The observable Universe, Gravity, and the Quantum. Ivan Agullo. Louisiana State University

Transcription

1 The observable Universe Gravity and Quantum Louisiana State University Home June

2 Motivation 2

3 Why Gravity is so difficult to quantize? 7 3

4 Motivation Louisiana State University Classical Gravitation: General Relativity Why Gravity is so difficult to quantize?

5 Motivation Louisiana State University Healthy 100 years celebration

6 Motivation Louisiana State University Equivalence principle: gravity is omnipresent and non-discriminating Gravity in GR is encoded in geometry of spacetime J. A. Wheeler: in GR matter tells space-time how to bend and gravity tells mater how to move

7 Motivation Louisiana State University A. Ashtekar: Before GR spacetime was immutable stage in which drama of physics unfolds. The actors are everything else: stars planets radiation matter you and me. In GR stage itself joins group of actors. There are no longer spectators in cosmic dance. 7

8 Motivation Louisiana State University This ory has received spectacular experimental confirmation 8

9 Motivation Quantization: Louisiana State University Main conceptual difficulty: dual role of gravitational field i) Provides spacetime structure ii) Is degree of freedom we want to quantize A couple of proposals... 1) g µ = µ + h µ Perturbative gravity super-gravity string ory 2) Retain full gravity-geometry duality but apply background independent quantization Loop Quantum gravity

10 Quantum fields in (classical but) curved spacetimes

11 QFT in CST Louisiana State University Wave equation of a (e.g. massless) particle: [@ 2 t ~r 2 ~x ] (~x t) =0 e i(wt ± ~ k ~x) Independent solutions: e i(wt ± ~ k ~x) positive frequency waves negative frequency waves In an expanding universe: 2 t + 3ȧ(t) t 1 a(t) 2 ~ r 2 ~x (~x t) =0 positive and negative frequency waves are not solutions anymore!!

12 QFT in CST Louisiana State University QFT in CST 12

13 QFT in CST Louisiana State University 13

14 QFT in CST Louisiana State University Physical Consequences I: Black hole evaporation But: T H 10 7 M M K too small for astrophysical back holes 14

15 QFT in CST Louisiana State University Physical Consequences II: Inflation Motivation (A.Guth 81Sato 81): an exponential expansion of early universe can solve some of problems of Big Bang model (flatness horizon problem magnetic monopoles) V ( 0 ) V ( 0 ) 0 0

16 QFT in CST Louisiana State University t x Formation of CMB

17 QFT in CST Louisiana State University But soon after people realize inflation can give much more than what its proponents imagined Mukhanov Chibisov Hawking Guth Pi Starobinsky Bardeen Steninhardt Turner (~x t )= 0 (t) + (~x t ) V ( 0) V ( 0) 0 0(t) source of gravitational field producing inflationary expansion 0 (~x t ) quantum filed (perturbation) propagating in inflationary space-time 0(t) QFT in CST: The expansion will create particles of field (~x t ) out from vacuum These particles are origin of density perturbations in universe

18 QFT in CST Louisiana State University t x Formation of CMB Generation of cosmic inhomogeneities

19 QFT in CST Louisiana State University Quantitative predictions: correlation functions Assuming perturbations are in vacuum at onset of inflation (Bunch-Davies vacuum): h0 ~ k 0i =0 h0 ~ k ~ k 0 0i =(2 ) 3 (3) ( ~ k ~ k 0 ) P (k) h0 ~ k1 ~ k2 ~ k3 0i 6=0 mean Power spectrum Non-Gaussianity 19

20 QFT in CST Louisiana State University Theory vs Observations (Planck 2015) Two-point correlation function of CMB temperature anisotropies in Fourier angular space `(` + 1) C`/2 Inflation Observations Spectacular agreement Some deviations for `. 30 Deviations from ory Note change to log scale here Non-Gaussianity have NOT been observed in CMB

