Dark Matter, Dark Energy: puzzles & alternative solution

1. Dark Matter, Dark Energy: puzzles & alternative solution • Review Success of LCDM • Most user-friendly concise description • Better understood than its alternatives • There are challenges to LCDM • Some confident of LCDM being ultimate theory • Alternative receipes worth pursuing? HongSheng ZHAO SUPA, Univ. of St. Andrews

2. Carroll’s KITP talk 2006

3. DM+DE+GR: 3 pillars of universe, baryons & neutrinos are accidental tracers of dark universe… • Successful larger scale (>100Kpc) • Precision science! (also <100AU scale) • Solar system GR tests, Pulsars, CMB peaks • Except: (vacuum) DE is a fudge factor • Mixed success in galaxies • No Single robust DM candidate emerged in 60 years • CDM, WDM, SIDM, FDM, RDM, BDM etc. all challenged by some observations

4. Usual NASA Headline: astronomers prove “DM+DE+GR” i.e., we “see” (via lensing, dynamics, candles, CMB) a misbalance of Einstein’s Equation: Observed space-time Curvature Gtt - Energy Density of Known source Ttt = Unidentified Source Ttt > 0 Ideas to restore Balance: *Assume w=0 pressure-less fluid  dark matter *Assume w=-1  Cosmological Constant, inflaton fluid *Vary w  evolving fields of (modified) metric-coupling detect an energy residue E/c2 – mknown> 0 in late time universe

5. We “see” extra metric perturbations:CDM or neutrinos or clumps of energy? Bullet: Clowe et al. (2006) NASA release A520 (Cosmic Train Wreck)

6. Acceleration of universe/galaxies:Einstein’s Eq. needs N new terms 1. RH approach ⇒ Various B/I/H/W/C DM +Inflaton+Vacuum Energy Source 2. LH approach ⇒ Modified R+1/Rn gravity e.g. Cosmological cst n=0, Interchangable, RH formulation easier, but N~1 preferred

7. He, Ne If inert gas gives few photons, interacts so weakly astronomers see via gravity with photons only… •  DM in the Sun, galaxies, universe •  Not in dense Earth, Neutron stars … • Or  Gravity is modified (0-25%) as f(R): function of density • Astronomers cannot tell DM or Vacuum fields • even after lab fusion 4H  HeliumDM, lab proof NeonLight

8. Merits of Cosmology using 3, 2 or 1 pillarsCould Dark Matter = Vacuum Energy = Inflaton Field= Projections of a 0.001eV-Particle/Fluid/Field + GR ?= A Non-Linear Gravity Perspective: Astronomers have the biggest vacuum lab of gravity just some numbers or “Coincidences in DE-DM: Clues for a simple alternative?” Zhao’07 (ApJ Letters Dec’07, arXiv0710.3616)

9. In 4D-Metric, what is modified gravity? • Space-time metric field in vacuum SEP-coupled to • all specifies of non-SEP-mutually-coupled matter

10. What is new? GR+ vacuum fields • Gravity modified twice by Einstein • Add cst c2 to Newton’s apple mc2 = E • Add cst L to his own theory rc2 = L • made L dynamical scalar field of vacuum (DE) to accelerate universe uniformly 3++? recycle DE as vector field, collapse as DM to accelerate stars in galaxies? Solve DM puzzles?

11. A Doesn’t-MatterW<0.1 universe (~ baryons ~ known neutrinos W=0.005-0.1)compatible with LHC etc. in 8 years Abundance set by ~ 256 coupling-consts of SUSY/MSSM Room for Vacuum! Still premature?

12. Why should WE at ICGC care? • Isn’t DM a temporary problem of • Too poor to run LHC sooner? Lack accurate prediction of SUSY theory? • Poor accounting by astronomers? • Poor resolution of galaxy simulators? NOT Quite! • Uncertain DM surely tells us nothing new about how space-time works?

13. Cosmological Simulations P(k)=kn Fits well with LSS 10 year Crisis: Cusps Satellites

14. the substructure ProblemSUBHALOS IN A RICH CLUSTER AND A MILKY WAY-SIZED HALO Halo with 5x1014 M⊙ Moore et al. (1999) Moore et al. (1999), Klypin et al. (1999):Where are all the missing satellites? Halo with 2x1012 M⊙

15. Rocks in LCDM universe: dumps of angular momentum • Overpredicts satellites: survive tide -- including SDSS satellites (Cambridge group’07) -- WDM helps on Draco, but barely enough to cause quasar-lensing flux fluctuations or anomalies (Metcalf & Zhao 2002, ApJL, Miranda & Maccio’07 for reliable radio quadruple lens) • Overpredicts Bulges in disks: dense -- simulations of Steinmaintz’07 • Overpredicts cusps: irreversible bary -- Gnedin & Zhao 2002, MNRAS, Read & Gilmore 2003, MNRAS

16. Slowly grow a massive disk/bulge in NFW halo • Lowest ang. J • Highest init. Mb/Mdm • Rapidly remove all gas (by SNe with top-heavy IMF) • “Spring out” some DM: STILL To CUSPY! ====??===

