Misao Sasaki. KIAS-YITP joint workshop 22 September, 2017

Transcription

1 Misao Sasaki KIAS-YITP joint workshop September, 017

2 Introduction

3 Inflation: the origin of Big Bang Brout, Englert & Gunzig 77, Starobinsky 79, Guth 81, Sato 81, Linde 8, Inflation is a quasi-exponential expansion of the Universe at its very early stage; perhaps at t~10-36 sec. It was meant to solve the initial condition (singularity, horizon & flatness, etc.) problems in Big-Bang Cosmology: if any of them can be said to be solved depends on precise definitions of the problems. Quantum vacuum fluctuations during inflation turn out to play the most important role. They give the initial condition for all the structures in the Universe. Cosmic gravitational wave background is also generated. 3

4 4 温故知新 (learning from the past) ds dt a ( t) dh ; ( 3) 1 a( t) H sinh Ht Creation of Open Universe! Now in the context of String Landscape

5 5 length scales of the inflationary universe targets for multi-frequency GW astronomy log L L=H 0-1 Size of the Observable Universe L=H cm ~ 46 e-folds 10 8 cm LIGO band (10 ~10 7(?) cm) Reheating stage log a(t) Inflationary Universe Hot Bigbang Universe

6 Dynamics 6

7 Seed of cosmological perturbations Mukhanov 81,. 7 Zero-point (vacuum) fluctuations of f : f k 3 H fk ( t) fk 0 ; () t f k k a ( t) f () ik x k te harmonic oscillator with friction term and time-dependent f k fk const. frozen when < H (on superhorizon scales) tensor (gravitational wave) modes also satisfy the same eq. Starobinsky 79

8 Generation of Curvature Perturbation 8 curvature (potential) perturbation R : 4 R a ( 3) comoving curvature perturbation R c ~ - Newton potential f is frozen on flat (R=0) 3-surface (t=const. hypersurface) Inflation ends/damped osc starts comoving (f =const.) on 3-surface. c H f f f t T const., c 0 hot bigbang universe 0 f 0 end of inflation f f f 0 x i 0 f 0

9 Generic predictions of inflation 9 Spatially flat universe Almost scale invariant, adiabatic, Gaussian primordial scalar (curvature) perturbations Almost scale invariant, Gaussian primordial tensor (gravitational wave) perturbations Generates CMB anisotropy Origin of galaxies, stars,

10 Quantitative Predictions 10 Amplitude of curvature perturbation: c H f k/ ah Mukhanov (1985), MS (1986) Power spectrum index: 18 4 k ( ) M pl Tensor (gravitational wave) spectrum: 1 8G 3 H n 1 P ( ) S 1 3 S k Ak ; ns MP f k/ ah 3 4 k n 1 P ( ) T S k r ( ) ; 3 P T k Ak nt ( ) 8P ( k) 8 T consistency relation ~. 410 GeV: Planck mass V V 3 V V Stewart-Lyth (1993) Liddle-Lyth (199)

11 Observational results 11

12 Planck TT, TE & EE spectrum 1

13 Amplitude of curvature perturbation: 13 c H f k/ ah Mukhanov (1985), MS (1986) Power spectrum index: ns 4 k ( ) c ~ V ( f ~ 5 1/ 4 16, obs 10 ) 10 GeV? M P 3 H n 1 P ( ) S 1 3 S k Ak ; ns MP f k/ ah 1 ~. 8G Tensor (gravitational wave) spectrum: GeV: Planck mass V V 3 V V Stewart-Lyth (1993), Planck ns 1~ for a typical model 3 4 k n 1 P ( ) T S k r ( ) ; 3 P T k Ak nt ( ) 8 P ( k) 8 Liddle-Lyth (199) to be observed... T Mukhanov & Chibisov (1981)

14 Planck constraints on inflation Planck 015 XX 14 V f scalar spectral index: n s ~ 0.96 tensor-to-scalar ratio: r < 0.1 simplest V f model is almost excluded n s 1 d 3 log[ k PS ( k)] dlog k PT ( k) r P ( k) S

