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July 2009MPA-Garching
Michael S. TurnerKavli Institute for Cosmological Physics
The University of Chicago
2009 Biermann Lectures:“Quarks and the Cosmos”
I. Cosmic Acceleration and Dark Energy (8 July) I. Inflation and Beyond (23 July)
II. Future Opportunities and Challenges (28 July)
• Contributions to the theory of convection in stars• Modeled the solar chromosphere and corona• Computed atomic physics parameters needed for stars• Predicted the solar wind (based upon comets) • Magnetic fields in the solar system and in the Galaxy
Where is he now?
Profound Connections
Between Quarks and the Cosmos
Basic Features of the Universe
tied to Fundamental
Physics
Michael S Turner
Cosmology Cosmology is is a a
young scienceyoung scienceits story only 300 years after its story only 300 years after
the invention of the telescopethe invention of the telescope
Michael S Turner
1916-1918: General Relativity & 1916-1918: General Relativity & ΛΛ
PS: Never mind Λ
Michael S Turner
1929: Just One Number K 1929: Just One Number K (error bars not needed, velocity in km)
Hubble & Humanson: few 100 galaxies, z < 0.1Hubble & Humanson: few 100 galaxies, z < 0.1
K (H 0) = 550 km/s/Mpc
Gamow’s Hot Big Bang“alpher, bethe, gamow,” 1948
1948: Steady State Theory
Michael S Turner
Cosmology: The Search for Cosmology: The Search for Two Numbers Two Numbers … Sandage 1970
Michael S Turner
Landau on Landau on CosmologistsCosmologists
Often in Error, Often in Error, Never in Doubt!Never in Doubt!
Michael S Turner
and at U Mass
The Redbook, a manual for faculty members that explained what a university was, and
what it wasn't. It cited two courses one wouldn't find in a curriculum of higher education: witchcraft and cosmology.
Michael S Turner
Discovery of Cosmic Microwave Background, 1964
Michael S Turner
““The Standard Model”The Standard Model”Hot Big Bang (circa 1972)Hot Big Bang (circa 1972)
““Reality (physics) Based”Reality (physics) Based”• BBN (nuclear physics)BBN (nuclear physics)• CMB (atomic physics)CMB (atomic physics)• Structure Formation (grav. Structure Formation (grav.
physics)physics)• Begins at 0.01 secBegins at 0.01 sec• ΩΩ00 ~ 0.1 (baryons) ~ 0.1 (baryons)Big QuestionsBig Questions• ““The naughts”: HThe naughts”: H00, t, t00, Ω, Ω00
• Large entropy per baryonLarge entropy per baryon• Hadron WallHadron Wall• Origin of density Origin of density
perturbationsperturbations
Michael S Turner
Michael S Turner
1980s: The Go Go Junk Bond Days 1980s: The Go Go Junk Bond Days of Early Universe Cosmologyof Early Universe Cosmology
““Creativity Based”Creativity Based”• InflationInflation• Cosmic StringsCosmic Strings• BaryogenesisBaryogenesis• Magnetic Magnetic
MonopolesMonopoles• Phase TransitionsPhase Transitions• Hot and Cold Dark Hot and Cold Dark
MatterMatter• Decaying ParticlesDecaying Particles• Kaluza-KleinKaluza-Klein
Michael S Turner
Two Really Important IdeasTwo Really Important IdeasThat Changed CosmologyThat Changed Cosmology
with deep connections between quarks and the cosmos
Inflation:Inflation: brief period of rapid (accelerated) expansion accounts for smoothness, flatness; heat of the big bang; and seed inhomogeneities
Particle dark matter:Particle dark matter: bulk of the dark matter that holds the Universe together resides in a sea of elementary particles left over from the big bang
Michael S Turner
Cold Dark Matter Transformed “Astrophysical Cosmology”
… and this Institute!