21 QFT in CST Louisiana State University Steven Weinberg: Cosmology now offers excitement that particle physicists had experienced in 1960s and 1970s Reason: we have observational data! WMAP PLANCK 2dFGRS SDSS BOSS EUCLID QUIJOTE DESI BICEP2 KECK and MANY more Fascinating field. Huge activity. This is where my present and future work belongs to. 21

22 QFT in CST duction S. Plaszczynski73 E. Pointecouteau100 9 G. Polenta4 46 L. Popa63 G. W. Pratt75 G. Prézeau11 69 S. Prunet Agullo J.-L. Puget60 J. P. Rachen23 82 R. Rebolo M. Reinecke82 M. Remazeilles C. Renault77 Ivan A. Renzi I. Ristorcelli100 9 Astronomy G. Rocha C. Rosset M. Rossetti A. Rotti G. Roudier J. A. Rubiño-Martín c & Astrophysics manuscript no. planck_2015_iands ESO June B. Rusholme M. Sandri D. Santos M. Savelainen G. Savini D. Scott M. D. Seiffert E. P. S. Shellard T. Souradeep L. D. Spencer V. Stolyarov R. Stompor R. Sudiwala R. Sunyaev D. Sutton64 72 A.-S. Suur-Uski28 44 J.-F. Sygnet61 J. A. Tauber40 L. Terenzi41 48 L. Toffolatti M. Tomasi35 49 M. Tristram73 Planck 2015 results. XVI. Isotropy and statistics of CMB T. Trombetti48 M. Tucci18 J. Tuovinen10 L. Valenziano48 J. Valiviita28 44 B. Van Tent78 P. Vielva67 F. Villa L. A. Wade69 Planck B. D.Collaboration: Wandelt I. K. Wehus D. Yvon A.Aluri Zacchei 88J. P. Zibin101 and A. Zonca30 P. A. R. Ade N. Aghanim Y. Akrami P. K. M. Arnaud M. Ashdown ú Louisiana State University J. Aumont C. Baccigalupi A. J. Banday R. B. Barreiro N. Bartolo S. Basak E. Battaner K. Benabed61 99 A. Benoît58 A. Benoit-Lévy J.-P. Bernard100 9 M. Bersanelli35 49 P. Bielewicz J. J. Bock69 11 A. Bonaldi70 L. Bonavera67 J. R. Bond8 J. Borrill14 94 F. R. Bouchet61 92 F. Boulanger60 M. Bucher1 C. Burigana (Affiliations can 76 be1 found after 67 R. C. Butler48 E. Calabrese J.-F. Cardoso B. Casaponsa A. references) Catalano77 74 A. Challinor planck_2015_iands A&A proofs: manuscript no. A. Chamballu H. C. Chiang P. R. Christensen S. Church D. L. Clements56 S. Colombi61 99 L. P. L. Colombo25 69 C. Combet77 D. Contreras24 F. Couchot73 A. Coulais74 B. P. Crill69 11 M. Cruz21 A. Curto June 5Bernardis A. de Rosa48 G. de Zotti45 88 J. Delabrouille1 70 Cuttaia48 L. Danese88 R. D. Davies70 R. J. Davis P. de A&A proofs:f. manuscript planck_2015_iands 67 F.-X. Désert54 J.no. M. Diego H. Dole60 59 S. Donzelli49 O. Doré69 11 M. Douspis60 A. Ducout61 56 X. Dupac39 G. Efstathiou64 F. Elsner T. A. Enßlin82 H. K. Eriksen65 Y. Fantaye37 J. Fergusson12 R. Fernandez-Cobos67 F. Finelli48 50 O. Forni100 9 M. Frailis47 A. A. Fraisse29 E. Franceschi48 A. Frejsel86 A. Frolov91 S. Galeotta47 S. Galli71 ABSTRACT K. Ganga1 C. Gauthier1 81 T. Ghosh60 M. Giard Y. Giraud-Héraud1 E. Gjerløw65 J. González-Nuevo20 67 K. M. Górski S. Gratton72 64 A. Gregorio A. Gruppuso48 J. E. Gudmundsson29 F. K. Hansen Hanson83 69 D.Gaussianity L. Harrison64 72 S. Hernández-Monteagudo D. Herranz anisotropies using obwe test statisticals. D. isotropy and ofhenrot-versillé cosmic C.microwave background (CMB) R. Hildebrandt69 11 E. Hivon61 99 M. Hobson6 W. A. Holmes69 A. Hornstrup17 W. Hovest82 Z. Huang full Planck 14 for temperature servations made K. bym. Planck satellite. are100based mission Huffenberger G. Hurier60 A.Our H. Jafferesults T. R. Jaffe W. C. mainly Jones29 M.on Juvela E. Keihänen28 R. Keskitalo J. Kim T. S. Kisner J. Knoche M. Kunz H. Kurki-Suonio G. Lagache A. Lähteenmäki but also include some polarization measurements. In particular we consider CMB anisotropy maps derived from J.