Physics Commons^™

Efficient, Dual-Particle Directional Detection System Using A Rotating Scatter Mask, Robert Olesen, Bryan V. Egner, Darren E. Holland, Valerie Martin, James E. Bevins, Larry W. Burggraf, Buckley E. O'Day Iii

AFIT Patents

A directional radiation detection system and an omnidirectional radiation detector. The omnidirectional radiation detector detects radiation comprising at least one of: (i) gamma rays; and (ii) neutron particles. A radiation scatter mask (RSM) of the radiation detection system includes a rotating sleeve received over the omnidirectional radiation detector and rotating about a longitudinal axis. The RSM further includes: (i) a fin extending longitudinally from one side of the rotating sleeve; and (ii) a wall extending from the rotating sleeve and spaced apart from the fin having an upper end distally positioned on the rotating sleeve spaced apart or next to …

Tunable Non-Hermitian Acoustic Filter, S. Puri, J. Ferdous, A. Shakeri, A. Basiri, M. Dubois, Hamidreza Ramezani

Physics and Astronomy Faculty Publications and Presentations

We propose, design, and experimentally test a non-Hermitian acoustic superlattice that acts as a tunable precise filter. The superlattice is composed of two concatenated sublattices. The first sublattice is Hermitian, while the other can be adjusted to be Hermitian or non-Hermitian. The existence of non-Hermiticity, in terms of an induced loss in the second sublattice, results in the generation of absorption resonances that appear in the reflected spectrum. This provides us with a powerful knob to absorb or reflect several frequencies at will with high accuracy. The number of filtered frequencies can be controlled by designing the resonances in the …

Exact Christoffel-Darboux Expansions: A New, Multidimensional, Algebraic, Eigenenergy Bounding Method, Carlos Handy

Faculty Publications

Although the Christoffel-Darboux representation (CDR) plays an important role within the theory of orthogonal polynomials, and many important bosonic and fermionic, multidimensional, Hermitian and Non-Hermitian, systems can be transformed into a moment equation representation (MER), the union of the two into an effective, algebraic, eigenenergy bounding method has been overlooked. This particular fusion of the two representations (CDR and MER), defines the Orthonormal Polynomial Projection Quantization-Bounding Method (OPPQ-BM), as developed here. We use it to analyze several one dimensional and two dimensional systems, including the quadratic Zeeman effect for strong-superstrong magnetic fields. For this problem, we match or surpass the …

Awegnn: Auto-Parametrized Weighted Element-Specific Graph Neural Networks For Molecules., Timothy Szocinski, Duc Duy Nguyen, Guo-Wei Wei

Mathematics Faculty Publications

While automated feature extraction has had tremendous success in many deep learning algorithms for image analysis and natural language processing, it does not work well for data involving complex internal structures, such as molecules. Data representations via advanced mathematics, including algebraic topology, differential geometry, and graph theory, have demonstrated superiority in a variety of biomolecular applications, however, their performance is often dependent on manual parametrization. This work introduces the auto-parametrized weighted element-specific graph neural network, dubbed AweGNN, to overcome the obstacle of this tedious parametrization process while also being a suitable technique for automated feature extraction on these internally complex …

Relating Dust Reference Models To Conventional Systems In Manifestly Gauge Invariant Perturbation Theory, Kristina Giesel, Bao-Fei Li, Parampreet Singh

Faculty Publications

Models with dust reference fields in relational formalism have proved useful in understanding the construction of gauge invariant perturbation theory to arbitrary orders in the canonical framework. These reference fields modify the dynamical equations for perturbation equations. However, important questions remain open on the relation with conventional perturbation theories of inflaton coupled to gravity and of multifluid systems, and on understanding modifications in terms of physical degrees of freedom. These gaps are filled in this manuscript for Brown-Kuchar and Gaussian dust models, both of which involve three scalar physical degrees of freedom. We establish a relationship of these models with …

Biochemical Impact Of Solar Radiation Exposure On Human Keratinocytes Monitored By Raman Spectroscopy; Effects Of Cell Culture Environment, Ulises Lopez Gonzalez, Alan Casey, Hugh Byrne

Articles

Understanding and amelioration of the effects of solar radiation exposure are critical in preventing the occurrence of skin cancer. Towards this end, many studies have been conducted in 2D cell culture models under simplified and unrealistic conditions. 3D culture models better capture the complexity of in vivo physiology, although the effects of the 3D extracellular matrix have not been well studied. Monitoring the instantaneous and resultant cellular responses to exposure, and the influence of the 3D environment, could provide an enhanced understanding of the fundamental processes of photocarcinogenesis. This work presents an analysis of the biochemical impacts of simulated solar …

