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Recent Progress in CMB. 郭宗宽. 北京工业大学 2014.4.17. 内容. 一、宇宙学发展现状 二、 CMB 物理 三、 CMB 的最新进展. 一、宇宙学发展现状. 大爆炸宇宙学 (1920s-1970s) 宇宙在膨胀( 1929 ) BBN 的预言与观测一致( 1998 ) CMB 的黑体谱( 1994 ) 标准 模型 (1980s-2000s) 暴胀 + Λ + 冷暗物质 + 重子 + 中微子 精确 宇宙学 (2000s-now) CMB , LSS(BAO, RSD, GC, WL), SNIa. 二、 CMB 物理.
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Recent Progress in CMB 郭宗宽 北京工业大学 2014.4.17
内容 一、宇宙学发展现状 二、CMB物理 三、CMB的最新进展
一、宇宙学发展现状 • 大爆炸宇宙学(1920s-1970s) • 宇宙在膨胀(1929) • BBN的预言与观测一致(1998) • CMB的黑体谱(1994) • 标准模型(1980s-2000s) • 暴胀+Λ+冷暗物质+重子+中微子 • 精确宇宙学(2000s-now) • CMB, LSS(BAO, RSD, GC, WL), SNIa
二、CMB物理 • CMB的形成 • CMB的发现和探测实验 • CMB的数据分析 • CMB各向异性的物理起源
1. CMB的形成 recombination: Compton scattering: decoupling during recombination 400 now
2. CMB的发现和探测实验 • The CMB was first predicted by G. Gamow, R. Alpherand R. Herman in 1948. (T~5 K) • the first discovery of the CMB radiation in 1964-1965. the Nobel Prize in Physics 1978: A.A. Penzias and R.W. Wilson • It is interpreted by R. Wilson, B. Burke, R. Dicke and J. Peebles in 1965. • COBE (Cosmic Background Explorer) — the first generation CMB experiment, launched on 18 Nov. 1989, 4 years. the Nobel Prize in Physics 2006: J.C. Mather and G.F. Smoot
isotropy Hot big bang
23 GHz • WMAP (Wilkinson Microwave Anisotropy Probe)the second generation CMB experiment, launched on 30 June 2001, 9 years foreground mask 33 GHz 141° 41 GHz 61 GHz 94 GHz
14, 5, 8, 6, 2 papers, 6873 citations We have entered a new era of precision cosmology.
Planck — the third generation CMB experiment, launched on 14 May 2009, 30 months, 5 full-sky surveys LFI: 30, 44, 70 GHz HFI : 100, 143, 217, 353, 545, 857 GHz • full-sky coverage • high sensitivity • wide frequency • high resolution ~ 5′(15′,7º)
cosmological parameters Mar 2013, 29papers, 1609 citations CMBspectrum
BICEP2 (Background Imaging of Cosmic Extragalactic Polarization) experiment — evidence for primordial B-mode is first detected. BICEP1 (2006-2008) BICEP2 (2010-2012) SPT The Dark Sector Lab (DSL)
26 cm aperture 150 GHz 383.7 deg2 2010-2012 4 tiles 8×8 array of detector pairs antenna networks band-defining filters bolometers
“BICEP2 2014 I: Detection of B-mode Polarization at Degree Angular Scales”, arXiv:1403.3985, cited by 153 records “BICEP2 2014 II: Experiment and Three-year Data Set”, arXiv:1403.4302
nextgeneration space-based CMB experiment • NASA: CMBPol • ESA: COrE
Other experiments • ground-based experiments • ACBAR, BICEP, CBI, VSA, QUaD, POLARBEAR, … • ACT, ACTPol from 2013 • SPT, SPTpol from 2012 • BICEP2 (r ~ 0.2) • QUBIC (r ~ 0.01, bolometer, interferometer) • balloon-borne experiments • BOOMRANG, MAXIMA, … • EBEX • Spider
3. CMB的数据分析 • CMB temperature fluctuations time-ordered data CMB temperature sky map ~10−5
for Gaussian random fluctuations, the statistical properties of the temperature field are determined by the angular power spectrum for a full sky, noiseless map cosmological parameter estimation likelihood function for a full sky:
CMB polarization raw timestreams(2010~2012) Glitches and flux jumps are flagged. map making (T, Q, U) detector transfer function, gain calibration, noise, beam function, polarization leakage, …
from maps to power spectra • rotationally invariant • B has the opposite parity of T and E • scalar modes contribute only to E
9 data bandpowers: ∆l=35, 20<l<340 model bandpowers by band window functions cosmological parameter constraints • direct likelihood • bandpower likelihood
4. CMB各向异性的物理起源 • primary CMB anisotropies (at recombination) inflation model (A.H. Guth in 1981) • secondary CMB anisotropies (after recombination) thermal/kinetic Sunyaev-Zel’dovich effect integrated Sachs-Wolf effect reionization weak lensing effect
slow-roll inflationary model V (φ) reheating inflation φ for slow-roll inflation, the primordial power spectra of scalar and tensor perturbations:
reconstruction of power spectrum • parameterization: • scale-invariant(As) • power-law (As, ns) • running spectral index (As, ns, as) • method: • advantages: • It is easy to detect deviations from a scale-invariant or a power-law spectrum. • Negative values of the spectrum can be avoided by using ln P(k) instead of P(k). • It reduces to the scale-invariant or power-law spectrum as a special case when N bin= 1, 2, respectively.
