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An Experimentalist’s Perspective on Testing Field Theories with the CMB. L. Page, AlbaNova, June 2007 The current cosmological model agrees with virtually all cosmological measurements regardless of redshift or method. The model assumes a flat geometry (a couple %), a new form of matter (>15), something that mimics a cosmological constant (many ), and a deviation =1, ~3). from scale invariance ( WMAP3 only WMAP3 + all Models based on some kind of field theory of the early universe predict ns. closed “Geometric Degeneracy” CMB alone tells us we are on the “geometric degeneracy” line open WMAP3 only best fit LCDM 1 b c Assume flatness Reduced Testing Specific Field Theories Experimental handles (1) Spectrum of Fluctuations & (2) Anisotropies from Gravitational Waves. (3) Non-Gaussanity Types of Cosmological Perturbations Temperature Scalars: , E polarization Temperature Tensors: h (GW strain) E polarization B polarization 0.3 Or less! n and r are predicted by models of the early universe Physical size = plasma speed X age of universe at decoupling Angular Power Spectrum. Power spectrum ~10 early in inflation ~0.40 later in inflation The overall tilt of this spectrum--encoded in the “scalar spectral index” ns--- is the new handle on the early universe. Spectral Index, Experimental Challenges Three different spectra that differ only in spectral index. The black line is the best WMAP model. Spectral Index Normalize the spectra to l=220 (mimics nsamplitude degeneracy) The two window functions are for 0.1 deg FWHM beams with a 1% difference in solid angle. Only WMAP has achieved anything like this accuracy. Spectral Index Divide by fractional window function. Conclusion: To probe the index the beams need to be understood to the 1% level. In addition, there are astrophysical challenges. Spectral Index: Astrophysical Challenges The formation of the first stars produces free electrons that: (1) rescatter CMB photons thereby reducing the anisotropy and (2) polarize the CMB at large angular scales. These effects mimic a change in ns: “the ns - tau” degeneracy WMAP measures (2) to break the degeneracy TT TE EE BB r=0.3 Approx EE/BB foreground BB inflation BB Lensing (not primordial) Low-l EE/BB EE EE Polarization: from reionization by the first stars Just Q and V bands. BB BB Polarization: null check and limit on gravitational waves. r<2.2 (95% CL) from just EE/BB Degeneracy 1yr WMAP No SZ marg WMAP1+ ACBAR+ CBI L 3yr WMAP Knowledge of optical depth breaks the degeneracy Index and Tensors ns=0.95 ( in 2d) ( in 2d ) ns=1 What Does the Model Need to Describe the Data? changing one of the 6 parameters at a time…. Model needs Model needs , 8 not unity, Model needs dark matter, { (“2.8 sigma”) 6 248 ….but Eriksen & Huffenberger (“15 sigma”) Model does not need: “running,” r, or massive neutrinos, < 3. The data are, of course, less restrictive when there are more parameters. Gravitational Waves TT Approx EE/BB foreground TE EE B modes from tensors only. G-waves decay once inside the horizon. BB r=0.3 B modes from lensing of E modes (not primordial). Reionization peak (zr=10) Horizon size at decoupling (zdec=1089) Expectations at l=100 Dust at 150 GHz from FDS Lensing BB 1000 close packed dets for 1 year at 350 uK-sec^{1/2} raw or 700 uKsec^{1/2} on sky. Boxes inst sensitivity not sky rms sens. Lensing B modes From Jo Dunkley Non-Gaussanity The quadrapole is not anomalously low. For the full sky, the 2-pt correlation function is not anomalous. All “detections” of non-Gaussanity are based on a posteriori statistics. That is, one seeks any oddity in the maps and quantifies it. The North-South asymmetry was visible in the COBE data. It would be fantastic to find a clear signature of cosmic nonGaussanity. The WMAP team has not found one. A significant fraction of the full-sky quadrupole comes from: Alignment? See Max! (de Oliveira-Costs et al. 2004) (Hajian 2007) Detection of SH persists! Note “fingers” present in the southern Galactic hemisphere. Extra cold spot: (Vielva et al. 2004, Cruz et al. gave 1.8% prob. 2005) Distribution by map temp. by frequency (accounting for uneven weighting) Gaussian Data are an excellent representation of a Gaussian! 