Physics Commons^™

Mot-Based Lifetime Measurements Of Potassium-39 5p1/2 And 5p3/2 States, Huan Q. Bui

Honors Theses

This thesis presents measurements of the lifetimes of 5p1/2 and 5p3/2 of K39 via exciting a cloud of K39 atoms in a magneto-optical trap by a linearly-polarized pulse of 405 nm light followed polarization-specific, time-resolved fluorescence detection. We find that $\tau_{5p1/2} = $ 138.8 $\pm$ 1.6 ns, which is consistent with past measurements \cite{triumf}, \cite{berends} and calculations \cite{safranova}. The $\tau_{5p3/2}$ measurement is naturally more involved since quantum beats due to hyperfine and Zeeman effect are present. Our observation of $\tau_{5p3/2} =$ 137.6 $\pm$ 3.1 ns and $\tau_{5p3/2} =$ 136.0 $\pm$ 2.4 ns, obtained from two slightly different approaches, are compared …

Search For Continuous Gravitational-Wave Signals In Pulsar Timing Residuals: A New Scalable Approach With Diffusive Nested Sampling, Yu-Yang Songsheng, Yi-Qian Qian, Yan-Rong Li, Pu Du, Jie-Wen Chen, Yan Wang, Soumya Mohanty, Jian-Min Wang

Physics & Astronomy Faculty Publications

Detecting continuous nanohertz gravitational waves (GWs) generated by individual close binaries of supermassive black holes (CB-SMBHs) is one of the primary objectives of pulsar timing arrays (PTAs). The detection sensitivity is slated to increase significantly as the number of well-timed millisecond pulsars will increase by more than an order of magnitude with the advent of next-generation radio telescopes. Currently, the Bayesian analysis pipeline using parallel tempering Markov Chain Monte Carlo has been applied in multiple studies for CB-SMBH searches, but it may be challenged by the high dimensionality of the parameter space for future large-scale PTAs. One solution is to …

Enhancing Student Learning In Introductory Physics Through Funds Of Knowledge, Liang Zeng, Guang Zeng

Physics & Astronomy Faculty Publications

Researchers have reported the funds of knowledge (FK) pedagogical approach effective in engaging minority students in learning. However, there are a lack of studies connecting FK to introductory college physics or physical science classes. By using examples from regional Mexican-American lived experiences at an Hispanic-serving institution located along the recently politicized U.S.-Mexico border, this paper provides evidence to show how physics educators can use FK to engage students in learning introductory college physics concepts.

Signal-Background Analysis For New Physics At Particle Colliders And The Criteria For Its Discovery, Prudhvi Nikhil Bhattiprolu

Graduate Research Theses & Dissertations

Although the Standard Model (SM) is now complete with the spectacular discovery of the Higgs boson at the Large Hadron Collider (LHC), there are many unsolved puzzles such as the electroweak hierarchy problem, dark matter, neutrino masses, etc., that need to be addressed. Theories proposed to solve these issues often involve new and exotic particles at the TeV scale and beyond. It is therefore of great importance to devise novel strategies to extract new physics signals with small rates lurking in huge backgrounds. My research detailed here is broadly along those lines.

Vectorlike leptons (VLL) are an intriguing possibility for …

Collisional Methods With Applications To Charged Particle Beams, Afnan Al Marzouk

Graduate Research Theses & Dissertations

Accurate and efficient computational methods are essential to study the dynamics of charged particle beams. Most of the available numerical methods in beam physics are based on the collisionless model which is sufficient for applications that does not depend on Coulomb collisions of the simultaneously interacting particles. However, the development of collisional numerical methods has become greatly important in recent years for applications where collisions play an important role such as the electron cooling of high energy hadron beams. While collisional methods can provide very accurate simulations, their algorithms are very complex, and they face efficiency challenges. In this work, …

Tensor Network Approach For Simulation Of Quantum Many-Body Systems, Danylo Lykov

Graduate Research Theses & Dissertations

The simulation of quantum many-body systems and many-body statistical systems presents a challenge for classical computers. Quantum computation, which recently gained significant scientific interest, can provide a potential advantage over classical approaches in this area. While there are multiple methods for the simulation of the physics of many-body quantum systems, most of them scale exponentially with the number of elements. A Tensor Network approach allows to reduce this exponential scaling for some cases and reduces the pre-factor for others. This approach can be used for the simulation of classical statistical physics models, quantum many-body systems, and quantum computers in particular. …

Design And Optimization Of Superconducting Radio-Frequency Electron Sources, Osama Mohsen