-M. Lamarre74 A. Lasenby6 72 M. Lattanzi33 C. R. Lawrence69 R. Leonardi39 J. Lesgourgues62 98 F. Levrier multi-frequency Planck data by several component-separation methods. P.For temperature anisotropies we find M. Liguori P. B. Lilje M. Linden-Vørnle H. Liu M. López-Caniego M. Lubin J. F. Macías-Pérez G. Maggio D. Maino N. Mandolesi A. Mangilli D. Marinucci M. Maris P. G. Martin excellent agreement between results based on se sky maps over both a very large fraction of sky and a broad E. Martínez-González67 S. Masi34 S. Matarrese P. McGehee57 P. R. Meinhold30 A. Melchiorri34 51 L. Mendes affect our range of angulara.scales establishing that residuals do not Tests of skewness Mennella35 M. Migliaccio64 K.potential Mikkelsen65 foreground S. Mitra55 69 M.-A. Miville-Deschênes D. Molinari67 48studies. A. Moneti L. Montier G. Morgante D. Mortlock A. Moss D. Munshi J. A. Murphy P. Naselsky F. Nati kurtosis multi-normality N -point functions and Minkowski functionals indicate consistency with Gaussianity while P. Natoli C. B. Netterfield22 H. U. Nørgaard-Nielsen17 F. Noviello70 D. Novikov80 I. Novikov86 80 C. A. Oxborrow ways for a power deficit at large angular scales manifested several example variance. The results of a F. Paci L. Pagano F.isPajot N. Pant55 in D. Paoletti F. Pasian47 G. Patanchon1low T. J.map Pearson O. Perdereau L. Perotto with F. Perrotta V. Pettorino F.of Piacentini M. Piatrandom E. Pierpaoli D. The Pietrobon peak statistics analysis are consistent expectations a Gaussian field. Cold Spot is detected S. Plaszczynski73 E. Pointecouteau100 9 G. Polenta4 46 L. Popa63 G. W. Pratt75 G. Prézeau11 69 S. Prunet with several methods peak statistics and temperature profile. We thoroughly probe J.-L.including Puget60 J. P. map Rachenkurtosis R. Rebolo M. Reinecke82 M. mean Remazeilles C. Renault A. Renzi I. Ristorcelli G. Rocha C. Rosset M. Rossetti A. Rotti G. Roudier J. A. Rubiño-Martín large-scale dipolar power asymmetry detecting it with several independent tests and address subject of a posteb. Rusholme57 M. Sandri48 D. Santos77 M. Savelainen28 44 G. Savini87 D. Scott24 M. D. Seiffert69 11 E. P. S. Shellard small scales but at a riori correction. Tests of directionality suggest 6presence of angular clustering from large T. Souradeep L. D. Spencer V. Stolyarov R. Stompor R. Sudiwala R. Sunyaev D. Suttonto Suur-Uski on J.-F. Sygnet J. A. Tauber L. Terenzi We L. Toffolatti M.first Tomasi M. Tristramof polarization data significance that isa.-s. dependent details of approach. perform examination T. Trombetti48 M. Tucci18 J. Tuovinen10 L. Valenziano48 J. Valiviita28 44 B. Van Tent78 P. Vielva67 F. Villa consistent statistically finding morphologyl. of stacked peaks be with expectations A. Wade B. D. Wandeltto I. K. Wehus69 D. Yvon16 A. Zacchei J. P. Zibinof and A. Zonca30 isotropic simulations. Well-understood physical processes due to integrated Sachs-Wolfe (ISW) effect (Planck Collaboration oduction Well-understood physical processes due to gravitainteper one of a set associated with 2015 release XVII 2014; Planck Collaboration XXI 2015) and 1 Sachs-Wolfe effect (Planck Collaboration from Planck mission (Planck Collaboration I grated tional lensing (Planck(ISW) Collaboration XIX 2014; Planck Colaper one of a set associated with 2015 release XVII 2014; Planck Collaboration XXI 2015) and gravitaescribes a set of 1studies undertaken to determine laboration XV 2015) lead to secondary anisotropies that from Planck mission (Planck Collaboration I lensing (Planck Collaboration XIX 2014; Planck Colstical properties of both temperature and po- tional exhibit marked deviation from Gaussianity. In addition describes a setofof studies undertaken determine laboration XV 2015) lead to secondary anisotropies that n anisotropies cosmic microwavetobackground Doppler boosting due to our motion with respect to tistical properties of both temperature and po- exhibit marked deviation from Gaussianity. In addition CMB rest frame induces both a dipolar modulation of on anisotropies of cosmic microwave background Doppler boosting due to our motion with respect to temperature anisotropies and an aberration that cor.standard cosmological model is described well by CMB rest frame induces