15 Implications 15

16 16 Inflation as the Origin of All Structures of the Universe

17 Current status 17 scalar spectral index: n s <1 at ~ 5 s tensor/scalar ratio: r < 0.1 implies E inflation < GeV simple, canonical models are on verge of extinction (m f model excluded at > s) R (Starobinsky) model seems to fit best. But why? (large R correction but negligible higher order terms) f NL local <O(1) suggests (effectively) single-field slow-roll (but non-slow-roll models with f NL local =O(1) not excluded) element of non-canonicality is needed

18 18 Beyond (standard model of) Inflation

19 non-canonical models 19 Non-canonical kinetic term? (c s <1?) 1 equil 1 P ( cs: sound speed), fnl c c s non-minimal coupling to gravity? V Planck: c s > 0.04 at 95% CL ( f) f R T 1 r P ( k) P k scalar-tensor with derivative couplings (Hordeski)? c 1, cst, 1, c c, s s s T tensor propagation speed s ( ) Planck: > O(10)? multi-field models, non-attractor inflation, non-existence of Einstein frame? definition of inflation?

20 Anomalies & Features 0 Wiggles (dip) in the power spectrum signature of a heavy field? Chen 11, step/feature in potential? Leach et al. 01,. non-bd vaccum? Easther et al. 0,. Suppressed large scale fluctuations featured potential? open inflation? Linde, MS & Tanaka 99,.

21 Cosmic Landscape? 1 string theory suggests an intriguing picture of the early universe taken from Maybe we live in one of these vacua

22 Universe jumps around in the landscape by quantum tunneling expansion rate it can go up to a vacuum with larger r v de Sitter (ds) space ~ thermal state with T =H/ if it tunnels to a vacuum with negative r v, it collapses within t ~ M P / r v 1/. so we may focus on vacua with positive r v : ds vacua r v 0 Sato, Kodama, MS & Maeda ( 81)

23 Open Inflation in Cosmic Landscape 3 Universe inside nucleated bubble = spatially open universe Friedmann eq. H a r 1 a M a 3 P negative spatial curvature r 1 1 W W 3 M P H a H Observational data indicate 1-W 0 = W K,0 ~< 10 - : almost flat ( 0 stands for current value) K density parameter

24 What if this is the case? 4 two possibilities 1. inflation after tunneling was short enough (N~60) W 1W 10 ~10 K,0 0 3 open universe signatures in large angle CMB anisotropies? Kanno, MS & Tanaka ( 13), White, Zhang & MS ( 14),. inflation after tunneling was long enough (N>>60) W 1 W 1 K,0 0 flat universe signatures from bubble collisions Sugimura, Yamauchi & MS ( 1),

25 scalar suppression on large scales Linde, MS & Tanaka (1999) White, Zhang & MS (014) 5 scalar tensor (no suppression) scalar suppression begins at smaller scale curvature radius H 0-1 if W K 0.01 break scale

26 dipole power asymmetry P( k; n) 1 Adˆ n P ( k) line of sight dipole iso 6 no asymmetry in the direction of ell=1 dipole asymmetry in the direction maximizing the asymmetry

27 Planck 013 XXIII 7 T T 1 T Acos T iso A 0.07

28 Gradient of a field over the horizon scale = Super-curvature mode in open inflation MS, Tanaka & Yamamoto 95 8 curvature radius size of observable universe may modulate the amplitude of perturbation depending on the direction. leading order effect is dipolar 3 if this is the case, then K ~ 10 W Kanno, MS & Tanaka 13 Brynes, Domenech, MS & Takahashi 16

29 9 Scale-dependent non-gaussianity? Planck XVII Slightly above 1-s deviation from zero What if this is primordial? may be due to TSS coupling in a massive tensor theory Domenech, Hiramatsu, Lin, MS, Shiraishi, Wang 16