Graduate Research Theses & Dissertations

High brightness electron beams are an essential component that drives current and future accelerators and accelerator-based light sources including Free-Electron lasers (FELs), electron cooling experiments, and compact ultrafast electron probe setups (e.g. ultrafast electron diffraction). In FEL, the possible use of a superconducting radiofrequency (SRF) electron gun to support the generation of high-repetition-rate bright-beam can produce copious amounts of radiation over a broad range of the electromagnetic spectrum which can be used in several scientific experiments while in electron probes, the use of SRF gun can enable the generation of high brightness electron beams at high repetition rates, e.g., necessary …

Superconducting Cuprates: Synthesis, Characterization And Diffuse Scattering Properties, Bisham Poudel

Graduate Research Theses & Dissertations

Since its discovery more than a century ago, the fascinating phenomenon of superconductivity remains as mysterious as ever with the greatest challenge facing the condensed matter community being the elusive understanding of the microscopic origin leading to its inception. Many outstanding questions remain of which the role played by nematic fluctuations and structural disorder for the stabilization of superconductivity is not well understood. In this respect, superconducting YBa2Cu3O6+x (YBCO)-type cuprates present an ideal framework in which charge doping, structural disorder and various site manipulations can be explored in efforts to address some of these questions. Extensive synthesis and characterization efforts …

Spectral Analysis Of Cyclotron Radiation For Electron Beam Diagnostics, Brendan Leung

Graduate Research Theses & Dissertations

The spectral distribution of the cyclotron radiation emitted by non-ultra-relativistic electrons traveling through solenoidal lenses can be used to characterize ensemble-averaged properties of a beam. In this paper we explore the potential use of cyclotron radiation to measure the energy spread and transverse emittance of a beam while remaining unintrusive. We specifically discuss the relation between the spectral properties of cyclotron radiation and the beam statistical properties and perform first principle particle-in-cell simulation to validate our findings.

Clinical Applications And Feasibility Of Proton Ct And Proton Radiography, Christina Marie Sarosiek

Graduate Research Theses & Dissertations

Proton therapy is a form of radiation treatment for cancer that utilizes the Bragg peak to create conformal high dose regions around the tumor volume. However, the use of x-ray computed tomography (CT) and x-ray radiography for treatment planning and pre-treatment quality assurance procedures improves the achievable effectiveness of proton treatment plans (using proton CT) and the pretreatment verification (using proton radiography). Errors in the conversion from x-ray Hounsfield units (HU) to proton relative stopping powers (RSP) leads to errors in the predicted proton range. To account for the errors, 3.5% margins are included in the treatment plan. This means …

Beam Phase Space Diagnostic Techniques Along The Fermilab Muon Campus Extraction Line, Benjamin Simons

Graduate Research Theses & Dissertations

The pursuit of physics beyond the Standard Model relies on the ability to make highly sensitive measurements with a high level of precision. Particle accelerators have been a cornerstone for the foundation of tools that have allowed us to continue to probe the limits of what the Standard Model can predict.

This thesis is focused on applying various measurement techniques, some standard and one not so standard, that provide crucial information about beam optics and beam quality for the purposes of monitoring the beam as it is guided throughout a beam transport system. After the measuring techniques have been described, …

Efficient Nonreciprocal Mode Transitions In Spatiotemporally Modulated Acoustic Metamaterials, Zhaoxian Chen, Yugui Peng, Haoxiang Li, Jingjing Liu, Yujiang Ding, Bin Liang, Xue-Feng Zhu, Yanqing Lu, Jianchun Cheng, Andrea Alù

Advanced Science Research Center

In linear, lossless, time-invariant, and nonbiased acoustic systems, mode transitions are time reversible, consistent with Lorentz reciprocity and implying a strict symmetry in space-time for sound manipulation. Here, we overcome this fundamental limitation by implementing spatiotemporally modulated acoustic metamaterials that support nonreciprocal sound steering. Our mechanism relies on the coupling between an ultrathin membrane and external biasing electromagnetic fields, realizing programmable dynamic control of the acoustic impedance over a motionless and noiseless platform. The fast and flexible impedance modulation of our metamaterial imparts an effective unidirectional momentum in space-time to realize nonreciprocal transitions in k-ω space between different diffraction …

Observation Of Anti-Parity-Time-Symmetry, Phase Transitions And Exceptional Points In An Optical Fibre, Arik Bergman, Robert Duggan, Kavita Sharma, Moshe Tur, Avi Zadok, Andrea Alù

