Wei-Tou NI Department of Physics National Tsing Hua University

1. Gravitational Waves, Dark Energy and Inflation ---Classification of gravitational waves, dark energy equation, and probing the inflationary physics using space gravitation-wave detectors Wei-Tou NIDepartment of Physics National Tsing Hua University Probing the inflationary physics empirically W.-T. Ni

2. Dedicated to H C Yen – a devoted physicist and educator Probing the inflationary physics empirically W.-T. Ni

3. Probing the inflationary physics empirically W.-T. Ni

4. OUTLINE • Classification of Gravitational Waves • Space GW detector as dark energy probe • Inflation & Primordial Gravitational Waves • CMB Polarization Detection of Tensor Modes • Two potential frequency regions to detect primordial GWs in Space by Interferometers • General Concept of --- ASTROD I, ASTROD, ASTROD-GW, Super-ASTROD • Outlook Probing the inflationary physics empirically W.-T. Ni

5. Importance of Gravitational Wave Detection • Explore fundamental physics and cosmology； • As a tool to study Astronomy and Astrophysics Primordial GWs and their detectablity W.-T. Ni

6. Frequency Classification of Gravitational Waves－ similar to frequency classification of electromagnetic waves to radio wave, millimeter wave, infrared, optical, ultraviolet, X-ray and γ-ray etc. LOWER Frequency: Bigger events • Very high frequency band (100 kHz – 1 THz): high-frequency ground resonators are most sensitive to this band. • High frequency band(10 Hz – 100 kHz): low-temperature and laser-interferometric ground detectors are most sensitive to this band. • Middle frequency band (0.1 Hz – 10 Hz): space detectors of short armlength (1000-100000 km). • Low frequency band(100 nHz – 0.1 Hz): laser-interferometer space detectors are most sensitive to this band. • Very low frequency band(300 pHz – 100 nHz): pulsar timing observationsare most sensitive to this band. • Ultra low frequency band (10 fHz– 300 pHz): astrometry of quasars. • Extremely low frequency band(1aHz–10fHz), cosmic microwave backgroundexperiments are most sensitive to this band. Primordial GWs and their detectablity W.-T. Ni

7. 在荷兰Leiden建造的MiniGRAIL低温共振球形引力波侦测器。左图为实体照片，右图为实验结构图。侦测球为直径65cm的铜铝(6%)合金，其共振频率为3250Hz，频宽230Hz。运作温度将为20mK。在罗马和圣保罗将各建造一个类似的球形侦测器──Sfera和Graviton。三个侦测器共同侦测3250Hz附近频率引力波的目标灵敏度将比LIGO II的目标灵敏度好上几倍。 Gravitational Wave Detectors on Ground and in Space W.-T. Ni

8. Gravitational Wave Detectors on Ground and in Space W.-T. Ni

9. LIGO Gravitational Wave Detectors on Ground and in Space W.-T. Ni

10. LIGO instrumental sensitivity for science runs S1 (2002) to S5 (present) in units of gravitational-wave strain per Hz1/2 as a function of frequency Gravitational Wave Detectors on Ground and in Space W.-T. Ni

11. The displacement sensitivity of the three LIGO interferometers across the gravitational-wave frequency band of interest to LIGO. The solid curve is the optimum sensitivity predicted in 1995 Science Req.’s Document Gravitational Wave Detectors on Ground and in Space W.-T. Ni

12. Evolution of the Virgo strain sensitivity Gravitational Wave Detectors on Ground and in Space W.-T. Ni

13. No detection yet Advanced LIGO – completion 2014-15 12-13 times more sensitive Chance by volume 2000 times Now 0.05 per year for ns-ns inspirals To 100 per year for ns-ns inspirals Probing the inflationary physics empirically W.-T. Ni

14. Probing the inflationary physics empirically W.-T. Ni

15. Primordial GWs and their detectablity W.-T. Ni

16. Massive Black Hole Systems: Massive BH Mergers &Extreme Mass Ratio Mergers (EMRIs) Primordial GWs and their detectablity W.-T. Ni

17. Primordial GWs and their detectablity W.-T. Ni

18. Primordial GWs and their detectablity W.-T. Ni

19. Primordial GWs and their detectablity W.-T. Ni

20. Space GW detectors as dark energy probes Luminosity distance determination to 1 % or better Measurement of redshift by association From this, obtain luminosity distance vs redshift relation, and therefore equation of state of dark energy Probing the inflationary physics empirically W.-T. Ni

