Physics Commons^™

Nanoscale Assembly Of Dectin-1 And Its Glucan Ligand In Immunocyte Membranes And Pathogen Cell Walls, Akram Etemadi Amin

Physics & Astronomy ETDs

Candida spp. pathogens continue to be a significant health care burden with high mortality and exceeding enormous healthcare costs. Candida infection range varies from dermatological infection to more severe bloodstream infection in debilitated patients. Due to this, research dedicated to understanding biophysical interactions between Candida species and the host’s immune cells is essential. The C-type lectin’s (CtLs) are known to bind to Candida cell walls and play a crucial role in downstream immune signaling. It is known that β-glucans, the highly immunogenic polysaccharide in Candida’s cell wall, are mostly masked underneath a layer of mannosylated proteins. The amount of …

Fundamental Aspects Of The Interaction Between Light And Nanostructures, Stephen Keith Sanders

Physics & Astronomy ETDs

Recent breakthroughs in nanophotonics have brought new opportunities to control and manipulate light at the nanoscale. The optical properties of metallic nanostructures have attracted particular interest because of their plasmon resonances, which couple strongly with visible light, and generate large near-field enhancements in their vicinity. In the first part of this thesis, we investigate the fundamental limits of the local density of photonic states near nanostructures by analyzing a sum rule relating its spectral integral to the field induced by a static dipole. Next, we analyze how the design of metallic nanoantennas can benefit from incorporating active materials that display …

Searching For The Global 21 Cm Cosmic Dawn Absorption Signal With The Long Wavelength Array, Christopher Dilullo

Physics & Astronomy ETDs

The redshifted 21 cm signal from neutral hydrogen offers one of the best observational probes of Cosmic Dawn and the Epoch of Reionization. This dissertation presents an effort to detect the redshifted 21 cm signal using the Long Wavelength Array station located on the Sevilleta National Wildlife Refuge in New Mexico, USA (LWA-SV). The major goal is to validate the potential detection reported by the EDGES collaboration. This measurement requires a dynamic range on the order of 10⁵ in order to disentangle the cosmological signal from the Galactic foregrounds. The beamforming capability of LWA-SV is novel to this search. …

Non-Gaussian Measurements Of Coherent States Of Light For Metrology And Communication, Matthew Dimario

Physics & Astronomy ETDs

Conventional measurement technology is unable to extract the most amount of information possible from coherent states of light. Non-Gaussian measurements which can count individual photons can surpass the sensitivity limits of ideal conventional strategies, and approach the ultimate limits achievable given by quantum mechanics. This thesis presents investigations and demonstrations of these unconventional measurements, which utilize coherent operations and single photon counting. This thesis shows that non-Gaussian measurements can outperform conventional strategies in estimation tasks as well as a variety of communication problems. This thesis also investigates novel approaches and algorithms for building robustness to static and dynamic noise which …

A Search For New Physics In B(S) To Mu+Mu- Decays Using Multivariate Data Analysis, And Development Of Particle Detection Technology With Silicon Pixel Detectors, Aidan Grummer

Physics & Astronomy ETDs

A suite of linked research projects is undertaken, combining a search for phenomena beyond the Standard Model of particle physics, development of new instruments for greater precision in detecting fundamental particles, and tracking and understanding the effect upon the detectors of the radiation that is an indelible element of their operating environment. Data recorded by the ATLAS Detector at CERN are employed in a search for evidence of undiscovered particles contributing to the rate of decays of B⁰ and B⁰_s mesons to dimuon final states. New applications of machine learning techniques are implemented to separate this signal …

Probing The Galactic Agb Population Through Infrared And Sio Maser Emission, Megan O. Lewis

Physics & Astronomy ETDs

Stars on the Asymptotic Giant Branch (AGB) are of low to intermediate mass and have reached the end stages of stellar evolution. The mass-loss that stars undergo at this phase enshrouds the central star in a circumstellar envelope (CSE) that redistributes most of the stellar light into the infrared (IR) regime of the spectrum. In the CSEs of oxygen-rich AGB stars molecules including SiO form, and under certain conditions maser emission from SiO can make AGB stars bright beacons at radio frequencies (e.g., 43 and 86 GHz). SiO masers are ideal observational probes of AGB sources, providing data on their …

