PHYSICAL COSMOLOGY & COMPLEXITY

Transcription

1 PHYSICAL COSMOLOGY & COMPLEXITY The Quest for the Invisible Universe Pier Stefano Corasaniti CNRS & Observatoire de Paris

2 OUTLINE Epistemological Perspective: Invisible Universe and Cosmic Structure Formation: Past & Future Bottom Line: Deal with Complexity

3 PHYSICAL COSMOLOGY Principles General Covariance + Copernican Principle General Relativity & FRW space-time Gauge Theories Standard Model of Particles Nuclear Physics Plasma Physics Atomic Physics

4 COSMIC PHENOMENA BBN CMB Large Scale Clustering Cosmic Expansion

5 COSMIC MONISM Nuclear vs Hubble Rates! X (t), H(t) Linearized Gravity and Matter Perturbations!G µ" = 8#G!T µ" Coarse Grained Standard Candle Relations M peak (B) =! "m 15 (B)

6 INTENSIVE VS EXTENSIVE Looking at the development of science in the Twentieth Century one can distinguish two trends, which I will call intensive and extensive research, lacking a better terminology. In short: intensive research goes for the fundamental laws, extensive research goes for the explanation of phenomena in terms of known fundamental laws.solid state physics, plasma physics and perhaps also biology are extensive. High energy physics and a good part of nuclear physics are intensive Once new fundamental laws are discovered, a large and ever increasing activity begins in order to apply the discoveries to hitherto unexplained phenomena. V.F. Weisskopf, Amer. Scientist 65, 405 (1977)

7 THE INVISIBLE UNIVERSE

8 THE QUEST FOR THE INVISIBLE UNIVERSE Modify Principles Work Out Phenomenology

9 MORE DIFFERENT MORE INFORMATIVE Model Parameter Degeneracies Combine Complementary Observations Increase Statistics Probe Larger Volumes & Smaller Scales Non-Linear Clustering Predictions Hidden Model Dependencies Baryonic Processes

10 GRAVITATIONAL COLLAPSE & BARYONS AN EXTREME EXAMPLE Supernova Ia Binary System: C/O WD Accreting Mass Explosion at ~ M Ch G -3/2 L M Ni f(α 1,.., α N,G) M Ch G-varying consequences: Cosmological: Modification Magnitude-Distance Relation Astrophysical: Different Properties at Different Redshifts

11 NON-LINEAR STRUCTURE FORMATION N Body Simulations Monte Carlo Integration Background Expansion Newtonian Regime d v dt + 2H v =! 3 2 " m H 2 #! with $!=" Cosmological Imprints Initial Amplitude & Linear Growth History! = ln D(t) f = ln D ln a d!v d! + 1 " df % + (1! q) f f 2 # $ d ln a & '!v =! 3 2 f ( m)* 2 A. Nusser & J. Colberg, MNRAS. 294, 457 (1998)

12 EXEMPLE: PREDICTING BAO SPECTRA Baryon Acoustic Oscillations Range 0.03< k[h Mpc -1 ] < 0.3 Non-Linear Effects Degrade BAO Features Upcoming Measurements at 1% level (see e.g. BOSS DR10) Simulation Requirements Large Volumes Large Number of Particles DEUS Full Universe Runs L = 21 Gpc h -1 N = M p M sun h -1

13 COSMIC VARIANCE LIMITED PREDICTION z=0 z=1 Y. Rasera, PSC, et al., MNRAS 440, 1420 (2014)

14 COSMIC VARIANCE LIMITED PREDICTION z=0 z=1 Y. Rasera, PSC, et al., MNRAS 440, 1420 (2014)

15 P(K) COVARIANCE MATRIX Non-Linear Mode Correlations cov(k 1, k 2 ) = 2 N k1 P 2 (k 1 )! k1,k V!! d 3! k 1` V k1 d! 3 k 2` T( k! `," 1 k! 1`, k! 2`," k! 2`) V k2 Monte Carlo Sampling cov(k 1, k 2 ) = N s 1 " ˆP i (k 1 )! ˆP(k 1 ) $ " & ˆPi N s!1 # %# (k 2 )! ˆP(k 2 ) i=1 $ % DEUS Parallel Universe Runs N s = L = 648 Mpc h -1 N = M p M sun h -1 L. Blot, PSC, et al., arxiv:

