Physics Commons^™

The Role Of Local Winds And A Semi-Persistent Coastal Front On The Diurnal Heat Budget In An Upwelling Bay, April P. Thibodeau, Ryan K. Walter, Piero L.F. Mazzini, Thomas P. Connolly, Christopher A. Edwards, Ian C. Robbins

Physics

Coastal embayments in nearshore upwelling systems (“upwelling bays”) play a disproportionately large role in regional oceanography. In these systems, local diurnal wind forcing and thermal gradients associated with an upwelling shadow front that forms between warmer sheltered waters inside the bay and colder recently upwelled waters outside the bay strongly influence local temperature dynamics. Despite their importance to local ecosystems, there are no long-term studies that assess the heat budget inside upwelling bays. In this study, we analyzed approximately two years of water temperature throughout the water column using an autonomous profiler in a small upwelling bay in central California …

Synthesis And Characterization Of Carbon Quantum Dots And Gold Nanoparticles For Norovirus Biosensing Applications In Water Systems, Breanne Evans

Master's Theses

Rapid, reliable detection of viral pathogens remains a significant challenge across water-treatment and environmental monitoring systems, including drinking-water, wastewater, water reuse, and environmental surveillance applications. Waterborne viral contamination can pose substantial public-health risks, making early detection essential for protecting water quality and responding quickly to treatment failures or contamination events. Direct potable reuse (DPR) is one particularly demanding example because it requires continuous verification of treatment performance and the broader need for rapid virus monitoring extends across many water-treatment and environmental surveillance applications. Norovirus is a priority target because of its widespread occurrence in wastewater, environmental persistence, and exceptionally low …

Ecological Insights From Field And Laboratory Studies Of Akashiwo Sanguinea, Alexis L. Pasulka, Matthew J. Harke, Jaden Hansen, Ryan K. Walter, Eva Kokkino

Physics

Blooms of the dinoflagellate Akashiwo sanguinea occur in coastal ecosystems worldwide and can have significant ecological consequences. Along the central California coast, long-term oceanographic and harmful algal bloom observations indicate that A. sanguinea has exhibited seasonal blooms since approximately 2017, coinciding with negative upwelling anomalies and warm, stratified conditions characteristic of late summer and early fall. In laboratory experiments, three A. sanguinea strains isolated from different sites and/or environmental conditions along the central California coast exhibited variation in growth rates, temperature sensitivity, and transcriptional responses. Under the conditions tested in this study, one strain exhibiting higher maximum growth rates and …

Electrical Resistivity Tomography Investigation Of Hard Rock Aquifers In The Salinian Block, Roxanne C. Chambers

Physics

Identifying a productive groundwater source in hard rock terrain is often a challenge. Conventional hard rock aquifer models commonly describe a weathering derived layered system consisting of a laminated layer, an underlying fractured zone, and a competent granitic basement. This study investigates the applicability of this conceptual model at Lockshaw Ranch, a granitic site within the Salinian Block of central California located near the Rinconada Fault.

Previous electrical resistivity tomography (ERT) surveys and time domain electromagnetic (TDEM) data were integrated with a newly acquired ERT profile (ERT-06) are used to characterize the subsurface structure and identify potential groundwater bearing zones. …

Muon Lifetime: Theory, Experiment, And Simulation, Soren Agustin Munoz

Physics

This senior project investigates the muon lifetime through three complementary approaches: theoretical calculation, laboratory measurement, and computational simulation. The theoretical component develops the necessary background from relativistic field theory to the effective weak interaction, culminating in the leading-order Fermi-theory prediction of τ ≈ 2.2 μs, which explains why the muon lifetime lies on the microsecond scale.

