Digital Commons Network^™

Search For Photoproduction Of Axionlike Particles At Gluex, Shankar Adhikari, C.S. Akondi, M. Albrecht, Moskov Amaryan, Tyler P. Viducic, Z. Zhang, Z. Zhao, J. Zhou, The Gluex Collaboration, Et Al.

Physics Faculty Publications

We present a search for axionlike particles, a, produced in photon-proton collisions at a center-of-mass energy of approximately 4 GeV, focusing on the scenario where the a-gluon coupling is dominant. The search uses a → γγ and a → π⁺π⁻π⁰ decays, and a data sample corresponding to an integrated luminosity of 168  pb⁻¹ collected with the GlueX detector. The search for a → γγ decays is performed in the mass range of 180 < m_a <480  MeV, while the search for a → π⁺π⁻π⁰ decays explores the 600 < m_{a …}

Study Of The Λ/Σ⁰ Electroproduction In The Low-Q² Region At Jlab, K. Okuyama, K. Itabashi, S. Nagao, S. N. Nakamura, K. N. Suzuki, T. Gogami, B. Pandey, L. Tang, D. Abrams, T. Akiyama, D. Androic, K. Aniol, C. Ayerbe Gayoso, J. Bane, S. Barcus, J. Barrow, V. Bellini, H. Bhatt, D. Bhetuwal, D. Biswas, A. Camsonne, J. Castellanos, J.- P. Chen, J. Chen, S. Covrig, D. Chrisman, R. Cruz-Torres, R. Das, E. Fuchey, K. Gnanvo, F. Garibaldi, T. Gautam, J. Gomez, P. Gueye, T. J. Hague, O. Hansen, W. Henry, Florian Hauenstein, D. W. Higinbotham, Charles E. Hyde, M. Kaneta, C. Keppel, T. Kutz, N. Lashley-Colthirst, S. Li, H. Liu, J. Mammei, P. Markowitz, R. E. Mcclellan, F. Meddi, D. Meekins, R. Michaels, M. Mihovilovic, A. Moyer, D. Nguyen, M. Nycz, V. Owen, C. Palatchi, S. Park, T. Petkovic, S. Premathilake, P. E. Reimer, J. Reinhold, S. Riordan, V. Rodriguez, C. Samanta, S. N. Santiesteban, B. Sawatzky, S. Širca, K. Slifer, T. Su, Y. Tian, Y. Toyama, K. Uehara, G. M. Urciuoli, D. Votaw, J. Williamson, B. Wojtsekhowski, S. A. Wood, B. Yale, Z. Ye, J. Zhang, X. Zheng

Physics Faculty Publications

We performed an experiment using tritium and hydrogen cryogenic gas targets at Thomas Jefferson National Accelerator Facility (JLab) in 2018 (E12-17-003)[1, 2]. In this article, we discuss the Λ/Σ⁰ hyperon electroproduction from hydrogen target. Elementary Λ/Σ⁰ hyperon production processes are important not only for an absolute mass scale calibration in our experiment, but also for the study of the electroproduction mechanisms themselves. In this article, we reported the results of the differential cross section for the p(e, e’K⁺)Λ/Σ⁰ reaction at Q² ∼ 0.5 (GeV/c)².

Lower Temperature Annealing Of Vapor Diffused Nb3Sn For Accelerator Cavities, Jayendrika K. Tiskumara, Jean R. Delayen, G. V. Eremeev, U. Pudasaini

Physics Faculty Publications

Nb₃Sn is a next-generation superconducting material for the accelerator cavities with higher critical temperature and superheating field, both twice compared to Nb. It promises superior performance and higher operating temperature than Nb, resulting in significant cost reduction. So far, the Sn vapor diffusion method is the most preferred and successful technique to coat niobium cavities with Nb₃Sn. Although several post-coating techniques (chemical, electrochemical, mechanical) have been explored to improve the surface quality of the coated surface, an effective process has yet to be found. Since there are only a few studies on the post-coating heat treatment …

