Session H01: Poster Session

Soft Robotic Prosthetics Utilizing Granular Materials

Many open-sourced prosthetics are relatively inexpensive but struggle to grip irregular objects. To solve this problem, we propose using a soft robotic universal gripper that utilizes the jamming transition of a granular material. Prior work with such universal grippers have successfully gripped irregular objects by controlling the jamming transition of a confined granular material using compressed air. However, the use of compressed air makes these devices relatively slow and cumbersome for a prosthetic. We propose to instead use iron filings confined in a flexible membrane for our granular material and then induce the jamming transition in our gripper electromagnetically instead of pneumatically. The iron filling can be made to transition from an unjammed state to a jammed state when a solenoid held behind the gripper is turned on or off. When the solenoid is off the gripper is pressed into the object to be gripped, and the loose fillings confined in the flexible membrane easily conform to the shape of the object. Then, the solenoid is turned on and the fillings jam and firmly grip the object. With this technique, we have successfully held and released several irregularly shaped objects providing a promising new avenue for open-source upper prosthetics.   

Single Mode Microwave Processing of Thermoelectric Materials

Thermoelectric materials are promising solid state energy conversion devices, whose energy conversion efficiency depends on the material's thermal and electrical conductivity, as described by the Figure of Merit. Previous work has indicated that the Figure of Merit can be affected favorably by microstructural refinement via a variety of methods. Single-mode microwave processing has the potential to dramatically impact microstructures, but little study has been done of the impact on thermoelectric efficiency. We initiate a study of the effect of 2.45 GHz single-mode microwaves on several thermoelectric materials, including half-Heusler and Zintl phases. We report the effects of electromagnetic field coupling on the composition and transport properties, as affected by the material's phase purity, compositional variation, grain size, and thermoelectric transport properties.   

Detection Of Natural Radiation In Soils Near The Mississippi River By $\gamma \gamma $-Coincidence Spectroscopy

Many external factors like climate, geography, wind and water currents have a great influence on the accumulation of naturally radioactive minerals around the world. Mostly present in soil, humans get exposed to natural radiation daily. This exposure only increases on lands classified as High Background Radiation Areas (HBRAs). Nile River, one of these HBRAs, has previously been investigated and confirmed for the presence of minerals rich in U and Th from Monazite minerals, with some locations having higher concentrations of radionuclides than accepted internationally.$^{[1]}$ One of the similarities between the Nile and the Mississippi River Delta includes that they are both undergoing erosion. The discussed work is an exploration of monazite in the Great River Road State Park, near the Mississippi River. The samples were measured with a low-background NaI(Tl) spectrometer and a digital data acquisition system. $\gamma \gamma $-Coincidence spectroscopy was used to reduce background; applying coincidence conditions of known gamma-ray energies from $^{238}$U and $^{232}$Th decay chains enabled us to identify the presence of natural radiation. These results indicate the presence of minerals containing $^{238}$U and $^{232}$Th near the river. $^{[1]}$ Mubarak, Fawzia, et al. Scientific Reports, vol. 7, no. 1, 2017.   

Monolayer FeSe deposited on SrTiO$_{3}$

Monolayer FeSe deposited on SrTiO$_{3}$ exhibits a superconducting T$_{C}$ of 40 -- 80 K compared to 8 K in bulk FeSe. We have investigated how the electronic structure of FeSe depends on changes in the atomic structure of the substrate. To do this, we used density function theory (DFT) to simulate the atomic structure of FeSe on top of STO. We see that oxygen vacancies and the alignment of Se above the substate both affect the interlayer distance. With the altering of the interlayer distance doping of the compound is also affected. We also found that Ti impurities placed on the double-TiO layer further affected the bond lengths between FeSe and the surface below. The exact atomic structure of the FeSe/SrTiO$_{3}$ interface is difficult to determine from experimental data alone, and furthermore the real interface will inevitably be imperfect. We account for both this uncertainty and the likelihood of defects by implementing a Wannier-orbital-based approach that allows us to project the electronic structure, isolate the effect of impurities, and generate structures with arbitrary impurity concentrations. The resulting unfolded band structures are comparable to experimental ARPES spectra and may provide insight into how to isolate and replicate this enhances superconductivity in other materials.   

Microstrip Patch Antenna

We present a microstrip based patch antenna design which is suitable for the high-band spectrum of 5G communications. The miniature size of this antenna makes it suitable to be integrated in various types of communication devices. We have chosen commonly available Fire Resistant 4 (FR4) epoxy board with relative permittivity of 4.4 and a thickness of 1.6mm as the di-electric material for this design. The antenna has been analyzed for its return loss, current distribution and radiation pattern. Reflection coefficient of the scattering matrix element S11 from our experimental design closely match the simulated values of S11 over a wide range of frequencies. This low-cost and compact design is ideal for mobile and other wireless communication applications.   

Physical Vapor Transport Growth and Characterization of Fe:Znse crystals

Recent progress in iron-doped II-VI chalcogenide laser materials enabled significant advancements in room temperature high-energy, high-power laser systems operating over 3.5-6.0 $\mu $m. Iron doped ZnSe/ZnS crystals are potential choice for lasers with direct access to the mid-wave infrared spectral range with promising energy scaling capability. One of the most common Fe:ZnSe gain elements fabrication method is based on chemical vapor transport growth of polycrystalline ZnSe followed by post-growth thermal diffusion of iron. Due to the relatively small coefficient of Fe$^{2+}$ ions diffusion in ZnSe (D$=$3.7x10$^{-10}$ cm$^{2}$/s at 950$^{0})$, this approach limits the fabrication of considerable size, homogenously doped Fe:ZnSe crystals. Here we report on a simple method of large size (12x50 mm) Fe:ZnSe elements fabrication in sealed vacuumed ampoules via physical transport growth from thin Fe:ZnSe workpieces prepared by post-growth thermal diffusion of Fe in ZnSe starting material. The growth process was optimized in terms of temperature gradient through the ampoule, annealing temperature, exposure time, and the crystal's optical loss. Fabricated iron doped and undoped ZnSe crystals were characterized by XRD and Raman spectroscopy.   