Monitoring The Low Frequency Radio Transient Sky With The Long Wavelength Array, Savin Shynu Varghese

Physics & Astronomy ETDs

Transient searches in radio astronomy have discovered some of the most extreme astrophysical phenomena in our universe. This has enabled us to study the physics of these explosive and dynamic sources. Most of the transient searches over the past 70 years have been at frequencies higher than 100 MHz leaving the transient sky below 100 MHz unexplored. The Long Wavelength Array (LWA) telescope offers an excellent opportunity to study the transient sky below 100 MHz with its wide field of view, high sensitivity and fast imaging at shorter timescales. This dissertation presents the transient searches carried out using the all-sky …

Monte Carlo Simulations Of Awkward Actions, David John Amdahl

Physics & Astronomy ETDs

Time derivatives of scalar fields occur quadratically in textbook actions. A simple Legendre transformation turns the Lagrangian into a Hamiltonian that is quadratic in the momentum. The partition function over the momentum is Gaussian. Mean values of operators are basically euclidian path integrals of their classical counterparts with positive weight functions. Monte Carlo simulations can estimate such mean values. This familiar framework falls apart when the time derivatives do not occur quadratically. The Legendre transformation becomes difficult or so intractable that the Hamiltonian can’t be determined. Even if the Hamiltonian is found, it usually is so complicated that the partition …

Exploring Hidden Structure Of The Nearby Universe And The Limits And Capabilities Of Two Neutral Hydrogen Surveys, Monica Sanchez Barrantes

Physics & Astronomy ETDs

We can use the 21 cm neutral hydrogen (HI) emission line to detect galaxies in optically obscured regions, but it is also a faint line that is difficult to detect at higher redshifts. This work presents two HI surveys. The ALFAZOA Survey maps new and predicted large-scale structure across the Galactic plane, and finds a total of 217 completely new galaxies across both of the survey phases. The completeness limits for ALFAZOA Shallow and Deep are presented. Follow-up observations of confused galaxies in ALFAZOA using the VLA determine that confusion in this survey will not cause significant deviations for the …

Understanding Solar Wind Formation By Identifying The Origins Of In Situ Observations, Samantha Wallace

Physics & Astronomy ETDs

Over the past century, significant progress has made on the subjects of two fundamental unresolved questions in Heliophysics, namely 1) how is the solar corona heated to multi-million-degree temperatures, and 2) how is the solar wind formed, from its origin, to its release and acceleration. While the two are in many ways intertwined, this dissertation focuses on the latter. Our current understanding of solar wind formation has developed largely through relating the general origins of the observed solar wind on global spatial scales to the corresponding observed speed at 1 au. However, we are now at a point where long-standing …

Bayesian Analysis Of Single Molecule Fluorescence Microscopy Data, Mohamadreza Fazel

Physics & Astronomy ETDs

The diffraction limit can be circumvent by creating and exploiting independent behaviors of the sample at lengths scale below the diffraction limit. In fluorescence microscopy, the independence arises from individual fluorescent labels switching between dark and fluorescence states. The fluorophores can then be localized employing the generated sparse image frames. Finally, the resulting list of coordinates is utilized to generate high resolution images or to gain quantitative insight into the underlying biological structures. Therefore image processing and post-processing are essential stages of SMLM techniques.

In this dissertation, Reversible Jump Markov Chain Monte Carlo was employed to implement Bayesian analysis of …

Cherenkov Gamma Ray Detectors On High-Energy-Density Systems, Kevin Daniel Meaney

Physics & Astronomy ETDs

High energy density (HED) systems are some of the most extreme environments ever created by mankind. Systems with pressures greater than 1 MBar can only be created by a handful of devices on earth, often utilizing high intensity lasers or pulsed power machines. HED systems offer a view into an extreme form of matter only seen in stellar cores, supernovas and other powerful astrophysical systems. Creating HED systems on Earth offer the possibility, if the physics and technology can be matured, to one day create a fusion power plant. If a system is hot and dense enough, the fusion reaction …