Michael S Turner
1990s: Beginning of Data-driven 1990s: Beginning of Data-driven CosmologyCosmology
• COBE! and CMB experiments• Redshift surveys (CfA, IRAS, 2dF, SDSS)• Large-scale velocity field measurements• Gravitational lensing• Big telescopes (Keck, …) with big CCD
cameras• HST, X-ray, gamma-ray, IR, …
Big Glass on the Ground: Big Glass on the Ground: 4 VLT, 2 Kecks, 2 Geminis and 4 VLT, 2 Kecks, 2 Geminis and
2 Magellans2 Magellans
Great Observatories in Space: Great Observatories in Space: Hubble, Spitzer, Chandra, and Hubble, Spitzer, Chandra, and
FermiFermi
How far can you see on a clear
day?Back to the birth
of galaxies
How far can you see on a clear day with x-ray eyes?To supermassive black holes at the
edge of the Universe!
Michael S Turner
2000s: Era of Precision Cosmology2000s: Era of Precision Cosmology
““Fisher Based”Fisher Based”• Cosmological
parameters• Tests of inflation, CDM• Correlating large,
complex data sets• Cosmological
Consistency• Physical parameters
(e.g., neutrino mass)
Michael S Turner
The Consensus CosmologyThe Consensus Cosmologydark matter, dark energy, inflation inspired
fits a large body of precision data!
Michael S Turner
The Universe circa 380,000 yrsThe Universe circa 380,000 yrsWMAP
±0.001% Fluctuations
Michael S Turner
Curve = concordance cosmology
Michael S TurnerSloa
n D
igita
l Sky
Sur
vey
sdss
.org
Large-scale structure: Distribution of 106 galaxies
in the Universe today
Michael S Turner
Tracing the history from a slightly lumpy Universe to galaxies ablaze
Michael S Turner
The “Consensus Cosmology”The “Consensus Cosmology”based upon precision measurements
• From quark soup to nuclei and atoms to galaxies and large-scale structure
• Flat, accelerating Universe• Atoms, exotic dark matter & dark energy• Consistent with inflation• Precision parameters
–Ω0 = 1.005 ± 0.006 (uncurved)–ΩM = 0.280 ± 0.013–ΩB = 0.045 ± 0.0015–ΩDE = 0.72 ± 0.015–H0 = 70 ± 1.3 km/s/Mpc–t0 = 13.73 ± 0.12 Gyr–Nν = 4.4 ± 1.5
Consistent with Consistent with all data, all data,
laboratory and laboratory and cosmological!cosmological!
Michael S Turner
Cosmic Acceleration is a central feature of the
consensus cosmology
no cosmic acceleration, no consensus cosmology!
Discovery! – 1998Discovery! – 1998
Hi z Supernova TeamSupernova Cosmology Project
Mark Philips
Two Technological Enablers:Two Technological Enablers:
1.1. Large (100 Mpixel) CCD Large (100 Mpixel) CCD CamerasCameras
2.2. SNe Ia: Bright, SNe Ia: Bright, Standardizable Candles (1.4 solar mass bomb)
The Discovery DataThe Discovery Data
Perlmutter et al, 1999 Riess et al, 1998
Carl Sagan:Carl Sagan:
Extraordinary Extraordinary Claims Claims RequireRequire
Extraordinary Extraordinary EvidenceEvidence
… … in any case, the in any case, the extraordinary evidence is extraordinary evidence is
now in placenow in place
Michael S Turner
Curve = concordance cosmology Ω0 = 1.005 ± 0.006 ΩM = 0.28 ± 0.015
only consistent ifΩΛ-like = 0.72 ± 0.015
1000 SNe from: 1000 SNe from: the original teams + the original teams +
SNLS, ESSENCE, SDSS, SNLS, ESSENCE, SDSS, CfA, CSP, …CfA, CSP, …
More data stronger signalMore data stronger signal
SDSS-II Supernova SurveySDSS-II Supernova Survey
~500 Well studied SNe Ia, suitable for framing