MnP nanorod films with desired magnetocaloric and thermoelectric properties for novel magnetic cooling device $\backslash $\textbf{f1}

h $-abstract-$\backslash $pard A novel magnetic cooling device (MCD) that comprises thermoelectric (TE) and magnetocaloric (MC) materials is proposed. A sandwiched structure has a MC material in the center and two TE materials at the outer parts. The presence of a TE material in the MCD guides the heat flow direction and enhances heat pulsation. In this case, the usage of a TE material that combines large thermopower (TP) with small MC responses within a similar temperature region enhances not only magnetic flux density but also heat exchange efficiency. In this study, we demonstrate that MnP thin films with integrated TE and MC functionalities are an potential candidate for the proposed MCD. The MnP films were grown on Si substrates at 300, 400 and 500\textdegree C, and both the MC and TE effects were investigated systematically. The results indicate 400 $^{o}$C sample has the optimal TC and MC responses. A large TC effect is observed in the temperature region 300 -- 450 K. The largest power factor of 41.46 $\mu $W m$^{-1}$ K$^{-2\, }$is achieved at T $=$ 400 K. Therefore, in this temperature region, the film shows a low MC effect but a strong magnetic response that gives rise to the enhanced TC effect. In addition, these properties would enable the MCD to operate at high frequency. $\backslash $pard-/abstract-$\backslash $\tex   

Surface pinning effect and emergent magnetic properties in bi-phase iron oxide nanorods

Over the years, iron oxide (Fe$_{3}$O$_{4})$ nanorods (NRs) have been investigated for advanced magnetic hyperthermia, and spintronics applications. Here we propose a unique approach in creating a novel class of bi-phase (BP) iron oxide NRs. We demonstrate the formation of Fe$_{3}$O$_{4}+\alpha $-Fe$_{2}$O$_{3\, }$BP$_{\, }$NRs through a controlled annealing process. Hydrothermally grown Fe$_{3}$O$_{4}$ NRs were annealed at 250$^{0}$C for different periods (1-9h) to form Fe$_{3}$O$_{4}+\alpha $-Fe$_{2}$O$_{3\, }$BP structures. Magnetometry measurements indicate the sharpening of the Verwey transition with the increment of the annealing duration, leading to the improved crystallinity of the Fe$_{3}$O$_{4\, }$phase. Compared to the as-synthesized, the annealed NRs have a reduced saturation magnetization ($M_{S})$ owing to reduced volume fraction of Fe$_{3}$O$_{4\, }$and concomitant formation of the antiferromagnetic $\alpha $-Fe$_{2}$O$_{3}$ phase. With 5h of annealing a sharp drop in magnetization is observed due to Morin transition around 260K associated to $\alpha $-Fe$_{2}$O$_{3\, }$phase. The presence of canted/disordered spins at the phase boundary between the Fe$_{3}$O$_{4}$ and $\alpha $-Fe$_{2}$O$_{3}$ phases can be observed as the NRs are cooled down in 1T field from room temperature. With these observations the Fe$_{3}$O$_{4}+\alpha $-Fe$_{2}$O$_{3\, }$BP NRs would be an excellent model system for probing interfacial nanomagnetism.   

Epsilon-Near-Zero Metamaterial Geometry for Nonlinear Optical Generation

Epsilon-near-zero (ENZ) thin films show promise in generating nonlinear optical phenomena, such as second and third harmonic generation, phase conjugation, and negative refraction, due to their ability to densely confine incident light energy in a thin film structure. However, ENZ materials on their own suffer from high coefficients of reflection. One method devised to increase coupling of incident light energy into ENZ thin films is the inclusion of metallic nanophotonic structures, allowing incident light to excite the localized surface plasmon polaritons (LSPP) of the metals and be more efficiently coupled into the ENZ thin film. In this work, we simulated four ENZ thin films, seven nanophotonic geometries, and three metals in Ansys Lumerical's FDTD to find an optimal combination of elements for maximizing energy density in the ENZ thin films. We found that optimal combinations resulted in surface energy density magnification of more than 300x the incident light energy density. This poses ENZ metamaterials as strong candidates for improving many fields of photonics, including solar cell technology and all-optical signal processing.   

"Chronos is not absolute"

In my research paper, I have disproved sir Issac newtons Theory on time is absolute, He said Time only moves in one direction but I say Time moves in different directions it can move in 2 directions or more than 2 directions, In my paper, I have tried to explain this thing with an example for better understanding.   

Building a Manipulatable Sputter Coating System as a Means to Controlling Sn Whiskers

As technology advances the need to lessen Sn Whisker growth has become vital. With modern guidelines about Pb in electronics short-circuiting due to spontaneous whisker growth is a concern. The growth of whiskers is believed to come from internal stress in Sn films. Our main goal is to study the growth of Sn Whiskers to understand the stress within the Sn and how whisker growth may be reduced or guided. To study Sn whisker growth, we seek to build an internal Sn whisker sample production facility. A key component to this facility is to alter an existing sputter coater to meet the requirements to sputter thin layers of Sn onto samples for study. It is necessary to be able to adjust the voltage within the vacuum chamber to ionize Ar at lower pressures and to decrease the pressure within the vacuum chamber to less than 10 mTorr and a pressure gauge to measure the pressure. We have included a voltage adjuster, improved the cooling within the sputter coater, gained new pumps, and an apparatus to attach a pressure gauge. With these changes, we will produce Sn Whisker samples and study the effects of varying pressures. Through studying whisker samples, we will be able to understand their growth, reduce short-circuiting due to whiskers, and develop new technologies using whisker growth.   

