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Michael S Turner The Big Picture celebrating the accomplishments and identifying the challenges

The Future of Cosmology Series Eckhardt Research Center 7 October 2015

Michael S. Turner Kavli Institute for Cosmological Physics University of Chicago* The collection of powerful ideas formerly known as Edwin Hubble galaxies (1924) and expansion (1929)

Hubble’s law: v = H0d K (H0) = 550 km/s/Mpc

Hubble & Humason Michael(1955): S Turnerfew 100 galaxies, z < 0.1 The Big Picture, circa 1980 Cosmology circa 1980

• ~30 “full-” cosmologists worldwide – all astronomers • Cosmological data

– H0 (= expansion rate, ~1/age) = 50±1 or 100±1 km/s/Mpc – High redshift (1+z = λrcvd/λemit = size of Unow/size of Uthen) • Galaxies z ~ 0.8, clusters z ~ 0.1, QSOs z ~ 4 • ~few thousand redshifts total

– Age of : 10 to 20 Gyr; in conflict with H0? – Ω0 (= average density/critical density) = ΩMatter ~ 0.1 – CMB: 2.96±0.05 K blackbody + dipole + δT/T < 10-4 • NB: CCD cameras new, HST 10 years from launch

The Big Picture, 2015 ΛCDM with its flat (critical density), dark , , inflation, hot gas and stars, , gravity-driven structure formation, nucleosynthesis, precision cosmology, …

And yes, Dr Sandage

H0 = 70 ± 2 km/s/Mpc

q0 = -0.55 ± 0.06 H0 = 72 ± 1 ± 4 km/s/Mpc The Chicago School of Cosmology established 1980 and still going strong! Beginnings of ΛCDM InnerSpace/OuterSpace at (1984) Fermilab = the mother church

Inflation, Monopoles, CDM rising, HDM falling, CMB limits only,

LSS: CfA1, Cosmic Strings, , SUSY still to come

ΛCDM: today’s big picture

• Standard hot big bang (t >10-6 sec) • Three big ideas from inner space/outer space – Inflationary beginning (t << 10-6 sec) – Dark Matter is comprised of slowly moving particles, born of the soup – Dark Energy and accelerated expansion (t > 10 Gyr)

Michael S Turner Inflation implemented as scalar-field dynamics ‘inflaton’ Quantum Fluctuations Seed Density Perturbations Inflation + Cold Dark Matter

Structure in the Universe forms “bottom up”:

First Stars (z ~ 10 - 20) Galaxies (z ~ 2 - 5), Clusters (z ~ 0 - 2), and Superclusters (z ~ 0)

Michael S Turner ΛCDM: today’s big picture precision, accuracy, full accounting and consistency • From quark soup to nuclei and atoms to galaxies and large-scale structure • Flat, accelerating Universe, inflationary beginning • Atoms, exotic dark matter & dark energy • Precision cosmological parameters

• T0 = 2.7255 ± 0.0006 K • Ω0 = 1.005 ± 0.005 (uncurved = flat) • ΩM = 0.315 ± 0.01 • ΩB = 0.048 ± 0.001 Consistent with • Ω = 0.685 ± 0.01 DE immense body • H0 = 67 ± 0.5 km/s/Mpc • t0 = 13.80 ± 0.02 Gyr of high-quality • ns = 0.965 ± 0.005 data! • Nν = 3.0 ± 0.33

The Universe circa 380,000 yrs WMAP

and don’t forget the gnd- based experiments: ACT, Michael S Turner Boomerang, DASI, SPT, … Planck CMB Sky 9 frequencies

Michael S Turner Planck Power Spectrum a thing of beauty!

6 parameter fit to ΛCDM

Michael S Turner The Largest Things in the Universe Began from Subatomic Quantum Fluctuations! Full power spectrum

l > 3000: • dusty galaxies • radio sources • S-Z clusters (1000s)

Michael S Turner CMB Polarization

Michael S Turner CMB anisotropy is a non-trivial map of 2 density inhomogeneity ΩMh to temperature fluctuations  Mapping depends upon cosmological parameters (good news!)

Michael S Turner Astrophysical cosmology the story of stars, galaxies, planets and how we got here built upon the “good enough” ΛCDM foundation The future: challenges and opportunities

Loose ends  new physics and insights or new big picture needed? Small details or threads that unravel the picture?

H.L. Mencken: “For every complex problem, there is a solution that is simple, elegant and wrong!”

