Gravity in the Quantum World and the CosmosXXXIII SLAC Summer Institute, August 2005

Rocky Kolb, Fermilab & Chicago

Gravity in the Quantum World and the CosmosXXXIII SLAC Summer Institute, August 2005

Rocky Kolb, Fermilab & Chicago

Einstein, ca. 1952 Einstein, ca. 1912

Einstein, ca. 1905

"When the Special Theory of Relativity began to germinate in me, I was visited by all sorts of nervous conflicts... I used to go away for weeks in a state of confusion."

"A storm broke loose in my mind."

Special Relativity

1905

General Relativity1915

Beyond Einstein?Beyond Einstein?Beyond Einstein?Did Einstein have the last word on gravity?

• Classical: are we confidentof GR in the classical limit?

– Scalar-tensor, bi-metricPPN, etc.

– Singularities, naked + clothed

– Test GR in the strong-field limit (astro)

– Test gravity at alllength scales (astro/lab)

– Gravitational radiation

Beyond Einstein?Beyond Einstein?Beyond Einstein?Did Einstein have the last word on gravity?

• Quantum: what will be thequantum theory?

– Strings/M-theory/SUGR– Loop Quantum Gravity– Extra dimensions– Branes– Black hole information

issues (semiclassical)– Singularities – Experimental evidence– Astrophysical evidence – Cosmological evidence

Beyond Einstein?Beyond Einstein?Beyond Einstein?Did Einstein have the last word on gravity?

• Cosmic: is the “standard”cosmological model correct?

– Initial singularity – Inflation– Dark Matter– Dark Energy– Baryo/leptogenesis– Primordial gravitational

waves

Cosmology, ca. 1005 (and present-day Kansas)Cosmology, ca. 1005 Cosmology, ca. 1005 (and present(and present--day Kansas)day Kansas)

1) Arrangement:

2) Composition: starz’ in the ‘hood3) Evolution: unchanging in time

4) Origin: ???

5) Space and time: absolute

30,000 light years

6,500light years

Solar system

Cosmology, ca. 1905Cosmology, ca. 1905Cosmology, ca. 1905

Absolute space,

in its own nature,

without relation

to anything external,

remains always similar

and immovable.

Isaac Newton 1687

Philosophiae NaturalisPrincipia Mathematica

Modern Laws of GenesisModern Laws of Genesis

(10 nonlinear partial differential equations)

gµν+Λcosmological

term

ΛCDMΛΛCDMCDM

• Inflation-produced perturbations• Baryo/leptogenesis

What We “Know”What We “Know”What We “Know”

2) The matter density is dominated by cold dark matter …

3) The perturbations arise from inflationary dynamics, which depends on particle physics at high energies …

1) The baryon asymmetry arises in the GUT or EWK era 2) through B, CP, and nonequilibrium (Sakharov)

polenta, 4) The universe is dominated by a cosmological term

(dark energy, phantom energy, quintessence, cosmological constant, ….) … cosmo-illogical constant, ….) …

"It ain't so much the things we don't know that get us in trouble. It's the things we know that ain't so."

Artemus WardAmerican writer1834-1867

• Beware the known unknowns!• Not everything “self-evident” is true!

Standard cosmological model*Standard cosmological model*Standard cosmological model*

* Do we want one? The goal is not a standard one, but the correct one!

• Radiation• Dark baryons• Neutrinos• Bright baryons• Dark matter• Dark energy• Inflation• Baryo/leptogenesis

• Hypotheses?• Saving the appearances?

• Epicycles?

Pto

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aic

Sys

tem

From

Th

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aic

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aic

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What Copernicus “Knew”What Copernicus “Knew”What Copernicus “Knew”“First of all, we must note that the universe is spherical.”

Uniform velocities

Motions are centered on the sun

Equal areas in equal times!

Sun at a focus!

Elliptical orbits!

