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Inflation, infinity, equilibrium and the observable Universe Andreas Albrecht UC Davis UCD Colloquium October 3, 2011 1 A. Albrecht @ UCD 10/3/11

Inflation, infinity, equilibrium and the observable Universe Andreas Albrecht UC Davis UCD Colloquium October 3, 2011 1A. Albrecht @ UCD 10/3/11

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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

E

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 10

Friedmann Eqn.

2

2 8

3 k r m DE

aH G

a

A. Albrecht @ UCD 10/3/11 11

Friedmann Eqn.

2

2 8

3 k r m DE

aH G

a

Curvature

2a

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 15

-30 -20 -10 0 10-20

0

20

40

60

80

100

120

log(a/a0)

log( / c0 )

r

m

A. Albrecht @ UCD 10/3/11 16

-30 -20 -10 0 10-20

0

20

40

60

80

100

120

log(a/a0)

log( / c0 )

r

m

A. Albrecht @ UCD 10/3/11 17

-5 -4 -3 -2 -1 0 1 2

-10

-5

0

5

10

15

log(a/a0)

log( / c0 )

r

m

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 36

2

2 8 8

3 3I k r m DE Tot

aH G G

a

Hubble Length

1/2

1H

Tot

cR

H

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 39

-60 -40 -20 0 20-20

0

20

40

60

80

100

120

log(a/a0)

log( / c0 )

Tot

A. Albrecht @ UCD 10/3/11 40

-60 -40 -20 0 20

-100

-50

0

50

100

log(a/a0)

log( / c0 )

Tot

A. Albrecht @ UCD 10/3/11 41

-60 -40 -20 0 20

-100

-50

0

50

100

log(a/a0)

log( / c0 )

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 63

Brown et al.Astrophys.J.705:978-999,2009

A. Albrecht @ UCD 10/3/11 64

Brown et al.Astrophys.J.705:978-999,2009

A. Albrecht @ UCD 10/3/11 65

Keiser et al. 2011

A. Albrecht @ UCD 10/3/11 66

Keiser et al. 2011

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 96

5 SHd R

t0t

Classically Rolling

Self-reproduction regime

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 10/3/11 107

Eternal inflation features

• Most of the Universe is always inflating

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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0

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-4 -2 0 2 4

-6

-5

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0

1

2

3

log(a/a0)

log[

(RH/R

H0)]

domination

A. Albrecht @ UCD 10/3/11 136

-4 -2 0 2 4

-6

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-4

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-2

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0

1

2

3

log(a/a0)

log[

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domination

Asymptotic behavior de Sitter Space

A. Albrecht @ UCD 10/3/11 137

-4 -2 0 2 4

-6

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0

1

2

3

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log[

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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

-4 -2 0 2 4

-6

-5

-4

-3

-2

-1

0

1

2

3

log(a/a0)

log[

(RH/R

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

-4 -2 0 2 4

-6

-5

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-3

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-1

0

1

2

3

log(a/a0)

log[

(RH/R

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

-4 -2 0 2 4

-6

-5

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-1

0

1

2

3

log(a/a0)

log[

(RH/R

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 10/3/11 145

Equilibrium Cosmology

A. Albrecht @ UCD 10/3/11 146

Rare Fluctuation

A. Albrecht @ UCD 10/3/11 147

Rare Fluctuation

A. Albrecht @ UCD 10/3/11 148

Concept:

Realization:

“de Sitter Space”

A. Albrecht @ UCD 10/3/11 149

Rare Fluctuation

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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I

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m

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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m

• 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 10/3/11 167

Friedmann Eqn.

2

2 8

3 I k r m DE

aH G

a

2a

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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log(a/a0)

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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