21. 3 Focused Issues in Cosmology Dark Matter Issue Dark Energy Issue What is the Physical Mechanism of Inflation Probing the inflationary physics empirically W.-T. Ni

22. Issues in the Standard Cosmology Large-Scale Smoothness Small-Scale Inhomogeneity Spatial Flatness Unwanted Relics (monopoles  Guth 1981, Inflation) Cosmological Constant Except for the last one: Explained by Inflation Probing the inflationary physics empirically W.-T. Ni

23. Inflation Scenario & Potentialslow-roll inflationary model（Linde；Albrecht & Steinhardt, 1982）(from Kolb & Turner 1990) • Barrier penetration • Slow-roll • Coherent oscillation around potential minimum • If the parameters at the beginning of inflation is M=10^14 GeV H^(-1)=10^(-34) sec and T=100 H^(-1)=10^(-32) s Tc=T_RH=10^14 GeV H^(-1)=10^(-23) cm（initial size） 3 ×10^20 cm（after inflation） • S (entropy)=T^3 (H^(-3))=10^14  10^144 (10^130 fold increase) Probing the inflationary physics empirically W.-T. Ni

24. A Comparison(from Kolb & Turner 1990) Standard Cosmology vs. Inflationary Cosmology Can we probe the inflationary physics? Probing the inflationary physics empirically W.-T. Ni

25. Inflationary GW Background = h_0^2(1/ρ_c) dρ_gw/d(logf) ~ 10^(-13) (H/10^(-4)M_pl) De Sitter Probing the inflationary physics empirically W.-T. Ni

26. Ressel & TurnerPrimordial GW Model (1989): Compare with the numerical values nowadays RDMD IRD Probing the inflationary physics empirically W.-T. Ni

27. 3 predictions of inflation Flat Universe Nearly scale-invariant spectrum of Gaussian density perturbations Nearly scale-invariant spectrum of Gravitational Waves Probing the inflationary physics empirically W.-T. Ni

28. Amplification of vacuum fluctuations of GWs for wavelengths larger than transition time (Hubble time) Sudden (Instantaneous) Transition Transition between an inflationary phase and the radiation-dominated phase (RD): I  RD Transition between radiation-dominated phase and the matter dominated phase (MD): RD  MD Probing the inflationary physics empirically W.-T. Ni

29. Spectral energy density in gravity waves produced by inflation (for T/S = 0.018, dnT/dlnk =-10^(-3), 0, 10^(-3). T/S = 0.18 (heavy curve) maximizes the energy density at f = 100 microHz) WMAP5 Data Scalar spectral index n_s = 0.960 ± 0.013, r < 0.22 (95% CL) Planck 0.5 % in n_s (0.957) r>~0.0046 For Coleman-Weinberg inflation  >~1.61×10^(-17) arXiv:astro-ph/9704062v1 Probing the inflationary physics empirically W.-T. Ni

30. LIGO or VIRGO ms pulsars (single intf) bar-intf Nv = 4 2 intf Nv = 3.2 (c) cosmic strings (b) String LIGO II/LCGT/VIRGO II (2 adv intf) LISA cosmology Log [h02Ωgw] Extragalactic Extrapolated WMAP (a) inflation DECIGO/BBO-grand (correlation detection) ‘Average’ ASTROD Super-ASTROD * ASTROD (correlation detection) Super-ASTROD (correlation detection) * Log f [[[ [f(Hz)] Primordial Gravitational Waves[strain sensitivity  (ω^2) energy sensitivity] Probing the inflationary physics empirically W.-T. Ni

31. WMAP 3 year Polarization Maps TT TE foreground EE BB(lensing) BB(r=0.3) Probing the inflationary physics empirically W.-T. Ni

32. B-Pol: detecting primordial GWsgenerated during inflation (Exp. Astron.) Paolo de Bernardis · Martin Bucher · Carlo Burigana · Lucio Piccirillo ·For the B-Pol Collaboration Probing the inflationary physics empirically W.-T. Ni

