @ UCD 10/3/11 110
Eternal inflation features
• Most of the Universe is always inflating• Leads to infinite Universe, infinitely many pocket universes. The
self-reproduction phase lasts forever.• Inflation “takes over the Universe”, seems like a good theory of
initial conditions.
A. Albrecht @ UCD 10/3/11 111
Eternal inflation features
• Most of the Universe is always inflating• Leads to infinite Universe, infinitely many pocket universes. The
self-reproduction phase lasts forever.• Inflation “takes over the Universe”, seems like a good theory of
initial conditions.• Need to regulate ’s to make predictions, typically use a cutoff.
A. Albrecht @ UCD 10/3/11 112
Eternal inflation features
• Most of the Universe is always inflating• Leads to infinite Universe, infinitely many pocket universes. The
self-reproduction phase lasts forever.• Inflation “takes over the Universe”, seems like a good theory of
initial conditions.• Need to regulate ’s to make predictions, typically use a cutoff.• For a specific time cutoff, the most recently produced pocket
universes are exponentially favored (produced in an exponentially larger region).
A. Albrecht @ UCD 10/3/11 113
Eternal inflation features
• Most of the Universe is always inflating• Leads to infinite Universe, infinitely many pocket universes. The
self-reproduction phase lasts forever.• Inflation “takes over the Universe”, seems like a good theory of
initial conditions.• Need to regulate ’s to make predictions, typically use a cutoff.• For a specific time cutoff, the most recently produced pocket
universes are exponentially favored (produced in an exponentially larger region). Young universe problem
End of time problemMeasure problems
A. Albrecht @ UCD 10/3/11 114
Eternal inflation features
• Most of the Universe is always inflating• Leads to infinite Universe, infinitely many pocket universes. The
self-reproduction phase lasts forever.• Inflation “takes over the Universe”, seems like a good theory of
initial conditions.• Need to regulate ’s to make predictions, typically use a cutoff.• For a specific time cutoff, the most recently produced pocket
universes are exponentially favored (produced in an exponentially larger region). Young universe problem
End of time problemMeasure problems
State of the art: Instead of making predictions, the experts are using the data to infer the “correct measure”
A. Albrecht @ UCD 10/3/11 115
Eternal inflation features
• Most of the Universe is always inflating• Leads to infinite Universe, infinitely many pocket universes. The
self-reproduction phase lasts forever.• Inflation “takes over the Universe”, seems like a good theory of
initial conditions.• Need to regulate ’s to make predictions, typically use a cutoff.• For a specific time cutoff, the most recently produced pocket
universes are exponentially favored (produced in an exponentially larger region). Young universe problem
End of time problemMeasure problems
State of the art: Instead of making predictions, the experts are using the data to infer the “correct measure”
A. Albrecht @ UCD 10/3/11 116
Eternal inflation features
• Most of the Universe is always inflating• Leads to infinite Universe, infinitely many pocket universes. The
self-reproduction phase lasts forever.• Inflation “takes over the Universe”, seems like a good theory of
initial conditions.• Need to regulate ’s to make predictions, typically use a cutoff.• For a specific time cutoff, the most recently produced pocket
universes are exponentially favored (produced in an exponentially larger region). Young universe problem
End of time problemMeasure problems
State of the art: Instead of making predictions, the experts are using the data to infer the “correct measure”
“True infinity” needed here
A. Albrecht @ UCD 10/3/11 117
Eternal inflation features
• Most of the Universe is always inflating• Leads to infinite Universe, infinitely many pocket universes. The
self-reproduction phase lasts forever.• Inflation “takes over the Universe”, seems like a good theory of
initial conditions.• Need to regulate ’s to make predictions, typically use a cutoff.• For a specific time cutoff, the most recently produced pocket
universes are exponentially favored (produced in an exponentially larger region). Young universe problem
End of time problemMeasure problems
State of the art: Instead of making predictions, the experts are using the data to infer the “correct measure”
“True infinity” needed here
Multiply by 10500 to get landscape story!
