Constraining Physics Beyond the Cosmological Standard Model
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CONSTRAINING PHYSICS BEYOND THE COSMOLOGICAL STANDARD MODEL ADissertation Presented to the Faculty of the Graduate School of Cornell University in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy by Eva-Maria Katarina Mueller February 2016 c 2016 Eva-Maria Katarina Mueller All Rights Reserved CONSTRAINING PHYSICS BEYOND THE COSMOLOGICAL STANDARD MODEL Eva-Maria Katarina Mueller, Ph.D. Cornell University 2016 In this thesis we consider cosmological constraints arising from the background expansion history on the effective field theory (EFT) of cosmic acceleration, a theoretical framework that allows for a unified way to classify both models of dark energy and modified gravity within the linear regime. In the Einstein frame, the most general action for the background can be written in terms of a canonical scalar field which is nonminimally coupled to matter. The leading corrections to the action are expressible through a quartic kinetic term, and scalar couplings to a Gauss-Bonnet curvature term and the Einstein tensor. We determine the implications of the terms in this general action for the predicted expansion history in the context of dynamical attractors. We find that each modifies the matter dominated and/or accelerative eras in ways that allow us to place cosmological constraints on them. We present current constraints on the effective action using the latest Type Ia supernovae, cosmic microwave background (CMB), and baryonic acoustic oscillation (BAO) data. This includes the finding that the scalar field EFT with a coupled Gauss-Bonnet term and the data are significantly discrepant. In addition, we calculate the constraints on dark energy and cosmic modifications to gravity achievable with upcoming CMB surveys sensitive to the Sunyaev-Zel’dovich (SZ) effects. The analysis focuses on using the mean pairwise velocity of clusters as observed through the kinematic SZ effect (kSZ), an approach based on the same methods used for the first detection of the kSZ effect, and includes a detailed derivation and discussion of this statistic’s covariance under a variety of different survey assumptions. The potential of current, “Stage II” (ACTPol + BOSS), and upcoming, “Stage III” (Advanced ACTPol + BOSS), and “Stage IV” (CMB-S4 + DESI), CMB observations are considered, in combination with contemporaneous spectroscopic and photometric galaxy observations. A detailed assessment is made of the sensitivity to the assumed statistical and systematic uncertainties in the optical depth determination, the magnitude and uncertainty in the minimum detectable mass, and the importance of pairwise velocity correlations at small separations, where nonlinear effects can start to arise. In combination with Stage III constraints on the expansion history, such as those projected by the Dark Energy Task Force, we forecast 5% and 3% for fractional errors on the growth factor, γ,forStageIIIandStageIVsurveysrespectively,and2%constraintsonthegrowth rate, fg,foraStageIVsurveyfor0.2 <z<0.6. The results suggest that kSZ measurements of cluster peculiar velocities, obtained from cross-correlation with upcoming spectroscopic galaxy surveys, could provide robust tests of dark energy and theories of gravity on cosmic scales. We present the mean pairwise momentum of clusters, as observed through the kSZ effect, as a novel probe of massive neutrinos. We find that kSZ measurements with current and upcoming surveys will provide complementary constraints on the sum of neutrino masses from large scale structure (LSS) and will improve on Planck satellite measurements of the primordial cosmic CMB and CMB lensing. Central to the constraints is a distinctive scale dependency of the kSZ neutrino signature on the mean pairwise momentum of clusters that we do not expect to be mirrored in systematic effects that change the overall amplitude of the signal, like the cluster optical depth. Assuming a minimal ΛCDM cosmology including massive neutrinos with Planck primordial CMB priors combined with conservative kSZ specifications, we forecast 68% upper limits on the neutrino mass sum of 310, 240, 110 meV for Stage II, Stage III, and Stage IV surveys respectively, compared to the Planck alone forecast of 540 meV. These forecasts include the ability to simultaneously constrain the neutrino mass sum and the mass-averaged optical depth of the cluster sample in each redshift bin. If the averaged optical depth of clusters can be measured with few percent accuracy and a lower limiting mass is assumed, the projected kSZ constraints improve further to 100, 85 and 33 meV (Stage II, III and IV). These forecasts represent a conservative estimate of neutrino constraints using cross-correlations of arcminute-resolution CMB measurements