The Effects Of An Ultrafast Pulsed Laser On Ybco Thin Film Circuit Transients, Matthew L. Rustad

Browse all Theses and Dissertations

Terahertz (THz) frequency light has shown promise for a wide variety of applications due to its material characterization and imaging capabilities. Its nondestructive nature coupled with its submillimeter spatial resolution provides the most value for terahertz light as an imaging tool. The application of terahertz technology has been limited by a lack of novel and powerful sources. It has been shown that that Yttrium Barium Copper Oxide (YBCO), a type II superconductor, has certain properties that would allow YBCO to be an effective source for THz light. Recent microwave work has shown that when a persistent supercurrent is placed on …

Optical Signal Processing With Discrete-Space Metamaterials, Mohammad Moein Moeini

Wayne State University Dissertations

As digital circuits are approaching the limits of Moore’s law, a great deal of efforthas been directed to alternative computing approaches. Among them, the old concept of optical signal processing (OSP) has attracted attention, revisited in the light of metamaterials and nano-photonics. This approach has been successful in realizing basic mathematical operations, such as derivatives and integrals, but it is difficult to be applied to more complex ones. Inspired by digital filters, we propose a radically new OSP approach, able to realize arbitrary mathematical operations over a nano-photonic platform. We demonstrate this concept for the case of spatial differentiation, image …

Giant Acoustically-Induced Synthetic Hall Voltages In Graphene, Pai Zhao, Chithra H. Sharma, Renrong Liang, Christian Glasenapp, Lev Mourokh, Vadim M. Kovalev, Patrick Huber, Marta Prada, Lars Tiemann, Robert H. Blick

Publications and Research

Any departure from graphene’s flatness leads to the emergence of artificial gauge fields that act on the motion of the Dirac fermions through an associated pseudomagnetic field. Here, we demonstrate the tunability of strong gauge fields in nonlocal experiments using a large planar graphene sheet that conforms to the deformation of a piezoelectric layer by a surface acoustic wave. The acoustic wave induces a longitudinal and a giant synthetic Hall voltage in the absence of external magnetic fields. The superposition of a synthetic Hall potential and a conventional Hall voltage can annihilate the sample’s transverse potential at large external magnetic …

First And Third Order Susceptibility Of Organic Molecules, Hao-Jung Chang

Electronic Theses and Dissertations, 2020-2023

Illuminating a material with intense laser excitation may change its properties and result in nonlinear absorption (NLA) and nonlinear refraction (NLR). In this dissertation we study the nonlinear absorption of organic compounds, the effect of extremely nondegenerate NLR in semiconductors, and the linear refractive index of organic solvents. In liquids, the refractive index has been studied for decades and different kinds of refractometers have been proposed. However, most of the reported values are in the visible region and only for commonly used solvents. We proposed a new interferometer-based refractometer that allows us to measure the refractive index from the visible …

Third Order Nonlinear Optics In Solids, Nicholas Cox

Electronic Theses and Dissertations, 2020-2023

Nonlinear optical effects occur when strong electromagnetic waves induce changes in a medium that affect its own propagation or that of another wave. Third order optical nonlinearities scale linearly with irradiance and lead to effects like two-photon absorption and nonlinear refraction. This work focuses on the experimental and theoretical study of two-photon absorption in crystalline solids. We begin by detailing the quantum mechanical states of electrons in solids along with the computational approaches to calculate their band structure. Next, a theoretical model for the linear and nonlinear optical interaction of light with matter is presented in a many-body formalism. This …

Light Trapping Transparent Electrodes, Mengdi Sun

Electronic Theses and Dissertations, 2020-2023

Transparent electrodes represent a critical component in a wide range of optoelectronic devices such as high-speed photodetectors and solar cells. Fundamentally, the presence of any conductive structures in the optical path leads to dissipation and reflection, which adversely affects device performance. Many different approaches have been attempted to minimize such shadowing losses, including the use of transparent conductive oxides (TCOs), metallic nanowire mesh grids, graphene-based contacts, and high-aspect ratio metallic wire arrays. In this dissertation I discuss a conceptually different approach to achieve transparent electrodes, which involves recapturing photons initially reflected by highly conductive electrode lines. To achieve this, light-redirecting …