both a dipolar modulation of responds to a change in apparent arrival directions of dmann-lemaître-robertson-walker solution of temperature anisotropies and an aberration that corstandard cosmological model is described well by CMB photons (Challinor & van Leeuwen 2002). Both field equations. This model is characterized by a edmann-lemaître-robertson-walker solution of responds to a change in apparent arrival directions of of se effects are aligned with CMB dipole and were neous isotropic background and a scale n fieldand equations. This model is metric characterized by a CMB photons (Challinor & van Leeuwen 2002). Both detected at a statistically level dipole on small angular expanding Universe. It is hyposized that of se effects are aligned significant with CMB and were neous and isotropic background metric and a scale scales in Planck Collaboration XXVII (2014). Beyond se early times Universe went through a period of expanding Universe. It is hyposized that detected at a statistically significant level on small angular PlanckinCollaboration XXIII (2014 PCIS13) esrated so-called infla- scales Planck Collaboration XXVII hereafter (2014). Beyond se early expansion times Universe went cosmological through a period tablished that with Planck 2013 data set showed eviriven a hypotical scalar inflaton. Where field y overlap se results are consistent XXIII Planck 2013 analysis based onlittle nominal mission data and Planck Collaboration (2014 hereafter PCIS13) eseratedbyexpansion so-called cosmological infla(affiliations can be found after references) provideapproximately our most thorough of for statistics of CMB fluctuations to date. dence non-gaussianity with data exception of little a number nflation Universe behaves as view a tablished that Planck 2013 set showed evidriven by a hypotical scalar field inflaton. A&A proofs: manuscript June of CMB temperature anisotropy anomalies on large angur inflation space providing conditions by which some of for non-gaussianity with exception of a number Universe behaves approximately as a dence Key words. cosmology: observations cosmic background radiation polarization methods: data analysis methods: larcmb scalestemperature that confirmed earlier anomalies claims based on WMAP properties can be realized and statistical anisotropy on large anguerntspace providing conditions by specifically which somereof of ABSTRACT data. Moreover given 1. that claims broaderbased frequency coverhe of initial In particular Introduction scales that confirmed earlier on WMAP entproblem properties can beconditions. realized and specifically re- lar We test statistical isotropy and Gaussianity of cosmic microwave background (CMB) anisotropies using obage ofmoreover Planck instruments allowed improved compoat gave rise to present large-scale matter distriservations made bydata. Planck satellite. Our results are that based mainly full Planck mission for temperature given on broader frequency cover problem of initial conditions. In particular but also include some polarization measurements. In particular we consider CMB anisotropy maps derived from nent separation methods to be applied in derivation of ia gravitational instability originatedmatter as quantum This methods. paper of a anisotropies set compoassociated with 2015 release Planck instruments allowed improved hat gave rise to present large-scale distri- age multi-frequency Planckof data by several component-separation For one temperature we find 1 excellent agreement between results based on se sky maps over both a very large fraction of sky and a broad foreground-cleaned CMB maps it was generally considered ons gravitational of inflaton about itsoriginated vacuum state. These nent separation methods be applied in derivation of (Planck Collaboration I of to data from Planck mission via instability as quantum range of angular