The experimental component measures the lifetime of stopped cosmic-ray muons using a plastic scintillator, photomultiplier tube, and analog timing electronics. A binned Poisson likelihood fit to the primary 15-day acquisition run τ = 2.17^+0.03_-0.09 μs, consistent with the accepted value within the …

Validation Of Electromagnetic Shower Development In A Reduced Alice Focal-E Detector Model Using Geant4, Isaac Lara Romo

Physics

This project focuses on the preliminary simulation of a reduced FoCal-E detector model for the ALICE experiment at CERN. Beamline tests were simulated using an electron gun at various incident energies, and the results were compared with those of the FoCal group. The longitudinal charge deposition per sensor layer was compared between the two setups to verify that the reduced model exhibited expected calorimeter behavior. Additionally, the transverse signal across the high-granularity sensor layers was examined to determine whether the reduced model reproduced the expected lateral development of electromagnetic showers. The results obtained from these measurements show that the reduced …

The Implementation Of Scintillation Detectors With The Cuore/Cupid Collaboration In The Search For Neutrinoless Double Beta Decay, Reese Sandra Cormier

Physics

CUORE (Cryogenic Underground Observatory for Rare Events) is an experiment at the Gran Sasso National Laboratory in Assergi, Italy, currently searching for an answer to the matter-antimatter asymmetry problem; the question: why do we exist? One proposed explanation is neutrinoless double beta decay, a theorized exotic decay that would prove that neutrinos are their own antiparticle, violating the current Standard Model for particle physics. However, current detection methods do not distinguish different types of particle interactions, resulting in alpha decays contributing to the background. Therefore, the experimental sensitivity is too limited to make confident determinations about the data. For this …

Improving The Reliability And Performance Of A Supersonic Indraft Tube Wind Tunnel, Christian J. Kaml

Master's Theses

Access to supersonic testing is increasing in demand, and wind tunnels remain one of the safest and most cost-effective methods for gathering high-speed flow data. Despite being more economical than alternative options, supersonic wind tunnel facilities often require substantial investment to construct, operate, and maintain.

The novel indraft tube tunnel architecture was conceived as a high-speed flow testbed that incorporates features of both Ludwieg tubes and indraft wind tunnels to maintain costs low enough to be accessible even to small universities. This design was first developed and tested in 2018 at California Polytechnic State University, featuring a cost per test …

Experimental Methods For Cryogenic Rare Event Detection: Cuore And Cupid, Alessandro Libenson

Physics

This senior project was written with the primary purpose of serving as a introductory guide for undergraduate students learning about the experimental methods used in the CUORE and CUPID Collaborations. In particular, this project is geared towards getting students in Dr. Gutierrez's research group at Cal Poly up to speed on what CUORE and CUPID actually do. I wrote this as an undergraduate aiming to help future undergraduates. For Cal Poly students, I would suggest the following prerequisites before reading this paper: Electronics and Instrumentation, Quantum Laboratory 1, and the equivalent of the coding/analysis class. It is also important to …

Spatial Extent And Vertical Structure Of Marine Heatwaves In Chesapeake Bay, Nathan P. Shunk, Piero L. F. Mazzini, Ryan K. Walter, Kyle E. Hinson, Pierre St-Laurent, Marjorie A. M. Friedrichs

Physics

Marine heatwaves (MHWs) adversely impact marine ecosystems globally, yet data scarcity limits our understanding of their subsurface extent, particularly in estuaries. Using a high-resolution regional ocean model, we characterized the horizontal extent and subsurface structure of MHWs across the Chesapeake Bay (CB). Additionally, we developed a supplementary definition for local climatology-identified MHWs, “Vertical MHWs,” which quantifies their water column presence, and developed a new MHW vertical classification scheme. Surface MHWs were generally shorter, more frequent and intense, and impacted ∼5% of the CB surface area, while the deepest MHWs were generally longer, less frequent and intense, and regularly occupied >50% …

Marine Heatwave Co-Occurrence Between Estuarine And Coastal Systems, Ricardo U. Nardi, Piero L. F. Mazzini, Ryan K. Walter