What Kepler “Knew”What What KeplerKepler “Knew”“Knew”Gravity is an inverse-square force

…

…

…

Kepler thought it was repulsive!

Epicycle I – Dark matterEpicycle I Epicycle I –– Dark matterDark matterWhat is dark matter?

“In questions like this, truth is only to be had by laying together many variations of error.”

-- Virginia WoolfA Room of Ones Own

matter?matter?• Modified Newtonian dynamics

• Milgrom pointed out dark matteris needed for accelerations

• Dark energy is needed for

• No relativistic formulation

• Lensing agrees with dark matter

• Is “halo” flattened?

18 110 sa − −≤

18 110 sH − −≤

• Modified Newtonian dynamics

matter?matter?

• Undiscovered new particle (WIMP)

• Black holes

• Size challenged stars

• Planets Microlensing

brown red white

Epicycle II – Dark EnergyEpicycle II Epicycle II –– Dark EnergyDark Energy

“In questions like this, truth is only to be had by laying together many variations of error.”

-- Virginia WoolfA Room of Ones Own

What is the nature of dark energy

Mass density of space:

Cosmo-illogical constant?CosmoCosmo--illogical constant?illogical constant?

( ) ( )4 430 -3 4 310 g cm 10 eV 10 cmρ −− − −Λ =

Cosmological constantCosmological constantCosmological constant

The unbearable lightness of nothing!( ) ( )2 229 338 10 cm 10 eVGπ ρ − −ΛΛ = = =

Numerology:( )4 8 4SUSY

3 45

exp 2

10 eV 10 cmV W V PlM M M

m Rν

ρ α ρ− −

= − =

= =

• 10−33 eV scalar fields!!!• modification of gravity• extra dimensions• branes and bulk• Lorentz violating vector fields• Friedmann equation incomplete•••• (then there are the crazy ideas)

Epicycle II – InflationEpicycle II Epicycle II –– InflationInflation

“In questions like this, truth is only to be had by laying together many variations of error.”

-- Virginia WoolfA Room of Ones Own

( )V φ

φ

The Universe 380,000 Years ABThe Universe 380,000 Years ABThe Universe 380,000 Years AB

age=380,000 yrs

opaque

age=0today

Sachs-Wolfe

temperature and densitycorrelations on scales

380,000 light years

v c≤v c≤

More than 380,000 light years in less than 380,000 years?

More than 380,000 light years More than 380,000 light years in less than 380,000 years?in less than 380,000 years?

v c≤• for velocity through space• no limit on expansion velocity of space• “acausal” requires “accelerated” expansion

Classical equations of motion0)( ≠φV 0)( =φV

“inflaton”

)(φV

φ

Potential energy: energy of ∞-wavelength modeParticle content: condensate of ∞-wavelength particles

“New” inflation: Linde;Albrecht & Steinhardt

Complete list of known fundamental scalar fields

(from Particle Data Book):

Complete list of known fundamental Complete list of known fundamental scalar fieldsscalar fields

(from Particle Data Book):(from Particle Data Book):

δφ

gµνδ

(When a hammer is your only tool, everything has theappearance of a nail.)

An Early Particle CosmologistAn Early Particle CosmologistAn Early Particle Cosmologist

1938-1939: Graz Vatican Gent, Belgium Dublin

In mid-1930s, influenced by Eddington & Lemaître,Schrödinger turned to cosmological issues

“… proper vibrations [positive and negative frequencies]cannot be rigorously separated in the expanding universe.… this is a phenomenon of outstanding importance. With particles it would mean production or annihilation of matter, merely by expansion,… Alarmed by these prospects, I have examined the matter in more detail.”

“… There will be a mutual adulteration of positive and negative frequency terms in the course of time, giving rise to … the ‘alarming phenomenon’…”

Introduction:

Conclusion:

The Proper Vibrations of the Expanding UniverseThe Proper Vibrations of The Proper Vibrations of the Expanding Universethe Expanding Universe

Erwin Schrödinger, Physica 6, 899 (1939)

Creation of a single pair of particlesper Hubble volumeper Hubble timewith “Hubble energy”

Alarming?