Characterizing the efficacy of methods to subtract terrestrial transient noise near gravitational wave events and the effects on parameter estimation

Gravitational wave signals received by the Laser Interferometer Gravitational Wave Observatory (LIGO) from binary black hole coalescences can overlap in time with non-gaussian transient instrumental noise, also known as a glitch. Glitches introduce errors in the analysis of a signal since the parameters of the astrophysical system (mass, spin, location, etc.) are inferred by comparing gravitational waveforms with the data. By adding known simulated signals into data containing glitches from both the LIGO Livingston and Hanford detectors, we study how different classes of glitches affect parameter estimation. In extension, we use BayesWave (software that models a glitch and a signal as a separate sum of wavelets) to explore how one of our most promising methods of glitch-subtraction improves the analysis.   

Characterizing the rapid optical variability of blazars with TESS

Blazars are extreme examples of the Active Galactic Nuclei (AGN) phenomeno.The blazar class of radio loud AGN are those oriented such that we are looking nearly down the throat of the relativistic jet, resulting in the observed emission being dominated by processes at work in the jet and being both amplified and time-compressed in our frame. The defining characteristics of blazars are a featureless or nearly featureless optical continuum, large amplitude and highly variable polarization, and large amplitude continuum variability at all wavelengths and on timescales ranging from minutes to decades. The dearth, and in some cases complete absence, of discrete features in their spectra leaves us with only continuum variability and/or polarization variability as a diagnostic of the emission mechanisms at work in many of these objects. In this presentation, I show the results of the analysis of precise, time resolved photometry by the NASA Transiting Exoplanet Survey Satellite of 84 blazars, with the primary goal of determining the optical variability characteristics of blazars on the most rapid timescales that can be sampled. I will discuss the selection of the objects, the process I developed and used to of create light curves (plot of brightness vs time) from the TESS observations, our preliminary conclusions concerning blazar variability on rapid timescales and future directions for this project.   

Recalibrating the NJL Model to Neutron Star Observations

Dense quark matter in neutron stars is often described by the Nambu---Jona-Lasinio (NJL) model. The NJL model parameters are often determined by ensuring that the vacuum properties of the model (e.g. the mass of the pion) match with experiments. In this work, we re-envision the NJL model as a purely phenomenological model designed to describe quark matter at high densities. We calibrate the model with neutron star observations, rather than the properties of matter in a vacuum. This allows us to explore a large range of possible descriptions of dense quark matter, while still retaining the underlying symmetries of quantum chromodynamics (QCD). We construct a Gibbs phase transition between the NJL model and a Skyrme model for the equation of state of nucleons. Additionally, we describe the set of NJL parameters that lead to neutron star mass-radius curves that match recent gravitational wave and photon-based neutron star observations.   

Will the black hole still collapse?

The density of black holes is so huge that light cannot escape. Does nature have "matter" that is denser than black holes? exist! The black hole will also collapse and become a denser "matter" than the black hole. My theory of calculating the density of black holes at the 2021 spring meeting of the American Physical Society believed that the linear velocity at the edge of the black hole is the speed of light. If the black hole collapses again, the density will inevitably be greater, and its linear speed of rotation will inevitably exceed the speed of light. This "matter" is even darker than the black hole, and may be the dark matter that scientists are looking for. This theory provides new ideas for the exploration of the origin of the universe, because the observational facts now believe that the beginning of the universe was faster than light.   

Not Participating

Type Ia Supernovae (SNe Ia) are important tools as cosmological distance scales, and are laboratories for the study of physical processes like radiation transport and hydrodynamical instabilities. Thought to be the thermodynamic explosion of a degenerate white dwarf star, their use as standaradizable candles have led to important discoveries like the accelerating expansion of the universe. The spectrum of SNe Ia give information on characteristics like the chemical make-up of the expanding layers, and while early time spectra have been extensively modeled for the past 30+ years, it is only within the last decade that later nebular phases have been taken under serious consideration as modern telescopes are able to probe this regime. A particular characteristic that is relatively uncertain is the ionization structure of the elements throughout the envelope, which is important in calculating relative line strengths of the spectra. With a new, fast code focused on the transitional and nebular phases of SNe IA, we calculate the spectra and ionization stages for various ignition scenarios across multiple times, and we show how the ultraviolet flux plays an important role on the line strengths via incomplete Rosseland cycling and the ionization balance through stimulated recombination.   

Electron Ionization of the W Atom

Electron-impact ionization cross sections are calculated for the ground configuration of the W atom. Time-dependent close-coupling cross sections for the direct ionization of the 5d and 6s subshells leading to single ionization are calculated with and without a polarization potential. Configuration-average distorted-wave cross sections for the direct ionization of the 5d and 6s subshells leading to single ionization are also calculated with and without a polarization potential.   

Dielectronic Recombination in Pb+78

Semi-relativistic perturbation theory calculations are carried out for dielectronic recombination cross sections involving the 1s2 2s 2p nl subshells of Pb+77 as found above the 1s2 2s2 ionization threshold of Pb+78. We included levels in the 1s2 2s 2p nl subshells of Pb+77 for n = 7-20 and l = 0-4. Theoretical dielectronic recombination cross sections are compared with experimental dielectronic recombination rate coefficients for the 1s2 2s 2p 19l subshells of Pb+77.   

High temperature refractive index determination from polarization-dependent reflectance spectra

Determining the temperature dependence of the refractive index of a material is critical in the design of technologies like high temperature electronics, photovoltaics, and other self-heating devices. Conventional refractive index measurement techniques, such as ellipsometry, become very challenging in the case of ultra high temperatures. Theoretical options like material models work in some cases but are not universally accurate. We propose a method of analysis of polarization-dependent reflection measurements as an experimentally feasible option at higher temperatures. Our method utilizes Fresnel analysis and the transfer matrix method to extract refractive index information from same-angle s and p polarization measurements. It works by numerically generating a series of solutions to the relevant system of equations. Due to the transcendental nature of these functions, this process generates many extraneous solutions, which we then filter to extract a single, continuous data set for both the real and imaginary components of the refractive index. We test this method on calculated reflectance spectra for a variety of materials and sample thicknesses. Over each tested material and thickness, our model accurately recovered the refractive index information used to generate the data set, motivating further testing of this model with experimental data as a method for determining refractive index information at ultra-high temperatures.   

