Transcript The First 10

Theoretical Cosmology and
Particle Astrophysics at Caltech
Marc Kamionkowski
July 21, 2004
HEP Experiment at Caltech:
People: Hitlin, Barish, Weinstein, Peck, Porter,
Newman, Doug Michael....
Nuclear
Physics at
Caltech
HENP Theory at Caltech:
• Strings
•Phenomenology
•Nuclear/Neutrino Physics
•QFT/QC/QI
Active postdoc program (e.g., Rajagopal,
Horava....)
Astronomy/Astrophysics at Caltech:
Also, SIRTF, GALEX, Hershel..... and everything
at JPL. And Carnegie Observatories
down the road....
Caltech/JPL will be US center for
experimental early-Universe
cosmology over next decade
• Caltech faculty: Readhead, Lange, Zmuidzinas,
Golwala
• Boomerang was first experiment to map acoustic
peaks in CMB
• CBI was first to measure power on smaller scales
• Have vigorous ongoing ground/balloon-based
programs (BICEP, QUaD, QUIET, B2K, CBI,
ACBAR, JAKNIFE….)
• Are US PI institution for Planck LFI and HFI, and
will have US Planck data analysis center
Theoretical Astrophysics
and Relativity:
Thorne, Sari, Phinney, Goldreich (part)
stellar astrophysics, relativity, gravitational
waves, cosmology, high-energy
astrophysics....
Strong postdoc program (Narayan, Tremaine,
Bildsten, Hogan....)
Cosmology/  Particle/Nuclear
Astrophysics
Physics
•Dark matter
•Dark energy
•Inflation
•Neutrino astrophysics
•Ultrahigh-energy cosmic rays
•Baryogenesis
People now (at least loosely) affiliated
with Caltech theoretical cosmology
and particle astrophysics
Postdocs:
• Asantha Cooray (Sherman
Fairchild Senior Research
Fellow; DoE research expenses)
• Milos Milosavljevic (Fairchild
Fellow)
• Steven Furlanetto (DuBridge
Fellow; ~20% Task B)
• Andriy Kurylov (~30% Task B)
• L. Arielle Phillips (Irvine
Fellow)
• Amr El-Zant (other sources)
• Nicole Bell (Fairchild Fellow
beginning Fall 2004)
• James Taylor (arriving this fall;
supported by R. Ellis)
Graduate Students:
• Mike Kesden (NASA GSRP)
• Nevin Weinberg (NASA ATP)
• Kris Sigurdson (NSERC/DoE)
• Jonathon Pritchard (TA)
• Tristan Smith (NSF Fellow)
• 3 more arriving this fall, one
with NSF fellowship, one with
4-year Moore fellowship, and
one with 1-year Caltech
fellowship
People now (at least loosely) affiliated
with Caltech theoretical cosmology
and particle astrophysics
Other Researchers:
• Kris Gorski (JPL Visiting
associate)
• Elena Pierpaoli (senior research
fellow supported by NSF
ADVANCE fellowship; arriving
fall 2005)
Visitors:
• Robert Caldwell (sabbatical
visit from Dartmouth 20032004)
• Rashid Sunyaev (Moore
distinguished scholar; 2003-4)
• Tsvi Piran (Moore distinguished
scholar; 2004-5)
Some Recent Alumni
Students:
• Mike Santos (PhD 2003; now
postdoc at Cambridge)
• Catherine Cress (PhD 1999;
(Columbia) Natal faculty)
• Alexandre Refregier (PhD 1998
(Columbia); CNRS faculty)
• Xuelei Chen (PhD 1999
(Columbia) KITP postdoc)
Postdocs:
• Piero Ullio (1999-2000; SISSA
faculty)
• Ken Nollett (2000-2002;
permanent member, Argonne
nuclear theory group)
• Peng Oh (2000-2003; UCSB
faculty)
• Andrew Benson (2000-2003;
Roy Soc advanced fellow)
• Eric Agol (2000-2003;
Washington faculty)
Caltech is building in particle
astrophysics:
Experiment:
Theory:
Added Sunil Golwala (dark
matter, dark energy, CMB)
to faculty 2003
Have just made tenured offer
to Matias Zaldarriaga
(CMB, inflation, dark
energy….)
“Heart of Darkness” initiative will seek private funding
for theoretical activity at string/particle/cosmology interface
Our recent (~year) research
topics
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Effects of dark-matter dipole moments, decays…
Variable fine-structure constant
Probes of dark matter at Galactic center
Dark energy, phantom energy, “Big Rip”
Galactic-halo merger rates
CMB tests of inflation
“Cooling” problem in galaxy clusters
Intergalactic medium
Supersymmetric dark matter
Large-scale structure, weak lensing, inflation, and dark
energy
• The first stars and reionization
~100 refereed publications over past 5 years
Our work is relevant for
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SNAP/JDEM
CMB experiments (WMAP, Planck, CMBPOL…
GLAST/VERITAS/STACEE/….
Collider experiments (to some extent)
Neutrino experiments
CDMS, etc.
Super-K, IceCube….
LSST
SDSS/2dF….
AMS….
Benefits of this program to
DoE
• DoE funding heavily leveraged by Caltech
• Maintains theoretical activity at major center for
experimental particle astrophysics and earlyUniverse cosmology
• Supports training of some of the best postdocs
and students in the field
• Grad student support goes only to students in
final year of research, when they are most
productive
• “One-professor” budget supports theory program
in exciting emerging area that competes with
programs with larger faculty numbers
Funding profile
• 1999-2003: ~$100K/year (PI summer salary plus
student)
• 2003-2004: ~$150K/year (PI summer salary,
student, plus 2nd student or 50% postdoc)
• Current request: continued funding at current
level
Eventually, would like to be able to support 100%
postdoc plus student from this Task.
Science Menu
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Spintessence
Dipole dark matter
Galaxy-halo mergers
Cluster cooling
Phantom energy and Big Rip
CMB and inflation
Charged-particle decay and small-scale power
Dark clusters, dark energy, and weak lensing
WMAP, CBI, and the first stars
Dark matter at Galactic center
Dipole dark matter (Sigurdson,
Caldwell, Doran, Kurylov, MK, 2004)
Phenomenological
investigation of
largest dark-matter
electric or magnetic
dipole moment
consistent with
experiments and
observations
II. The Cosmic Microwave
Background (CMB) and
Inflation
Kesden, Cooray, MK, PRL 89, 011304 (2002)
Boomerang
1998
MK, Spergel, Sugiyama 1994
Geometry
Baryon
density
Hubble
constant
Cosmological
constant
"Precision cosmology": Jungman, MK, Kosowsky, Spergel 1996
Results as of 2001:
CBI, May 2002
Archeops 2002
ACBAR, December 2002
(some of) What we have
learned:
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lpeak ~ 200  W=1.00±0.03;
the Universe is flat
(MK, Spergel, Sugiyama '94)
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Structure grows from nearly scale
invariant spectrum of primordial
density perturbations
on right track with inflation!
(also, increasingly precise determinations of
matter and baryon density, Hubble constant....)
WHAT
NEXT???
10-43
sec
sec
T~ 1019 GeV T~ 1012 GeV
10-22
10-36 sec
T~ 1016 GeV
today
galaxies form
Decoupling: (e-+p H)
Nucleosynthesis:
n+p H, D, He, Li
quarks} n,p
electroweak }EM,weak
SUSY breaking??
PQ symmetry breaking??
The big bang
!!!
quantum gravity,
strings???
GUT
electroweak,strong??
INFLATION
1010 yr
10-9 sec
Seconds
T~meV
T~100 GeV
T~MeV
105 yr
10-3 sec
T~eV
T~100 MeV
GEOMETRY
SMOOTHNESS
STRUCTURE
FORMATION
INFLATION
What is
Einfl?
STOCHASTIC GRAVITATIONAL-WAVE
BACKGROUND with amplitude Einfl2
Detection of gravitational waves with
CMB polarization
(MK, Kosowsky, Stebbins 1997; see also cover article of
Jan 2001 Sci. Am, reprinted in Sci Am special edition 10/02)
Temperature map:
Polarization Map:
T n
A 
 B
 n