Physics

Marine heatwaves (MHWs), prolonged periods of anomalously warm ocean temperatures, pose significant threats to marine ecosystems. While MHWs in coastal and estuarine systems have been studied separately, their spatial coherence remains significantly understudied. Here we analyze over 2 decades of high-frequency in situ temperature data from 54 stations across 20 U.S. estuaries and 13 coastal buoys to assess MHW co-occurrences. We find that estuarine and coastal MHWs co-occur only ∼21% of the time, a 57% decrease compared to co-occurrence within estuaries (∼49%). Maximum co-occurrence occurs at zero lag, suggesting synchronous synoptic-scale atmospheric forcing, likely via air–sea heat fluxes. Co-occurrence shows …

Spatially Resolved [O Iii] Emission Line Kinematics Of Reverberation-Mapped Active Galactic Nuclei With The Keck Cosmic Web Imager, Raymond P. Remigio, Vivian U, Aaron J. Barth, Nico Winkel, Vardha N. Bennert, Tommaso Treu, Matthew A. Malkan, Sebastian Contreras, Peter R. Williams, Jordan N. Runco

Physics

We present optical integral-field spectroscopic data of ten nearby (0.02 ≤ z ≤ 0.05) Seyfert 1 galaxies taken with the Keck Cosmic Web Imager. We map the spatially resolved kinematics of the [O iii] gas and stars, and investigate the alignments between their global kinematic position angles (PAs). Large-scale gas motions are primarily dominated by rotation and are kinematically aligned with the stars (ΔPA ≤ 30°). However, eight galaxies exhibit nonrotational kinematic signatures (e.g., kinematic twists, possible outflows) in their ionized gas velocity fields near the nucleus. We compare aperture-wide measurements of the gas and stellar velocity dispersions (σ …

Gravitational Torques From Lopsided Young Stellar Component Sustain High Black Hole Accretion Rates In Ngc 4593, N. Winkel, K. Jahnke, J. A. Fernández-Ontiveros, T. A. Davis, F. Combes, M. Gaspari, J. Neumann, M. Singha, J. S. Elford, Vardha N. Bennert, M. A. Malkan

Physics

Context. Supermassive black holes (SMBHs) grow primarily through gas accretion, observed as active galactic nuclei (AGNs). While mergers can drive luminous AGN episodes, secular processes may fuel a substantial portion of cosmic black hole growth. Whether these mechanisms can sustain high black hole accretion rates remains uncertain.

Aims. The aim of this study is to identify the secular mechanism driving high SMBH accretion rates, by targeting a galaxy with a moderately massive SMBH, high central gas densities, accretion rates of a few percent of the Eddington limit, and gas kinematics resolved close to black-hole-dominated scales.

Methods. A blind search led …

Spatially Resolved Kinematics Of Slacs Lens Galaxies. I. Data And Kinematic Classification, Shawn Knabel, Tommaso Treu, Michele Cappellari, Anowar J. Shajib, Chih-Fan Chen, Simon Birrer, Vardha N. Bennert

Physics

We obtain spatially resolved kinematics with the Keck Cosmic Web Imager (KCWI) integral-field spectrograph for a sample of 14 massive (11 < log₁₀(M₍★₎/M☉) < 12) lensing early-type galaxies at z ∼ 0.15–0.35 from the Sloan Lens ACS (SLACS) Survey. We integrate kinematic maps within the galaxy effective radius and examine the rotational and dispersion velocities, showing that 11/14 can be classified as slow rotators. The data set is unprecedented for galaxy-scale strong lenses in terms of signal-to-noise ratio (S/N), sampling, and calibration, vastly superseding previous studies. We find the primary contributions to systematic uncertainties to be the stellar template library and wavelength range of the spectral fit. Systematics …

Marine Heatwaves Detected By A Network Of Buoys Along The Entire Us West Coast Shelf, Gavin Plume, Ryan K. Walter, Piero L.F. Mazzini, Michael Dalsin

Physics

Marine heatwaves (MHWs), prolonged periods of anomalously warm waters, pose an increasing threat to marine ecosystems globally. While satellite-based data offer insights into MHW patterns, coastal upwelling regions are prone to satellite biases and require long-term in-situ datasets for accurate characterization. Using two decades of temperature data from 22 surface buoys distributed along the US West Coast continental shelf (10–50 km offshore) spanning nearly 2000 km of coastline, we investigated, for the first time, coast-wide patterns of MHWs in this valuable region. The spatial extent of MHWs varied from 100% of buoys during the 2014–2016 North Pacific MHW, to less …