Charge-Exchange Factor in EBIT Spectral Analysis

The intensity analysis of the spectra of highly charged ions in electron beam ion traps (EBIT) requires accurate experimental or theoretical ionization, excitation, and recombination cross sections and device parameters, like electron beam density and energy, and trapped ion temperatures. Because of the generally high charge state of the trapped ions, charge exchange recombination with residual gases requires sophisticated analysis to correctly account for. By introducing the charge exchange factor, the constraint of accurate charge exchange cross section and device conditions are replaced by the determination of a single parameter, which is a combination of all these factors. If accurately determined experimentally, the charge exchange factor allows for accurate prediction of relative spectral line intensity ratios, determination of ionization or recombination cross sections, or device parameters. As an example, X-ray spectra of highly charged ions of Fe produced in the EBIT at National Institute of Standards and Technology with the beam energy varying between 9.21 keV and 18.00keV will be presented. Spectra were recorded by an array of transition-edge sensor (TES) x-ray microcalorimeters. The analysis of the measured spectra was performed via detailed collisional-radiative modeling of the non-Maxwellian plasma. [1] P. Szypryt et al., Rev. Sci. Instrum. 90, 123107 (2019). [2] Yu. Ralchenko and Y. Maron, J. Quant. Spectr. Rad. Transf. 71, 609 (2001).   

Spectral Signature of Molecular Charge Migration

Attosecond laser technology has opened the way to study ultrafast charge-transfer processes at their natural time scale and at the molecular level. Interpreting these processes is a challenge due to i) correlation in excited electronic states, ii) the loss of electronic coherence caused by entanglement with nuclear degrees of freedom within the same molecule as well as with other molecules in the matrix, and iii) the non-perturbative character of light-matter interaction. Here employ a new ab initio method to simulate the evolution of N-Methlyacetamide under the action of arbitrarily polarized non-ionizing light pulses, in the presence of decoherence. The electronic states are obtained from MCSCF calculations while the effects of the driving pulses and decoherence are taken into account by solving the time-dependent Lindblad equation for the molecular electronic density matrix. We reconstruct the susceptibility from the dipolar response of the molecule, which is experimentally observable, and use Becke’s charge-partitioning algorithm to predict the migration of charge associated to each spectroscopic signal.   

Cellular Responses to Patterned Laser Wounding

An increase in cytosolic calcium is a ubiquitous cellular response to wounding. Experimentally these wounds are produced via pulsed-laser ablation. One limitation to this approach is the creation of cavitation bubbles which damage the plasma membranes of surviving cells along the wound margin. The inability to minimize this damage interferes with attempts to isolate non-mechanical mechanisms behind the calcium signal observed post wounding. In this project, patterned ablation is explored as a method to minimize the creation of cavitation bubbles in pulsed-laser ablation wounding assays. Preliminary results suggest variations in cellular responses to patterned wounding when compared to previously employed single shot wounding methods. Promisingly, a lack of cell fusions around the wound margin implies the method may successfully minimize the plasma membrane damage inflicted on surviving cells by cavitation bubbles.   

Interactions of APOA and EMI

The APOA proteins role in lipid metabolism is crucial, as it contributes to the high-density lipoprotein (HDL) particles that circulate in the blood to transport fat from tissues to the liver. The conformation of the APOA protein is important in its functioning within the HDL particles. Interactions with solutes or molecules can influence the hydrogen bonding of the protein, which can alter its conformational structure and tertiary shape. These interactions can potentially increase stability but also potentially denature the protein. Our goal is to study this protein and understand how it interacts with the EMI ions. We will determine the interactions of the APOA protein with different concentrations of the ions and water by running molecular dynamic simulations using GROMACS. We hope to understand if the ion can potentially stabilize the APOA protein, making it more effective in the body.   

Brownian motion of passive particles in a bath of E. coli bacteria.

With aim to understand the dynamics of passive colloids surrounded for active particles. Here, we study the Brownian movement of latex particles in a bath of E. coli bacteria. Vials were mixed with latex particles, luria broth and E Coli. Some of the vials were treated with an antibiotic to see how mutations to the antibiotic altered movement of the bacteria. The single particle tracking method, based on observations of the trajectories of individual particles, is compared Brownian simulation and theoretical results that characterize the motions of a large collection of particles. Determination of diffusion coefficients and viscosity from correlation of positions of the particles is discussed.   

Schrodinger's Equation and Symmetric Proximity Effect Film Sandwiches

This study sought to use Schr\"odigner's equation to model superconducting proximity effect systems of symmetric forms. As N. R. Werthamer noted, [Phys. Rev. \textbf{132} (6), 2441 (1963)] one to one analogies between the standard superconducting proximity effect equation and the one-dimensional, time-independent Schr\"odinger's equation can be made, thus allowing one to model the behavior of proximity effect systems of metallic film sandwiches by solving Schr\"odinger's equation. In this project, film systems were modeled by infinite square wells with simple potentials. Schr\"odinger's equation was solved for sandwiches of the form $S(NS)_M$ and $N(SN)_M$, where $S$ and $N$ represent superconducting and nonsuperconducting metal films, respectively, and $M$ is the number of repeated bilayers, or the period. A comparison of Neumann and Dirichlet boundary conditions was done in order to explore their effects. The Dirichlet type produced eigenvalues for $S(NS)_M$ and $N(SN)_M$ sandwiches that converged for increasing $M$, but the Neumann type produced eigenvalues for the same structures that approached two different limits as $M$ increased. Although unexpected, this implies a dependence upon the type of film end layer.   