Optimization-Based Approaches To Low-Coherence Optical Diffraction Tomography, Seth Smith-Dryden

Electronic Theses and Dissertations, 2020-2023

Quantitative optical phase imaging techniques, such as optical diffraction tomography (ODT), are useful tools for refractive-index profiling. Many of them, however, rely on the weak-scattering assumptions, thus cannot be applied to multiple-scattering objects, or turbid media. In this thesis, I report several approaches for expanding the efficacy of ODT techniques and adapting them to new applications by use of low-coherence broadband illumination. First, I developed a method for ODT reconstruction using regularized convex optimization with a new phase-based fidelity criterion. The new criterion is necessary because objects with very different refractive-index distributions may produce similar diffracted fields (magnitude and principal-phase) …

The Fine Spectral Tuning Of Plasmon Mode And Quantum Emitter Coupling And Itscomparison With The Dark-Hot Resonances, Hira Asif, Rasi̇m Volga Ovali, Ramazan Şahi̇n

Turkish Journal of Physics

Localization of incident fields into very small volumes (hot-spots) allows strong light-matter interactions at the hot spots. This makes path interference effects, Fano resonances, visible. Fano resonances can appear due to the coupling of a bright plasmon (i) to a longer lifetime dark plasmon mode or (ii) to a quantum object (QO) of a much longer lifetime. The second phenomenon provides a very important utility: the voltage tunability of the linear/nonlinear response. The level-spacing of the QO, such as defect-centers and quantum dots, are voltage-tunable which can make a sharp Fano resonance appear and disappear. Here, we compare the two …

Topical Review: Greybody Factors And Quasinormal Modes For Black Holes Invarious Theories - Fingerprints Of Invisibles, İzzet Sakalli, Sara Kanzi

Turkish Journal of Physics

We give a pedagogical introduction to black holes (BHs) greybody factors (GFs) and quasinormal modes (QNMs) and share the recent developments on those subjects. To this end, we present some particular analytical and approximation techniques for the computations of the GFs and QNMs. We first review the gravitational GFs and show how they are analytically calculated for static and spherically symmetric higher dimensional BHs, consisting the charged BHs and existence of cosmological constant (i.e. de Sitter (dS)/anti-de Sitter (AdS)AdS BHs). The computations performed involve both the low-energy (having real and small frequencies) and the asymptotic (having extremely high frequency of …

Extinction And Growth On An Inhomogeneous Seascape, Tung Tran, Mehran Kardar

Turkish Journal of Physics

The effects of noise and nonuniformity on dynamics of populations are relevant and timely subjects of investigation. One form of variation is the time dependence of the reproduction rate (fitness), referred to as ?seascape? noise; another is time-independent intrinsic dependencies of fitness on location (in the parlance of statistical physics, corresponding to annealed and quenched disorder, respectively). The former was studied recently and demonstrated to lead to novel universality classes for extinction and growth. To reduce the gap between this theoretical model and reality, we develop a new formalism for seascape noise where growth and migration parameters are inhomogeneous. In …

Critical Dynamics In Biological Boolean Networks Follows From Symmetric Response To Input Genes, Hamza Çoban, Alkan Kabakçioğlu

Turkish Journal of Physics

A recent observation on an extensive collection of biological gene regulatory networks suggests that the regulatory dynamics is tuned to remain close to the order-chaos boundary in the Lyapunov sense [1]. We here investigate, from a mathematical perspective, the structural/functional constraints which give rise to such accumulation around criticality in these systems. While the role of canalizing functions in this respect is well established, we find that critical sensitivity to small input variations also follows from an over-abundance of symmetrical inputs, i.e. regulatory genes invoking identical or complementary responses on their common target. A random network ensemble constructed to have …