Michael S Turner The Origin of Atoms

Matter and no today  tiny net baryon number in the Early Universe. Why/how? Jim Cronin: must be related to CP violation! Sakharov Conditions for Baryogenesis (1967) ?Famous April’s Fools Seminar?

• Baryon number violation

• CP violation

Just look • Departure from Thermal Equilibrium around! Current view: Lepto/Baryogenesis

Begin with a produced in the early universe

Transmuted into a by number violating interactions within the of

Punch line: We are here because of small Majorana neutrino masses

Consensus Cosmology

INFLATION

DARK MATTER DARK ENERGY DARK

Rests upon three mysterious pillars All implicateMichael newS Turner physics! Michael S Turner Airtight Evidence for Nonbaryonic Dark Matter

CMB & BBN 2 Ωbh = 0.0222 ± 0.0002 vs. CMB/SDSS 2 ΩMh = 0.142 ± 0.0013 Michael S Turner> 50 σ discrepancy contribute a few 0.1%

th 79 Nobel Symposium1990Michael S (TurnerGräftåvallen , SE) Full Court Press!! • Produce at LHC • Detect particles in our halo • Detect annihilation products

Dark matter: where we are • Baryonic dark matter: most of the baryons, hot gas (~4% = 4.8% - 0.5%) • Neutrinos! – 1981 30 eV neutrino to close Universe

– Ων ≈ 0.3% to 3% (similar to stars ≈ 0.5%) • > 50σ evidence that it is non-baryonic • Compelling case for the “WIMP”, lots of hints (gamma rays, , …) – but no “Sagan- class evidence”

Carl Sagan:

“Extraordinary Claims Require Extraordinary Evidence”

Dark matter: where we are

The story be more complicated: Many different kinds of dark matter A whole dark world waiting to be discovered!

The Complicated Universe • Atoms : Democritus to 1964 • + Photons: 1964 • + Neutrinos (e, μ): 1967 • + Exotic dark matter: 1981 • + CDM: 1983/4 • + Massive neutrinos: 1998 • + Dark energy: 1998 • + τ neutrino: 2000 • Done? Not likely! I.I. Rabi Who ordered that? • Why ΩCDM/ΩB ≈ 5?

Dark Energy = very elastic stuff (p < -ρ/3) with repulsive gravity

Simplest example: Λ = quantum vacuum energy (p = -ρ)

but ρvac is a little too big Describing Dark Energy

• Defining feature of dark energy: large negative pressure, smoothly distributed which leads to repulsive gravity • Described by equation-of-state parameter w < -⅓ w = pressure/energy density

3(1+w) ρDE ~ (1 + z) 1. Not necessarily constant 2. Vacuum energy = -1 3. -1 to 1

4. Ghostly quintessence < -1 (ρDE increases with time) 5. w = w0 + wa(1 – a) Betoule et al (1401.4064) Joint Lightcurve Analysis w = -1.02 ± 0.06 (stat + sys) wa ≈ -0.5 ± 0.8

Michael S Turner Sullivan et al 2011

Λ fits perfectly!

Michael S Turner Why isn’t lambda good enough? Short answer: no good theory for it!

Λ is equivalent to vacuum energy & quantum zero-point energy diverges:

-4 4 ΩΛ ~ (Ecutoff/10 eV)

Michael S Turner Eddington Criterion The Extravagant Universe “the left-coast solution”

• M-theory  10500 vacua 4 4 • ρvac~ O(mPl ) ± O(mPl ) • Universe has a multiverse structure & we were lucky (narcissistic principle) • Testable? What to do about the multiverse

• Most important discovery since Copernicus? • Is it science? (not testable) • Many true believers (left coast) and not enough doubters Two big questions

1. Does dark energy vary with time?

w and wa

1. Does general relativity self consistently describe accelerated expansion? Growth of structure … Dark Energy Survey

LSST

WFIRST/Euclid …. but not established fact yet Michael S Turner Inflation scorecard

Key Predictions • Flat Universe • Almost scale-invariant, Gaussian perturbations: |(n-1)| ~ 0.1 and |dn/dlnk| ~ 0.001 • Gravity waves: spectrum, but not amplitude • Cold Dark Matter Scenario Key Results

• Ω0 = 1.00 ± 0.006 • n = 0.965 ± 0.005; dn/dlnk = -0.002 ± 0.013; no evidence for nonGaussianity • r < 0.10 (95% cl) E mode