16 P(K) COVARIANCE MATRIX Non-Linear Mode Correlations cov(k 1, k 2 ) = 2 N k1 P 2 (k 1 )! k1,k V!! d 3! k 1` V k1 d! 3 k 2` T( k! `," 1 k! 1`, k! 2`," k! 2`) V k2 Monte Carlo Sampling cov(k 1, k 2 ) = N s 1 " ˆP i (k 1 )! ˆP(k 1 ) $ " & ˆPi N s!1 # %# (k 2 )! ˆP(k 2 ) i=1 $ % DEUS Parallel Universe Runs N s = L = 648 Mpc h -1 N = M p M sun h -1 L. Blot, PSC, et al., arxiv:

17 P(K) COVARIANCE MATRIX Non-Linear Mode Correlations cov(k 1, k 2 ) = 2 N k1 P 2 (k 1 )! k1,k V!! d 3! k 1` V k1 d! 3 k 2` T( k! `," 1 k! 1`, k! 2`," k! 2`) V k2 Monte Carlo Sampling cov(k 1, k 2 ) = N s 1 " ˆP i (k 1 )! ˆP(k 1 ) $ " & ˆPi N s!1 # %# (k 2 )! ˆP(k 2 ) i=1 $ % DEUS Parallel Universe Runs N s = L = 648 Mpc h -1 N = M p M sun h -1 L. Blot, PSC, et al., arxiv:

18 BARYONIC PROCESSES Hardcore Extensive Matter Constituents Ansatz Believes: No Cosmological Dependencies Large vs Small Scale Separations Data Driven Gas Physics & Feedback Phenomena Simulations - Sub-grid Models Local vs Global Pattern Anomalies Extensive vs Intensive

19 E.G. TOO-BIG-TOO FAIL Intensive Approach M. Boylan- Kolchin, J. Bullock & M. Kaplinghat, The Milky Way s bright satellites as an apparent failure of LCDM, in MNRAS 422, 1203 (2012) Excessive Feedback Needed Penarubia et al., The coupling between the core/cusp and missing satellite problems, in Astroph. J. 759, L42 (2012) S. Garrison- Kimmel et al., Can feedback solve the too- big- to- fail problem, in MNRAS 433, 3539 (2013) M. Lovell et al., The halos of bright satellite galaxies in a warm dark matter universe, in MNRAS 420, 2318 (2012) M. Vogelsberger, J. Zavala & A. Loeb, Subhaloes in self- interacting galactic dark matter haloes, in MNRAS 423, 3740 (2012) E. Polisensky & M. Ricotti, Massive Milky Way Satellites in Cold and Warm Dark Matter: Dependence on Cosmology, in MNRAS in press (2013)

20 THINGS WON T GET EASIER Exascale Cosmology Era ARE WE READY? LSST EUCLID SKA

21 THE COMPLEX SCIENCE LESSON COMPLEXITY IS NOT OPPOSITE TO FINDING NEW FUNDAMENTAL LAWS AND PRINCIPLES see More is Different, P. W. Anderson, Science, 177, 393 (1972)

22 FUNDAMENTAL LAWS AND COMPLEXITY Living Organisms Y! M! with!!1 4 in Science, 276, 122 (1997) New Principles 1) Space- [illing fractal- like networks 2) Network branch is size- invariant 3) Energy is minized

23 CONCLUDING REMARKS Main Source of Information from Cosmic Phenomena at Monistic Scales Cosmology Developments due to alternating phases of Intensive to Extensive Research Modus Operandi will (is) break(ing) down due to small scale probes and advent of exascale data Multidisciplinarity against system complexity

24 THE LAST PROVOCATION Would you have discovered inflation if you were an observer during inflation? w!! "1# "1

25 THE LAST PROVOCATION Would you have discovered inflation if you were an observer during inflation? w!! "1# "1 Of course not there was no complexity to test it!