Collective Neutrino Flavor Oscillations In Multiple Dimensions And Scales, Joshua D. Martin

Physics & Astronomy ETDs

Hot and dense astrophysical environments such as the early universe, core collapse novae and binary neutron star mergers generate dense neutrino gases which can sub- sequently have an important effect on processes which occur in these environments. In this thesis we will present the results from several numerical simulations of these gases particularly in cases which are relevant to core collapse supernovae. These simulations employ fewer imposed spatial symmetries than those used in earlier works, and provide insight into behavior which may be expected to occur in three key regions of the explosion. We observe that when the neutrino gas …

On The Complexity Of Boson Sampling Using Atoms In Optical Lattices, Gopikrishnan Muraleedharan

Physics & Astronomy ETDs

The extended Church-Turing thesis says that any computation that can be done by a physically realizable model of computers can be efficiently computed by the simplest model of classical computer, a Turing machine. Since the introduction of the concept of quantum computers, a central goal has been to find instances where the extended Church- Turing thesis fails. In the current noisy intermediate-scale quantum devices era, one looks for such instances that can be simulated on modest devices of small scale in the presence of noise. In this thesis, we work with one such problem, namely the Boson Sampling problem. We …

Investigation Of Membrane Protein Dynamics Using Correlative Single-Particle Tracking And Super-Resolution Microscopy Combined With Bayesian Inference Of Diusion In Arbitrary Landscapes, Hanieh Mazloom Farsibaf

Physics & Astronomy ETDs

Many experiments have shown that the diffusive motion of lipids and membrane proteins are slower on the cell surface than those in artificial lipid bilayers or blebs. One hypothesis that may partially explain this mystery is the effect of the cytoskeleton structures on the protein dynamics. To test this hypothesis, we designed a high-speed single particle tracking microscope and use a hybrid tracking and super-resolution approach on the same cell. We labeled the high-affinity FceRI receptor as a transmembrane protein and GPI-anchored proteins as an example of outer leaflet protein in Rat Basophilic Leukemia (RBL) cells and tracked these membrane …

Direct Observation Of Atomic Exchange During Surface Self-Diffusion, Matthew Aaron Koppa

Physics & Astronomy ETDs

The diffusion of adatoms across the (100) plane of iridium has been previously inferred to occur by an exchange mechanism based on site mapping. This study provides the first direct observation that surface self-diffusion can occur by exchange. Iridium enriched to ≥93% ¹⁹¹Ir was deposited onto an atomically clean and smooth Ir(100) plane as observed in an atom probe field ion microscope. Following thermally activated surface self-diffusion the adatom was field desorbed and mass analyzed. Observation of the ¹⁹³Ir isotope in one-half of the cases demonstrates conclusively that atomic exchange can occur during surface self-diffusion.

Dark Matter Production Beyond The Thermal Wimp Paradigm: An Exploration Of Early Matter Domination Scenarios, Jacek Ksawery Osinski

Physics & Astronomy ETDs

In the standard thermal history of the Universe, the energy density is dominated by radiation throughout the postinflationary era, until matter-radiation equality after big bang nucleosynthesis (BBN). However, we currently do not have any observational probes of the pre-BBN period, and radiation domination (RD) is therefore an assumption. Generic early Universe models predict the presence of additional components in the postinflationary Universe which can lead to periods of nonstandard evolution before the onset of BBN. A prominent example of such a period is a phase of early matter domination (EMD) in which the Universe undergoes matter-dominated expansion for a time, …

Using Natural Phenomena To Study The Ionosphere, Joseph Benjamin Malins

Physics & Astronomy ETDs

This dissertation explores novel techniques for observing the ionosphere using natural signals. The ionosphere is a region of plasma hundreds of kilometers above the Earth that affects communication and remote sensing applications across the world. Traditional techniques for observing the ionosphere involve using man made radio signals, either to reflect the signal at HF frequencies or to pass several signals through the ionosphere and compare the difference the ionosphere makes in the signals. However, such techniques are limited by the ability of equipment to produce these signals and by the numerous laws and regulations governing transmission of signals in the …