Spatio-Temporal Variability Of San Francisco Bay Plume From Space, Piero L. F. Mazzini, Cassia Pianca, L. Fernando Pareja-Roman, Kelly L. Cole, Ryan K. Walter, Renato M. Castelao, Elias J. Hunter, Robert J. Chant

Physics

As brackish turbid waters exit San Francisco Bay, one of the largest estuaries in the U.S. West Coast, they form the San Francisco Bay Plume (SFBP), which spreads offshore and influences the Gulf of the Farallones (GoF), an ecologically significant region in the California Current System that is also home to three National Marine Sanctuaries. This paper provides the first observationally based investigation of the spatio-temporal variability of the SFBP, using a plume tracking algorithm applied to more than two decades (2002-2023) of ocean color data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard satellites Aqua and Terra. The …

The Gauge/Gravity Holographic Duality Between String Theory And Quantum Field Theory: A Full Introduction, Alex A. Short

Physics

The Anti-deSitter Spacetime / Conformal Field Theory (AdS/CFT) correspondence is a well known holographic duality between ten dimensional superstring theories and conformal quantum field theories. The existence of such a correspondence is fascinating and the duality provides a powerful tool-set for working out problems in both string theory and quantum field theory. The correspondence defines a dictionary of terms that exist dual to one another in each theory, allowing theorists to understand the dynamics in one system based on quantities from another. Furthermore, when one side of the duality has strong coupling (meaning the approximations of perturbation theory are no …

Seoul National University Agn Monitoring Project. V. Velocity-Resolved Hβ Reverberation Mapping And Evidence Of Kinematics Evolution, Shu Wang, Jong-Hak Woo, Aaron J. Barth, Vardha N. Bennert, Elena Gallo, Edmund Hodges-Kluck, Minjin Kim, Suvendu Rakshit, Tommaso Treu, Hojin Cho

Physics

We present velocity-resolved reverberation lags of Hβ for 20 active galactic nuclei (AGNs) from the Seoul National University AGN Monitoring Project. We detect unambiguous velocity-resolved structures in 12 AGNs, among which eight objects exhibit symmetric structures, two objects show inflow-like characteristics, and two objects display outflow-like signatures. For two AGNs, we successfully measure the velocity-resolved lags in different years, revealing evidence of evolving broad-line region (BLR) kinematics. By combining our sample with the literature velocity-resolved lags, we find that the symmetric velocity-resolved lags are the most common (40%) type among this sample. The frequency of inflow kinematics is also …

Climate Change And Variability Drive Increasing Exposure Of Marine Heatwaves Across Us Estuaries, Ricardo U. Nardi, Piero L. F. Mazzini, Ryan K. Walter

Physics

Marine heatwaves (MHWs) are among the greatest threats to marine ecosystems, and while substantial advances have been made in oceanic MHWs, little is known about estuarine MHWs. Utilizing a temperature dataset spanning over two decades and 54 stations distributed across 20 estuaries in the United States National Estuarine Research Reserve System, we present a comprehensive analysis of estuarine MHW characteristics and trends. Long-term climate-change-driven warming is driving more frequent MHWs along the East Coast, and if trends continue, this region will be in a MHW state for ~ 1/3 of the year by the end of the century. In contrast, …

Muon Veto Panel Uniformity Tests At Yale Wright Laboratory For The Cuore And Cupid Experiments And Visualizing Dirac Spinors In The Chiral Basis With The Bloch Sphere, Reagen Neeva Garcia

Physics

This senior project is divided into three sections that describe my path and experiences in under graduate research. The first provides an introduction to the field of particle physics and the search for neutrinoless double beta decay (0νββ) with the Cryogenic Underground Observatory for Rare Events (CUORE) experiment, as well as its upgrade, CUPID (CUORE Upgrade with Particle IDentification). The second section details my contributions to these experiments, including my summer working at Yale’s Wright Laboratory on R&D for the CUPID experiment. In this section I describe my work on the experiment’s muon veto system and on light detector development …

