Gravity in the Quantum World and the Cosmos XXXIII SLAC Summer Institute, August 2005 Rocky Kolb, Fermilab & Chicago

Transcription

1 Gravity in the Quantum World and the Cosmos XXXIII SLAC Summer Institute, August 2005 Rocky Kolb, Fermilab & Chicago

2 Einstein, ca Einstein, ca. 1912

3 "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." Einstein, ca. 1905

4 Special Relativity 1905 General Relativity 1915

5 Beyond Einstein? Did Einstein have the last word on gravity? Classical: are we confident of GR in the classical limit? Scalar-tensor, bi-metric PPN, etc. Singularities, naked + clothed Test GR in the strongfield limit (astro) Test gravity at all length scales (astro/lab) Gravitational radiation

6 Beyond Einstein? Did Einstein have the last word on gravity? Quantum: what will be the quantum theory? Strings/M-theory/SUGR Loop Quantum Gravity Extra dimensions Branes Black hole information issues (semiclassical) Singularities Experimental evidence Astrophysical evidence Cosmological evidence

7 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

8 Cosmology, ca (and present-day Kansas)

9 1) Arrangement: 6,500 light years Cosmology, ca Solar system 30,000 light years 2) Composition: starz in the hood 3) Evolution: unchanging in time 4) Origin:??? 5) Space and time: absolute

10 Absolute space, in its own nature, without relation to anything external, remains always similar and immovable. Isaac Newton 1687 Philosophiae Naturalis Principia Mathematica

11 Modern Laws of Genesis +Λg µν cosmological term (10 nonlinear partial differential equations)

12 ΛCDM Inflation-produced perturbations Baryo/leptogenesis

13 What We Know 1) The baryon asymmetry arises in the GUT or EWK era 2) through B, CP, and nonequilibrium (Sakharov) 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 4) The universe is dominated by a cosmological term (dark energy, phantom energy, quintessence, polenta, cosmological constant,.) cosmo-illogical constant,.)

14 "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 Ward American writer Beware the known unknowns! Not everything self-evident is true!

15 Standard cosmological model* Radiation Dark baryons Neutrinos Bright baryons Dark matter Dark energy Inflation Baryo/leptogenesis Hypotheses? Saving the appearances? Epicycles? * Do we want one? The goal is not a standard one, but the correct one!

16 Ptolemaic System From The Almagest

17 From Book I of De Revolutionibus

18 From Book III of De Revolutionibus

19 What Copernicus Knew First of all, we must note that the universe is spherical. Elliptical orbits! Motions are centered on the sun Sun at a focus! Uniform velocities Equal areas in equal times!

20 What Kepler Knew Gravity is an inverse-square force Kepler thought it was repulsive!

21 Epicycle I Dark matter What is dark matter? In questions like this, truth is only to be had by laying together many variations of error. -- Virginia Woolf A Room of Ones Own

22 matter? Modified Newtonian dynamics Milgrom pointed out dark matter is needed for accelerations a 10 s 18 1 Dark energy is needed for H 10 s 18 1 No relativistic formulation Lensing agrees with dark matter Is halo flattened?

23 matter? Modified Newtonian dynamics Planets Size challenged stars brown red white Black holes Microlensing Undiscovered new particle (WIMP)

24 Epicycle II Dark Energy What is the nature of dark energy In questions like this, truth is only to be had by laying together many variations of error. -- Virginia Woolf A Room of Ones Own

25 Mass density of space: ρ Cosmological constant ( ) ( ) ( 29 ) 2 ( 33 ) 2 10 g cm 10 ev = 10 cm Λ Λ= = = 8πG ρ 10 cm 10 ev Λ The unbearable lightness of nothing! Cosmo-illogical constant? Numerology: ρ = M exp 2 α ρ = M M m ( ) V W V SUSY Pl ν = 10 ev R = 10 cm 3 4 5

26 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)

27 V ( φ) Epicycle II Inflation In questions like this, truth is only to be had by laying together many variations of error. -- Virginia Woolf A Room of Ones Own φ

28 The Universe 380,000 Years AB temperature and density correlations on scales 380,000 light years today age=380,000 yrs age=0 Sachs-Wolfe opaque

29 More than 380,000 light years in less than 380,000 years? v c v c for velocity through space no limit on expansion velocity of space acausal requires accelerated expansion

30 Potential energy: energy of -wavelength mode Particle content: condensate of -wavelength particles New inflation: Linde; Albrecht & Steinhardt V (φ) inflaton Classical equations of motion V ( φ) 0 V ( φ) = 0 φ

31 Complete list of known fundamental scalar fields (from Particle Data Book):

32 δ g µν δφ (When a hammer is your only tool, everything has the appearance of a nail.)

33 An Early Particle Cosmologist In mid-1930s, influenced by Eddington & Lemaître, Schrödinger turned to cosmological issues : Graz Vatican Gent, Belgium Dublin

34 The Proper Vibrations of the Expanding Universe Erwin Schrödinger, Physica 6, 899 (1939) Introduction: 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. Conclusion: There will be a mutual adulteration of positive and negative frequency terms in the course of time, giving rise to the alarming phenomenon

35 The Proper Vibrations of the Expanding Universe Erwin Schrödinger, Physica 6, 899 (1939) Creation of a single pair of particles per Hubble volume per Hubble time with Hubble energy H V t H E H H 60 km s Mpc ( c H) H H Mpc 10 years ev Alarming?

36 Even Earlier Graz Cosmologist 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 : Graz Prague Linz Sagan Ratisbon

37 Disturbing the Vacuum Strong gravitational field particle production (Hawking radiation) Black Hole

38 Particle creation: finite-wavelength modes φ not smooth V ( φ) inflaton Quantum fluctuations δφ δρ δt φ

39 Scalar Perturbations: density perturbations! semi-classical quantum gravity Tensor Perturbations: perturbations of transverse, traceless component of the metric: gravitational waves (gravitons) QUANTIZATION of perturbations of small perturbations about conformally flat background

40 The Quantum and the Cosmos

41 Imprint of Inflation Inflation Big Bang plus 10-35? seconds Seeds of Structure + Gravitational Waves Big Bang plus 380,000 Years Big Bang plus 14 Billion Years

42 CMB Polarization Stebbins, Kosowsky, Kamionkowski Seljak & Zaldarriaga E modes B modes (gravitational waves)

43 LIGO LISA BBO Laser Interferometer Space Antenna LISA uses a laser based Michelson interferometer to monitor the separation between proof masses in separate spacecraft Joint ESA-NASA project 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 Flight demonstration of disturbance reduction system ST-7 on ESA SMART-2 mission in 2006 micro-newton thrusters

44 LIGO LISA BBO Cornish, Bennett, Spergel

45 log λ log R H ; Inflationary cosmology Could Planck (string, extradimension, brane, ) scale effects appear in CMB? λ λ a λ = R H ( ) GeV 1 R H λ = R Pl ( ) GeV 1 16 e-folds before crossing log a

46 Intelligent Design? Chemical Elements: (other than H & He) 0.03% ν ν ν Neutrinos: 0.47% Stars: 0.5% Dark Energy: 70% Dark Matter: 25% Free H & He: 4% 95% Mystery

47 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

48 Gravity in the Quantum World and the Cosmos XXXIII SLAC Summer Institute, August 2005 Rocky Kolb, Fermilab & Chicago