17. Cusp to Core: 1,2,3,…10Dwarf Feedback is limited • Gnedin & Zhao’02: no core after 1-outflow (strongest) • Read & Gilmore’03: core at last after 3-resurrections with fb =0.2 each time • Or use 10 BHs …

18. C.D.M.: C for Cold, Collisionless, or Contradiction Doesn’t Matter? • DM is collisionless as galaxies: Bullet Cluster (Bradacet al.’07) • DM is collisional as gas: Abel 520 (Mahdavi et al. 07) • warmer DM m<0.5kev: cores in Ursa, Fornax • colder DM m>2kev: substructure in lensing, Ly-alpha (Metcalf & Zhao’02, Maccio et al.’07) • Tidal Dwarf Galaxies want dark CO disks (Bournard etal. Science) • Milky Way wants extended halos (Klypin, Zhao, Somerville’02) … • Dilemma removed if DM isn’t a precisely w=0 fluid or field ~ some metric bending field like Photon, inflaton & DE

19. Budget Deficit ofZwicky’s “Dark Matter” (1933) • MACHO microlensing surveys’92-02 • Jupiters/BrownD ~ stars, Omega~0.01 • Neutrino oscillation’98 (SuperK, LSND’93-98, MiniBooNe’07) ~ low • Neutralino annihilation & scattering: EGRET GeV excess’97,DAMA modulation’97 • prefer big cross-section  Omega~0.01 • Low-Energy Vacuum, Omega~unity? Small rarely adds up to big!!

20. EGRET evidence for DM annihilation

21. Enter L~ m04 ! m0=0.001eV=10-30msusyscale of energy clumps in-of space-time

22. Just Six Numbers --Rees • Just 5 Numbers of gravity • 3+1: dimensions we live in • N: rela. strength of gravity to E&M • epsilon: metric fluctuation of vacuum (inflaton) • Lambda: energy scale constant of vacuum • Omega: dark matter • low-energy Vacuum Higgs or high energy SUSY Higgs? ----------------------------------------------------- • +Q: rate of Nucleosynthesis + age of universe + 3K CMB photons + neutrinos + … [STANDARD MODEL PARAMETERS ~ 20] ….[MSSM ~ 256 parameters ]

23. Merits of Cosmology using 3, 2 or 1 pillarsCould Dark Matter = Vacuum Energy = Inflaton Field= Projections of a 0.001eV-Particle/Fluid/Field + GR ?= A non-linear gravity DE:DM=3:1 (expect 0-Inf:1) DM:Bar=8:1 (expect 0.01-100:1) just some numbers or “Coincidences in DE-DM: Clues for a simple alternative?” Zhao’07 (ApJ Letters Dec’07, arXiv0710.3616)

24. A recipe for Value-Added DE to give Effective DM+DE Lagrangian Density = Lknown matter + LK +Lcurvature LDM + LDE +Linflaton Vector Field = Vacuum Flow = metric mesh “softening” fluid [collisonless, tracks mass like dielectric-MOND, adds stress to depress the metric]

25. Covariant Stress of Metric-tracking Fluid Four-Velocity Ua=Aa/mc2 Zhao (ApJ Letters, Dec’07 Issue)

26. Extra stress to the metric below a stress scale P0=(0.001eV)4 Zhao’07 (ApJL)

27. Einstein Eqs: Poisson+Hubble solar l(N)~0, mB =l(n)=2-n, m4 ~L ~L(0)~(na0)2 ~9P0 <- n=3,l(x)~(1+x/n)-n ,a0=1A/s2 , N=105

28. Parameters & Predictions • n,N,a0 are the only 3 free parameters • gravity tracks baryons approximately during feedback • NOT rigorous because time-dependent systems (CMB, tidal merger) • DE/DM properties of vacuum space-time • New LHC particles could exist, but are rare • New modes of gravitational waves

29. Cosmological Constant and eff. DM Come Out Naturally

30. Aether Fluid w = 0 (in static or matter-dominated), w=-1 (late universe)

31. Vacuum Between Two sheets: gravitation/E&M corrected • Lambda: sea of virtual pairs of m0 • P0=(m0c2)/(h/m0c)3 =(0.001eV)4= (cH0)2 • Freeman’s law: disk surface density. • P0=[a0/(8pG)] a0 • =(130g/m2)(1A/s2) Dielectric – gravity link !!! Einstein-Maxwell, Einstein-Aether theories  Durality: Photon as particle and a Vector-Field +Q

32. V-L fluid + GR + Baryonsfits 50 x 50 data points ... VDM4/GMbary =(gDM/gbary ).gDM ~a0 ~1/2 Su & Zhao Bruneton, Famaey, Gentile, Zhao (2007, PRD)

33. My V-Lfluid is like LCDM, but fits galaxy data better… • Compatible with • any neutralinos from LHC’2012, any neutrinos from KATRIN’2009, inflation induced perturbations, BBN, Solar system PPN, Bullet Cluster lensing/speed/annihilation … • Microlensing in MW Bar, RAVE escape speed, … Tidal Dwarf Galaxies, SDSS satellite velocities • Free Parameters: n, N • Perfect • L ~ (0.001eV)4 ~ 9 a02 ~ 3 rbar • cosmic MDM/Mbar~2n ~ 8 • nearly all rotation curves