Vertical Structure Of Subsurface Marine Heatwaves In A Shallow Nearshore Upwelling System, Gavin Plume, Ryan K. Walter, Isabelle Cobb, Michael Dalsin, Piero L. F. Mazzini, Nathan P. Shunk, Ian C. Robbins, Thomas P. Connolly

Physics

Marine heatwaves (MHWs) are increasing in frequency and intensity globally and are among the greatest threats to marine ecosystems. However, limited studies have characterized subsurface MHWs, particularly in shallow waters. We utilized nearly two decades of full water-column (~ 10 m) observations from a unique automated profiler in central California to characterize, for the first time, the vertical structure of MHWs in a shallow nearshore upwelling system. We found MHWs have similar average durations and intensities across all depths, but there were ~ 17% more bottom MHW days than surface MHW days. Nearly one third of bottom MHWs occurred independently …

Offshore Wind Farms Could Impact Coastal Marine Heatwaves In Eastern Boundary Upwelling Systems, Michael Dalsin, Ryan K. Walter, Piero L.F. Mazzini

Physics

Analysis of ecosystem impacts from offshore wind (OSW) farm development has primarily focused on localized effects. However, in Eastern Boundary Current Upwelling Systems (EBUS) like the California Current, OSW farms can modify the intensity and spatial structure of wind-driven upwelling, inducing non-local (tens of kms away) changes to seawater temperature. Recent numerical modeling research determined that a hypothetical upper bound full buildout of OSW farms in central California could warm coastal waters through a reduction in upwelling. Here, we examine the sensitivity of coastal marine heatwaves (MHWs), which are prolonged extreme seawater temperatures that are among the greatest threats to …

Jwst Lensed Quasar Dark Matter Survey – Ii. Strongest Gravitational Lensing Limit On The Dark Matter Free Streaming Length To Date, Ryan E. Keeley, A. M. Nierenberg, D. Gilman, C. Gannon, S. Birrer, T. Treu, A. J. Benson, X. Du, K. N. Abazajian, Vardha N. Bennert

Physics

This is the second in a series of papers in which we use JWST Mid Infrared Instrument multiband imaging to measure the warm dust emission in a sample of 31 multiply imaged quasars, to be used as a probe of the particle nature of dark matter. We present measurements of the relative magnifications of the strongly lensed warm dust emission in a sample of nine systems. The warm dust region is compact and sensitive to perturbations by populations of haloes down to masses ~ 10⁶ M☉. Using these warm dust flux-ratio measurements in combination with five previous narrow-line flux-ratio measurements, …

Spatial Planning Offshore Wind Energy Farms In California For Mediating Fisheries And Wildlife Conservation Impacts, Crow White, Yi-Hui Wang, Ryan K. Walter, Benjamin Ruttenberg, Danny Han, Eli Newman, Ethan R. Deyle, Sucharita Gopal, Les Kaufman

Physics

Achieving a blue economy will require reconciling the value of emerging ocean uses with their impacts on the seascape and sectors with historical access to marine resources and areas. To meet this challenge, we developed an analytical framework for conducting marine spatial planning through tradeoff analysis, and applied it to prospective offshore wind energy development in the ∼974 km2 Morro Bay, California, USA Wind Energy Area (WEA). We generated spatial data layers estimating MW power production and impacts on fisheries value and marine wildlife conservation (seabird and cetacean populations) from wind farm development. We then quantified each sector's response to …

High Resolution Assessment Of Commercial Fisheries Activity Along The Us West Coast Using Vessel Monitoring System Data With A Case Study Using California Groundfish Fisheries, Yi-Hui Wang, Benjamin Ruttenberg, Ryan K. Walter, Frank Pendleton, Jameal F. Samhouri, Owen R. Liu, Crow White