GPU-accelerated Search for Novel Optically Active Defects in Diamond and Silicon Carbide for Quantum Sensing Applications

The nitrogen-vacancy center in diamond (NV-) is the most researched color center in the field of quantum sensing. However, with hundreds of potential color centers, optically active defects may be found that demonstrate improvements in operation range or technological application as compared to the NV- site. Research into quantum sensors has explored various chemical element groups, but there is still considerable room for exploration and development. To help address this, we initiated a search for new defects in diamond and silicon carbide to determine their potential for quantum sensing application. Defect properties are calculated using density functional theory within a supercell framework with GPU-acceleration. We examined titanium, chromium, and yttrium defects in diamond, and titanium in silicon carbide. Defects are characterized with respect to formation energy, defect energy levels, and zero-phonon line (ZPL). We evaluate the sensing potential with regard to potential to form and optical accessibility.   

First-Principles Modeling of Mechanical Properties for High-Entropy Alloys under Extreme Pressure

High-entropy alloys (HEAs) formed by five or more principal components have raised significant interests due to their superior mechanical properties and thermal stabilities for extreme-environment applications. Here, we utilize density functional theory (DFT) combined with special quasi-random structure (SQS) to study the mechanical properties of five-metal refractory HEAs in body-centered cubic (bcc) structures. We compute the volume and elastic moduli versus external pressure up to 300 GPa, and our DFT calculations with different size of SQS supercells show that the results can converge quickly with a few tens of atoms. We also study the strain-stress relations along different high-symmetry directions, which provide information for the ideal strengths of materials under consideration. Our results indicate the combined approaches of DFT and SQS are powerful methods for modeling mechanical properties of substitutionally random alloys under extreme conditions.   

Magneto-optical reflectance studies of a quasi-one-dimensional topological insulator $\alpha-Bi_4I_4$

$\alpha-Bi_4I_4$, a small-bandgap, quasi-one-dimensional topological insulator, was predicted to host a rare high-order-topological order and helical hinge states. Recent high-resolution ARPES measurements found that the quasi-1D Dirac-like surface state on the (100) surface opens a gap of $\approx$ 35 meV within the bulk bandgap, consistent with the theoretic predictions. Here we report high-magnetic-field optical reflectance measurements of the (100) surfaces in the Voigt geometry ($B//E//(100)$) at liquid helium temperatures. The reflectance referenced to the zero-field data exhibits multiple prominent inter-band transitions both in the far-infrared and mid-infrared range, with constant, linear, quadratic, or non-monotonic dependences on the magnetic field. This allows the identification of Landau level dispersions and inverted band gaps. The observation of the two lowest energy band transitions at 14.2 meV and 16.4 meV may be related to the topological surface states.   

Effect of chemical substitution on valence state transition in EuPd2Si2

EuPd$_{2}$Si$_{2}$~undergoes a~valence state transition of Eu$^{3+}\to $Eu$^{2+}$~near T$_{v}$~$=$ 142 K~in the~temperature-dependent~DC~field magnetization measurements.~In addition, the DC M-vs-T measurements show a minor shift of $\approx $1 K in the T$_{v}$~with 6 T applied field.~Furthermore, temperature-dependent powder and single-crystal XRD measurements showed that EuPd$_{2}$Si$_{2}$~has an anisotropic thermal expansion across T$_{v}$.~To explore the effect of chemical substitution on valence state transition, doping at Pd site and Si site has been done. All the doped samples crystallize in the same tetragonal I4/mmm structure while the transition temperature moved significantly with the minimal doping of 5-10 {\%}. The T$_{v}$ moves to the lower temperature side with Ge doping at Si site while it moves toward higher side with Ni doping at Pd site which is confirmed via detailed DC magnetization measurements. Similar to the pristine sample, all the doped samples exhibit anisotropic~thermal expansion across T$_{v}$.   

Structure and Conductivity of Ionic Liquids

With the ever-growing importance of battery power, finding more efficient means of creating batteries is essential and our solution to this is through ionic liquids. Due to the fact that experimentation is very time consuming, we sought to create phase diagrams in order to speed up this process. With the assistance of the SCGLE (Self Consistent Generalized Langevin Equation) theory, we are able to create phase diagrams that can act as maps for these ionic liquids. After conducting our research, we tested the validity of the SCGLE program along with concluding that the area of mixed state within these ionic liquids is the phase in which electricity can be conducted and at increased temperatures conduction is no longer possible. In future research, we would like to explore the capability of calculating conductivity for these ionic liquids, using the SCGLE framework.   

Visualizing dispersion curves for spin waves in ferromagnetic thin films

Spin waves are the propagating disturbances of magnetic moments in ferromagnetic materials. Spin waves can be used to transfer information without the joule heating associated with moving charges. Information can be encoded in the amplitude, frequency, or phase of the spin waves. The propagation of spin waves is governed by material parameters and can be calculated with dispersion relations. In this work, a graphics user interface (GUI) was developed for calculating and displaying dispersion relations for spin waves in ferromagnetic thin films. The GUI produces plots from calculations that are based on dipole-dipole and exchange interactions of spins. A python platform was used to develop the GUI and offers users a series of input parameters such as applied external field, saturation magnetization, film thickness, and material damping parameter. The GUI provides users with a more efficient way of calculating and visualizing dispersion relations by reducing the time and need to build individual scripts.   