scales establishing that potential foreground residuals do not affect our studies. Tests of skewness that N forandanomalous features had been kurtosis multi-normality -pointcase functions Minkowski functionals consistency withconsidered Gaussianity while undertaken to determine ons inof density perturforeground-cleaned CMB maps itindicate wasin generally tions inflaton inflatonproduce about itsenergy vacuum state. These 2015) describes a CMB set of studies a power deficit at large angular scales is manifested in several ways for example low map variance. The results of a Article number page 1 ofand 61 postrengned. Hence such have attracted considthat are distributed as a statistically homogeneous that casewithfor features in The CMB had tions in inflaton produce energy density perturpeak statistics analysis are consistent anomalous expectations of anomalies astatistical Gaussian random field. Cold Spot isbeen detected properties of both temperature withrelates several methods including map kurtosis peak statistics and mean temperature We thoroughly probe erable attention in community since y could be ropic Gaussian random Linear ory strengned. Hence such anomalies haveprofile. attracted considthat are distributed as afield. statistically homogeneous large-scale dipolar power asymmetry detecting it with several independentanisotropies tests and address of subject of acosmic postelarization microwave background riorirelates correction. Tests of directionality presence of angular clustering from large tocould small occurring scales at a visible tracessuggest of in fundamental physical processes erable attention community since y bebut erturbations to temperature andory polarization tropic Gaussian random field. Linear significance that is dependent on details of approach. We perform first examination of polarization data (CMB). in early Universe. visible traces ofbefundamental physicalof processes occurring pies of CMB a distribution for erturbations to implying temperature and polarization finding morphology of stacked peaks to consistent with expectations statistically isotropic simulations. Where y overlap se results are consistent with Planck 2013 analysis based on nominal mission data and The standard cosmological model is described well by in early Universe. opies of CMB implying a distribution for pies very close to that of a statistically isotropic However literature also supports an ongoing debate provide our most thorough view of statistics of CMB fluctuations to date. Friedmann-Lemaître-Robertson-Walker solution of opies very field. close to that of a statistically Key isotropic However background literature also supports anthe ongoing debate n random about significance of se anomalies. issue words. cosmology: observations cosmic radiation polarization methods: datacentral analysis methods: statistical an random significance ofeinstein se anomalies. The issue in this discussion is connected with role central of a This posterifield equations. model is characterized by a aim of thisfield. paper is to use full mission Planck about discussion is connected with role of posteriori this choices wher interesting features in a data bias homogeneous and isotropic background metric and a scale aim of this paper is to useisotropy full of mission Planck test Gaussianity and CMB as in ori choices wher interesting features in data bias tests of or if arbitrary choices in It is hyposized that Gaussianity and of capacity CMB as choice of statisticalfactor expanding Universe. dtest in both intensity and in aisotropy more limited choice of statistical tests or if arbitrary choices in feaed in both intensity and in a more limited capacity subsequent data analysis enhance significance of Loops 15 Erlangen 2015 no. planc Well grated XVII 20 tional le laborati exhibit Doppler CMB re tem respond CM of se detected