Dissolution Of Alumina In Cryolite Melts: A Conceptual Dft Study, Ali̇met Sema Özen, Zehra Akdeni̇z

Turkish Journal of Physics

Interactions between alumina and cryolite clusters were investigated using chemical reactivity descriptors based on Conceptual DFT such as global hardness, $\eta$, global softness, $S$, fukui functions, $f$, and local softness, $s$. Hard and Soft Acids and Bases (HSAB) Principle was applied for identifying clusters that are most likely to interact with alumina, Al$_2$O$_3$. Local reactivity descriptors were employed to predict the most probable regions of interaction within the cluster.

Nb₃Sn Coating Of A 2.6 Ghz Srf Cavity By Sputter Deposition Technique, M. S. Shakel, Wei Cao, H. Elsayed-Ali, G. V. Eremeev, U. Pudasaini, A. M. Valente-Feliciano

Electrical & Computer Engineering Faculty Publications

Nb₃Sn is of interest as a coating for SRF cavities due to its higher transition temperature Tc ~18.3 K and superheating field Hsh ~400 mT, both are twice that of Nb. Nb₃Sn coated cavities can achieve high-quality factors at 4 K and can replace the bulk Nb cavities operated at 2 K. A cylindrical magnetron sputtering system was built, commissioned, and used to deposit Nb₃Sn on the inner surface of a 2.6 GHz single-cell Nb cavity. With two identical cylindrical magnetrons, this system can coat a cavity with high symmetry and uniform thickness. Using Nb-Sn multilayer sequential sputtering followed by …

Using Network Analysis To Contrast Three Models Of Student Forum Discussions, Hannah N. Benston

Browse all Theses and Dissertations

There is much research about how actors and events in social networks affect each other. In this research, three network models were created for discussion forums in three semesters of undergraduate general physics courses. This study seeks to understand what social network measures are most telling of a online forum classroom dynamic. That is, I wanted to understand more about things like what students are most central to the networks and whether this is consistent across different network models. I also wanted to better understand how students may or may not group together. What relationships (student to student, student to …

Superluminal Propagation On A Moving Braneworld, Brian Greene, Daniel Kabat, Janna Levin, Arjun S. Menon

Publications and Research

We consider a braneworld scenario in the simplest setting, M₄ × S¹, with a four-dimensional (4D) Minkowski metric induced on the brane, and establish the possibility of superluminal propagation. If the brane is at rest, the 4D Lorentz symmetry of the brane is exact, but if the brane is in motion, it is broken globally by the compactification. By measuring bulk fields, an observer on the brane sees a slice through a higher-dimensional field profile, which carries an imprint of the extra dimensions even when the brane is at rest. If the brane is in motion, we …

Defining Entanglement Without Tensor Factoring: A Euclidean Hourglass Prescription, Takanori Anegawa, Norihiro Iizuka, Daniel Kabat

Publications and Research

We consider entanglement across a planar boundary in flat space. Entanglement entropy is usually thought of as the von Neumann entropy of a reduced density matrix, but it can also be thought of as half the von Neumann entropy of a product of reduced density matrices on the left and right. The latter form allows a natural regulator in which two cones are smoothed into a Euclidean hourglass geometry. Since there is no need to tensor factor the Hilbert space, the regulated entropy is manifestly gauge invariant and has a manifest state-counting interpretation. We explore this prescription for scalar fields, …

Two-Loop Four-Fermion Scattering Amplitude In Qed, R. Bonciani, A. Broggio, S. Di Vita, A. Ferroglia, M. K. Mandal, P. Mastrolia, L. Mattiazzi, A. Primo, J. Ronca, U. Schubert, W. J. Torres Bobadilla, F. Tramontano

