Measurements of the polarization of the Cosmic Microwave Background (CMB) have the potential to provide very strong evidence for cosmic inflation. However, the polarization signal that is expected to have been created by inflation is extremely small. This has motivated the construction of extremely sensitive instruments with thousands of cryogenic detectors.

Simons Array is a CMB polarization experiment comprised of three telescopes located in northern Chile and each containing a cryogenic receiver. The Simons Array will observe in four frequency bands in order to measure the CMB signal as well as polarized foreground signals. The design of the detectors and readout system has been optimized to provide a low noise measurement and an experiment that can observe in varying weather conditions. Characterizing the detectors and readout system has been a crucial part of the development of the Simons Array receivers.

This dissertation describes the development and deployment of the Simons Array experiment with a focus on characterization of the cryogenic detector and readout electronics.

Measurements of the Cosmic Microwave Background (CMB) have proved pivotal

over the last few decades in the development of ΛCDM, the standard model of cosmology.

Coupled with the standard model of particle physics, these two theories describe a majority

of our observations of the Universe’s structure, dynamics, and evolution. Beyond discovering

the specifics of how our Universe was formed, remaining open questions regarding our

Universe include the masses of neutrino species, the exact nature of dark matter, and the

equation of state of dark energy – to name a few. The CMB is imprinted with information

that can help answer all these questions, making measurements of the temperature and

polarization field of the CMB at high precision an effective path to increasing our understanding

of fundamental physics. The polarization field especially, composed of parity even

E-mode and parity odd B-mode patterns, possesses untapped constraining power, at both

very large and very small angular scales.

This dissertation describes the design and characterization of cryogenic receivers for

the Simons Array CMB polarization experiment. The Simons Array is located at 5200 m

elevation in the Atacama desert, Chile and consists of three off-axis Gregorian-Dragone

telescopes, each coupled to a POLARBEAR-2 cryogenic receiver. Each receiver’s focal plane

is comprised of 7,588 transition edge sensor (TES) bolometers cooled to 250 mK and

read out using 4 K superconducting quantum interference devices (SQUIDs) using digital

frequency division multiplexing (DfMUX). The POLARBEAR-2 receiver cryostat consists of

an optics tube and backend cryostat, which are built and tested separately, then integrated

for final testing before deployment to the Chilean site. Here we describe fabrication

and cryogenic validation of two POLARBEAR-2 backends, and of the complete second

POLARBEAR-2 receiver: POLARBEAR-2b. Additionally, we discuss readout and detector

integration, including detailed SQUID characterization and TES array measurements, and

demonstration of deployment readiness of all selected devices and subcomponents. Finally,

we describe efforts and progress towards final lab validation of the POLARBEAR-2b receiver

and final demonstrations of deployment readiness.

Throughout history, human beings have always sought to answer the question ''what was the origin of the universe?'' The Cosmic Microwave Background (CMB) is one of the most essential scientific tools that will help us better understand the universe. The temperature maps of the CMB have allowed us to study the nature of the early universe through the standard ΛCDM model as well as to describe its evolution. Nevertheless, many questions remain. The next step in finding the answer lies in the measurement of the B-mode polarization of the CMB. These faint signals from the primordial universe are expected to be key pieces of evidence of the inflationary gravitational wave. Successful detection of this B-mode polarization would not only serve as direct evidence of the inflation theory but also lead to constraining of inflationary model and the energy scale of inflation. Moreover, the gravitational lensing of CMB E-mode polarization to B-mode polarization signal at small angular scales will allow us to trace back to the distribution of matter in our universe.

This dissertation describes the details of the Polarbear instrument which is designed to detect CMB B-mode polarization. The results from the first and second observational season are also described. Furthermore, this dissertation discusses the development of the Simons Array instrument, which is the expansion of Polarbear with expanded capabilities and increased sensitivity. The Simons Array is scheduled to deploy in 2018.

The Simons Array is a polarization-sensitive cosmic microwave background (CMB) experiment located in the Atacama Desert in northern Chile. Observations of the CMB, which consists of the oldest observable light in the universe, have been invaluable for cosmological research in recent decades, producing a wealth of information regarding the universe's beginning and evolution, and providing substantial evidence in support of the Lambda-Cold Dark Matter model of cosmology. The field continues to grow as technological advances enable ever more sensitive measurements of both the intensity and polarization patterns imprinted in the CMB. The Simons Array aims to further our understanding of cosmology by measuring the polarization pattern of the CMB at angular scales ranging from a few arcminutes to a few degrees, with a focus on the faint B-mode polarization signals predicted at these scales.