Optical Switching Performance Of Thermally Oxidized Vanadium Dioxide With An Integrated Thin Film Heater, Andrew M. Sarangan, Gamini Ariyawansa, Ilya Vitebskiy, Igor Anisimov

Electro-Optics and Photonics Faculty Publications

Optical switching performance of vanadium dioxide produced by thermal oxidation of vanadium is presented in this paper. A 100nm thick vanadium was oxidized under controlled conditions in a quartz tube furnace to produce approximately 200nm thick VO2. The substrate was appropriately coated on the front and back side to reduce reflection in the cold state, and an integrated thin film heater was fabricated to allow in-situ thermal cycling. Electrical measurements show a greater than three orders of magnitude change in resistivity during the phase transition. Optical measurements exhibit 70% transparency at 1500nm and about 15dB extinction across a wide spectral …

Determinantal Quantum Monte Carlo Solver For Cluster Perturbation Theory, Edwin W. Huang, Yao Wang

Open Access Publishing Fund

Cluster Perturbation Theory (CPT) is a technique for computing the spectral function of fermionic models with local interactions. By combining the solution of the model on a finite cluster with perturbation theory on intra-cluster hoppings, CPT provides access to single-particle properties with arbitrary momentum resolution while incurring low computational cost. Here, we introduce Determinantal Quantum Monte Carlo (DQMC) as a solver for CPT. Compared to the standard solver, exact diagonalization (ED), the DQMC solver reduces finite size effects through utilizing larger clusters, allows study of temperature dependence, and enables large-scale simulations of a greater set of models. We discuss the …

Droplet Impact, Part 1: Controlling Skirting Velocity, Ben Wilkerson, Nanami Mezaki, Jacob Hale Phd

Annual Student Research Poster Session

Droplet skirting occurs when a fluid droplet rolls over a bath of the same fluid without merging. To achieve skirting, we introduced a ~0.6 mm-diameter droplet of 1 cSt silicone oil into a bath of the same fluid by bouncing it off an angled glass slide coated with 100,000 cSt silicone oil. Our work suggests that initial skirting velocity increases as a function of slide angle and, to a lesser degree, droplet generator height. Furthermore, we conclude that the droplet lifetimes (initiation of skirting until rupture) and corresponding �� values (rate of decay of motion) appear consistent with theoretical predictions …

3d-Printing Habitable Structures On Mars, Addison Johnson, John Pugsley, Andrew Scherer

Faculty-Mentored Undergraduate Scholarship

This project developed technology to 3D-print habitable structures on Mars from in-situ materials, as part of the push to create a self-sustaining colony on Mars. The team designed a next generation sulfur concrete printhead capable of extruding with greater efficiency and better quality than the previous design.

Vibronic Coherence And Quantum Beats Of O₂⁺ Based On Laser Pump-Probe Dissociation Dynamics, Shan Xue, Shengjun Yue, Hongchuan Du, Bitao Hu, Anh-Thu Le

Physics Faculty Research & Creative Works

We report theoretical investigations of vibronic quantum beats (QBs) which can be observed in the molecular dissociation under the intense infrared (IR) laser pump-IR laser probe scheme. We show how the vibronic coherences can be probed by analyzing the interchannel QB signals obtained from the numerical solution of the time-dependent Schrödinger equation (TDSE) and the quantum Liouville equation in combination with the strong-field approximation for the treatment of coherences between multiple states of the target ion. The validities of our methods are first tested on a one-dimensional model of H₂⁺, for which exact solutions of the TDSE …

Friedel Oscillations In Graphene Gapped By Breaking Ƥ And T Symmetries: Topological And Geometrical Signatures Of Electronic Structure, Jin Yang, Ding-Fu Shao, Shu-Hui Zhang, Wen Yang

Department of Physics and Astronomy: Faculty Publications

The measurement of Friedel oscillations (FOs) is conventionally used to recover the energy dispersion of electronic structure. Besides the energy dispersion, the modern electronic structure also embodies other key ingredients such as the geometrical and topological properties; it is one promising direction to explore the potential of FOs for the relevant measurement. Here, we present a comprehensive study of FOs in substrate-supported graphene under off-resonant circularly polarized light, in which a valley-contrasting feature and topological phase transition occur due to the combined breaking of inversion (Ƥ) and time reversal (T) symmetries. Depending on the position of …