Advanced Science Research Center

The exotic physics emerging in non-Hermitian systems with balanced distributions of gain and loss has recently drawn a great deal of attention. These systems exhibit phase transitions and exceptional point singularities in their spectra, at which eigen-values and eigen-modes coalesce and the overall dimensionality is reduced. So far, these principles have been implemented at the expense of precise fabrication and tuning requirements, involving tailored nano-structured devices with controlled optical gain and loss. In this work, anti-parity-time symmetric phase transitions and exceptional point singularities are demonstrated in a single strand of single-mode telecommunication fibre, using a setup consisting of off-the-shelf components. …

Optically Transparent Microwave Absorber Based On Water-Based Moth-Eye Structures, H Kwon, G D’Aguanno, Andrea Alù

Advanced Science Research Center

We propose an approach to realize an optically transparent microwave absorber based on water-based moth-eye metamaterial structures. The absorber is made of a periodic array of properly shaped glass caps infiltrated with distilled water. Analytical calculations and numerical simulations show that the water-based metamaterial absorbs electromagnetic waves over a wide spectral band ranging from 4GHz to well above 120GHz, showing absorption levels close to 100% for incident radiation that ranges from normal to grazing angles, for both TE and TM polarizations. Yet, the structure is optically transparent, offering exciting opportunities in a variety of civil and military applications, such as …

Odd Willis Coupling Induced By Broken Time-Reversal Symmetry, Li Quan, Simon Yves, Yugui Peng, Hussein Esfahlani, Andrea Alù

Advanced Science Research Center

When sound interacts with geometrically asymmetric structures, it experiences coupling between pressure and particle velocity, known as Willis coupling. While in most instances this phenomenon is perturbative in nature, tailored asymmetries combined with resonances can largely enhance it, enabling exotic acoustic phenomena. In these systems, Willis coupling obeys reciprocity, imposing an even symmetry of the Willis coefficients with respect to time reversal and the impinging wave vector, which translates into stringent constraints on the overall scattering response. In this work, we introduce and experimentally observe a dual form of acoustic Willis coupling, arising in geometrically symmetric structures when time-reversal symmetry …

Revealing Topology With Transformation Optics, Lizhen Lu, Kun Ding, Emanuele Galiffi, Xikui Ma, Tianyu Dong, J. B. Pendry

Advanced Science Research Center

Symmetry deepens our insight into a physical system and its interplay with topology enables the discovery of topological phases. Symmetry analysis is conventionally performed either in the physical space of interest, or in the corresponding reciprocal space. Here we borrow the concept of virtual space from transformation optics to demonstrate how a certain class of symmetries can be visualised in a transformed, spectrally related coordinate space, illuminating the underlying topological transitions. By projecting a plasmonic system in a higher-dimensional virtual space onto a lower-dimensional system in real space, we show how transformation optics allows us to construct a topologically non-trivial …

Breakdown Of Universal Scaling For Nanometer-Sized Bubbles In Graphene, Renan Villarreal, Pin-Cheng Lin, Fahim Faraji, Nasim Hassani, Harsh Bana, Zviadi Zarkua, Maya N. Nair, Hung-Chieh Tsai, Manuel Auge, Felix Junge, Hans C. Hofsaess, Stefan De Gendt, Steven De Feyter, Steven Brems, E. Harriet Åhlgren, Erik C. Neyts, Lucian Covaci, FrançOis M. Peeters, Mehdi Neek-Amal, Lino M. C. Pereira

Advanced Science Research Center

We report the formation of nanobubbles on graphene with a radius of the order of 1 nm, using ultralow energy implantation of noble gas ions (He, Ne, Ar) into graphene grown on a Pt(111) surface. We show that the universal scaling of the aspect ratio, which has previously been established for larger bubbles, breaks down when the bubble radius approaches 1 nm, resulting in much larger aspect ratios. Moreover, we observe that the bubble stability and aspect ratio depend on the substrate onto which the graphene is grown (bubbles are stable for Pt but not for Cu) and trapped element. …

Acoustic Spoof Surface Plasmon Polaritons For Filtering, Isolation And Sensing, Nikolina Jankovi´, Selena Ilić, Vesna Bengin, Slobodan Birgermajer, Vasa Radonić, Andrea Alù

