1. Theoretical Cosmology and Particle Astrophysics at Caltech Marc Kamionkowski July 21, 2004

2. HEP Experiment at Caltech: People: Hitlin, Barish, Weinstein, Peck, Porter, Newman, Doug Michael....

3. Nuclear Physics at Caltech

4. HENP Theory at Caltech: Strings Phenomenology Nuclear/Neutrino Physics QFT/QC/QI Active postdoc program (e.g., Rajagopal, Horava....)

5. Astronomy/Astrophysics at Caltech:

6. Also, SIRTF, GALEX, Hershel..... and everything at JPL. And Carnegie Observatories down the road....

7. 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

8. 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....)

9. Cosmology/  Particle/Nuclear Astrophysics Physics Dark matter Dark energy Inflation Neutrino astrophysics Ultrahigh-energy cosmic rays Baryogenesis

10. 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

11. 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 2003- 2004) Rashid Sunyaev (Moore distinguished scholar; 2003-4) Tsvi Piran (Moore distinguished scholar; 2004-5)

12. 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)

13. Caltech is building in particle astrophysics: Experiment: Added Sunil Golwala (dark matter, dark energy, CMB) to faculty 2003 Theory: 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

14. Our recent (~year) research topics 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

15. Our work is relevant for 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….

16. Benefits of this program to DoE DoE funding heavily leveraged by Caltech Maintains theoretical activity at major center for experimental particle astrophysics and early- Universe 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

17. 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.

18. Science Menu 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

19. 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

20. II. The Cosmic Microwave Background (CMB) and Inflation Kesden, Cooray, MK, PRL 89, 011304 (2002)

21. Boomerang 1998

22. Geometry Baryon density Hubble constant Cosmological constant MK, Spergel, Sugiyama 1994 "Precision cosmology": Jungman, MK, Kosowsky, Spergel 1996

23. Results as of 2001:

24. CBI, May 2002

25. Archeops 2002

26. ACBAR, December 2002

27. (some of) What we have learned:  l peak ~ 200   =1.00±0.03; the Universe is flat (MK, Spergel, Sugiyama '94)  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....)

28. WHAT NEXT???

29. The big bang !!! today 10 10 yr T~meV Decoupling : (e - +p  H) 10 5 yr T~eV Nucleosynthesis : n+p  H, D, He, Li Seconds T~MeV galaxies form quarks} n,p 10 -3 sec T~100 MeV electroweak }EM,weak 10 -9 sec T~100 GeV quantum gravity, strings??? 10 -43 sec T~ 10 19 GeV 10 -36 sec T~ 10 16 GeV GUT  electroweak,strong?? 10 -22 sec T~ 10 12 GeV PQ symmetry breaking?? SUSY breaking?? INFLATION

30. GEOMETRYSMOOTHNESS STRUCTURE FORMATION What is E infl ? STOCHASTIC GRAVITATIONAL-WAVE BACKGROUND with amplitude  E infl 2

31. Detection of gravitational waves with CMB polarization Temperature map: Polarization Map: 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! (MK, Kosowsky, Stebbins 1997; see also cover article of Jan 2001 Sci. Am, reprinted in Sci Am special edition 10/02)

33. GWs  Recall, GW amplitude is l2 GWs  unique polarization pattern. Is it detectable? If E<<10 15 GeV (e.g., if inflation from PQSB), then polarization far too small to ever be detected. But, if E~10 15-16 GeV (i.e., if inflation has something to do with GUTs), then polarization signal is conceivably detectable by Planck or realistic post-Planck experiment And from COBE 

34. Jaffe, Wang, MK 2000

35. 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.

39. Kesden, Cooray, MK, PRL 2002

40. Possible solution: Use higher-order correlations in temperature map that measure stretching from cosmic shear as a function of position on sky

43. Hivon & MK, Science 296, 267 (2002)

44. Brief Aside: Large scale structure and inflation  Inflaton potential Matter power spectrum

45. MK & Liddle, PRL 84, 4525 (2000) Galactic substructure may probe inflaton potential near end of inflation

46. Another possibility: suppression of small- scale power by decay of charged dark- matter particles (Sigurdson-MK, 2004) Decay of charged particle with lifetime 3.5 year to dark matter suppresses small- scale power

47. III. Spin-dependent WIMPs in DAMA? Ullio, MK, Vogel, JHEP 0107, 044 (2001)

48. Earth density r r 0 =8 kpc core radius Velocity distribution ~ Maxwell- Boltzmann With 1/2 ~270 km/sec spherical halo: á 0 =0.3-0.6 GeV/cm 3 If halo flattened, á 0  The standard smooth halo model

49. WIMPs The relic density of a massive particle is about: Of Weak Interaction strength 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

51. Spin dependent WIMP-proton coupling Spin dependent WIMP-neutron coupling Ullio, MK, Vogel 2001

52. IV. Spintessence! And Phantom Energy: Some ideas for Dark Energy Boyle, Caldwell, MK, Phys Lett B 545, 17 (2002) Caldwell, Weinberg, MK, in preparation

55. Gravity with relativistic fluid: So if p<-  source for gravitational field is negative, and get repulsive gravity. Thus, 70% of critical density is in form of negative-pressure "dark energy".

56. One idea for dark energy: Quintessence, slowly-rolling scalar field: V(  )  Pressure Energy density w=p/ 

57. Spintessenc e!

58. Spintessence! Connections:  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?

59. Constraints to w (Wang et al. 2000) :

60. "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.

61. What about w < -1? ("phantom" energy)

63. 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 vacuum- energy density ultimately tears bound objects apart, roughly a dynamical time before the end of the Universe

64. Big bang !!! today 15 Gyr Atoms form 10 5 yr Light nuclei form Seconds First galaxies form quantum gravity, strings??? 10 - 43 sec 10 - 36 sec Inflation Big smash: the end of time!! t smash = 35 Gyr few Gyrs Galaxy clusters stripped t smash -few Gyr Milky way destroyed t smash -Myr Solar system destroyed t smash -3 months Earth falls apart t smash -30 mins Atoms dissociated t smash -10 - 19 sec

65. 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; Armendariz- Picon et al. 1999; Chiba et al. 2000) " "stringy" dark energy (related to Lorentz violation; Frampton 2002) " Nonminimal coupling (Faraoni 2002)

66. (More) Physics of "Phantom" Energy: " More possibilities: " Braneworld models: (Sahni & Shtanov 2002) " dS/CFT connections (McInnes 2002)

67. ....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.

68. Summary:  Particles/Fields  Cosmology/Astrophysics  Spectacular recent advances  Intriguing ideas  More to come