P
Density perturbations have no handedness”
so they cannot produce a polarization with a curl
Gravitational waves do have a handedness, so they
can (and do) produce a curl
Model-independent probe of gravitational waves!
Recall, GW amplitude is AGW E
l2
GWs  T 
T AGW
2
infl
5
T10
And from COBE T 
16
 E infl2 10 GeV
GWs  unique polarization pattern. Is it detectable?
If E<<1015 GeV (e.g., if inflation from PQSB),
then polarization far too small to ever be detected.
But, if E~1015-16 GeV (i.e., if inflation has
something to do with GUTs), then polarization
signal is conceivably detectable by Planck
or realistic post-Planck experiment
Jaffe, Wang, MK 2000
Problem: Weak gravitational lensing
of CMB polarization by density
perturbations along line of sight
("cosmic shear") turns part of curl-free
polarization pattern into curl.
Kesden, Cooray, MK, PRL 2002
Possible solution:
Use higher-order correlations
in temperature map that
measure stretching from
cosmic shear as a function
of position on sky
Hivon & MK, Science 296, 267 (2002)
Brief Aside: Large scale
structure and inflation
Matter power
spectrum
Inflaton
potential
Galactic substructure
may probe inflaton
potential near
end of inflation
MK & Liddle,
PRL 84, 4525 (2000)
Another possibility: suppression of smallscale power by decay of charged darkmatter particles (Sigurdson-MK, 2004)
Decay of charged
particle with
lifetime 3.5 year to
dark matter
suppresses smallscale power
III. Spin-dependent
WIMPs in DAMA?
Ullio, MK, Vogel, JHEP 0107, 044 (2001)
density
core
radius
r 2  a2
 (r )   0
0 r 2  a2
spherical halo:
á0=0.3-0.6 GeV/cm3
If halo flattened,
á0
r
Velocity ~ Maxwelldistribution Boltzmann
With <v2>1/2~270 km/sec
Earth
The standard smooth halo model
r0=8 kpc
WIMPs
The relic density of a massive particle is about:
27
3 1
3