A. Albrecht @ UCD 10/3/11 118
Eternal inflation features
• Most of the Universe is always inflating• Leads to infinite Universe, infinitely many pocket universes. The
self-reproduction phase lasts forever.• Inflation “takes over the Universe”, seems like a good theory of
initial conditions.• Need to regulate ’s to make predictions, typically use a cutoff.• For a specific time cutoff, the most recently produced pocket
universes are exponentially favored (produced in an exponentially larger region). Young universe problem
End of time problemMeasure problems
State of the art: Instead of making predictions, the experts are using the data to infer the “correct measure”
“True infinity” needed here
Multiple (∞) copies of “you” in the wavefunction Page’s “Born Rule Crisis”
A. Albrecht @ UCD 10/3/11 119
Eternal inflation features
• Most of the Universe is always inflating• Leads to infinite Universe, infinitely many pocket universes. The
self-reproduction phase lasts forever.• Inflation “takes over the Universe”, seems like a good theory of
initial conditions.• Need to regulate ’s to make predictions, typically use a cutoff.• For a specific time cutoff, the most recently produced pocket
universes are exponentially favored (produced in an exponentially larger region). Young universe problem
End of time problemMeasure problems
State of the art: Instead of making predictions, the experts are using the data to infer the “correct measure”
“True infinity” needed here
A. Albrecht @ UCD 10/3/11 120
A problem has been detected and your calculation has been shut down to prevent damage
RELATIVE_PROBABILITY_OVERFLOW
If this is the first time you have seen this stop error screen,restart your calculation. If this screen appears again, follow these steps:
Check to make sure all extrapolations are justified and equations are valid. If you are new to this calculation consult your theory manufacturer for any measure updates you might need.
If the problems continue, disable or remove features of the theory that cause the overflow error. Disable BS options such as self-reproduction or infinite time. If you need to use safe mode to remove or disable components, restart your computation and utilize to select holographic options.
S
A. Albrecht @ UCD 10/3/11 121
Eternal inflation features
• Most of the Universe is always inflating• Leads to infinite Universe, infinitely many pocket universes. The
self-reproduction phase lasts forever.• Inflation “takes over the Universe”, seems like a good theory of
initial conditions.• Need to regulate ’s to make predictions, typically use a cutoff.• For a specific time cutoff, the most recently produced pocket
universes are exponentially favored (produced in an exponentially larger region). Young universe problem
End of time problemMeasure problems
State of the art: Instead of making predictions, the experts are using the data to infer the “correct measure”
“True infinity” needed here
Or, just be happy we have equations to solve?
A. Albrecht @ UCD 10/3/11 122
OUTLINE
1. Big Bang & inflation basics
2. Eternal inflation
3. de Sitter Equilibrium cosmology
4. Cosmic curvature from de Sitter Equilibrium cosmology
A. Albrecht @ UCD 10/3/11 123
OUTLINE
1. Big Bang & inflation basics
2. Eternal inflation
3. de Sitter Equilibrium cosmology
4. Cosmic curvature from de Sitter Equilibrium cosmology
A. Albrecht @ UCD 10/3/11 124
de Sitter Equilibrium (dSE) cosmology
• Take ideas from Holography, to construct a finite cosmology
A. Albrecht @ UCD 10/3/11 125
de Sitter Equilibrium (dSE) cosmology
• Take ideas from Holography, to construct a finite cosmology
A. Albrecht @ UCD 10/3/11 126
de Sitter Equilibrium (dSE) cosmology
• Take ideas from Holography, to construct a finite cosmology
• Build on initial motivation re the appeal of an equilibrium system (no “initial conditions”)
A. Albrecht @ UCD 10/3/11 127
de Sitter Equilibrium (dSE) cosmology
• Take ideas from Holography, to construct a finite cosmology
• Build on initial motivation re the appeal of an equilibrium system (no “initial conditions”)
• Seek the “Bohr Atom” of cosmology
A. Albrecht @ UCD 10/3/11 128
de Sitter Equilibrium (dSE) cosmology
• Take ideas from Holography, to construct a finite cosmology
• Build on initial motivation re the appeal of an equilibrium system (no “initial conditions”)
• Seek the “Bohr Atom” of cosmology• A counterpoint to the infinities of eternal inflation
A. Albrecht @ UCD 10/3/11 129
de Sitter Equilibrium (dSE) cosmology
• Take ideas from Holography, to construct a finite cosmology
• Build on initial motivation re the appeal of an equilibrium system (no “initial conditions”)
• Seek the “Bohr Atom” of cosmology• A counterpoint to the infinities of eternal inflation• Unabashedly exploit uncertainties about the
fundamental physics (i.e. when continuum field theory is good, and when it breaks down) to construct a realistic cosmology
A. Albrecht @ UCD 10/3/11 130
de Sitter Equilibrium (dSE) cosmology
• Take ideas from Holography, to construct a finite cosmology
• Build on initial motivation re the appeal of an equilibrium system (no “initial conditions”)
• Seek the “Bohr Atom” of cosmology• A counterpoint to the infinities of eternal inflation• Unabashedly exploit uncertainties about the
fundamental physics (i.e. when continuum field theory is good, and when it breaks down) to construct a realistic cosmology
AA: arXiv:1104.3315AA: arXiv:0906.1047AA & Sorbo: hep-th/0405270
A. Albrecht @ UCD 10/3/11 131
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A. Albrecht @ UCD 10/3/11 135
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domination
A. Albrecht @ UCD 10/3/11 136
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domination
Asymptotic behavior de Sitter Space
A. Albrecht @ UCD 10/3/11 137
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The de Sitter horizon
Past horizon of observation event at this time
Past Horizon: Physical distance from (comoving) observer of a photon that will reach the observer at the time of the observation.