The Simons Array is composed of three identical telescopes, each coupled to a cryogenic receiver. The receivers are developed and characterized in laboratories before installation at the observatory site in Chile at an altitude of 5,200 m, with significant upgrades compared to POLARBEAR-1, the Simons Array's predecessor, to improve the experiment's sensitivity. In particular, the upgraded receivers employ larger focal planes with increased detector counts and sensitivity across multiple frequency bands. This dissertation describes the Simons Array experiment as a whole, with an emphasis on the telescope accessories and laboratory characterization of the POLARBEAR-2b receiver, the second receiver of the Simons Array.

Cosmological observations have great potential in searching for information about fundamental physics. The large distances and long time scales of distant sources of light allow us to leverage the vastness of the universe to search for tiny deviations to the currently accepted physical laws. This thesis will explore a number of ways that cosmological observations can help us search for new physics and learn about the evolution of the cosmos.

We will examine the dynamics of pseudo-Nambu-Goldstone bosons (PNGBs) and their behavior throughout cosmic history. Quantum scalar fields under the umbrella of PNGBs have been proposed to answer unsolved questions in physics, and they share the characteristic that they could be detected through Lorentz-violating polarization rotation of photons travelling over cosmological distances.

We will then move to a general framework for studying potential Lorentz-violating physics called the Standard Model Extension (SME), and use the framework to place limits on coefficients of the SME. Using wideband optical polarimetry of two active galactic nuclei we demonstrate the ability to place constraints with small aperture telescopes and show how combining multiple simultaneous measurements in adjacent frequency bands increase the constraining power of such observations.

We then probe the evolution of the large scale structure of the universe with a measument of the gravitational lensing deflection power spectrum using measurements of the polarization of the cosmic microwave background (CMB) taken from two years of observations with the POLARBEAR experiment.

And finally we will see how the CMB and other cosmological observations constrain the shape of the primordial power spectrum of scalar perturbations through a likelihood analysis that takes advantage of second order effects in the perturbative expansion of the gravitational metric.

Precise measurements of the polarization of the Cosmic Microwave Background (CMB) provide a wealth of knowledge regarding fundamental physics and the origins of our universe. We are currently in an era where the CMB polarization B-mode power spectrum is being measured at both small and large angular scales, providing increasingly tighter constraints on both the effects of gravitational lensing and the amount of primordial gravitational waves generated during the epoch of inflation. As we look toward the next generation of ground-based CMB experiments such as the Simons Observatory and CMB-S4, we must further our understanding of the systematic uncertainties that currently limit constraining power on both the tensor-to-scalar ratio and searches for exotic new physics.

Lorentz and parity violating physics such as cosmic birefringence have the effect of rotating the polarization of CMB photons as they traverse cosmological distances, generating B-mode polarization signal and non-zero correlations between the CMB temperature and B-mode power spectra as well as the CMB E-mode and B-mode power spectra, both of which are disallowed by the current standard model of cosmology. This cosmic polarization rotation (CPR) is degenerate with an overall detector misalignment of similar angle magnitude. The precision with which current state-of-the-art polarization calibrators are characterized is presently inadequate to allow for meaningful detections of non-zero CPR from physics that diverge from the standard model to be claimed.

This dissertation provides an overview of the current CMB polarization calibration standards and methodology in the context of the POLARBEAR-1 and Simons Array experiments, as well as the design and characterization of a novel ground-based absolute polarization calibrator that will enable new searches for Lorentz and parity violating physics. The calibrator's repeatability between calibrations scans was proven to better than 0.1 degrees, and results from calibration performed on the POLARBEAR-1 telescope and the POLARBEAR-2b receiver are presented in this work.

The cosmic microwave background (CMB) radiation contains great amounts of information that allow for studying the physics of the early universe through constraining cosmological parameters in the standard ΛCDM model. The CMB temperature signal has been measured to high precision, but measuring the CMB polarization signal is still in its early stages.

The theoretically small primordial CMB polarization B-mode signal has not yet been measured, but has principle importance in that its existence would be strong evidence of inflation. This measurement allows one to probe the earliest state of the universe at energy scales of 10^16 GeV thought to be near the Grand Unified Theory scale. The B-mode signal arising from weak gravitational lensing by large scale structures provides information about the matter composition of the universe and puts strong constraints on the sum of the neutrino masses.

This dissertation discusses the optical design, instrumentation, data analysis, and first season science results of the POLARBEAR experiment, a CMB polarization telescope aimed to measure the B-mode signal. The results show the first evidence of non-zero lensing B-modes at sub-degree angular scales on the sky. The development and measurement results of the Fourier transform spectrometer calibration instrument used to characterize the spectral response of the POLARBEAR detectors are also described. The optical design development and systematic studies for the Simons Array, the next generation installment of the experiment, are described as well. The cross polarization effect of Mizuguchi-Dragone breaking due to a prime focus half-wave plate, and the optical redesign of the Simons Array re-imaging optics for increased optical performance at higher frequencies were studied in detail. The Simons Array is planned to fully deploy in 2018 to further study the CMB with enhanced sensitivity.

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