B mode B-modes detected! 17 March 2014/BICEP2 Most exciting interpretation

• Smokin’ gun for inflation +0.07 – r = tensors/scalars = 0.2 -0.05

• The when and clues about how -38 – 10-38 sec 10 sec – Energy scale of 2 x 1016 GeV = 1012 x LHC – “Planck scale physics”:

• Δφ ~ mpl 16 4 2 • V ~ (2 x 10 GeV) , V’ ~ 1.2V/mpl, V’’ ~ 0.6V/mpl

• Remember, “extraordinary results require extraordinary evidence” … Carl Sagan The bane of astronomy: dust

Planck dust map of BICEP region When all the “dust” settled:

BICEP2/Keck/Planck joint analysis

Dust

: : 1502.00612 arXiv GWs

B-modes detected! Dust detected at > 3σ Evidence for something else (GWs?) Game changing idea, but not time for a coronation

• No fundamental theory • Initial singularity, initial conditions • Cosmological constant problem • Like “duct tape”, very useful but … – Only postpones appearance of inhomogeneity – not all initial conditions inflate • Unsettling, uncertain predictions: eternal inflation and the multiverse Crack in the cosmic egg? ... which we have been waiting for?!# • CDM anomalies – on small scales  SIDM? WDM? MDM?WMD? • CMB anomalies

– H0/σ8/Nν – Low ell • Time varying constants, dark flows, … ΛCDM

Theorem: real cracks get bigger – not smaller – with time! (2nd law)

Michael S Turner

8 “Planck/WMAP” H0 trade space

• Planck: “low” H0, high σ8 & Nν = 3

( Planck predicts 3X clusters SPT observes) σ to sensitive exponentially abundance Cluster

• WMAP: “consensus H0”, “right number of clusters” & Nν = 3.8

Michael S Turner Three possible futures

1. “Linear” (old guys feel good): New physics: dark matter and/or dark energy, and/or inflation

2. Non-linear (young guys and gals feel good): Surprises ahead and big ideas needed.

3. ΛCDM works better and better, no new physics revealed (same curse as the SM of particle physics): big ideas needed

Bullish on cosmology! especially in Chicago Direct detection Hints: Gamma-rays from dark matter annihilations at the GC? Daylan et al 1402.6703

30,000 ~2 GeV photons! Detecting Cosmic Axions Youbetcha Katie, I believe in Dark Energy – we can see it from Alaska!

From Here to Eternity In the Presence of Dark Energy, a Flat Universe Can Expand Forever, Re-collapse, or Even Experience a Big Rip!

Cannot Understand Our Cosmic Destiny Until We Understand What Dark Energy Is! The theory menu

• Vacuum energy (see above) • Rolling scalar field (quintessence) • Very elastic topological defects • Modified gravity • Dark energy/dark matter models • Hole in the Universe • ??

Michael S Turner Michael S Turner z = 6.43 Quasar: 1216 Å UV light shifted to Infrared: 1 + z = 9000/1216 = 7.43

Cosmic hint or misdirection?

Thermal EQ ΩM = 0.25 achieved for a “” annihilation cross section ΩM

Michael S Turner Particle DM interactions

3 for the price of 1!

EarlyUniverse

production

Accelerator

Th

Eq

Halo Annihilation Halo

DM detector scattering Dark matter challenge: New ideas

• DM is the tip of a new “Dark Sector” – Whole other world of particles and interactions – Asymmetric dark matter (relic abundance dictated by asymmetry between DM and anti- DM particles) – Many DM particles – Cosmic hint = cosmic misdirection! • Radical, less compelling idea: modified gravity, no DM

The two teams

Hi z Supernova Team Supernova Cosmology Project Astrophysical cosmology the “environmental science” of reconstructing the history of the Universe from gas and dark matter to stars and galaxies ΛCDM provides the cosmological background model: percent level accuracy is good enough for astronomers!

Armed with initial conditions (density inhomogeneities + composition) numerical simulations, “stellar modeling” can reproduce our Universe Michael S Turner The Discovery Data

Perlmutter et al, 1999 Riess et al, 1998

Discovery of Cosmic Microwave

Background,Michael 1964 S Turner accident 1992: COBE Maps & Blackbody Spectrum

Michael S Turner GWs: The Smokin’ Gun • Directly reveals epoch of inflation

• Reconstruct scalar potential

• Spectrum provides consistency check: T/S=-5nT • Direct detection: – LIGO & LISA unlikely; “Big Bang Observer” (a dream) • B mode of CMB polarization Carl Sagan:

Extraordinary Claims Require Extraordinary Evidence

B-modes detected! 17 March 2014/BICEP2