Advanced Science Research Center

We study a waveguide structure supporting acoustic spoof plasmon polaritons (aSSPPs) perturbed by a defect, whose specifically tailored geometry enables controllable transmission characterized by a uniform phase distribution and very steep narrowband response. The structure is analyzed using transmission-line theory and numerical simulations, providing evidence for its use in advanced filters, isolators and sensor technology. In order to demonstrate the applicability of the aSSPP waveguide with defect, two selective narrowband filter designs are discussed and explored. Furthermore, we propose an acoustic isolator that exploits steady fluid flow to break reciprocity and provide large isolation in a narrowband region. We also …

Hyperbolic Surface Wave Propagation In Mid-Infrared Metasurfaces With Extreme Anisotropy, Ahmed Mekawy, Andrea Alù

Advanced Science Research Center

Hyperbolic metasurfaces are characterized by an extreme anisotropy of their effective conductivity tensor, which may be induced at visible frequencies by sculpting metals at the subwavelength scale. In this work, we explore practical implementations of hyperbolic metasurfaces at mid-infrared wavelengths, exploiting devices composed of metals and high-index semiconductor materials, which can support the required field confinement and extreme anisotropy required to realize low loss hyperbolic surface waves. In particular, we discuss the role of broken symmetries in these hybrid metasurfaces to enable large and broadband hyperbolic responses spanning the entire mid-infrared wavelength range (3–30 μm). Our findings pave the way …

Free-Space Nonreciprocal Transmission Based On Nonlinear Coupled Fano Metasurfaces, Ahmed Mekawy, Dimitrios L. Sounas, Andrea Alù

Advanced Science Research Center

Optical nonlinearities can enable unusual light–matter interactions, with functionalities that would be otherwise inaccessible relying only on linear phenomena. Recently, several studies have harnessed the role of optical nonlinearities to implement nonreciprocal optical devices that do not require an external bias breaking time-reversal symmetry. In this work, we explore the design of a metasurface embedding Kerr nonlinearities to break reciprocity for free-space propagation, requiring limited power levels. After deriving the general design principles, we demonstrate an all-dielectric flat metasurface made of coupled nonlinear Fano silicon resonant layers realizing large asymmetry in optical transmission at telecommunication frequencies. We show that the …

Potential Applications Of Electrodynamic Tethers, Sai Charan Petchetti

International Journal of Aviation, Aeronautics, and Aerospace

In recent decades, alternative propulsion systems have been investigated and have attracted great interest in the space community. Most of these alternative propulsion systems need propellants. One alternative propulsion system that does not require propellants and is not often discussed is electrodynamic tethers (EDTs). This paper speculates the potential applications of EDTs ranging from radiation belt remediation to momentum exchange tether re-boosting.

Toward In-Situ Nanoscale Imaging And Spectroscopy: Applications In Growth And Catalysis Of Two-Dimensional Materials, Fernand Torres-Davila

Electronic Theses and Dissertations, 2020-2023

New challenges arise with advances in our understanding of two dimensional (2D) materials and their functionalities. The reactivity of defects engineered to drive targeted reactions, such as those relevant to sustainability, or to shape the electronic properties of the host material locally for new applications, such as in nanoelectronics or quantum computing, brings about the need to control the environment of the material and the defect. This is particularly important to advance fundamental studies of catalytic processes to mimic the reaction pathways taking place in large scale reactors at various defect sites. With atomic defects, this constitutes an outstanding challenge …

Monitoring Stem Cell Differentiation Using Raman Microspectroscopy: Chondrogenic Differentiation, Towards Cartilage Formation, Francesca Ravera, Esen Efeoglu, Hugh Byrne

Articles

Mesenchymal Stem Cells (MSCs) have the ability to differentiate into chondrocytes, the only cellular components of cartilage and are therefore ideal candidates for cartilage and tissue repair technologies. Chondrocytes are surrounded by cartilage-like extracellular matrix (ECM), a complex network rich in glycosaminoglycans, proteoglycans, and collagen, which, together with a multitude of intracellular signalling molecules, trigger the chondrogenesis and allow the chondroprogenitor to acquire the spherical morphology of the chondrocytes. However, although the mechanisms of the differentiation of MSCs have been extensively explored, it has been difficult to provide a holistic picture of the process, in situ. Raman Micro Spectroscopy (RMS) …

Griffiths-Like Phase In Manganese Intercalated Tantalum Disulfide And The 3-Dimensional Ising Model, Paul White

Honors Program Theses

Transition metal dichalcogenides have gained increasing interest due to properties that make them highly attractive for fundamental studies of novel physical phenomena and for applications ranging from nanoelectronics and nanophotonics to sensing and actuation at the nanoscale.^[1] The material described in this work is composed of layers of tantalum sulfide between which manganese was deposited. The number of manganese atoms per tantalum atom is called the concentration, x. In the research that was conducted for this thesis, the Griffiths Phase of crystalline bulk Mn_0.23TaS₂ and the 3-dimensional Ising model was investigated.