34. Tombstones of in Graveyard of Gravity: !!GO Back to GR!!

35. Various Lagrangians of the Vacuum (Renaissance 2005-2007) • Solar system, Black Holes, Waves • MOND: Lensing • Dark Energy, CMB, inflation/string • …unknowns in co-variant frameworksJacobson’97, Bekenstein’04, Sanders’05, Ferreira’07, Zhao’07 … B’04 (cite 170)

36. High-risk ideas… after packaging by a decent theory… Co-variant Bekenstein’04 (cite 170) Milgrom’83 (cite 417) Universal NFW’97 (cite 1997) Zwicky’33 (cite 236)

37. gravity = a0 somewhere inall objects 10-1pc-109pc • Spirals • Ga0 ~ Rotation V4 /BaryonMass • GlobularCluster, MolecularCloud, dwarf, Ellip, X-Cluster • a0 ~ Velocity2 /Length scale ~ cH0/6 ~ 100Msun/pc2 • My covariant model predicts tight baryon-DM-DE correlations: • (nearly) history-independent, but environment-dependent

38. Vacuum Fluid fits as good as LCDM, but no “L” no “CDM” SNeIa distance-z Dwarf & HSB Vcir(R) Collaborations with Su, Skordis. Mota, Angus, Famaey, Shan, Halle, Gentile

39. Proof of GR+LCDM in WMAP & Bullet: countered by MOND+our temporary ignorance of neutrinos • Toy TeVeS models Skordis et al’05 PRL, Angus etal.’07 ApJL, Feix et al.’07 • to wait for KATRIN’09 neutrino experiment <2eV, • to win time to study effects of four-velocity freedoms (e.g. the J-term in VL model)

40. Spherical TeVeS CASTELS lens Zhao, Bacon, Taylor, Horne (2006,MNRAS)

41. Non-covariant MOND means simply effective DM • Every mass hosts the potential of an effective DM halo (Flattened Isothermal), truncated by its neighbours • Geodesic eqs as GR with factor-2 for lensing (but Geff varies)

42. State-of-art galaxy bar formation: in DM and non-covariant MOND

43. Non-covariant MOND has zero freedom, falsifiable 1-to-1 relation • Intergalactic DM<0 • Check if your chi^2 (from tidal stream or lensing) favors DM positive everywhere. • Identical Baryons mandate identical DM • Spot differences in twins (globulars, dwarfs, galaxies …) • History-independent potential

44. A Fake Hybrid Spiral Galaxy MOND fails to fit(Good !!) DM fits fine Stars Gas Gas Stars (with smaller M/L) Scarpa; http://xxx.lanl.gov/pdf/astro-ph/0601478

45. Shoot, but avoid well-proven traps due to External Field Effect • Vcir NOT flat • Vesc NOT infinite • Potential NOT as flat as disk • Galaxies NOT always on Tully-Fisher • … • ! Attraction due to environment (cluster/filament) is important ! • EFE mimics LCDM tidal harassment

46. Read our 4p manual for EFE traps in MOND I Wu, Famaey, Gentile, Combes, Zhao et al. (2007, ApJ Letters)

47. EFE mimics LCDM tidal harassment • Internal potential is deep/shallow if more/less isolated • Tend to create 2nd generation of stars in distant globulars? • Dwarfs evaporate in Coma Cluster (mimic LCDM harassment)

48. Vulnerable because MOND predicts • History-independent DM potential • Both Tidal Dwarfs and Ordinary dwarfs, have DM effects (The Science article; Gentile et al. 2007, A&A, Letters) • Oblate Halos in disks … • Lack of Dyn. Fric. & Mergers …

49. Title: Resurrection from the Graveyard of Gravity:       Renaissance of MOND as Dark EnergyAbstract:While under-developed historically due to the lack ofa relativistic framework, Milgrom's empirical formulais a magical crystal ball, which forseed the ubiquitous existenceof an EFFECTIVE Dark Matter and Dark Energy well beforethe more physically motivated LCDM parametrization of the cosmos.The MOND formula works accurate in nearly all spiral galaxies, andis order of magnitude correct in clusters of galaxies and in cosmology.This is a remarkable achievementconsidering the tiny amount of man power and computational power spenton MONDified gravity research.  Theoretical physicists have recentlyimbeded MOND in a fully relativistic framework.I present new results which suggest thatMOND is fundementally a hypothesis about the vaccum andspace-time, which reduces to Dark Matter effects in collapsedgalaxy-like structures and Dark Energy effects in uniform cosmology.A proof of existence of dark matter(like known neutrinos or the promising LHC SUSY particles)is often not incompatible with a range of gravity theories,and is not a proof of General Relativity. The even more ellusive nature ofthe cosmological constant is the stronger motivation for modified gravity.

50. Aim of This Talk • Explain MOND as Empirical Law • As a co-variant gravity • As Vacuum Energy (V-Lambda) • As DM • Relation to LHC, DM annihilation • Relation to Neutrino