WMAP7+H0+BAO WMAP7+H0+BAO WMAP7+ACT+H0+BAO WMAP7+ACT+H0+BAO ZK Guo, D.J. Schwarz, YZ Zhang, JCAP 08 (2011) 031; ZK Guo, YZ Zhang, JCAP 11 (2011) 032; ZK Guo, YZ Zhang, PRD 85 (2012) 103519.
CMB temperature fluctuations gravity pressure The stronger the contraction, the higher these peaks should be. Acoustic oscillations are frozen in at recombination.
CMB polarization A monochromatic electromagnetic wave propagating in the z direction has an electric field vector
scalar mode tensor mode with
三、CMB的最新进展 • 去年发布了Planck 2013温度数据 • 平静之下,暗潮汹涌。 • 上月发布了BICEP2极化数据 • 至于你信不信,我反正信了。 • 今年将发布Planck 2014极化数据 • 灭火器?
六参数的ΛCDM模型 • 暴胀模型的限制 • 数据之间的不自洽 • CMB温度涨落的反常 • BICEP2分析结果
1. 六参数的ΛCDM模型 “None of these models are favouredover the standard six-parameter ΛCDM cosmology.”
Lorentz invariance violation in the neutrino sector the deformed dispersion relation • CMB anisotropies: (1) the energy density (2) the Boltzmann equation in the synchronous gauge
Big Bang nucleosynthesis: (1) the energy density (2) the weak reaction rate • cosmological constraints: ZK Guo, QG Huang, RG Cai, YZ Zhang, PRD 86 (2012) 065004; ZK Guo, JW Hu, PRD 87 (2013) 123519.
2. 暴胀模型的限制 slow-roll inflation (three parameters): As, ns, r, nt=-r/8 The data favor a concave potential rather than a convex one.
Inflation coupled to a GB term • motivations: higher-order corrections,a flat potential,a large tensor perturbation • model: where introducing Hubble and GB flow parameters: the predicted tensor-to-scalar ratio and spectral indices:
The standard consistency relation is broken by the GB coupling. The GB coupling may lead to a reductionof the tensor-to-scalar ratio. ZK Guo, N. Ohta, S. Tsujikawa, PRD 75 (2007) 023520; ZK Guo, D.J. Schwarz, PRD 80 (2009) 063523; ZK Guo, D.J. Schwarz, PRD 81 (2010) 123520; PX Jiang, JW Hu, ZK Guo, PRD 88 (2013) 123508.
3. 数据之间的不自洽 • 平静之下,暗潮汹涌。 • Cepheid+SNeIa, discrepant at the 2.5 σ level • SNLS, discrepant at the 2σ level • cosmic shear, discrepant at the 2 σlevel, • galaxy cluster, discrepant at the 3 σlevel,
4. CMB温度涨落的反常 (1) the quadrupole-octopolealignment (2) power deficit at low-l (3) parity asymmetry (4) hemispherical asymmetry (5) the cold spot ……
(4) hemispherical asymmetry the CMB temperature sky maps is modeled as
a super-horizon perturbation the Sachs-Wolfe effect the diploe modulation of curvature perturbation the asymmetry A is For a single-field slow-roll inflation,
primordial power spectrum: For the bounce inflation, ZG Liu, ZK Guo, YS Piao, PRD 88 (2013) 063539; ZG Liu, ZK Guo, YS Piao, arXiv:1311.1599
5. BICEP2分析结果 Step 1: is the data reliable? • some unknown sources of systematic error • data analysis pipeline • likelihood method • “至于你信不信,我反正信了。”
cosmic string • Faraday rotation • cosmic birefringence • reionization Step 2: primordial gravitational wave? Step 3: a tension with the Planck result • a large running of scalar spectral index • step potential • fast-slow-roll inflation • non-Bunch-Davis vacuum, false vacuum, trans-Planck • anti-correlated tensor-curvature • anti-correlated iso-curvature
Step 4: what is the inflation field? • Higgs field? • for slow-roll inflation, • challenge for slow-roll inflation with a large running Step 5: if confirmed by Planck, the tensor spectral index • scale-invariant tensor spectrum • the standard consistency relation? • blue spectrum? string gas cosmology bounce inflation super-inflation before slow-roll inflation