Publications and Research

We present the first fully analytic evaluation of the transition amplitude for the scattering of a massless into a massive pair of fermions at the two-loop level in quantum electrodynamics. Our result is an essential ingredient for the determination of the electromagnetic coupling within scattering reactions, beyond the currently known accuracy, which has a crucial impact on the evaluation of the anomalous magnetic moment of the muon. It will allow, in particular, for a precise determination of the leading hadronic contribution to the (g − 2)_μ in the MUonE experiment at CERN, and therefore can be used to …

A Template Method To Measure The $T \Bar T$ Polarisation, J. A. Aguilar-Saavedra, M. C. N. Fiolhais, P. Martín-Ramiro, J. M. Moreno, António Onofre

Publications and Research

We develop a template method for the measurement of the polarisation of $t \bar t$ pairs produced in hadron collisions. The method would allow to extract the individual fractions of $t_L \bar t_L$, $t_R \bar t_R$, $t_L \bar t_R$ and $t_R \bar t_L$ pairs with a fit to data, where L, R refer to the polarisation along any axis. These polarisation fractions have not been independently measured at present. Secondarily, the method also provides the net polarisation of t and $\bar t$, as well as their spin correlation for arbitrary axes.

The Octagon At Large M, Riccardo Argurio, Matteo Bertolini, Sebastían Franco, Eduardo García-Valdecasas, Shani Meynet, Antoine Pasternak, Valdo Tatitscheff

Publications and Research

Recently, the first instance of a model of D-branes at Calabi-Yau singularities where supersymmetry is broken dynamically into stable vacua has been proposed. This construction was based on a system of N regular and M = 1 fractional branes placed at the tip of the so-called (orientifolded) Octagon singularity. In this paper we show that this model admits a large M generalization, having the same low energy effective dynamics. This opens up the possibility that the effect on geometry is smooth, and amenable to describing the gauge theory all along the RG flow, including the deep IR, in terms of …

Development Of Computational Methods For Electronic Structural Characterization Of Strongly Correlated Materials: From Different Ab-Initio Perspectives, Uthpala K. Herath

Graduate Theses, Dissertations, and Problem Reports (ETD)

The electronic correlations in materials drive a variety of fascinating phenomena from magnetism to metal-to-insulator transitions (MIT), which are due to the coupling between electron spin, charge, ionic displacements, and orbital ordering. Although Density Functional Theory (DFT) successfully describes the electronic structure of weakly interacting material systems, being a static mean-field approach, it fails to predict the properties of Strongly Correlated Materials (SCM) that include transition and rare earth metals where there is a prominent electron localization as in the case of d and f orbitals due to the nature of their spatial confinement.

Dynamical Mean Field Theory (DMFT) is …

Hot-Carrier Dynamics And Transport Mechanisms In Inas/Alassb Multiple Quantum Wells, Herath Pathiranage Janaka Chathuranga Piyathilaka

Graduate Theses, Dissertations, and Problem Reports (ETD)

Semiconductor photovoltaics convert light into electricity through the extraction of photo-excited charge carriers. Among the most important parameters for a photovoltaic cell are good optical absorption in the desired region of the electromagnetic spectrum, and sufficient excited-state lifetimes and mobilities of the photocarriers to allow for charge separation and extraction before recombination. For solar cell applications there are significant challenges to overcome to improve the efficiency of the light-to-electricity conversion. The cells are most commonly made of silicon, which has a nearly perfect bandgap for absorbing the most solar radiation, an indirect bandgap to give a long photocarrier lifetime and …

Characterization And Coherent Spin Selective Manipulation Of Quantum Dot Energy Levels, Tristan Anthony Wilkinson

Graduate Theses, Dissertations, and Problem Reports (ETD)

Semiconductor quantum dots (QDs) are promising candidates to fulfill a wide range of applications in real-world quantum computing, communication, and networks. Their excellent optical properties such as high brightness, single-photon purity, and narrow linewidths show potential utility in many areas. In order to realize long term goals of integration into complex and scalable quantum information systems, many current challenges must be overcome. One of these challenges is accomplishment of all necessary computing operations within a QD, which might be enabled by coherent manipulation of single QD energy level structures. In the realm of scalability for quantum devices, a way to …