30 Future issues 30

31 31 L com H 0-1 =10 Gpc L cosmological scales M 10 4 M 10 Mpc beyond inflation? very large scales M N ~ cm g H inf -1 model dep 10 cm GeV GeV 10 9 GeV 1 ev 10-4 ev # e-folds (~ 1/T) inflation (assuming T reheat >10 9 GeV) damped osc (matter-dom) rad-dom matter-dom dark energy

32 3 L com H 0-1 =10 Gpc L cosmological scales M 10 4 M 10 Mpc 10 pc behind inflation? intermediate scales M 10 6 M 10 8 cm N ~ g H inf -1 model dep 10 cm GeV GeV 10 9 GeV 1 MeV 1 ev 10-4 ev # e-folds (~ 1/T) inflation (assuming T reheat >10 9 GeV) damped osc (matter-dom) rad-dom matter-dom dark energy

33 33 L com H 0-1 =10 Gpc L cosmological scales M 10 4 M 10 Mpc M 10 pc 10 6 M 0.1 pc particle physics? 10 8 cm N ~ small scales 1 M g H inf -1 model dep 1 GeV 10 cm GeV GeV 10 9 GeV 1 MeV 1 ev 10-4 ev # e-folds (~ 1/T) inflation (assuming T reheat >10 9 GeV) damped osc (matter-dom) rad-dom matter-dom dark energy

34 definition of inflation? (conformal trans can give any expansion law) ds dt a () t dx ds W ( t) ds dt W() t dt, a( t ) W( t) a( t) Domenech & MS initial condition before inflation, multiverse? successful reheating? non-linear effects, non-gaussianities? gravitational waves at second order, PBHs? massive gravity? Identification of Inflaton!

35 35 Inflation as the tool to explore physics of the early Universe Era of Observational Inflationary Cosmology!

36 Appendix: recollections May 004 : MOU between KIAS and YITP (renewed in March 008) 005 KIAS Cosmological Landscape: Strings, Gravity, and Inflation Organizers: Leonard Susskind (Stanford Univ.& KIAS) Kimyeong Lee (KIAS, Seoul) Piljin Yi (KIAS, Seoul) Misao Sasaki (YITP, Kyoto) Shigeki Sugimoto (YITP, Kyoto) 007 YITP String Phenomenology and Cosmology 009 KIAS Extended Workshop on DM, LHC and Cosmology 011 KIAS String Theory, Holography, and Beyond 013 YITP String Theory, Black Holes and Holography 015 KIAS Geometry in Gauge Theories and String Theory 017 YITP Strings, Gravity and Cosmology Organizers: Kimyeong Lee (KIAS) Sungjay Lee (KIAS) Shinji Mukhoyama (YITP) Misao Sasaki (YITP) Shigeki Sugimoto (YITP, Chair) Tadashi Takayanagi (YITP) Piljin Yi (KIAS)

37 Appendix: recollections May 004 : MOU between KIAS and YITP (renewed in March 008) 005 KIAS Cosmological Landscape: Strings, Gravity, and Inflation Organizers: Leonard Susskind (Stanford Univ.& KIAS) Kimyeong Lee (KIAS, Seoul) Piljin Yi (KIAS, Seoul) Misao Sasaki (YITP, Kyoto) Shigeki Sugimoto (YITP, Kyoto) 007 YITP String Phenomenology and Cosmology 009 KIAS Extended Workshop on DM, LHC and Cosmology 011 KIAS String Theory, Holography, and Beyond 013 YITP String Theory, Black Holes and Holography 015 KIAS Geometry in Gauge Theories and String Theory 017 YITP Strings, Gravity and Cosmology Organizers: Kimyeong Lee (KIAS) Sungjay Lee (KIAS) Shinji Mukhoyama (YITP) Misao Sasaki (YITP) Shigeki Sugimoto (YITP, Chair) Tadashi Takayanagi (YITP) Piljin Yi (KIAS)