10
cm
s
2
Wh 
v

v
 strength
Of Weak Interaction


the particle has to be coupled to SM particles
There is chance for detection:
Detectio
n
direct
indirect
Neutrinos
from sun/earth
anomalous
cosmic rays
WIMP candidate motivated by SUSY:
Lightest Neutralino, LSP in SUSY extension of SM
Spin dependent
WIMP-proton coupling
Ullio, MK, Vogel 2001
Spin dependent
WIMP-neutron coupling
IV. Spintessence! And
Phantom Energy: Some
ideas for Dark Energy
Boyle, Caldwell, MK, Phys Lett B 545, 17 (2002)
Caldwell, Weinberg, MK, in preparation
Gravity with relativistic fluid:
2
 4 G  3p
So if p<-/3,source for
gravitational field is negative,
and get repulsive gravity.
Thus, 70% of critical density
is in form of negative-pressure
"dark energy".
One idea for dark energy:
Quintessence, slowly-rolling scalar
field:
V(f)
p 1
2 V 
2
Pressure
w=p/
f
 3 H 
 V'  0

2

 1
2  V 
Energy density
Spintessenc
e!
Spintessence! Connections:
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Novel growth of perturbations
CPT/Lorentz violation
Baryogenesis/Q-balls
Rotation of polarization of distant radio sources
Spintessential inflational?
Exponential potentials may address "why now?"
problem
Non-circular orbits might reproduce oscillating
dark energy models
Fuzzy dark matter=
Open question: potential that accelerates long enough?
Constraints to w (Wang et al. 2000):
"Deep" implications:
If w<-1/3, then Universe expands forever.
However, scale factor grows more rapidly than
Hubble distance. Therefore, Universe becomes
exponentially colder, currently observable galaxies
disappear. Extragalactic astronomy becomes
less interesting, but Milky Way and local group
continue as usual.
What about w < -1?
("phantom" energy)
Fire and Brimstone!!
If w<-1, get
Death by
stretching!!
Vacuum-energy density increases with
scale factor a(t) as a-3(1+w). Scale factor
and vacuum-energy density blow up in
finite time.
Horizon shrinks, and increasing vacuumenergy density ultimately tears bound
objects apart, roughly a dynamical time
before the end of the Universe
Big smash: the end of time!!
Atoms dissociated
tsmash-10-19 sec
tsmash=35 Gyr
Earth falls apart
Solar system destroyed
Milky way destroyed
Galaxy clusters stripped
today
First galaxies form
Atoms form
Light nuclei form
Inflation
quantum gravity, strings???
tsmash-30 mins
tsmash-3 months
tsmash-Myr
tsmash-few Gyr
15 Gyr
few Gyrs
105 yr
Seconds
10-36 sec
10-43 sec
Big bang !!!
The Physics of "Phantom"
Energy:
Is weird: violates "dominant-energy" condition;
naively requires sound speed > c. Has increasing
energy density
"Possibilities:
" "negative" kinetic term, as from supergravity or
higher-derivative gravity (Caldwell 2002; ArmendarizPicon et al. 1999; Chiba et al. 2000)
" "stringy" dark energy (related to Lorentz violation;
Frampton 2002)
" Nonminimal coupling (Faraoni 2002)
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(More) Physics of "Phantom"
Energy:
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More possibilities:
" Braneworld models: (Sahni & Shtanov 2002)
" dS/CFT connections (McInnes 2002)
....just one more thing:
Nollett [Phys Rev D 66, 063507 (2002)] showed
that big bang nucleosynthesis restricts
fine structure constant to be within 10%
of its current value ~minutes after the
big bang.
Summary:
Particles/Fields
Cosmology/Astrophysics
Spectacular recent advances
Intriguing ideas
More to come
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