and spectroscopic galaxy surveys. More information relevant for neutrino constraints is available from these surveys, such as galaxy clustering, weak lensing, and CMB temperature and polarization. Biographical Sketch Eva-Maria Mueller was born in 1986 in N¨urnberg, Germany and grew up in the small town of Eckental, Forth. After graduating from high school in 2005, she went on an adventure to Central America, volunteering for the Red Cross in Panama and traveling across Costa Rica and Nicaragua. She attended the Ruprecht-Karls-Universit¨at Heidelberg from 2006 to 2009, getting her first research experience in Astrophysics working with Professor Dr. Burkhard Fuchs. In 2009, Eva moved to Ithaca, NY, to study Physics at Cornell University as a Fulbright scholar. She decided to continue her studies at Cornell, pursuing a graduate career in Cosmology working with Professor Rachel Bean. iii This dissertation is dedicated to my parents, Jutta M¨uller and Bernd Moll. iv Acknowledgements IwishtothankmyadvisorRachelBeanforteachingmehowtobeascientist.Your enthusiasm, support and advice kept me going. I would like to thank Professor Michael D. Niemack, whom I consider my co-advisor, for expanding my horizon to the experimental side of cosmology and countless useful discussions. Special thanks to Francesco de Bernardis and Scott Watson for very enjoyable collaboration, endless patience and guidance through my graduate career. Furthermore, I am very grateful for the many contributions to my scientific education here at Cornell University by Jolyon Bloomfield, Eanna´ Flanagan, Joyce Byun and Tom Loredo. I am in debt to the Department of Astronomy for friendly environment, hospitality and support during all these years. And finally, I specially wish to thank my family and Andrusha for supporting me during difficult times, Michael, Ryan, Mike and Tyler for distracting me from work and supplying me with coffee through numerous trips to the C-store, as well as Manolis for frequently coming to my office for no apparent reason. This research was supported in part by the Cornell University Physics Department, NASA ATP grants NNX11AI95G, NNX08AH27G and NNX14AH53G, NASA ROSES grant 12-EUCLID12- 0004, NSF CAREER grant 0844825, NSF grant PHY0968820, and DoE grant DE-SC0011838, and the John and David Boochever Prize Fellowship in Fundamental Theoretical Physics at Cornell University. v Table of Contents Page Biographical Sketch . iii Dedication . iv Acknowledgements ................................... v TableofContents.................................... v ListofFigures...................................... viii List of Tables . ix ListofAbbreviations.................................. x Preface . xi 1 Introduction 1 1.1 TheΛCDMUniverse............................... 1 IBackgroundevolution...........................2 II Perturbations ............................... 3 1.2 Physics beyond ΛCDM.............................. 3 IDarkenergyandmodifiedgravity....................3 II Massiveneutrinos............................. 6 1.3 Cosmologicalobservables............................. 8 IThecosmicmicrowavebackground...................8 II Supernovae ................................ 9 III LargescalestructureoftheUniverse . 10 1.4 LikelihoodAnalysis................................ 11 IMCMC..................................11 II Fisherinformation ............................ 12 2 Cosmological Implications of the effective field theory of Cosmic Acceler- ation 14 2.1 Introduction . 14 2.2 Effective field theory for dark energy . 17 2.3 Dynamical Attractor Solutions . 22 ILeadingorderterms...........................22 II Gauss-Bonnetterm............................ 24 III Quarticterm ............................... 26 IV Coupling to the Einstein tensor . 29 VAkineticnon-minimalcoupling.....................32 vi 2.4 Comparison with Data . 33 I AnalysisApproach ............................ 33 II Findings.................................. 37 2.5 Conclusions . 44 3 Constraints on gravity and dark energy from the pairwise kinematic Sunyaev- Zel’dovich effect 47 3.1 Introduction . 47 3.2 Formalism . 49 I Motionofclustersasaprobeofcosmology . 49 II Covariancematrix ............................ 52 III Cosmological Model . 58 IV Survey Specifications . 59 3.3 Analysis ...................................... 64 IPotentialkSZconstraintsondarkenergyandmodifiedgravity....64 II Dependenceonminimummassofthegalaxyclustersample . 68 III Dependence on the nonlinearity cut-off................. 70 IV Dependence on the measurement error . 72 V DependencyontheModifiedGravityparametrization . 74 3.4 Conclusions . 76 4 Constraints on massive neutrinos from the pairwise kinematic Sunyaev- Zel’dovich effect 81 4.1 Introduction . 81 4.2 Formalism . 82 ICosmicstructureandmassiveneutrinos................82 II Motionofclustersasaprobeofmassiveneutrinos