Examining The Temperature Dependence Of Louche Formation In Absinthe, Jessica E. Bickel, Anna Ellis, Andrew Resnick

Physics Faculty Publications

Absinthe is an anise-flavored alcohol that is typically served by adding cold water to form a cloudy green louche, similar to the cloudy white louche of ouzo. This microemulsion formation, due to the competing interactions within the oil-alcohol-water system, has been termed the ouzo effect. Previous work has examined the ternary oil-alcohol-water phase diagram in ouzo and limoncello. Additional work has also characterized the droplet size and stability of microemulsions in ouzo, limoncello, and pastis. However, less work has been done to examine the effect of temperature on louche formation despite the fact that the louche is traditionally formed by …

Design And Implementation Of The Amiga Embedded System For Data Acquisition, A. Aab, P. Abreu, M. Aglietta, J. M. Albury, I. Allekotte, A. Almela, B. Fick, D. F. Nitz, A. Puyleart, Et. Al.

Michigan Tech Publications

The Auger Muon Infill Ground Array (AMIGA) is part of the AugerPrime upgrade of the Pierre Auger Observatory. It consists of particle counters buried 2.3 m underground next to the water-Cherenkov stations that form the 23.5 km2 large infilled array. The reduced distance between detectors in this denser area allows the lowering of the energy threshold for primary cosmic ray reconstruction down to about 1017 eV. At the depth of 2.3 m the electromagnetic component of cosmic ray showers is almost entirely absorbed so that the buried scintillators provide an independent and direct measurement of the air showers muon content. …

Antimatter Free-Fall Experiments And Charge Asymmetry, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

We propose a method by which one could use modified antimatter gravity experiments in order to perform a high-precision test of antimatter charge neutrality. The proposal is based on the application of a strong, external, vertically oriented electric field during an antimatter free-fall gravity experiment in the gravitational field of the Earth. The proposed experimental setup has the potential to drastically improve the limits on the charge-asymmetry parameter ɛq of antimatter. On the theoretical side, we analyze possibilities to describe a putative charge-asymmetry of matter and antimatter, proportional to the parameters ɛq and ɛq, by Lagrangian methods. We found that …

Knot Theory In Virtual Reality, Donald Lee Price

Masters Theses & Specialist Projects

Throughout the study of Knot Theory, there have been several programmatic solutions to common problems or questions. These solutions have included software to draw knots, software to identify knots, or online databases to look up pre-computed data about knots. We introduce a novel prototype of software used to study knots and links by using Virtual Reality. This software can allow researchers to draw links in 3D, run physics simulations on them, and identify them. This technique has not yet been rigorously explored and we believe it will be of great interest to Knot Theory researchers. The computer code is written …

Measurement Of The Beam-Normal Single-Spin Asymmetry For Elastic Electron Scattering From ^12c And ^27al, D. Androic, David S. Armstrong, Et Al.

Arts & Sciences Articles

We report measurements of the parity-conserving beam-normal single-spin elastic scattering asymmetries Bn on 12C and 27Al, obtained with an electron beam polarized transverse to its momentum direction. These measurements add an additional kinematic point to a series of previous measurements of Bn on 12C and provide a first measurement on 27Al. The experiment utilized the Qweak apparatus at Jefferson Lab with a beam energy of 1.158 GeV. The average laboratory scattering angle for both targets was 7.7∘, and the average Q2 for both targets was 0.024 37 GeV2 (Q=0.1561 GeV). The asymmetries are Bn=−10.68±0.90(stat)±0.57(syst) ppm for 12C and Bn=−12.16±0.58(stat)±0.62(syst) ppm …

Deep-Learning Based Reconstruction Of The Shower Maximum Xmax Using The Water-Cherenkov Detectors Of The Pierre Auger Observatory, A. Aab, P. Abreu, M. Aglietta, J. M. Albury, I. Allekotte, A. Almela, B. Fick, D. F. Nitz, A. Puyleart, Et. Al.