40 pix Cold spot 10 pix Distribution by resolution. 0.250 pix What’s Next? ACT SZA (Interferometer) Owens Valley 2006 PAPPA BRAIN SCUBA2 (12000 bolometers) QUIET CLOVER EBEX SPIDER 2008 2009 (3000 bolometers) Chile QUAD BiCEP 2007 SPT (1000 bolometers) South Pole APEX (~400 bolometers) Chile Polarbear-I (300 bolometers) California Planck (50 bolometers) L2, data 2012 Science: Growth of structure Eqn. of state Neutrino mass Ionization history ACT Observations: CMB: l>1000 Cluster (SZ, KSZ Atacama Cosmology Telescope X-rays, & optical) Diffuse SZ OV/KSZ Lensing Inflation Power spectrum X-ray Optical Collaboration: Cardiff Rutgers Theory Columbia CUNY Haverford INAOE NASA/GSFC NIST Princeton UBC U. Catolica U. KwaZulu-Natal UMass UPenn U. Pittsburgh U. Toronto New Type of Telescope M. Devlin is lead Telescope at AMEC in Vancouver. Ship to Chile in 2006. Arrays of bolometers (S. Staggs is lead) Moseley et al, NASA/GSFC Irwin et al. Warm electronics based on SCUBA2 Halpern et al. UBC 8x32 Array of 1mm x 1mm detectors. Now in Chile on the telescope. First Light from ACT June 8, 2007 Expanding CMB Photosphere (with Temperature decrease scaled out) Stuart Lange, Senior Thesis, 2007 An Experiment for the Century Power spectrum of difference between two maps made 100 years apart. Error bars with a 3000x3000 array of detectors. Thank You! From Wayne Hu CMB Polarization Polarization of the CMB is produced by Thompson scattering of a quadrupolar radiation pattern. E 2 deg Whenever there are free electrons, the CMB is polarized. The polarization field is decomposed into “E” and “B” modes. B Seljak & Zaldarriaga Terminology: E/B Modes k k Density wave E-modes Gravitational wave B-modes Equation of State & Curvature Interpret as amazing consistency between data sets. WMAP+CMB+2dFGRS+SDSS+SN (3) The spectrum of scalar fluctuations. WMAP z=1089 2D 2dFGRS z<3 3D Lyman alpha Verde et al. 2003 and now SDSS as well. Low-l EE/BB EE (solid) BB (dash) EE/BB model at 60 GHz r=0.3 Since reionization is late we see it at large angular scales. This is our handle on the optical depth. More simulations of mm-wave sky. 1% 1.4 Survey area 0 2% High quality area 150 GHz SZ Simulation MBAC on ACT 1.5’ beam PLANCK Burwell/Seljak WMAP PLANCK / Diffuse KSZ Target Sensitivity (i.e. ideal stat noise only) SPT & APEX as well. ACT / Diffuse KSZ de Oliveira-Costa (2) Gaussanity Express sky as: T( , ) a Y ( , ) lm lm l ,m Gaussanity means that the real and imaginary parts of each alm are independent normal deviates. We quantify the Gaussanity with: Komatsu et al. ‘03 Current WMAP limit: Planck limit : fNL=5 Ultimate CMB limit : fNL=3 Simple models of inflation have fNL=0.05 More exotic models of inflation have fNL=10 to 100. Babich & Zaldarriaga 04 The scalar index, ns, with six parameters. WMAP +SDSS Tegmark et al. 2004 +SDSS Galaxies and Lya Seljak et al. 2004 Simple models of inflation predict: This is significant in that it is a clear departure from scale invariance. We expect ns to 1% by 2008 from the CMB. Running of the scalar index. SDSS Galaxies Tegmark et al. 2004 In the two recent analyses of WMAP plus SDSS there is no evidence for running. An analysis of CBI+WMAP+LSS shows evidence of running at the 3sigma level (-0.085+/-0.031) but the CBI team does not place a lot of weight on the result. Galaxies and Lya Seljak et al. 2004 Readhead et al. 2004 Stability of instrument is critical Physical temperature of B-side primary over three years. Model based on yr1 alone Three parameter fit to gain over three years leads to a clean separation of gain and offset drifts. 3yr Model Data based on dipole Jarosik et al.