( )

1 1

3 12 3

1 10

33

60 km s Mpc

10 Mpc

10 years

10 eV

H

H

H

H

V c H

t H

E H

− −

−

−

≡

≡

≡

The Proper Vibrations of the Expanding UniverseThe Proper Vibrations of The Proper Vibrations of the Expanding Universethe Expanding Universe

Erwin Schrödinger, Physica 6, 899 (1939)

Even Earlier Graz CosmologistEven Earlier Graz CosmologistEven Earlier Graz Cosmologist

1600-1630: Graz Prague Linz Sagan Ratisbon

“When the storms rage around us, and the state is threatened by shipwreck, we can do nothing nobler than to lower the anchor of our peaceful studies in the ground of eternity.” - J. Kepler

Disturbing the VacuumDisturbing the VacuumDisturbing the VacuumStrong gravitational field particle production

(Hawking radiation)

BlackHole

TδδρδφQuantum fluctuations

“inflaton”

Particle creation: finite-wavelength modesnot smoothφ

( )V φ

φ

• perturbations of transverse, traceless componentof the metric: gravitational waves (gravitons)

• QUANTIZATION of perturbations of small perturbations about conformally flat background

Tensor Perturbations:Tensor Perturbations:Tensor Perturbations:

• density perturbations!• semi-classical quantum gravity

Scalar Perturbations:Scalar Perturbations:Scalar Perturbations:

The Quantum and the CosmosThe Quantum and the CosmosThe Quantum and the Cosmos

InflationBig Bang plus

10-35? seconds

Big Bang plus 380,000 Years

Big Bang plus 14 Billion Years

Seeds of Structure+

Gravitational Waves

Imprint of InflationImprint of InflationImprint of Inflation

E modes B modes(gravitational waves)

Stebbins, Kosowsky, Kamionkowski Seljak & Zaldarriaga

CMB PolarizationCMB PolarizationCMB Polarization

Flight demonstration of disturbance reduction system ST-7 on ESA SMART-2 mission

in 2006

Joint ESA-NASA project

micro-newtonthrusters

Laser Interferometer Space AntennaLIGO LISA BBOLIGO LISA BBOLIGO LISA BBO

LISA uses a laser based Michelson interferometer to monitor the separation between proof masses in separate spacecraft

• 3 spacecraft separated by 5 million km

• Each spacecraft includes two freely falling test masses with drag free operation

• Distance changes measured with precision of 4 ppm RMS over 100 seconds

Cornish, Bennett, Spergel

LIGO LISA BBOLIGO LISA BBOLIGO LISA BBO

log a

log λ

aλ ∝λ

RH

log

RH

;

( ) 11310 GeVHRλ−

= ∼

( ) 11910 GeV16 e-folds before crossing

PlRλ−

= ∼

Inflationary cosmologyInflationary cosmologyInflationary cosmologyCould Planck (string, extra-dimension, brane, …) scale effects appear in CMB?

ν

ν

ν

Dark Matter: 25%

Dark Energy: 70%

Stars:0.5%

Free H & He:4%

IntelligentDesign?IntelligentIntelligentDesign?Design?

Chemical Elements: (other than H & He) 0.03%

Neutrinos: 0.47%

95%Mystery

“The most beautiful thing we can experience is the mysterious. It is the source of all true art and all science. Those to whom this emotion is a stranger, who can no longer pause to wonder and stand rapt in awe, are as good as dead: their eyes are closed.”

Albert Einstein

Gravity in the Quantum World and the CosmosXXXIII SLAC Summer Institute, August 2005

Rocky Kolb, Fermilab & Chicago

Gravity in the Quantum World and the CosmosXXXIII SLAC Summer Institute, August 2005

Rocky Kolb, Fermilab & Chicago