33. The sensitivity goal of B-Pol Probing the inflationary physics empirically W.-T. Ni

34. Probing the inflationary physics empirically W.-T. Ni

35. Probing the inflationary physics empirically W.-T. Ni

36. The sensitivity goal of LiteBIRD Probing the inflationary physics empirically W.-T. Ni

37. B modes From tensor mode of polarization (GW) From electromagnetic propagation with pseudoscalar-photon interaction From lensing effects From magnetic field Probing the inflationary physics empirically W.-T. Ni

38. The Gravitational Wave Background from Cosmological Compact BinariesAlison J. Farmer and E. S. Phinney (Mon. Not. RAS [2003]) Optimistic (upper dotted), fiducial (Model A, lower solid line) and pessimistic (lower dotted) extragalactic backgrounds plotted against the LISA (dashed) single-arm Michelson combination sensitivity curve. The‘unresolved’ Galactic close WD–WD spectrum from Nelemans et al. (2001c) is plotted (with signals from binaries resolved by LISA removed), as well as an extrapolated total, in which resolved binaries are restored, as well as an approximation to the Galactic MS–MS signal at low frequencies. ASTROD-GW & Super-ASTROD Region DECIGO BBO Region Probing the inflationary physics empirically W.-T. Ni

39. Primordial GW and Space Detectors • For detection of primordial GWs in space. One may go to frequencies lower or higher than LISA bandwidth where there are potentially less foreground astrophysical sources to mask detection. • DECIGO and Big Bang Observer look for gravitational waves in the higher range • ASTROD-GW, Super-ASTROD look for gravitational waves in the lower range. • Super-ASTROD: 3-5 spacecraft with 5 AU orbits together with an Earth-Sun L1/L2 spacecraft and ground optical stations to probe primordial gravitational-waves with frequencies 0.1 μHz - 1 mHz and to map the outer solar system. Probing the inflationary physics empirically W.-T. Ni

40. Probing the inflationary physics empirically W.-T. Ni

41. LISA LISA consists of a fleet of 3 spacecraft 20º behind earth in solar orbit keeping a triangular configuration of nearly equal sides (5 × 106 km). Mapping the space-time outside super-massive black holes by measuring the capture of compact objects set the LISA requirement sensitivity between 10-2-10-3 Hz. To measure the properties of massive black hole binaries also requires good sensitivity down at least to 10-4 Hz. (>2018) Probing the inflationary physics empirically W.-T. Ni

42. LISA Pathfinder in Assembly Clean Room Probing the inflationary physics empirically W.-T. Ni

43. ASTROD • ASTROD I • ASTROD • ASTROD-GW • Super-ASTROD Probing the inflationary physics empirically W.-T. Ni

44. ASTROD I(Cosmic Vision 2015-25) submitted to ESA by H. Dittus (Bremen)arXiv:0802.0582 v1 [astro-ph] • Scaled-down version of ASTROD • 1 S/C in an heliocentric orbit • Drag-free AOC and pulse ranging • Launch via low earth transfer orbit to solar orbit with orbit period 300 days • First encounter with Venus at 118 days after launch; orbit period changed to 225 days (Venus orbit period) • Second encounter with Venus at 336 days after launch; orbit period changed to 165 days • Opposition to the Sun: shortly after 370 days, 718 days, and 1066 days Probing the inflationary physics empirically W.-T. Ni

45. ASTROD configuration (baseline ASTROD after 700 days from launch) Probing the inflationary physics empirically W.-T. Ni

46. Summary of the scientific objectives in testing relativistic gravity of the ASTROD I and ASTROD missions Probing the inflationary physics empirically W.-T. Ni

47. S/C 1 (L4) 60 地球 (L3) S/C 2 L1 L2 60 S/C 3 (L5) ASTROD-GW Mission Orbit Earth Sun Considering the requirement for optimizing GW detection while keeping the armlength, mission orbit design uses nearly equal arms. 3 S/C are near Sun-Earth Lagrange points L3、L4、L5，forming a nearly equilateral trianglewith armlength260 million km（1.732AU）. 3 S/C ranging interferometrically to each other. Probing the inflationary physics empirically W.-T. Ni

48. Heliocentric Distance of 3 S/Cin 10 years Probing the inflationary physics empirically W.-T. Ni

49. Armlenth in 10 years Probing the inflationary physics empirically W.-T. Ni

50. Difference of Armlengths in 10 years Probing the inflationary physics empirically W.-T. Ni