%0 Thesis
%A Rubira, Henrique
%T Across scales in our Universe: Gravitational Waves and the Large-Scale Structure
%N DESY-THESIS-2021-021
%I Universität Hamburg
%V Dissertation
%C Hamburg
%M PUBDB-2021-04467
%M DESY-THESIS-2021-021
%B DESY-THESIS
%P 250
%D 2021
%Z Dissertation, Universität Hamburg, 2021
%X The first two decades of this century mark the beginning of the precision cosmologyand astrophysics era. Two remarkable cosmological results include the measurementsof the cosmic microwave background (CMB) anisotropies by the Planck satellite andof the baryonic acoustic oscillations (BAO) by the Sloan Digital Sky Survey. From theastrophysics side, we had the exciting detection of gravitational waves (GWs) from binarysystems achieved by the LIGO/VIRGO collaboration. It has opened a new channelto test fundamental physics by probing the existence of a stochastic gravitationalwavebackground sourced by early Universe phenomena. This thesis builds upongravitational waves and the large-scale structure (LSS) of the Universe. Throughoutthis thesis, we explore the interplay between the smallest and the largest scales of ourUniverse.The first part of this thesis focus on GWs from stochastic sources. First, we showthat the detected gravitational wave power spectrum differs from the sourced spectrumdue to density perturbations in the line of sight. This effect is analogous to the(integrated) Sachs-Wolfe frequency and amplitude shift for the CMB. We provide ananalytical expression for the distortion of the GW spectrum and show that this effectcan be used to probe small-scale fluctuations on curvature perturbations. Next, wedevelop a new simulation scheme to calculate the GW spectrum sourced by soundwaves propagating in the primordial plasma. Those sound waves are triggered bybubbles expansion in first-order phase transitions and they can last for a long time.Our method’s main advantage is that it does not demand to solve the scale of thebubble wall thickness in the lattice. Compared to other lattice schemes, out methodis less numerical demanding, which allows a more in-depth exploration of the phasetransition parameter space.In the second part of this thesis, we explore the non-linear dynamics of the LSS ofthe Universe. First, we focus on applications of techniques that are widely used in particlephysics community, such as Feynman diagrams and renormalization, to improvethe analytical prediction for dark matter clustering. Using the so-called effective fieldtheory approach, we extend previous calculations to three-loop order showing thatthe perturbative series has a restricted convergence radius at low redshift (k  0.45Mpc􀀀1h at z = 0). We also explore the effect of a non-linear log transformation in thematter density field, which Gaussianize and linearize the density field. Next, we modifythe so-called Halo Model to include voids, underdense structures in our Universe.We provide a self-consistent way to include those voids through the excursion set formalismand show that they improve the analytical prediction for the Halo Model onintermediate length scales. Finally, we study how the Schrödinger equation can beused to probe the dark matter phase space on the largest scales. We then characterizethe systematic errors that are intrinsic to this approach.
%F PUB:(DE-HGF)3 ; PUB:(DE-HGF)11
%9 BookDissertation / PhD Thesis
%R 10.3204/PUBDB-2021-04467
%U https://bib-pubdb1.desy.de/record/471515