Growth of superconducting YB$_{6\, }$thin films for the study of proximity effect in the topological Kondo insulator SmB$_{6}$

Proximity-induced superconductivity in topological insulators has been predicted to exhibit various novel phenomena including Majorana zero modes [1]. Our goal is to study this proximity effect using bilayer thin films consisting of the topological Kondo insulator samarium hexaboride (SmB$_{6})$ and superconducting yttrium hexaboride (YB$_{6})$ due to their excellent lattice match. The superconducting properties of YB$_{6\, }$ have been reported to be strongly dependent on the stoichiometry with the maximum T$_{c\, }$(\textasciitilde 7.5 K [2] and 6.1 K [3] in single crystal and thin film forms, respectively) observed in boron deficient YB$_{6}$. We have grown YB$_{6\, }$thin films by co-sputtering YB$_{6\, }$and Y targets in an ultrahigh-vacuum-compatible chamber. Towards achieving the highest T$_{c}$ (\textasciitilde 5.7 K currently), various growth parameters are explored/optimized including the sputter power, substrate temperature, and post-deposition annealing. Their composition and microstructure are characterized by energy-dispersive X-ray spectroscopy, ellipsometry, and atomic force microscopy. The superconducting properties are investigated using resistivity, magnetization, and tunneling spectroscopic measurements. [1] L. Fu {\&} C. L. Kane, Phys. Rev. Lett. \textbf{100}, 096407 (2008). [2] N. Sluchanko \textit{et al}., Phys. Rev. B. \textbf{96}, 144501 (2017). [3] S. Lee \textit{et al}., \textit{Nature}~\textbf{570,~}344--348 (2019).   

Analysis of Stoichiometry and Valence in LaVO3 Thin Films

LaVO3 (LVO) has been proposed as a promising material for photovoltaics because its strongly correlated 3d electrons can facilitate creation of multiple electron-hole pairs per incoming photon, which would lead to increased device efficiency. Our group grows thin films of LVO on SrTiO3 substrates using pulsed laser deposition. We can control the electronic properties and stoichiometry of the films by adjusting laser fluence during growth [1]. A quantitative analysis of multiple samples was done using x-ray photoemission spectroscopy (XPS) to deduce the relative concentrations of Vanadium and Lanthanum. An XPS machine was used to measure the binding energies of these elements, with Carbon 1s (284.6eV) measurements being used to reference any charging on the surface of the material. Resulting peak areas were then used to determine the stoichiometry and measure the valence states. [1] B. Zhang et al. , Phys. Rev. Mater., 5, 085006 (2021).   

Handling Spectrosopic Calculations in Aperiodic Systems

This work is intended to report on a workflow for handling calculations of aperiodic systems with particular focus on calculations of spectroscopy and to demonstrate a sample application of its usage. The workflow is intended to be integrated into the Corvus workflow machinery - a Python-based package designed to automate complex simulations requiring multiple scientific software packages.The workflow has been then applied to the calculation of Ti K-edge X-ray absorption spectra of SrTi\textsubscript{1-x}Sn\textsubscript{x}O\textsubscript{3}, in tandem with FEFF9 ab initio code for calculating x-ray and related spectra. Calculated results compare well to experimental results from a recent study, and allow for an interpretation of doping related differences in terms of structure and chemistry. As the workflow and the Corvus machinery are general in nature, the approach can be applied to calculations in a wide variety of systems and phenomena, e.g., glasses, defects, liquids, or vibrational effects.   

Realization of Supersymmetry and Its Spontaneous Breaking in Quantum Hall Edges

Supersymmetry (SUSY) relating bosons and fermions plays an important role in unifying different fundamental interactions in particle physics. Since no superpartners of elementary particles have been observed, SUSY, if present, must be broken at low-energy. This makes it important to understand how SUSY is realized and broken, and study their consequences. We show that an $\mathcal{N}=(1,0)$ SUSY, arguably the simplest type, can be realized at the edge of the Moore-Read quantum Hall state. Depending on the absence or presence of edge reconstruction, both SUSY-preserving and SUSY broken phases can be realized in the same system, allowing for their unified description. The significance of the gapless fermionic Goldstino mode in the SUSY broken phase is discussed.   

Point Cloud Based Machine Learning for Event Classification and Track Identification of Nuclear Reactions

PointNet++, a deep neural network architecture for three-dimensional point cloud data, was used for classification tasks of time-projection chamber data of nuclear reactions at the National Superconducting Cyclotron Laboratory at Michigan State University. This chamber, known as the Active-Target Time Projection Chamber (AT-TPC), functions as both target and detector for nuclear reactions. We used simulated data from the $^{22}$Mg + $^4$He experiment [1] and the upcoming $^{10}$Be + $^4$He experiments in the AT-TPC to train our models. Event classification models achieved an accuracy and F1 score of .96 in both experiments, which is comparable to the performance achieved by Convolutional Neural Networks with significantly less data processing. Track identification tasks achieved an accuracy of .96 and an F1 score of 0.94 for the selection of alpha particles in the $^{22}$Mg + $^4$He experiment.   

Examining the $E_x$=7262 and 7249 keV States of Fluorine-19 with the $^{15}$N($\alpha, \gamma$)$^{19}$F Reaction

Properties of important neon-19 levels affect the production of the radioisotope fluorine-18 in novae and can be constrained from studies of the mirror nucleus fluorine-19. The $^{15}$N($\alpha, \gamma$)$^{19}$F reaction has been used to study the astrophysically important but under-examined region of $^{19}$F between $E_x$=7.0-7.3 MeV ($E_\alpha$=3.9-4.2 MeV). A previously known $^{19}$F state at $E_x$=7.262 MeV was studied and a new higher spin state was discovered near 7.249 MeV. Measured information for these states include branching ratios and resonance strengths from which the gamma decay widths were extracted. Preliminary results will be presented.   

Probing $^{11}$B for a hypothesized resonance via neutron transfer reaction

Recent results from the pAT-TPC at TRIUMF showed direct observation of the rare beta-minus delayed proton emission from $^{11}$Be. A discrepancy in the theoretical branching ratio differed from the experimental value obtained, which prompted their proposition of a previously unknown excited state of the $^{11}$B nucleus. Motivated by the potential observation of a previously unobserved resonance in $^{11}$B at 11.425 MeV, we are presenting our data of two transfer reactions and our preliminary analysis of the predicted excited state. A Tandem accelerator and the Super-Enge Split-Pole Spectrograph at Florida State University were used to conduct the experiment on $^{10}$B and $^{11}$B targets. Neutron transfer reactions of $^{10}$B(d,p)$^{11}$B and $^{11}$B(d,p)$^{12}$B populated excited states of $^{11}$B and $^{12}$B. Focal plane detectors were used to measure the positions of proton ejectiles from the reactions at scattering angles of 10 to 50 degrees at five-degree increments. Angular distributions for observed states are constructed.   

