Michael Turner - Fermilab Center for Particle Astrophysics

Future of the
Cosmic Frontier:
where do we go (next)
Experiments on the Cosmic Frontier: Astrophysical
Studies of Matter, Energy, Space and Time
Fermilab, 26 March 2011
Michael S. Turner
Kavli Institute for Cosmological Physics
The University of Chicago

Where we are

The Universe circa 380,000 yrs
WMAP
±0.001% Fluctuations

Curve = concordance cosmology

Polarization: Where we are today
Chiang et al, arXiv: 0906.1181
r = 0.1

Astrophysical cosmology: star formation
peaked 13 billion years ago, almost done

Deep connections

• Dark matter
• Dark energy
• Inflation
• (Atoms
Some Connections
• Origin of the Universe
• New particle of nature
• Energy of the vacuum or
breakdown of GR
• Galaxies and LSS from
quantum fluctuations
• Particle interactions in
the Early Universe)
• Origin of Space/time

Our great progress has
illuminated more clearly
our ignorance

Terra
Incognita
exciting ideas
Inflation,
multiverse, ##!!
Well understood:
0.000001 sec to
400,000 yrs
Story to be
revealed by
new
telescopes

Not complete: too many
particles and forces and what
about gravity, dark matter, dark
energy and inflation?
Great achievement – but there
must be something grander!

The Consensus Cosmology
DARK MATTER
DARK ENERGY
All implicate Michael new S Turner physics!
INFLATION
Rests upon three mysterious pillars

Progress of science

Linear
progress guaranteed, strong program in place
• Dark matter(s), Dark Energy, Inflation,
UHECR, γ-ray sky, Higgs/LHC − well
covered here
• Questions ripe to answered
– What is the dark matter?
– Nature of dark energy?
– Test inflation/epoch of inflation?
– How do cosmic accelerators work, what are
they accelerating?

Youbetcha Katie,
I believe in Dark
Energy – we can
see it from
Alaska!

Dark energy is the most important problem
in out time; send me your craziest ideas!
http://
www2.slac.stanford.edu/
softball/images/softball97/
sb8.jpg

Two Big Dark Questions
Does Dark Energy change with time
(i.e., is dark energy vacuum energy)?
No, at the 10 to 20% level
Does Cosmic Acceleration require
going beyond General Relativity?
Not well tested

Birther: A conspiracy theorist who believes that Barack
Obama is ineligible for the Presidency of the United
States, based on any number of claims related to his
place of birth, birth certificate, favorite birthday, or
whether or not he has heard the song Africa by Toto.
Birthers also believe cosmic acceleration is part of the
very same conspiracy.

How Much is Enough?!#
Michael S Turner

1. w = -1 & theory breakthrough
Percent level measurements of w and w a and LSS
consistent with ΛCDM
+
Theoretical understanding of small vacuum
energy
=
Problem Solved for Cosmologists and
Particle Physicists + lots of astronomy

Serious testing of
Inflation has begun
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
• Ω 0 = 1.00 ± 0.006
• (n-1) = -0.04 ± 0.014*; dn/dlnk = -0.032 ± 0.02; no
robust evidence for nonGaussianity
• r < 0.2 (95% cl)*
*Depends significantly upon the priors assumed

E mode
B mode

Not enough atoms to account for the dark
matter – it must be a new form of matter

Full Court Press!!!
• Produce at LHC"
• Detect particles in our halo"
• Detect annihilation products"
• Dark Stars"

Non-linear
preparations in place, results not guaranteed
• Axions
• Nearby SNe-II
• Gravitational waves
• UHE neutrinos
• SUSY particles
• Stochastic GW background, holographic noise
• Dark matter astronomy
• Mapping the observed Universe: optical or 21 cm

Framework tests
could reveal cracks/clues
• Measuring N ν : BBN, CMB, Lab, …
• BBN: consistency of light-element abundances
• CMB/Large scale structure through gravitational
instability
• Gravitational waves from BH coalescences and
signal timing
• DM abundances vs. properties measured in the Lab
• Birefringence of the vacuum
• Time variation of redshifts

Stretch goals
• 21 cm mapping of observable Universe
• Stochastic GWs from the early Universe
• Spatial variation of dark energy
• 2K cosmic neutrinos
• Laboratory evidence of quantum gravity
• Time variation of redshifts (cm/s/decade)
• Direct measurement of neutrino mass

43 to 1981; O(100)
remain to be made
1981

Most discoveries are accidental enabled by
new, innovative instrumentation,* often
made by outsiders
*increasing the number
of lamp posts

Harwit phase space
• Type: i = CPs, γ, ν, g, DM, …
• Energy resolution/spectrum: R
• Flux limit: F min
• Time resolution: Δt
• Time duration: τ
• Cadence: t
• Sky coverage: ΔΩ
• Cross section, polarization

Some innovations
• Rydberg atom detectors
• Atomic interferometry
• Quantum non-demolition
• Radio detection of CRs
• ????

Discovery vs. understanding
Discovery often involves opening new
windows and seeing surprises
Understanding can involve unexpected
discoveries (e.g., cosmic acceleration), but
can also involve targeted improvement to
answer questions (e.g., LHC, axion DM,
WIMP DM)

Progress and Vitality of Astronomy
Driven by Ideas, People and
Technology from Physics
Doubtless, physics has profited greatly from
astronomy: Newton, Einstein, new
elements, new forms of matter and energy,
neutrino mass, a heavenly lab and new
puzzles!

Five Modern Waves
• Quantum Mechanics
• General Relativity
• Nuclear Physics
• Radio (followed later by x-ray, infrared, gamma, cosmic
rays, neutrinos, gravity waves, …)
• Elementary Particle Physics

Simon is right – there are distortions, nonperturbative
changes and even collateral
damage – but it is outweighed by the benefits
• Expands and entangles the agendas of both
fields
• Maintains the vitality of both fields by
bringing in new people and new ideas
• Cross fertilization
• The interdisciplinary nature of astronomy is
truly an examplar for modern science

Really big questions

The stakes are very high
Understand matter, energy, space and
time and the complete history of the
Universe

Final thoughts
• The opportunities are large and not completely
known − still a frontier
• Many fertile directions to pursue − and a panoply
of powerful experiments … but some choices to
be made as the field matures
• Still time to be bold and innovative & to have an
open mind
• This is now a legitimate field − even DOE
recognizes it – and we are still having fun!