A. Albrecht @ UCD 10/3/11 138
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0
1
2
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log[
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H0)]
The de Sitter horizon
Past horizon of observation event at this time
Past Horizon: Physical distance from (comoving) observer of a photon that will reach the observer at the time of the observation.
A. Albrecht @ UCD 10/3/11 139
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0
1
2
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log[
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H0)]
The de Sitter horizon
Past horizon of any observation event deep in the de Sitter era
Past Horizon: Physical distance from (comoving) observer of a photon that will reach the observer at the time of the observation.
A. Albrecht @ UCD 10/3/11 140
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H0)]
Past horizon of any observation event deep in the de Sitter era
Future horizon of event at reheating (distance photon has traveled, in SBB).Hd
Past Horizon: Physical distance from (comoving) observer of a photon that will reach the observer at the time of the observation.
A. Albrecht @ UCD 10/3/11 141
Implications of the de Sitter horizon
• Maximum entropy
• Gibbons-Hawking Temperature
12
3S A H
8
3GH
GT H
Gibbons & Hawking 1977
A. Albrecht @ UCD 10/3/11 142
2 1S A H
“De Sitter Space: The ultimate equilibrium for the universe?
Horizon
8
3GH
GT H
A. Albrecht @ UCD 10/3/11 143
Banks & Fischler & Dyson et al.
Implications of the de Sitter horizon
• Maximum entropy
• Gibbons-Hawking Temperature
• Only a finite volume ever observed
• If is truly constant: Cosmology as fluctuating Eqm.
• Maximum entropy finite Hilbert space of dimension
12
3S A H
8
3GH
GT H
SN e
A. Albrecht @ UCD 10/3/11 144
Banks & Fischler & Dyson et al.
Implications of the de Sitter horizon
• Maximum entropy
• Gibbons-Hawking Temperature
• Only a finite volume ever observed
• If is truly constant: Cosmology as fluctuating Eqm.?
• Maximum entropy finite Hilbert space of dimension
12
3S A H
8
3GH
GT H
?SN e
dSE
cosm
olog
y
A. Albrecht @ UCD 10/3/11 150
Fluctuating from dSE to inflation:
• The process of an inflaton fluctuating from late time de Sittter to an inflating state is dominated by the “Guth-Farhi process”
• A “seed” is formed from the Gibbons-Hawking radiation that can then tunnel via the Guth-Farhi instanton.
• Rate is well approximated by the rate of seed formation:
• Seed mass:
s s
GH
m m
T He e
1/2416
3110
0.0013s I II
GeVm cH kg
A. Albrecht @ UCD 10/3/11 151
Fluctuating from dSE to inflation:
• The process of an inflaton fluctuating from late time de Sittter to an inflating state is dominated by the “Guth-Farhi process”
• A “seed” is formed from the Gibbons-Hawking radiation that can then tunnel via the Guth-Farhi instanton.
• Rate is well approximated by the rate of seed formation:
• Seed mass:
s s
GH
m m
T He e
1/2416
3110
0.0013s I II
GeVm cH kg
Small seed can produce an entire universe Evade “Boltzmann Brain” problem
A. Albrecht @ UCD 10/3/11 152
Fluctuating from dSE to inflation:
• The process of an inflaton fluctuating from late time de Sittter to an inflating state is dominated by the “Guth-Farhi process”
• A “seed” is formed from the Gibbons-Hawking radiation that can then tunnel via the Guth-Farhi instanton.
• Rate is well approximated by the rate of seed formation:
• Seed mass:
s s
GH
m m
T He e
1/2416
3110
0.0013s I II
GeVm cH kg
See important new work on G-F process by Andrew Ulvestad & AA
A. Albrecht @ UCD 10/3/11 153
degrees of freedom temporarily break off to form baby universe:
time
Eqm.
Seed Fluctuation
Tunneling
Evolution
Evolution
Evolution
Inflation
Radiation
Matter
de Sitter
IS SN e e
Recombination
A. Albrecht @ UCD 10/3/11 154
SN e Implications of finite Hilbert space
• Recurrences
• Eqm.
• Breakdown of continuum field theory
A. Albrecht @ UCD 10/3/11 155
SN e Implications of finite Hilbert space
• Recurrences
• Eqm.
• Breakdown of continuum field theory
A. Albrecht @ UCD 10/3/11 156
SN e Implications of finite Hilbert space
• Recurrences
• Eqm.
• Breakdown of continuum field theory
A. Albrecht @ UCD 10/3/11 157
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This much inflation fills one de Sitter horizon
A. Albrecht @ UCD 10/3/11 158
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This much inflation fills more than one de Sitter horizon, generating total entropyand affecting regions beyond the horizon of the observer
MaxS S
A. Albrecht @ UCD 10/3/11 159
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• In dSE cosmology this region is unphysical.