Microscopic Descriptions of 12C+α for the Oxygen-16 States in the Stellar Alpha-Capture Rate Evaluation

We report the first calculations of low-lying excited $0^+$ states in $^{16}$O and their rotational bands within a no-core shell-model framework. Such descriptions pose a challenge because of the cluster and collective nature of these states but become feasible in the no-core symplectic shell model (NCSpM). The model utilizes the almost perfect symmetry of nuclear dynamics that preserves equilibrium shapes. It uses an inter-nucleon interaction deduced in the symplectic effective field theory with only four parameters. The NCSpM yields the low-lying positive-parity energy spectrum of $^{16}$O and other observables in reasonable agreement with experiment. We use the NCSpM wave functions of $^{16}$O to project onto $^{12}$C+$\alpha$ cluster wave functions to calculate alpha partial widths and asymptotic normalization coefficients. Our results are in good agreement with available experimental data and point to the importance of collectivity to reproduce the data. These results are crucial to further improving the evaluation of the $^{12}$C$(\alpha, \gamma)^{16}$O reaction rate at astrophysical temperatures. This rate is of cosmological importance and may further inform studies of the masses of black holes that pulse pair instability supernovae produce.   

Foundation of b-tagging applied to long-lived particles

The study refers to the identification of b-jets observed by the ATLAS experiment at the Large Hadron Collider. It aims for the detection of signals due to long-lived particles from Higgs boson decays predicted by various theories beyond the standard model. The applications of this study could potentially extrapolate the b-tagging performance used on tt-bar to ZH events, allowing for uncertainties for the ZH events to be analyzed. The tt-bar events are simulations of top-anti-top quark pairs that decay into b-quarks, ideal for training algorithms. However, ZH events model the production of b quarks through the decay of Higgs-like, long-lived particles. The methods used were to apply the same techniques of b-tagging on ZH and reweighting to account for differences in kinematic dependencies. However, the ZH event has decays more displaced from the beam interaction point than the tt-bar events. To functionally make the efficiencies the same, cuts were applied to only include entries of b-hadron decay paths that are collinear with the path of the long-lived particles. In this way, the study concludes that the algorithms are not optimized for b-jets that originate far from the beam interaction point and algorithms need improvement for future studies.   

Camera Tests for IceCube Upgrade

The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector embedded into the ice of the South Pole. The detector consists of a 3D array of photomultiplier tubes (PMTs) grouped in spherical glass spheres called Digital Optical Modules (DOMs). The detector is designed to detect Cherenkov radiation emitted in neutrino interactions in ice. The charge, spatial and temporal distribution of the Cherenkov radiation is used to measure the energy and direction of the incident neutrino. Antarctic ice is ideal for measurements of this nature because the scattering length of light is much longer in pure ice than other mediums. A low energy extension of the detector consisting of 7 additional strings is planned in the near future. The upgrade will also include a better calibrated system in order to understand the optical properties of the ice and how the detector interacts with the ice. Cameras are an integral part of the new calibration system. This project explores the behavior of a camera system developed by the IceCube collaboration and characterizes the dark noise introduced in the setup. A further study with illuminated sources is in progress.   

Designing Data Read Out Electronics for the CHANDLER Neutrino Detector

CHANDLER is a reactor neutrino detector technology with applications in nuclear security, nuclear instrumentation, and basic science. In 2017, a prototype named MiniCHANDLER was deployed at North Anna Nuclear Generating Station where it demonstrated the detection of reactor antineutrinos. The CHANDLER collaboration has been working on improvements including the readout electronics. The old electronics were not able to effectively measure higher energy neutron-proton recoils, as there was cross-talk between neighboring channels, and high-energy pulses would lead to a large oscillation of the baseline. The new electronics consist of a custom all-in-one base that will digitize and process the PMT signals with improved dynamic range, no cross-talk, and provide the high voltage. This all-in-one base is based on a field programmable gate array (FPGA), which allows coding capabilities that were not present in the previous electronics. To improve the trigger algorithm, a new running baseline code was designed that takes an average of previous ADC counts and accounts for baseline fluctuations. Having this new baseline potentially allows for a more precise online separation of neutrons and gammas in the FPGA. Once these electronics are fully assembled testing will take place.   

NaI detector characterization for coherent elastic neutrino-nucleus scattering (CEvNS)

Coherent elastic neutrino-nucleus scattering (CEvNS) is the process of a low-energy neutrino elastically scattering off a nucleus that subsequently recoils as a whole unit. The suite of detector targets ranging in neutron number (N) as part of the COHERENT experimental program includes a ton-scale array of NaI[Tl] crystals to measure CEvNS on sodium with the smallest N. Comparing CEvNS as a function of N to the Standard Model predictions will constrain new physics models. CEvNS is an irreducible background for direct dark matter measurements. The CEvNS scattering is expected to be the dominant mechanism in neutrino transport within supernovae and neutron stars, directly impacting model calculations. The 7.7 kg NaI[TI] crystals are repurposed detector modules that must be characterized for quality and suitability for the measurement of low-energy signals. The characterization procedure uses known gamma-ray sources and background lines for testing the crystal quality, analyzing gain response, determining energy resolution, and comparing the crystal response in different regions along its length. An initial 5 modules of 63 crystals each will be deployed to ``Neutrino Alley'' located at the Oak Ridge National Laboratory Spallation Neutron Source experimental site.   

Update on the Ruby Phosphorescence Senior Lab: Cr$^{\, 3+\, \, 2}$E Lifetime and $^{4}$T Absorption Studies.

