Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 135 for “"CMB"”.
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High-Resolution CMB Bispectrum Estimator
The Cosmic Microwave Background (CMB) is one of the most valuable probes of the universe we have today. Anisotropies present in the ancient light contain rich statistical information about the perturbations in the early universe and their subsequent evolution until now. The CMB bispectrum, the …
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Dark energy and CMB anisotropy
… observations, the Cosmic Microwave Background (CMB) anisotropy power on large angular scales appears to be significantly lower than predicted by the standard model of cosmology. We propose a scalar field model of the dark energy as a mechanism for suppressing low l multipoles through …
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CMB analysis with ACT and Planck
The Cosmic Microwave Background (CMB) and especially its anisotropies have been a key source of information for cosmology and have played a major role in establishing the now-standard ΛCDM model. Upcoming experiments aim to extend CMB measurements even further, hoping to measure the sum of neutrino …
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Reconstructing the Sky with CMB Lensing methods
Current and future high significance CMB lensing-galaxy cross-correlations will soon precisely probe the growth of structure and provide powerful tests for parameter tensions, non-Gaussianity, neutrino mass, and modifications to Λ−CDM and gravity. However, such cross-correlations are sensitive to …
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Cosmology with CMB and Large Scale Structure
… tools to study the Cosmic Microwave Background (CMB) radiation and Large Scale Structure(LSS), in order to test different models of the Universe. This is the main aim of this thesis. The standard inflationary $\Lambda$-dominated Cold Dark Matter ($\Lambda$CDM) model is based on the premise that …
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Probing the Cosmological Initial Conditions Using the CMB
Finally, using our estimator we found (Yadav and Wandelt 2008) evidence for primordial non-Gaussianity of the local type (fNL) in the temperature anisotropy of the Cosmic Microwave Background. Analyzing the bispectrum of the WMAP 3-year data up to lmax=750 we find 27< fNL<147 (95% CL). This amounts …
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280 GHz receivers for the SPIDER CMB polarimeter
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2024-03-01 without embargo terms
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Cosmology from the CMB and Lyman-α forest
… using data from the cosmic microwave background (CMB), remnant radiation from the Big Bang, and the Lyman-α forest, absorption features in spectra of distant quasars. A six-parameter standard model of cosmology, the ΛCDM model, can explain to great accuracy how the Universe evolved from a hot, …
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Temperature anisotropies: covariant CMB anisotropies and nonlinear corrections
… structure come from?". I hoped that work in the CMB and its cosmological implications would give me insight into this. It is an adventure that is still young. I began my PhD with an investigation of some formal aspects of Ehlers-Ellis Relativistic Kinetic Theory in mind { the implications of the …
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Analysis and Measurement of Horn Antennas for CMB Experiments
… horn antennas for Cosmic Microwave Background (CMB) experiments is presented. This computational work particularly concerns the analysis of the multimode channels of the High Frequency Instrument (HFI) of the European Space Agency (ESA) Planck satellite using mode matching techniques to model …
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Accurate Characterisation of Refractive Components for Future CMB Missions
… to measure the Cosmic Microwave Background (CMB) radiation. The specific components that were characterised were a set of dielectric lenses. These were made as part of a European Space Agency contract to further the refractive technology in the terahertz band of the frequency spectrum. Two …
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Probes of cosmic inflation: from the CMB to quantum analogues
… anisotropies of the cosmic microwave background (CMB). The first part of the thesis focuses on parity-odd B-mode polarization patterns, which are a distinctive imprint of primordial gravitational waves (PGW) on large scales. The Simons Observatory (SO), a new ground-based CMB experiment, is …
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The Universe through a magnifying glass: Precision cosmology with CMB lensing
… lensing deflections experienced by the CMB photons as they travel from the last scattering surface to our telescopes enables the mapping of the matter distribution to very high redshifts. This lensing signal provides a clean window for constraining fundamental physics, such as the sum of …
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The Weak Lensing Hat-Trick: Constraining Cosmology with Galaxy, CMB, and Kinematic Lensing
… weak lensing, and cosmic microwave background (CMB) lensing can probe both cosmology and baryonic feedback in our universe using data from the Dark Energy Survey (DES) and the Planck satellite mission.
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CMB lensing measurements with two years of data from the SPT-3G survey
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-03-28 without embargo terms
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Design and analysis of a quasi-optical beam combiner for the QUBIC CMB interferometer
… Paris to discuss the prospect of observing the CMB B-mode polarization using a novel technique called bolometric interferometry. This was the first meeting of what would later become the QUBIC collaboration. In this thesis we discuss the scientific reasons for CMB observation, we present a …
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Design and Analysis of Quasioptical Components for use in Terahertz Optics and Future CMB Missions
… and analysis of optical components used in CMB (Cosmic Microwave Background) missions in the terahertz frequency spectrum. In particular, the optical performance of PRISTINE, a mission proposal for the ESA fast (F) mission call and a PLA (Polylatic Acid) GRIN (Gradient Index) lens was …
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Experimental and analytical study of electrical crosstalk in CMB cold readout systems and implications for power spectra
The Cosmic Microwave Background Radiation (CMB) originated in the early phases of the life of the Universe, during the recombination epoch, when protons and electrons combined to form hydrogen, emitting photons that free-streamed to the present epoch. The CMB frequency and power spectra have been …
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