Michigan Tech Publications

The atmospheric depth of the air shower maximum Xmax is an observable commonly used for the determination of the nuclear mass composition of ultra-high energy cosmic rays. Direct measurements of Xmax are performed using observations of the longitudinal shower development with fluorescence telescopes. At the same time, several methods have been proposed for an indirect estimation of Xmax from the characteristics of the shower particles registered with surface detector arrays. In this paper, we present a deep neural network (DNN) for the estimation of Xmax. The reconstruction relies on the signals induced by shower particles in the ground based water-Cherenkov …

Probing The Structure Of Deuteron At Very Short Distances, Frank Vera

FIU Electronic Theses and Dissertations

We study the electro-disintegration of deuteron at quasi-elastic kinematics and high transferred momentum as a probe for the short distance structure in nuclei. In this reaction, an electron hits a nucleus of deuterium, which breaks up into a pair of nucleons (proton-neutron). We focus our attention on events where fast nucleons emerge, corresponding to nuclear configurations where the bound nucleons have a high relative momentum (exceeding 700 MeV/c). The present research is relevant to physical systems where high-density nuclear matter is present. This condition covers a wide range of physics, from neutron stars to nuclei stability and the repulsive nuclear …

Localization Of The Higgs Mode At The Superfluid-Mott Glass Transition, Jack Crewse, Thomas Vojta

Physics Faculty Research & Creative Works

The amplitude (Higgs) mode near the two-dimensional superfluid-Mott glass quantum phase transition is studied. We map the Bose-Hubbard Hamiltonian of disordered interacting bosons onto an equivalent classical model in (2+1) dimensions and compute the scalar susceptibility of the order parameter amplitude via Monte Carlo simulation. Analytic continuation of the scalar susceptibilities from imaginary to real frequency to obtain the spectral densities is performed by a modified maximum entropy technique. Our results show that the introduction of disorder into the system leads to unconventional dynamical behavior of the Higgs mode that violates naive scaling, despite the underlying thermodynamics of the transition …

Observation Of Gravitational Waves From Two Neutron Star-Black Hole Coalescences, R. Abbott, T. D. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We report the observation of gravitational waves from two compact binary coalescences in LIGO's and Virgo's third observing run with properties consistent with neutron star-black hole (NSBH) binaries. The two events are named GW200105_162426 and GW200115_042309, abbreviated as GW200105 and GW200115; the first was observed by LIGO Livingston and Virgo and the second by all three LIGO-Virgo detectors. The source of GW200105 has component masses 8.9^+1.2_-1.5 and 1.9^+.03_-.02 M_⊙, whereas the source of GW200115 has component masses and 5.7^+1.8_-2.1 and 1.5^+0.7_-0.3 M_⊙ (all measurements quoted at the 90% credible …

Campbell Penetration Depth In Low Carrier Density Superconductor Yptbi, Hyunsoo Kim, Makariy A. Tanatar, Halyna Hodovanets, Kefeng Wang, Johnpierre Paglione, Ruslan Prozorov

Physics Faculty Research & Creative Works

Magnetic penetration depth, λ_m, was measured as a function of temperature and magnetic field in single crystals of low carrier density superconductor YPtBi by using a tunnel-diode oscillator technique. Measurements in zero DC magnetic field yield London penetration depth, λ_L(T), but in the applied field the signal includes the Campbell penetration depth, λ_C(T), which is the characteristic length of the attenuation of small excitation field, H_AC, into the Abrikosov vortex lattice due to its elasticity. Whereas the magnetic field dependent λ_C exhibit λ_C ~ B^P with p = 1/2 …

Estimating Turbulence Distribution Over A Heterogeneous Path Using Time‐Lapse Imagery From Dual Cameras, Benjamin Wilson, Santasri Bose-Pillai, Jack E. Mccrae, Kevin J. Keefer, Steven T. Fiorino

Faculty Publications

Knowledge of turbulence distribution along an experimental path can help in effective turbulence compensation and mitigation. Although scintillometers are traditionally used to measure the strength of turbulence, they provide a path-integrated measurement and have limited operational ranges. A technique to profile turbulence using time-lapse imagery of a distant target from spatially separated cameras is presented here. The method uses the turbulence induced differential motion between pairs of point features on a target, sensed at a single camera and between cameras to extract turbulence distribution along the path. The method is successfully demonstrated on a 511 m almost horizontal path going …

Observation Of Gravitational Waves From Two Neutron Star–Black Hole Coalescences, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Karla E. Ramirez, W. H. Wang

Physics and Astronomy Faculty Publications and Presentations

We report the observation of gravitational waves from two compact binary coalescences in LIGO's and Virgo's third observing run with properties consistent with neutron star–black hole (NSBH) binaries. The two events are named GW200105_162426 and GW200115_042309, abbreviated as GW200105 and GW200115; the first was observed by LIGO Livingston and Virgo and the second by all three LIGO–Virgo detectors. The source of GW200105 has component masses and , whereas the source of GW200115 has component masses and (all measurements quoted at the 90% credible level). The probability that the secondary's mass is below the maximal mass of a neutron star is …

