王 斌 上海交通大学

1. 宇宙“婴儿期”的哭声 --原初引力波的发现及其意义 王 斌 上海交通大学

2. Breaking News: 2014.3.17 Harvard-Smithsonian Center for Astrophysics: Clem Pryke Jamie Bock Chao-Lin Kuo John Kovac BICEP2: Background Imaging of Cosmic Extragalactic Polarization

3. The Dark Sector Lab, located ¾ of a mile from the Geographic South Pole, BICEP2 telescope (left) and the South Pole Telescope (right).

5. Basic concepts of Polarization: Elliptical polarization for the electromagnetic wave The transverse electromagnetic wave E(z,t) 椭圆角 半长轴与x-轴之间的夹角

6. intensity (I) degree of polarization (p), Stokes vector: 庞加莱球 The Stokes parameters I, Q, U and V:provide an alternative description of the polarization state, which is experimentally convenient Linearly polarized (horizontal) Linearly polarized (+45°) Right-hand circularly polarized Linearly polarized (vertical) Linearly polarized (−45°) Left-hand circularly polarized Representations in fixed (x,y) basis Unpolarized

7. Polarization by Scattering: Polarization by reflection off of a surface partially polarized incident unpolarized light outgoing light "shakes" the electrons This is why polarized sunglasses reduce the glare from reflection in the plane polarized Thomson scattering provides a similar means of polarizing CMB light.  Since light cannot be polarized along its direction of motion, only one linear polarization state gets scattered. Thomson Scattering Linear polarization only one linear polarization state gets scattered the intensity of the radiation varies at 90 degrees left and top are of equal intensity, no polarization in the outgoing direction quadrupole pattern

8. density fluctuations The orange line: magnitude and orientation of linear polarization. fixed line of longitude E mode gravitational wave polarization pattern is highly symmetrical B mode we have chosen a specific longitude and rotated in latitude polarization by gravitational waves

9. Polarization Diagram: Density wave: propagating in the direction of the arrow, an electron will always see hotter and colder photons in a direction parallel or perpendicular to the plane of this single wave. E-mode Gravitational wave: it propagates in the same direction as the density wave, it stretches and squeezes space in a direction perpendicular from it. Depending on the orientation of this stretch/squeeze motion, the gravitational wave is capable of producing either E- or B-mode polarization patterns.

10. GWs from inflation generate a twisting pattern in the polarization of the CMB, known as a "curl" or B-mode pattern. For the density fluctuations that generate most of the polarization of the CMB, this part of the primordial pattern is exactly zero. Shown here is the actual B-mode pattern observed by BICEP2, with the line segments showing the polarization from different spots on the sky. The red and blue shading shows the degree of clockwise and anti-clockwise twisting of this B-mode pattern

11. B mode power: • Gravitational waves show  a power spectrum with both E and B mode contributions • Limits on the gravitational wave contribution to the temperature anisotropy imply B-modes < a few tenths of a microKelvin. • Gravitational waves probe the physics of inflation but will require a thorough understanding of foregrounds and secondary effects for their detection. B-mode corresponds to a tenth of a micro Kelvin signal on scales of l~100

12. Lensing B mode detected: arXiv: 1307.5830, 22 Jul 2013 Gravitational lensing of E mode

14. Difficulty in detecting B mode:

15. Detection of B mode by BICEP2:

16. Physical meanings： 1、Particle Physics 2、Gravitation 3、Cosmology

17. 1、Particle Physics，Grand Unified Theory 10^18 Gev no physics? Tev LHC: 2008 Higgs: 126Gev, 2012 BICEP2: set a new energy scale

18. 2、Gravitation：Gravitational wave，Quantum gravity Gravity: Newton theory Einstein GR (1915) （1）GR is valid from submillimeter scale to solar system （2）GR is considered as a classical theory，how to describe the quantum property of gravity? L.D. Landau: Most beautiful theory!!