Physics

Commercial fisheries along the US West Coast are important components of local and regional economies. They use various fishing gear, target a high diversity of species, and are highly spatially heterogeneous, making it challenging to generate a synoptic picture of fisheries activity in the region. Still, understanding the spatial and temporal dynamics of US West Coast fisheries is critical to meet the US legal mandate to manage fisheries sustainably and to better coordinate activities among a growing number of users of ocean space, including offshore renewable energy, aquaculture, shipping, and interactions with habitats and key non-fishery species such as seabirds …

Identifying Ion-Scale Waves In Parker Solar Probe Sub-Alfvénic Intervals, Nicholas Henry Androski, Kristoff Paulson

Physics

Identification of coherent quasi-parallel ion-scale (1-32 Hz) wave activity in sub-Alfvénic regions of the solar wind observed by NASA's Parker Solar Probe during perihelion encounters 8 to 16. Wave activity is filtered computationally by coherency, circular polarization and propagation angle with respect to the mean magnetic field. Initial statistical results are presented with suggestions for future improvements and studies. A general overview of the heliosphere and the context of ion-cyclotron waves (an ion-scale wave) in the coronal heating problem. Along the way to identify ion-scale wave activity, tables of sub-Alfvénic intervals and current sheet crossings for encounters 8 to 16 …

Focused Led Sintering, Dylan Defazio, Nilav Maulik, Branden Majors, Michael Fontillas

Mechanical Engineering

This report provides a detailed overview of the final design of our light-emitting diode (LED) focusing system. Our system incorporates a converging lens and a specially designed "glass funnel," which acts as a thick fiber optic that narrows the light to a fine point through internal reflection. The glass components of our system are precisely housed in a part made using advanced computer-numeric controlled (CNC) Mill and CNC Lathe manufacturing processes. This ensures high precision and durability of the overall system. Our LED focusing system is designed with a 60-watt stage light. The decision to use a glass funnel as …

Representation Theory And Its Applications In Physics, Max Varverakis

Master's Theses

Representation theory, which encodes the elements of a group as linear operators on a vector space, has far-reaching implications in physics. Fundamental results in quantum physics emerge directly from the representations describing physical symmetries. We first examine the connections between specific representations and the principles of quantum mechanics. Then, we shift our focus to the braid group, which describes the algebraic structure of braids. We apply representations of the braid group to physical systems in order to investigate quasiparticles known as anyons. Finally, we obtain governing equations of anyonic systems to highlight the differences between braiding statistics and conventional Bose-Einstein/Fermi-Dirac …

Compound Marine Cold Spells And Hypoxic Events In A Nearshore Upwelling System, Ryan K. Walter, Michael Dalsin, Piero L.F. Mazzini, Cassia Pianca

Physics

Prolonged periods of extreme warm and cold seawater temperature anomalies, known as marine heatwaves (MHWs) and marine cold spells (MCSs), respectively, can have significant impacts on coastal marine ecosystems. Prior research has examined the co-occurrence of multiple extremes [low dissolved oxygen (DO) and/or low pH] during MHWs, with the impact of these compound events potentially exceeding that of a single stressor due to synergistic effects. However, we are not aware of any studies that have examined compound extreme events during MCSs, despite the ecosystem implications. Along Eastern Boundary Current Upwelling Systems (EBUS), strong-wind driven upwelling has led to …

Empirical Models Of The Hβ Broad Emission Line Gas Density Field, Lizvette Villafaña, Tommaso Treu, Lourenzo Colleyn, Brendon J. Brewer, Aaron J. Barth, Matthew A. Malkan, Vivian U, Vardha N. Bennert

Physics

We present the second iteration of the caramel-gas code, an empirical model of the broad-line region (BLR) gas density field. Building on the initial development and testing of caramel-gas, we expand the meaning of the model parameter α, which initially represented only the power-law index of the dependency of emissivity on radial distance. In this work, we test a more generalized radial power-law index, α, that also includes a description of the effective emitting size(s) of the BLR structure as a function of radial distance. We select a sample of 10 active galactic nuclei (AGN) from three different …