Direct Observation Of Chaotic Resonances In Optical Microcavities, Shuai Wang, Shuai Liu, Yilin Liu, Shumin Xiao, Zi Wang, Yubin Fan, Jiecai Han, Li Ge, Qinghai Song

Publications and Research

Optical microcavities play a significant role in the study of classical and quantum chaos. To date, most experimental explorations of their internal wave dynamics have focused on the properties of their inputs and outputs, without directly interrogating the dynamics and the associated mode patterns inside. As a result, this key information is rarely retrieved with certainty, which significantly restricts the verification and understanding of the actual chaotic motion. Here we demonstrate a simple and robust approach to directly and rapidly map the internal mode patterns in chaotic microcavities. By introducing a local index perturbation through a pump laser, we report …

Somatic Inhibition By Microscopic Magnetic Stimulation, Hui Ye

Biology: Faculty Publications and Other Works

Electric currents can produce quick, reversible control of neural activity. Externally applied electric currents have been used in inhibiting certain ganglion cells in clinical practices. Via electromagnetic induction, a miniature-sized magnetic coil could provide focal stimulation to the ganglion neurons. Here we report that high-frequency stimulation with the miniature coil could reversibly block ganglion cell activity in marine mollusk Aplysia californica, regardless the firing frequency of the neurons, or concentration of potassium ions around the ganglion neurons. Presence of the ganglion sheath has minimal impact on the inhibitory effects of the coil. The inhibitory effect was local to the …

Kapitza-Dirac Blockade: A Universal Tool For The Deterministic Preparation Of Non-Gaussian Oscillator States, Wayne Cheng-Wei Huang, Herman Batelaan, Markus Arndt

Department of Physics and Astronomy: Faculty Publications

Harmonic oscillators count among the most fundamental quantum systems with important applications in molecular physics, nanoparticle trapping, and quantum information processing. Their equidistant energy level spacing is often a desired feature, but at the same time a challenge if the goal is to deterministically populate specific eigenstates. Here, we show how interference in the transition amplitudes in a bichromatic laser field can suppress the sequential climbing of harmonic oscillator states (Kapitza-Dirac blockade) and achieve selective excitation of energy eigenstates, cat states, and other non-Gaussian states. This technique can transform the harmonic oscillator into a coherent two-level system or be used …

A Study Of Magnetism And Possible Mixed-State Superconductivity In Phosphorus-Doped Graphene, Julian E. Gil Pinzon

FIU Electronic Theses and Dissertations

Evidence of superconducting vortices, and consequently mixed-state superconductivity, has been observed in phosphorus-doped graphene at temperatures as high as 260 K. The evidence includes transport measurements in the form of resistance versus temperature curves, and magnetic measurements in the form of susceptibility and magnetic Nernst effect measurements. The drops in resistance, periodic steps in resistance, the appearance of Nernst peaks and hysteresis all point to phosphorus-doped graphene having a broad resistive region due to flux flow as well as a Berezinskii-Kosterlitz-Thouless (BKT) transition at lower temperatures.

The observation of irreversible behavior in phosphorus-doped graphene under the influence of a thermal …

Rotating Scatter Mask For Directional Radiation Detection And Imaging, Darren Holland, Robert Olesen, Larry Burggraf, Buckley O'Day, James E. Bevins

AFIT Patents

A radiation imaging system images a distributed source of radiation from an unknown direction by rotating a scatter mask around a central axis. The scatter mask has a pixelated outer surface of tangentially oriented, flat geometric surfaces that are spherically varying in radial dimension that corresponds to a discrete amount of attenuation. Rotation position of the scatter mask is tracked as a function of time. Radiation counts from gamma and/or neutron radiation are received from at least one radiation detector that is positioned at or near the central axis. A rotation-angle dependent detector response curve (DRC) is generated based on …

Lessons From The Classroom – Assessing The Work Of Postgraduate Students To Support Better Hygrothermal Risk Assessment, Joseph Little, Beñat Arregi, Christian Bludau

Conference papers

The widespread adoption of transient simulation modelling tools by building design professionals to support hygrothermal risk assessment of building design specifications is a crucial component in a multi-pronged drive to reduce moisture risk in buildings. Structured upskilling is essential. Much can be learnt about the ways practitioners use such tools by reviewing the work of professional postgraduate student groups. Such review could inform the creation of a user protocol. Peer-review under the responsibility of the organizing committee of the ICMB21.