19. Classical tests of GR: Submillimeter tests of the gravitational inverse-square law Phys. Rev. D 70 (2004)

20. 广义相对论基础的实验检验： gr-qc/0510072 EEP WEP+ LLI+ LPI gravity curved spacetime

22. 广义相对论的经典实验检验 1)水星轨道近日点的进动 2）光线在太阳附近的偏折 3）光线的引力红移 Arthur Stanley Eddington (1882-1944) Solar eclipse of 29 may 1919

23. 4）引力波 脉冲双星，PSR 1913+16 引力辐射导致的系统动能损失表现为双星轨道的衰减，进一步表现为轨道运动周期的逐渐降低，这一理论预言和实验观测结果符合得相当好。 第一次间接证明有引力波存在。 1993诺贝尔奖

24. BICEP2：引力波的又一间接证据 支持广义相对论！！ 量子引力？？

25. 引力波的直接证据? Do black holes have a characteristic “sound”? • Yes. During a certain time interval the evolution of initial perturbation is dominated by damped single-frequency oscillation. Relate to black hole parameters, not on initial perturbation.

26. Can the gravitational wave be detected during the merge of black holes? Needs accurate waveforms produced by GR community!! Gravitational Radiation • Black hole binaries produce gravitational waves in all phases of their evolution • Test of GR in all three phases

28. 3、现代宇宙学

29. Three startling predictions of Einstein’s relativity: The expansion of the Universe (from a big bang) Black holes Dark energy acting against the pull of gravity Einstein’s Predictions Observations confirm these predictions . . . . . . the last only twelve years ago Hubble discovered the expanding Universe in 1929 Black holes found in our Galaxy and at the center of quasars over the past three decades Evidence for an accelerating Universe was observed in 1998

30. Completing Einstein’s Legacy Einstein’s legacy is incomplete, his theory fails to explain the underlying physics of the very phenomena his work predicted • BIG BANG • What powered the Big Bang? • BLACK HOLES • What happens at the edge of a Black Hole? • DARK ENERGY • What is the mysterious Dark Energy pulling the Universe apart?

31. The Brief History of the Universe

32. What Powered the Big Bang? What Powered the Big Bang? Gravitational Waves Can Escape from Earliest Moments of the Big Bang Inflation (Big Bang plus 10-34 Seconds) Big Bang plus 300,000 Years light Now gravitational waves Big Bang plus 15 Billion Years

33. Winners of the 1978 Nobel Prize in Physics Robert Woodrow Wilson 1936, USA Arno Allan Penzias 1933, Germany T=3.1K ~ -270 0C in 1965 T=2.725K, in 2003 * A.A.Penzias and R.Wilson, APJL 142,419 (1965) * R. Dicke. P. Peebles, P. Roll and D. Wilkinson, APJL 142, 414 (1965)

34. Cosmic Background Explorer (COBE, Nov. 1989)

35. 2006 Nobel Prize in Physics (G.F. Smoot) (J. C. Mather)

36. Wilkinson Microwave Anisotropy Probe (WMAP, 30 June 2001) (WMAP-1,2003) (WMAP-7, 2010) (COBE)

37. (Planck， 2009） (CMB,2013)

38. 宇宙38万年老时的面容

40. 我们为什么要早期宇宙暴涨模型？ • Why the universe is homogeneous and isotropic? • Why the universe is so closed to flat case? • The horizon problem • Unwanted particles (monopole…) • ……..

41. The inflation model (1981, A. Guth) V(φ) φ It solves those problems in the big bang model, and in particular, provides a mechanism to give rise to the primordial fluctuations, which are seeds of large scale Structures we observe today.

42. Flatness Problem: matter dominated universe: radiation dominated universe: Recollaspe Open universe T0 Te Time Ts

43. Horizon Problem Log(physical scale) Physical scale, a/k Hubble length,1/H Inflation Log(time)

44. Inflation: Slow roll parameter: reheating The number of e-foldings:

45. 量子涨落，原初谱 背景： 涨落： 标量，矢量和张量:

46. 原初引力波：

48. Constraints on inflation models