Ion Velocity Distribution Functions In Cutting-Edge Plasmas, Mitchell Cameron Paul

Graduate Theses, Dissertations, and Problem Reports (ETD)

Cutting-edge plasma experiments continue to push the frontiers of plasma science. Two such groups of experiments, helicon sources and laboratory magnetic reconnection, are the focus of this thesis. The relatively high plasma density achieved for modest input powers makes helicon source plasmas ideal testbeds for fusion-relevant phenomena without the complexities associated with fusion devices. Examples include plasma-material interaction (PMI) studies, divertor region studies, and boundary physics studies. As advancements in helicon source design and technology make operation at higher power for longer times possible, understanding of the plasma dynamics, particularly ion dynamics, is vital.

Laboratory experiments are essential to advancing …

Modeling, Fabrication, And Characterization Of Rf-Based Passive Wireless Sensors Composed Of Refractory Semiconducting Ceramics For High Temperature Applications, Kavin Sivaneri Varadharajan Idhaiam

Graduate Theses, Dissertations, and Problem Reports (ETD)

Real-time health monitoring of high temperature systems (>500^oC) in harsh environments is necessary to prevent catastrophic events caused by structural failures, varying pressure, and chemical reactions. Conventional solid-state temperature sensors such as resistance temperature detectors (RTDs) and thermocouples are restricted by their operating environments, sensor dimensions and often require external power sources for their operation. The current work presents the research and development of RF-based passive wireless sensing technology targeting high temperatures and harsh environmental conditions. Passive wireless devices are generally classified as near-field and far-field devices based on the interrogation distance. Near-field sensors are placed at …

Electronic Structure Of Early Transition Metal Complexes Supported By Pyridine Polypyrrolide Ligands, Dylan Connor Leary

Graduate Theses, Dissertations, and Problem Reports (ETD)

A thorough study of photoluminescent molecules involving the pyridine polypyrrole(ide) ligand platform has been conducted. A detailed analysis on speciation of the proligand H₂(^MesPDP^Ph) (H₂^MesPDP^Ph = 2,6-bis(5-mesityl-3-phenyl-1H-pyrrol-2-yl)-pyridine) and its dilithium salt Li₂(^MesPDP^Ph) revealed temperature- and solvent-dependent effects. These molecules, along with the hydrochloric acid adduct [H₃(^MesPDP^Ph)]Cl were found to exhibit short-lived photoluminescence in both tetrahydrofuran and benzene solution. These findings confirm the hypothesis that heavy-atom involvement is crucial for the favorable photophysical properties observed for the Zr(PDP)_{2 …}

On An Econophysics Model, Miron Kaufman

Turkish Journal of Physics

Krugman has proposed a continuous in time and space model for the emergence of polycentric urban areas in the regional space. By using a discrete version of this model on spatial networks, we predicted the distribution of jobs among the different localities inside a couple of economic regions in Ohio and Texas. The time evolution of the distribution of jobs is governed by a market potential. Employment gradually moves towards locations considered relatively attractive if their market potential is above the spatial average. Similarly, jobs move away from locations with below-average market potential. First, I will show that the market …

Dynamic Multicritical Phase Diagrams Of The Mixed Spin (2, 5/2) Blume-Emery-Griffiths Model With Repulsive Biquadratic Coupling, Mustafa Gençaslan, Mustafa Keski̇n

Turkish Journal of Physics

We investigated the dynamic phase transitions (DPTs) in the mixed spin (2, 5/2) Blume-Emery Griffiths model with repulsive biquadratic interaction in the presence of a time-varying magnetic field. We used the path probability method to obtain the set of the dynamic equations. We numerically solved these dynamic equations to characterize the nature of first- and second-order phase transitions and to find the DPT temperatures as well as obtain the phases in the system. We constructed the dynamic phase diagrams (DPDs) in reduced temperature and amplitude of oscillating magnetic field plane. We observed that the DPDs display richer, complex and more …