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CMB 物理

CMB 物理. 郭宗宽. l unch seminar, ITP/CAS 2014.4.8. 内容. 一、 宇宙学发展现状 二、 CMB 物理 三、最新 的 CMB 观测 结果 四、中国 的 CMB 物理. 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)

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CMB 物理

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  1. CMB物理 郭宗宽 lunch seminar, ITP/CAS 2014.4.8

  2. 内容 一、宇宙学发展现状 二、CMB物理 三、最新的CMB观测结果 四、中国的CMB物理

  3. 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, GC, WL), SNIa • 宇宙学不再是个传说

  4. 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

  5. 1. CMB的形成 400 now decoupling during recombination

  6. 2. CMB的发现和探测实验 • The CMB was first predicted by G. Gamow, R. Alpher and 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.

  7. Hot big bang • 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 J.C. Mather G.F. Smoot (DMR) isotropy

  8. the COBE satellite experiments: • the Far InfraRed Absolute Spectrophotometer (FIRAS) team • the Differential Microwave Radiometer (DMR) team • advantages of satellite experiments: • no atmospheric thermal emission • full-sky map

  9. WMAP (Wilkinson Microwave Anisotropy Probe) - the second generation CMB experiment, launched on 30 June 2001, 9 years 141°

  10. 23 GHz 33 GHz 41 GHz 61 GHz • free-free emission: electron-ion scattering • synchrotron emission: the acceleration of cosmic ray electrons in magnetic fields • thermal emission from dust 94 GHz

  11. foreground mask • angular power spectrum of CMB

  12. WMAP science team publications 2003, WMAP1, 14 papers, cited by 6873 records 2007, WMAP3, 5papers, cited by 5289 records 2009, WMAP5, 8papers, cited by 3527records 2011, WMAP7, 6papers, cited by 3803 records 2012, WMAP9, 2papers, cited by 303 records We have entered a new era of precision cosmology.

  13. 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)

  14. cosmological parameters the temperature angular power spectrum 20 March 2013, 29 papers

  15. nextgeneration space-based CMB experiment • NASA: CMBPol • ESA: COrE

  16. 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

  17. South Pole Telescope (SPT) 10 meter telescope 3 frequencies (95, 150 and 220 GHz) arXiv:1105.3182: SPT+WMAP7+BAO+H0 arXiv:1212.6267: SPT+WMAP7+BAO+H0

  18. 3. CMB的数据分析 time-ordered data full sky map spectrum parameter estimates  time-ordered data  the temperature anisotropies can be expanded in spherical harmonics

  19.  for Gaussian random fluctuations, the statistical properties of the temperature field are determined by the angular power spectrum For a full sky, noiseless experiments,  cosmological parameter estimation likelihood function for a full sky: the sky-cut, MCMC

  20. 4. CMB各向异性的物理起源 • primary CMB anisotropies (at recombination) inflation model (Alan H. Guth in 1981)  primordial power spectrum of perturbations  angular power spectrum of CMB anisotropies • secondary CMB anisotropies (after recombination) thermal/kinetic Sunyaev-Zel’dovich effect integrated Sachs-Wolf effect reionization weak lensing effect

  21. inflation model V (φ) reheating inflation φ for slow-roll inflation, the primordial power spectra of scalar/tensor perturbations:

  22. 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.

  23. 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.

  24. CMB constraints on the energy scale of inflation Determining the energy scale of inflation is crucial to understand the nature of inflation in the early Universe. ZK Guo, D.J. Schwarz, Y.Z. Zhang, PRD 83 (2011) 083522.

  25. gravity pressure The stronger the contraction, the higher these peaks should be. Acoustic oscillations are frozen in at recombination.

  26. scalar tensor

  27. 三、最新的CMB观测结果 • 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？

  28. 六参数的ΛCDM模型 • 原初非高斯性 • 暴胀模型 • 数据之间的不自洽 • CMB温度涨落的反常 • BICEP2分析结果

  29. 1. 六参数的ΛCDM模型 “None of these models are favoured over the standard six-parameter ΛCDM cosmology.”

  30. 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

  31. 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.

  32. 2. 原初非高斯性 “Planck finds no evidence for non-Gaussian statistics of the CMB anisotropies.”

  33. 3. 暴胀模型 slow-roll inflation (three parameters): As, ns, r, nt=-r/8 The data favor a concave potential rather than a convex one.

  34. 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:

  35. 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.

  36. 4. 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,

  37. 5. 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 ……

  38. (1) the quadrupole-octopolealignment

  39. (2) power deficit at low-l

  40. (3) parity asymmetry

  41. (4) hemispherical asymmetry the CMB temperature sky maps is modeled as

  42. 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,

  43. 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

  44. 6. BICEP2分析结果 • “至于你信不信，我反正信了。” • primordial gravitational wave? cosmic string, Faraday rotation, cosmic birefringence, reionization, … • a tension with the Planck result a large running of scalar spectral index

  45. for slow-roll inflation • What is the inflaton field? Higgs field? • challenge for slow-roll inflation with a large running • If confirmed by Planck, the next step is to detect the tensor spectral index.

  46. 四、中国的CMB物理 • 研究组（引力、天文、高能） • 模型 • 数据处理 • 模型参数的拟合 • 微波探测实验 • 参与、主导、等待

  47. 谢谢大家！

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