• Breakdown of continuum field theory prevents inflation from filling more than one de Sitter horizon
A. Albrecht @ UCD 10/3/11 160
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• In dSE cosmology this region is unphysical.
• Breakdown of continuum field theory prevents inflation from filling more than one de Sitter horizon
Equivalent to Banks-Fischler holographic constraint on number of e-foldings of inflation (D Phillips 2011)
A. Albrecht @ UCD 10/3/11 161
Fluctuating from dSE to inflation:
• The process of an inflaton fluctuating from late time de Sittter to an inflating state is dominated by the “Guth-Farhi process”
• A “seed” is formed from the Gibbons-Hawking radiation that can then tunnel via the Guth-Farhi instanton.
• Rate is well approximated by the rate of seed formation
• Seed mass:
s s
GH
m m
T He e
1/2416
3110
0.0013s I II
GeVm cH kg
Large exponentially favored saturation of dSE bound
I
A. Albrecht @ UCD 10/3/11 162
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dSE bound on inflation given by past horizon
A. Albrecht @ UCD 10/3/11 163
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dSE bound on inflation given by past horizon
A variety of inflation models, all saturating the dSE bound
A. Albrecht @ UCD 10/3/11 164
OUTLINE
1. Big Bang & inflation basics
2. Eternal inflation
3. de Sitter Equilibrium cosmology
4. Cosmic curvature from de Sitter Equilibrium cosmology
A. Albrecht @ UCD 10/3/11 165
OUTLINE
1. Big Bang & inflation basics
2. Eternal inflation
3. de Sitter Equilibrium cosmology
4. Cosmic curvature from de Sitter Equilibrium cosmology
A. Albrecht @ UCD 10/3/11 166
dSE Cosmology and cosmic curvature
• The Guth-Farhi process starts inflation with an initial curvature set by the curvature of the Guth-Farhi Bubble
• Inflation dilutes the curvature, but dSE cosmology has a minimal amount of inflation
Bk
A. Albrecht @ UCD 10/3/11 168
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Banks & Fischler & Dyson et al.
Evolution of curvature radius 1
k
ca
H
A. Albrecht @ UCD 10/3/11 169
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Curvature radius set by initial curvature
Bk
Banks & Fischler & Dyson et al.
Evolution of curvature radius 1
k
ca
H
A. Albrecht @ UCD 10/3/11 170
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A variety of inflation models, all saturating the dSE bound
Curvature radius set by initial curvature
Bk
Evolution of curvature radius 1
k
ca
H
A. Albrecht @ UCD 10/3/11 171
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A variety of inflation models, all saturating the dSE bound
Curvature radius set by initial curvature
Bk
is given by this gap0
22
0
Hk kk
c k
RH
H R
Evolution of curvature radius 1
k
ca
H
A. Albrecht @ UCD 10/3/11 172
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AA: arXiv:1104.3315
A. Albrecht @ UCD 10/3/11 173
dSE Cosmology and cosmic curvature
• The Guth-Farhi process starts inflation with an initial curvature set by the curvature of the Guth-Farhi bubble
• Inflation dilutes the curvature, but dSE cosmology has a minimal amount of inflation
Bk
A. Albrecht @ UCD 10/3/11 174
Image bySurhud More
Predicted from dSE cosmology is:• Independent of almost
all details of the cosmology
• Just consistent with current observations
• Will easily be detected by future observations
k
k
0 /m
A. Albrecht @ UCD 10/3/11 175
Image bySurhud More
Predicted from dSE cosmology is:• Independent of almost
all details of the cosmology
• Just consistent with current observations
• Will easily be detected by future observations
k
k
0 /m
Work in progress on expected values of (Andrew Ulvestad & AA)
Bk
0.5Bk
0.25Bk
0.1Bk
A. Albrecht @ UCD 10/3/11 176
Conclusions• The search for a “big picture” of the Universe that explains
why the region we observe should take this form has proven challenging, but has generated exciting ideas.
• We know we can do science with the Universe
• It appears that there is something right about cosmic inflation
• dSE cosmology offers a finite alternative to the extravagant (and problematic) infinities of eternal inflation
• Predictions of observable levels of cosmic curvature from dSE cosmology will give an important future test
A. Albrecht @ UCD 10/3/11 177
Conclusions• The search for a “big picture” of the Universe that explains
why the region we observe should take this form has proven challenging, but has generated exciting ideas.
• We know we can do science with the Universe
• It appears that there is something right about cosmic inflation
• dSE cosmology offers a finite alternative to the extravagant (and problematic) infinities of eternal inflation
• Predictions of observable levels of cosmic curvature from dSE cosmology will give an important future test