Evidence for past acceleration: Evidence for past acceleration: Important reality checkImportant reality check
HST ACS Sample of high-z SNe: A. Riess et al, Ap.J 607, 665 (2004)
Michael S Turner
gri
SDSS
Low
-red
shift
Lig
ht c
urve
s w
ill le
ad to
bet
ter u
nder
stan
ding
of
Typ
e Ia
Sup
erno
vae
Baryon Acoustic Oscillations (BAO): Zel’dovich’s Standard Ruler
Clusters as Standard RulersClusters as Standard Rulers
Use constancy of the baryon-to-total
mass ratio as a standard ruler
S. Allen et al, MNRAS 353, 457 (2004); 383, 879 (2007)
Michael S Turner
New stand alone evidence for cosmic acceleration from
clusters observed by Chandra
A.Vikhlinin et al, ApJ 692, 1060 (2009) [arXiv:0812.2720]36 Clusters w/<z>~0.55 and 49 w/<z>~0.05
Michael S Turner
Michael S Turner
Consistent with all observations:
ΩΛ = 0.71 ± 0.02
Consistent Age for UniverseConsistent Age for Universe
EddingtonEddingtonCriterionCriterion
Very elastic stuff (p < -ρ/3) with repulsive
gravity is called “dark
energy”
Dark EnergyDark EnergyDefining features:• Large negative pressure, p ~ -ρ, so that (ρ + 3 p) < 0• w = p/ρ (equation-of-state parameter) ~ -1• Smoothly distributed• Not particulate (dark matter has p ~ 0)
Simplest example: • Energy of the quantum vacuum: w = -1
The Gravity of Nothing
Is Repulsive
… But How Much DoesNothing Weigh?
Apparently, Way Too Much
or Possibly Nothing
to be more precise, the answer is nonsensical
(infinite) – not as bad as a finite answer that is off by
orders of magnitude
ρvac ≈ 3 x 10-11 eV4
Vacuum Energy Problem Solved Vacuum Energy Problem Solved by Supersymmetry or ?by Supersymmetry or ?
Now we have two puzzles:
Why does nothing weighs so little?&
What is dark energy?
Puzzles could be related or unrelated!
Theorists: When in
doubt, just add a
scalar field
NB: does not address of the
lightness of nothing
“Old Gravitational Physics” Hitherto Undiscovered Aspects of GR?
• Primordial inflation explains why the universe is accelerating today, E. W. Kolb, S. Matarrese, A. Notari, A. Riotto (astro-ph/0503117)
• On cosmic acceleration without dark energy, E.W. Kolb, S. Matarrese, A. Riotto (astro-ph/0506534)
• Comments on Backreaction and Cosmic Acceleration, E. Kolb, S. Matarrese, A. Riotto (astro-ph/0511073)
• Cosmological background solutions and cosmological backreactions, E. Kolb, V. Marra, S. Matarrese, (arXiv: 0901.4566)
Dark Theory Summary
• Can easily accommodate cosmic acceleration (meets Eddington criterion)
• No satisfactory or even compelling explanation (lots of interesting ideas)
• “GR exceptionalism” (hard to create a viable alternative)
• Very important problem
Why dark energy is importantWhy dark energy is important Not in the list of players in the standard model
(new physics) Non-particulate (counterexample to the 2000 yr
reductionist approach), repulsive gravity Could be related to inflation or dark matter or both
or neither! May have other effects (long range forces,
neutrino mass) Controls the destiny of the Universe (though
probably not evolution of structure etc)
From Here to EternityFrom Here to Eternity
Cannot Understand Our CosmicDestiny Until We Understand What
Dark Energy Is!
In the Presence of DarkEnergy, a Flat UniverseCan Expand Forever, Re-collapse, or EvenExperience a Big Rip!
Youbetcha Katie, I believe
in Dark Energy – we can see it from Alaska!