38 Appendix: recollections May 004 : MOU between KIAS and YITP (renewed in March 008) 005 KIAS Cosmological Landscape: Strings, Gravity, and Inflation Organizers: Leonard Susskind (Stanford Univ.& KIAS) Kimyeong Lee (KIAS, Seoul) Piljin Yi (KIAS, Seoul) Misao Sasaki (YITP, Kyoto) Shigeki Sugimoto (YITP, Kyoto) 007 YITP String Phenomenology and Cosmology 009 KIAS Extended Workshop on DM, LHC and Cosmology 011 KIAS String Theory, Holography, and Beyond 013 YITP String Theory, Black Holes and Holography 015 KIAS Geometry in Gauge Theories and String Theory 017 YITP Strings, Gravity and Cosmology Organizers: Kimyeong Lee (KIAS) Sungjay Lee (KIAS) Shinji Mukhoyama (YITP) Misao Sasaki (YITP) Shigeki Sugimoto (YITP, Chair) Tadashi Takayanagi (YITP) Piljin Yi (KIAS)

39 Appendix: recollections May 004 : MOU between KIAS and YITP (renewed in March 008) 005 KIAS Cosmological Landscape: Strings, Gravity, and Inflation Organizers: Leonard Susskind (Stanford Univ.& KIAS) Kimyeong Lee (KIAS, Seoul) Piljin Yi (KIAS, Seoul) Misao Sasaki (YITP, Kyoto) Shigeki Sugimoto (YITP, Kyoto) 007 YITP String Phenomenology and Cosmology 009 KIAS Extended Workshop on DM, LHC and Cosmology 011 KIAS String Theory, Holography, and Beyond 013 YITP String Theory, Black Holes and Holography 015 KIAS Geometry in Gauge Theories and String Theory 017 YITP Strings, Gravity and Cosmology Organizers: Kimyeong Lee (KIAS) Sungjay Lee (KIAS) Shinji Mukhoyama (YITP) Misao Sasaki (YITP) Shigeki Sugimoto (YITP, Chair) Tadashi Takayanagi (YITP) Piljin Yi (KIAS)

40 Appendix: recollections May 004 : MOU between KIAS and YITP (renewed in March 008) 005 KIAS Cosmological Landscape: Strings, Gravity, and Inflation Organizers: Leonard Susskind (Stanford Univ.& KIAS) Kimyeong Lee (KIAS, Seoul) Piljin Yi (KIAS, Seoul) Misao Sasaki (YITP, Kyoto) Shigeki Sugimoto (YITP, Kyoto) 007 YITP String Phenomenology and Cosmology 009 KIAS Extended Workshop on DM, LHC and Cosmology 011 KIAS String Theory, Holography, and Beyond 013 YITP String Theory, Black Holes and Holography 015 KIAS Geometry in Gauge Theories and String Theory 017 YITP Strings, Gravity and Cosmology Organizers: Kimyeong Lee (KIAS) Sungjay Lee (KIAS) Shinji Mukhoyama (YITP) Misao Sasaki (YITP) Shigeki Sugimoto (YITP, Chair) Tadashi Takayanagi (YITP) Piljin Yi (KIAS)

41 Appendix: recollections May 004 : MOU between KIAS and YITP (renewed in March 008) 005 KIAS Cosmological Landscape: Strings, Gravity, and Inflation Organizers: Leonard Susskind (Stanford Univ.& KIAS) Kimyeong Lee (KIAS, Seoul) Piljin Yi (KIAS, Seoul) Misao Sasaki (YITP, Kyoto) Shigeki Sugimoto (YITP, Kyoto) 007 YITP String Phenomenology and Cosmology 009 KIAS Extended Workshop on DM, LHC and Cosmology 011 KIAS String Theory, Holography, and Beyond 013 YITP String Theory, Black Holes and Holography 015 KIAS Geometry in Gauge Theories and String Theory 017 YITP Strings, Gravity and Cosmology Organizers: Kimyeong Lee (KIAS) Sungjay Lee (KIAS) Shinji Mukhoyama (YITP) Misao Sasaki (YITP) Shigeki Sugimoto (YITP, Chair) Tadashi Takayanagi (YITP) Piljin Yi (KIAS)

42 some say old physicists never die, they just fade away

43 some say old physicists never die, they just fade away but I will NOT disappear yet! Thank You!