Electromagnetic Analysis Of Bidirectional Reflectance From Roughened Surfaces And Applications To Surface Shape Recovery, Julian Antolin Camarena

Physics & Astronomy ETDs

Scattering from randomly rough surfaces is a well-established sub area of electrodynamics. There remains much to be done since each surface and optical processes that may occur in within the scattering medium, and countless other scenarios, is different. There are also illumination models that describe lighting in a scene on the macroscopic scale where geometrical optics can be considered adequate. Of particular interest for us is the intersection of the physical scattering theories and the illumination models. We present two contributions: 1) A minimum of two independent images are needed since any opaque surface can be uniquely specified in terms …

The Production Cross Section Of The J/Ψ Meson Measured Using The Phenix Detector At √ S =510 Gev, Katherine Marie Deblasio

Physics & Astronomy ETDs

The inclusive differential production cross section of the J/ψ meson is measured with the PHENIX detector for p + p collisions at √ s = 510 GeV using the 2013 RHIC dataset. The measurement is performed using the dimuon decay channel at forward and backward rapidity ranges of 1.2 < |y| < 2.2 and for transverse momenta up to 12 GeV/c. The experimental results are compared to current predictions in NRQCD and serves to shed light on the ambiguity of the J/ψ production mechanism. The 2013 RHIC dataset provides unique challenges to the cross section measurement due to the effects of detector pile-up from multiple collisions. Techniques to quantify these effects are discussed.

Measurement And Control For Quantum State Tomography, State Preparation, And Metrology, Ezad Shojaee Mr.

Physics & Astronomy ETDs

Quantum information science can deliver its promises in technology if we have access to near-perfect quantum states, quantum channels, and readout. These are the building blocks of any quantum informatics in computation, communication, and simulation. Invasiveness of quantum measurement is one of the major challenges in this realm. The fact that after a measurement the quantum state changes is now a rule of the game. We need smart ways to gain information about a quantum state, given finite resources, in order to characterize it prior to any task.

In this dissertation, we realize the optimal way to do quantum state …

Quantum Algorithms With Applications To Simulating Physical Systems, Anirban Ch Narayan Chowdhury

Physics & Astronomy ETDs

The simulation of quantum physical systems is expected to be an important application for quantum computers. The work presented in this dissertation aims to improve the resource requirements of quantum computers for solving simulation problems, by providing both novel quantum algorithms and improved implementations of existing ones. I present three main results that cover diverse aspects of simulation including equilibrium physics, the preparation of useful quantum states, and simulations based on classical stochastic processes. The results rely on established quantum algorithms and other recent techniques which I review. My first original contribution is a new quantum algorithm to sample from …

Searching For Supermassive Binary Black Holes And Their Gravitational Waves, Karishma Bansal

Physics & Astronomy ETDs

The recent discovery of gravitational waves (GWs) by the LIGO collaboration has opened a new observing window on the universe, but it is limited to the GWs in the frequency range of 10-1000 Hz. The main motivation of this thesis is to consider the possibility of detecting low frequency (nHz) GWs. In the pursuit of these waves, we need to understand their source of origin and build a detector with the required sensitivity. Low-frequency waves are expected as a result of coalescing binary supermassive black holes (SMBBHs). We hope to detect these waves in the near future using pulsar timing …

Studying The Properties Of Sf6 Gas Mixtures For Directional Dark Matter Detection, Randy J. Lafler

Physics & Astronomy ETDs

Although dark matter comprises approximately 85\% of the matter content of the universe, direct detection of dark matter remains elusive. As the available parameter space for dark matter candidates is pushed to lower and lower limits, the demand for larger, more sensitive detectors continues to grow. Although upscaling the detector improves the sensitivity, it greatly increases the cost and complexity of the experiment. Even after a dark matter signal is detected, there remains the possibility that an unknown background mimics the dark matter signal. Consequently, verifying the dark matter origin of a detection signal is an issue for any dark …