Current null hypothesis (Λ/quantum vacuum energy) is not acceptable (maybe enough for astrophysical
cosmologist).It is a signal for new physics: gravitational, particle, or ? And
fundamental to our understanding of the cosmological framework
Important clue or
coincidence?At the very
least, we can now say that cosmology is the battle between two dark titans
Two Big Dark QuestionsTwo Big Dark Questions
Does Dark Energy change with time (i.e., is dark energy vacuum energy)?
Does Cosmic Acceleration require going beyond General Relativity?
No, at the 10 to 20% level
Not well tested
Probing Cosmic Acceleration Probing Cosmic Acceleration and Dark Energyand Dark Energy
• Primary effect is on the expansion rate
• Expansion rate controls distances, structure growth
• Two Qualitatively Different Probes– Geometric: distances– Dynamic: growth of structure – NB: if not GR, changes in growth, lensing
Known Probes of Dark EnergyKnown Probes of Dark Energy• Supernovae: Geometric• BAO: Geometric + simple physics• Weak Lensing: Geometric + dynamic• Clusters: Dynamics + geometric• Evolution of large-scale structure (dynamic)
– Must reproduce LCDM– Growth factor/red-shift space distortions
• CMB and other precision data that pin down cosmological parameters (provide priors)
Dark Energy:ΩDE = 0.76 ± 0.02 w = -0.94 ± 0.1
(± 0.1 sys)
Where We Are Today
New Results 400d SurveyNew Results 400d SurveyAlexey Vikhlinin et al, CCCP
Allow w to vary:
w = w0 + wa(1-a) a = scale factor
ΩDE = 0.76 ± 0.02 w0 = -1 ± 0.2
wa ~ 0 ± 1Possible variation is not well constrained
No Reason to Believe w is Constant
• Observational side– >1000 SNeIa; better studied (more colors, esp. IR, spectra,
better LC coverage)– Warts yes; cancer no
• Theoretical side– Significant improvement in handling of combustion; ignition
mechanism still a big issue (source of diversity?)– Producing more observables– Evidence for 1.4 Msun explosion– Tests for and models of SNeIa outliers
• Issues– Dust, percent level photometry, need larger local sample/training
set; demographics, outliers, – Better theoretical understanding
Supernovae: Significant ProgressSupernovae: Significant Progress
Pandora’s Box and SNeIa
OR
Clusters:Cosmic Frogs: very sensitive
to cosmic environment
• Observational side– Big surveys underway (ACT, SPT)– First blind detections of clusters (SPT)– Results from 400d: constraints to w & stand alone evidence for
DE– Clusters can be found by O, X, and SZ
• Theoretical side– Exponential leverage!– Significant progress on understanding mass/observable relations
and formation history
• Open issues– Robustness of mass/observable relations– Selection– Cluster physics: how much more than
ClustersClusters
Staniszewski et al, astro-ph/0810.1578
First Results from the South Pole Telescope
Michael S Turner
eROSITA 2011
• Observational side– Two (three) detections with 4% errors!– Big surveys underway– Need lots of “spectroscopic class” red shifts
• Theoretical side– Powerful & clean; good probe of curvature– Geometric + “simple physics”
• Open issues– Exploit other scales (damp, Silk)– Systematics: what are they??; how bad?? Small
compared to 1%
BAOBAO
• Observational side– Steady progress ( 100 sq deg): signal out to 4
degrees (CFHTLS), on the way to 1000 sq deg and beyond
– mild constraints on w; WMAP tension on σ8 gone• Theoretical side
– Theory well understood, but γ ~ σ8 ΩM0.4 z0.8 |w|0.15
– Shear ratio test isolates geometric side• Issues
– Better knowledge of non-linear power spectrum– Systematics (image, photo-z: δw ~ 15δz) – see