23 Beyond standard inflationary paradigm

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26 Motivation Louisiana State University

27 Louisiana State University Summary of main assumptions: (~x t ) V ( ) 1. Existence of and a phase of domination: INFLATION 2. Cosmic Inhomogeneities during inflation are well approximated by first order perturbations 3. Scalar perturbations were in vacuum state at onset of inflation Assumptions may seem ad-hoc but what one gets is far more than what one puts in

28 Louisiana State University 3. Scalar perturbations were in vacuum state at onset of inflation Why vacuum state at onset of inflation if we ignore pre-inflationary evolution of universe??? t x Extended point of view: huge inflationary expansion will dilute any quanta initially present washing away deviations from vacuum. 28

29 Louisiana State University Intuition certainly true for classical perturbations. But evolution of quantum excitation is more subtle: Non-gaussianities and Stimulated creation of quanta in inflationary universe and Leonard Parker Physics Department University of Wisconsin-Milwaukee P.O.Box 413 Milwaukee WI USA (Dated: August ) Spontaneous particle creation during inflation comes toger with Stimulated creation The stimulated creation process compensates for dilution of quanta initially present keeping ir number density constant during inflation hn ~k ~ k ~ k 0 N ~k i =(2 ) 3 (3) ( ~ k ~ k 0 ) P (k) (1 + 2N ~k + oscillatory terms) Very interesting consequences for Non-Gaussianity (in so called squeezed configurations) (I.A. and L. Parker ) (I.A. and S. Shandera 2012) (I.A. J. Navarro-Salas and L. Parker 2012) 7

30 Louisiana State University Importance: observational window to pre-inflationary universe t x

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33 Louisiana State University

34 Louisiana State University t x 34

35 Loop Quantum Cosmology

36 Louisiana State University Loop Quantum Gravity Not a unifying ory. Retain gravity-geometry duality: background independent nonperturbative In classical GR: H 0 In LQG: Ĥ =0 Wheeler- De-Witt equation What distinguishes LQG is: The use of Ashtekar variables g µ A i µ A quantization procedure suited for background independent ories 36

37 Louisiana State University Loop Quantum Cosmology Less ambitious problem: Symmetry reduced scenarios Loop Quantum Cosmology (LQC): LQG-like quantization of space-times with symmetries of cosmological spacetimes: homogeneity and isotropic The quantization program can be completed: Hilbert space: H Operators (e.g. energy density curvature volume of some region) Ô

38 Louisiana State University A pice of History J.A. Wheeler and DeWitt: quantum geometrodynamics For cosmology: (in this talk focus on spatially flat Friedmann-Lemaitre-Robertson-Walker) Classical degrees of freedom: a Quantum mechanically: (a ) â ˆ J.A. Wheeler s intuition: Heisenberg principle a p a ~ will avoid Bing Bang singularity. 38

39 Louisiana State University Loop Quantum Cosmology This intuition is realized in a precise way in LQC: Mamatically rigorous result: (Ashtekar Bojowald Corichi Pawlowski Singh 06) All operators representing physical quantities are bounded above in Hilbert space: no Big Bang singularity For example: hˆ i apple max / ~ 1 where max 0.41 P ` Physically Big Bang is replaced by a Big Bounce Results has been extended to more complicated space-times: Bianchi k=1 Gowdy models etc. 39

40 Artistic conceptions of Big Bang and Big Bounce Big Bang Big Bounce Credits: Pablo Laguna Credits: Cliff Pikover

41 Louisiana State University Loop Quantum Cosmology

42 Louisiana State University Loop Quantum Cosmology Goal: Obtain a Quantum Gravity Extension of inflationary scenario Challenges Since bounce is quantum need to learn how quantum fields propagate in quantum space-times Obtain observational consequences able to constraint or rule out physical scenario