Our lab previously reported that many existing advanced laboratory experiences associated with the metastable $^{2}$E term of Cr$^{\, 3+}$ in ruby, which gives rise to the R-lines at 692.7 and 694.3 nm, focus on a room-temperature measurement of the radiative lifetime of the $^{2}$E term. We have since published [1] techniques for students to make a consistent Cr$^{\, 3+\, \, 2}$E lifetime measurement without systematic errors associated with the Cr concentration of the ruby samples. Our result for the room-temperature radiative-lifetime for the $^{2}$E term is 3.3 \textpm 0.1 ms [1]. This type of senior lab exercise typically uses commercially available ruby spheres for which the manufacturer(s) only state an approximately 2{\%} Cr concentration. The uncertainty in Cr concentrations in commercially available ruby spheres has motivated our lab to begin a detailed study of the Cr$^{\, 3+\, \, 4}$T absorption bands near 410nm and 544nm, respectively, using commonly available advanced-physics lab equipment. We provide a status report on this aspect of our work to enhance this senior-level laboratory activity. [1] Z. Jones, J. Hinds, S. Woznichak, {\&} A. Calamai, J. of Undergrad. Rept. in Phys. \textbf{30}, 100004 (2020), \textit{and references therein}   

Development of an Advanced Laboratory in Physics at Francis Marion University

An Advanced Laboratory in Physics (Phys410) was established at Francis Marion University. It is a 1-credit laboratory that meets once per week and lasts for three hours. It is required for physics majors and is normally taken in the junior or senior year. One of the principal goals of this laboratory is to expose physics majors to some of the important pieces of equipment that are used in experimental physics. Currently the lab focusses on five experiments, each of which lasts for two weeks. The experiments are the Digital Oscilloscope, the Michelson Interferometer, Diode Laser Spectroscopy, the Lock-In Amplifier, and the Fourier Spectrum Analyzer. Training on each of these instruments was provided to the instructor by the Advanced Laboratory Physics Association (ALPHA). ALPHA offers a series of Immersions in the summer months, in which faculty can be ``immersed'' in an advanced undergraduate physics experiment for approximately three days. The goal is to provide each faculty member with enough training to implement these experiments at his/her college or university. Immersion participants may apply for grant support.   

Vanishing Heat Conduction Through Two Qubits by Strong and Continuous Environmental Measurement

Given a system of two qubits coupled to two thermal baths with a temperature differential, it is well known from classical thermodynamics that heat will flow from the environment of higher temperature to the environment of lower temperature. Corresponding to classical predictions, numerical simulations have demonstrated that the rate of heat flow depends on the coupling strength between the system consisting of the two qubits and the two thermal environments. However, as the coupling strength is further increased, the rate of heat flow will rise to a maximum and then vanish in the steady state. This phenomenon is explained by strong, continuous measurement of the system by the environment, which leads to environment-induced decoherence. Applying Zurek's einselection, the decoherence will project the Gibb's state onto the pointer basis in the high coupling regime. Using numerical simulations of the hierarchical equations of motion (HEOM) and analytical theory, we reproduce these previous results and extend them by confirming that they are valid for multiple symmetric and asymmetric coupling configurations.   

Design and construction of a Modular NaI(Tl) Detector Array for use in the Parity and Time Reversal Violation Measurements for NOPTREX

The goal of the NOPTREX collaboration is to probe the Standard Model by utilizing the properties of low energy neutron-nucleus resonances to find evidence of parity- and time-reversal-odd violations. In order to conduct these sensitive experiments, it is needed to design and simulate an array of modular, high precision NaI(Tl) detectors. These detectors will be designed to operate in both pulse and current modes. We have tentative beam time at LANSCE to perform a search for new parity violation in heavy nuclei as candidates for time reversal and to perform a research and development effort on the n+d=t+gamma experiment. We will discuss the results of our experiments to determine the most efficient design of the detectors, electronics, and magnetic shielding, as well as our progress on the construction and characterization of the array.   

Vacuum studies in the BL2 neutron lifetime experiment

The neutron lifetime is a quantity that is important for the Standard Model of Particle Physics as well as Big Bang Nucleosynthesis calculations. The BL2 Experiment looks to measure the lifetime of a free neutron using the beam method, which aims to count the amount neutrons that have decayed. The data taken includes protons being captured by an electrode trap from the decayed neutrons, as well as neutrons that pass through the trap by a neutron flux monitor. The pressure inside the experiment is monitored continuously by pressure gauges on the apparatus, and fluctuations could affect the behavior of the trapped protons. The pressure data will be presented and plans for future analyses discussed.   

An Overview of Chern-Simons Theory

In recent years, Chern-Simons gauge theory has become a subject of interest to a large number of physicists due to the desire to understand the physics of nonabelian anyons in certain condensed matter systems. We present here a survey of the most relevant results for understanding braiding statistics (closely related to Wilson loop observables) and the computation of partition functions. What is novel in our presentation is the use of concrete/explicit formulas; we explain how fundamental yet quite abstract properties of topological field theory (namely, the mapping class group representations that are naturally furnished by the Hilbert space--in this case coming from a projective flat connection on a certain vector bundle over the moduli space of algebraic curves) may be understood using known properties of hypergeometric functions and theta functions that may be found in the usual textbooks on special functions. Our hope is that by making the mathematical statements sufficiently concrete, the principles underlying these results can be understood by a broader community of physicists.   

Optical Indistinguishability via Twinning Fields

Here we introduce the concept of the twinning field -- a driving electromagnetic pulse that induces an identical optical response from two distinct materials. We show that for a large class of pairs of generic many-body systems, a twinning field which renders the systems \emph{optically indistinguishable} exists. The conditions under which this field exists are derived, and this analysis is supplemented by numerical calculations of twinning fields for both the 1D Fermi-Hubbard model, and tight-binding models of graphene and hexagonal Boron Nitride. The existence of twinning fields may lead to new research directions in non-linear optics, materials science, and quantum technologies.