Taylor
Weak LensingWeak Lensing
• BAO: SDSS/2dF, WiggleZ, FMOS, BOSS HETDEX, WFMOS, PAU
• CL: SZA, SPT, DES, ACT, 400d, eROSITA• SNe: JDEM, DES, PanSTARRS• WL: PS, JDEM, EUCLID, DES, PanSTARRS• CMB et al: WMAP/ACT/SPT/Planck – cosmological
degeneracies make many other observations valuable
On the way to few % in w0, 10% in wa, significant tests of underlying gravity theory … and deeper understanding of dark energy
Impressive Array of Dark Energy Impressive Array of Dark Energy Projects on the HorizonProjects on the Horizon(pssst, don’t tell Simon “DM” White)
Dark SummaryDark Summary• Strong evidence for cosmic acceleration, central
part of consensus cosmology• Theory provides a framework for discussing, but
not understanding• Profound problem whose solution is likely to
have far reaching consequences• Powerful probes: Clusters, SNe, BAO, WL +
Planck priors • Cosmic complementarity:
– Kinematic and dynamic probes; error ellipses– Expt’l complementarity: different systematics/risks
• Open mind to new ideas: long range force
Michael S Turner
How Much is Enough?!#How Much is Enough?!#
Michael S Turner
Four “Stage IV” FuturesFour “Stage IV” Futures
1. w = -1 & theory breakthrough
Percent level measurements of w and wa and LSS consistent with ΛCDM
+Theoretical understanding of small vacuum
energy
=
Problem Solved for Cosmologists and Particle Physicists
2. “w = -1” & theory breakthrough
Percent level measurements of w and wa and LSS consistent with ΛCDM
+New compelling theoretical prediction for time
variation of w and/or wa – just beyond the reach of Stage IV
=Problem Solved for Cosmologists,
Particle Physicists think about Stage V
3. “w ≠ -1” or wa ≠ 0
Detection of signature that DE is not vacuum energy
Potential implications for both particle
physics and cosmology=
With or without theoretical breakthroughboth Cosmologists, Particle Physicists think about what to measure in Stage V
4. w = -1 & no theory breakthrough
Percent level measurements of w and wa and LSS consistent with ΛCDM
+No theoretical understanding of small vacuum
energy=
Problem solved for cosmologists, but not for particle physicists
“Time out”: take a break and think hard about what to do next
ΛΛ’s Checkered History’s Checkered History
• 1917 – 1929– Einstein: static, finite, positively curved Universe
ρM = 2ρΛ, R = 1/(4πG ρM)1/2
– de Sitter (1917): vacuum solution, first derivation of Hubble’s Law
– Eddington-Lemaitre long lived cosmologies– Hubble discovers expansion– Einstein: “my greatest blunder”– Eddington remains obsessed
Early ConfusionEarly Confusion
• 1948 – 1970 – Bondi & Gold, Hoyle: Steady State Cosmology:
“perfect cosmology”– Strong signs of evolution: quasars, radio sources
and CMB kills a beautiful theory– Petrosian, Salpeter & Szekeres (abudnace of z ~ 2
QSOs) and Gunn & Tinsley (data)– Rise of Standard Cosmology (Hot Big Bang)
RevivalsRevivals
• 1930s: Pauli, “Size of Universe could not reach to the moon”
• 1968: Zel’dovich articulates the problem• 1989: Weinberg, “Bone in the throat of
theorists”
Quantum Vacuum Energy: Quantum Vacuum Energy: Most Embarrassing Problem Most Embarrassing Problem
in all of Physicsin all of Physics
• 1981 – 1984: Inflation & CDM• 1984 on – “Ω problem”• 1984 – 1995: Λ solution, best fit
Universe, COBE and ΩM ~ 0.3 & triumph of ΛCDM
• 1998: The Accelerating Universe• 1998: Cosmology Solved Debate• 1998: Birth of Dark Energy
and a new puzzle
Most Anticipated Surprise EverMost Anticipated Surprise Ever
Rapid acceptanceit is the missing piece of the puzzle
Quarks and the Cosmos