Circumstellar Sio Masers In The Bulge Asymmetries And Dynamical Evolution Survey, Michael Cullen Stroh

Physics & Astronomy ETDs

The Bulge Asymmetries and Dynamical Evolution (BAaDE) project aims to explore the complex structure of the inner Galaxy and Galactic Bulge, by using the 43 GHz receivers at the Karl G. Jansky Very Large Array (VLA) and the 86 GHz receivers at the Atacama Large Millimeter/submillimeter Array (ALMA) to observe SiO maser lines in red giant stars. The SiO maser transitions occur at radio frequencies, where extinction is negligible, thus allowing a dense sampling of line-of-sight velocities in the most crowded regions of the Milky Way.

The overall goal of this thesis is to characterize the SiO masers in the …

Topics In Three-Dimensional Imaging, Source Localization And Super-Resolution, Zhixian Yu

Physics & Astronomy ETDs

The realization that twisted light beams with helical phasefronts could carry orbital angular momentum (OAM) that is in excess of the photon's spin angular momentum (SAM) has spawned various important applications. One example is the design of novel imaging systems that achieve three-dimensional (3D) imaging in a single snapshot via the rotation of point spread function (PSF).

Based on a scalar-field analysis, a particular simple version of rotating PSF imagery, which was proposed by my advisor Dr. Prasad, furnishes a practical approach to perform 3D source localization using a spiral phase mask that generates a combination of Bessel vortex beams. …

Studies On The Generation And Detection Of Orbital Angular Momentum Based On Beam-Shaping Techniques, Xijie Luo

Physics & Astronomy ETDs

Light carrying orbital angular momentum (OAM) has many applications ranging from optical manipulation, imaging and remote sensing, and optical communications, and can be used to perform fundamental studies in quantum mechanics and quantum information. Moreover, single photons with high-order OAM allow for increasing the amount of information carried per photon in quantum communication. This thesis describes the study of methods for the preparation and detection of OAM of light in high mode order by utilizing beam shaping techniques using spatial light modulators (SLMs). The quality of the generated high-order OAM mode is limited by optical aberrations which are induced by …

Improving The Readout Of Semiconducting Qubits, Matthew Jon Curry

Physics & Astronomy ETDs

Semiconducting qubits are a promising platform for quantum computers. In particular, silicon spin qubits have made a number of advancements recently including long coherence times, high-fidelity single-qubit gates, two-qubit gates, and high-fidelity readout. However, all operations likely require improvement in fidelity and speed, if possible, to realize a quantum computer.

Readout fidelity and speed, in general, are limited by circuit challenges centered on extracting low signal from a device in a dilution refrigerator connected to room temperature amplifiers by long coaxial cables with relatively high capacitance. Readout fidelity specifically is limited by the time it takes to reliably distinguish qubit …

Compact Optical Frequency Standards For Future Applications Beyond The Laboratory, Kyle Martin

Physics & Astronomy ETDs

Atomic clocks provide one of the fundamental building blocks upon which modern telecommunications systems are constructed. Since the invention of the frequency comb in the early 2000s, laboratory frequency standards have quickly outpaced their compact counterparts. Compact clocks, however, have continued to leverage microwave transitions not yet exploring the advantages of an optical atomic clock. With the recent development of robust frequency combs compact optical clocks can now be realized. In this dissertation two atomic species are investigated for a compact atomic frequency standards. Both of these clocks are in different development stages but offer unique advantages. The optical rubidium …

Towards Scalable Characterization Of Noisy, Intermediate-Scale Quantum Information Processors, Travis Luke Scholten

Physics & Astronomy ETDs

In recent years, quantum information processors (QIPs) have grown from one or two qubits to tens of qubits. As a result, characterizing QIPs – measuring how well they work, and how they fail – has become much more challenging. The obstacles to characterizing today’s QIPs will grow even more difficult as QIPs grow from tens of qubits to hundreds, and enter what has been called the “noisy, intermediate-scale quantum” (NISQ) era. This thesis develops methods based on advanced statistics and machine learning algorithms to address the difficulties of “quantum character- ization, validation, and verification” (QCVV) of NISQ processors. In the …