43 Louisiana State University PRL (2012) Selected for a Viewpoint in Physics PHYSICAL REVIEW LETTERS week ending 21 DECEMBER 2012 Quantum Gravity Extension of Inflationary Scenario Abhay Ashtekar and William Nelson Institute for Gravitation and Cosmos & Physics Department Penn State University Park Pennsylvania USA (Received 7 September 2012; published 17 December 2012) PHYSICAL REVIEW D (2013) Extension of quantum ory of cosmological perturbations to Planck era 12 * Abhay Ashtekar 1 and William Nelson 1 1 Institute for Gravitation and Cosmos and Physics Department Penn State University Park Pennsylvania USA 2 Center for Theoretical Cosmology DAMTP University of Cambridge Wilberforce Road Cambridge CB3 OWA United Kingdom (Received 6 November 2012; published 5 February 2013) IOP PUBLISHING Class. Quantum Grav. 30 (2013) (56pp) CLASSICAL AND QUANTUM GRAVITY doi: / /30/8/ The pre-inflationary dynamics of loop quantum cosmology: confronting quantum gravity with observations 12 AbhayAshtekar 1 and William Nelson 13 1 Institute for Gravitation and Cosmos and Physics Department Penn State University Park PA USA 2 Center for Theoretical Cosmology DAMTP University of Cambridge Wilberforce Road Cambridge CB3 OWA UK 3 Huygens Building Radboud Universiteit Nijmegen Institute for Mamatics Astrophysics 43

44 Quantum fields in quantum spacetimes

45 Louisiana State University QFT in Quantum Spacetimes Starting point: (a g µ ) Perturbation ory (a g µ )= FRW(a ) pert ( g µ ) Equations of motion: take expectation value in FRW Ĥ (a g µ t 2 pert + f(hâ n i h ˆm i) pert =0 One obtains a QFT in a quantum spacetime This is way in which QFT in curved spacetimes emerges from a more fundamental approach 45

46 Observational Consequences

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49 Motivation Louisiana State University

50 Louisiana State University Strategy: 1) Perturbations start in vacuum at early times 2) Evolution across bounce amplifies curvature perturbations for long wavelengths (compared to space-time curvature scale) 3) Then standard slow-roll inflation begins but perturbations reach onset of inflation in an excited state rar than vacuum 4) These excitations impact observables quantities 50

51 Louisiana State University The power spectra and its relation with observations have been analyzed in great detail (I.A.-Ashtekar-Nelson I.A.-Morris 2015) Example: Scalar Power Spectrum 51

52 Louisiana State University In angular space: Agreement with inflationary results for ` > 30 agreement with observational constraints LQC effects for ` < 30. Most important: reduction of tensor-to-scalar ratio (slightly alleviates constrains on quadratic potential) modification of consistency relation r< 8 n t effects on spectral indices and runnings But most of LQC-effects are swept away to super-hubble scales!

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55 LQC and CMB anomalies Non-Gaussian modulation of power spectrum

56 Louisiana State University Is re any way super-hubble modes can affect observable ones??? The Observable Universe obs SH The Universe Super-Hubble mode The answer is yes if modes SH and obs are correlated: Non-Gaussianity (Adhikari Brahma Bartolo Bramante Byrnes Carrol Dai Dimastrogiovanni Erickcen Hui Jeong Kamionkowski LoVerde Matarrese Mota Nelson Nurmi Peloso Pullen Ricciardone Shandera Schmidt Tasinato Thorsrud Urban...)

57 Louisiana State University

58 Non-Gaussian modulation: Louisiana State University A ha L=0 i { Monopole A ha L=1i ` { Dipole A A ha L=2 i ha L=3 i { Quadrupole { Octopole

59 SUMMARY OF THE TALK: INFLATION QFT + Gravity spontaneous creation of particles LQC QFT + Gravity stimulated creation of particles

60 SUMMARY OF THE TALK: INFLATION QFT + Gravity spontaneous creation of particles LQC QFT + Gravity stimulated creation of particles

61 SUMMARY OF THE TALK: INFLATION QFT + Gravity spontaneous creation of particles QFT + Gravity stimulated creation of particles LQC

62 SUMMARY OF THE TALK: OBSERVATIONS CMB & LSS Non-Gaussianities INFLATION QFT + Gravity spontaneous creation of particles LQC QFT + Gravity stimulated creation of particles THANKS FOR YOUR ATTENTION