Tri-Molybdenum Phosphide (Mo3P) And Multi-Walled Carbon Nanotube Junctions For Volatile Organic Compounds (Vocs) Detection, Baleeswaraiah Muchharla, Praveen Malali, Brenna Daniel, Alireza Kondori, Mohammad Asadi, Wei Cao, Hani E. Elsayed-Ali, Mickaël Castro, Mehran Elahi, Adetayo Adedeji, Kishor Kumar Sadasivuni, Muni Raj Mauya, Kapil Kumar, Abdennaceur Karoui, Bijandra Kumar

Electrical & Computer Engineering Faculty Publications

Detection and analysis of volatile organic compounds’ (VOCs) biomarkers lead to improvement in healthcare diagnosis and other applications such as chemical threat detection and food quality control. Here, we report on tri-molybdenum phosphide (Mo₃P) and multi- walled carbon nanotube (MWCNT) junction-based vapor quantum resistive sensors (vQRSs), which exhibit more than one order of magni- tude higher sensitivity and superior selectivity for biomarkers in comparison to pristine MWCNT junctions based vQRSs. Transmission electron microscope/scanning tunneling electron microscope with energy dispersive x-ray spectroscopy, x-ray diffraction, and x-ray photo- electron spectroscopy studies reveal the crystallinity and the presence of Mo and …

Understanding The Effects Of Water Vapor And Temperature On Aerosol Using Novel Measurement Methods, Tyler Jacob Capek

Dissertations, Master's Theses and Master's Reports

Aerosol and water are inexorably linked, and both are ubiquitous within our atmosphere and required components for cloud formation. Relative humidity (RH), a temperature dependent quantity, can have a significant influence on the size, shape, and ultimately, the optical properties of the aerosol. RH can vary substantially on small spatial and short temporal scales in turbulent conditions due to rapid fluctuations in temperature and water vapor mixing ratio. Accurate assessment of optical enhancements due to an increase in RH is key for determining the particles’ impact on the climate and visibility.

A humidity-controlled cavity attenuated phase-shift albedometer (H-CAPS-PM_SSA) …

Light Field Compression And Manipulation Via Residual Convolutional Neural Network, Eisa Hedayati

Dissertations, Master's Theses and Master's Reports

Light field (LF) imaging has gained significant attention due to its recent success in microscopy, 3-dimensional (3D) displaying and rendering, augmented and virtual reality usage. Postprocessing of LF enables us to extract more information from a scene compared to traditional cameras. However, the use of LF is still a research novelty because of the current limitations in capturing high-resolution LF in all of its four dimensions. While researchers are actively improving methods of capturing high-resolution LF's, using simulation, it is possible to explore a high-quality captured LF's properties. The immediate concerns following the LF capture are its storage and processing …

Improving The Temporal Accuracy Of Turbulence Models And Resolving The Implementation Issues Of Fluid Flow Modeling, Kyle J. Schwiebert

Dissertations, Master's Theses and Master's Reports

A sizeable proportion of the work in this thesis focuses on a new turbulence model, dubbed ADC (the approximate deconvolution model with defect correction). The ADC is improved upon using spectral deferred correction, a means of constructing a higher order ODE solver. Since both the ADC and SDC are based on a predictor-corrector approach, SDC is incorporated with essentially no additional computational cost. We will show theoretically and using numerical tests that the new scheme is indeed higher order in time than the original, and that the benefits of defect correction, on which the ADC is based, are preserved.

The …

Modeling And Numerical Simulations Of The Michigan Tech Convection Cloud Chamber, Subin Thomas

Dissertations, Master's Theses and Master's Reports

Understanding atmospheric clouds is essential for human progress, ranging from short-term effects such as when and how much it rains to long-term effects such as how much temperatures would rise due to global climate change. Clouds vary globally and seasonally; also they have length scales ranging from a few nanometers to a few kilometers and timescales from a few nanoseconds to a few weeks. Knowledge gaps in aerosol-cloud-turbulence interactions and a lack of sufficient resolution in observations pose a challenge in understanding cloud systems.

Experimental facilities like the Michigan Tech Cloud Chamber can provide a suitable platform for studying aerosol-cloud …