Bulletin of the American Physical Society
77th Annual Meeting of the Southeastern Section of the APS
Volume 55, Number 10
Wednesday–Saturday, October 20–23, 2010; Baton Rouge, Louisiana
Session DA: Poster Session (16:30-18:00) |
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Room: Second Floor, Nicholson Hall |
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DA.00001: Synthesis and Field Skin Depth Studies on Tin Doped CeIn$_{3}$ Kristen Collar, Jason Cooley, Stan Tozer CeIn$_{3}$ is a cubic antiferromagnetic heavy fermion metal that orders with a N\'{e}el temperature of 10.1K at zero magnetic field. It requires fields up to 64T in order to see the N\'{e}el transition, however, low doping of tin has been shown to greatly reduce the N\'{e}el temperature into more accessible fields. The partial replacement of trivalent indium by tetravalent tin increases the number of conduction electrons and the nearly spherical Fermi surface occupies a larger fraction of the Brillouin zone. Small dopings will be critical in order to make the N\'{e}el transition more accessible given the magnets available at the National High Magnetic Field Laboratory (NHFML). The crystals will be characterized by calculating the Residual Resistance Ratios (RRR) using the resistivity option on the Physical Property Measurement System (PPMS) to determine the quality of the crystals. Skin depth measurements of the samples will be conducted by employing a Tunnel Diode Oscillator (TDO). The oscillations observed using the TDO will yield information about the Fermi surface and hopefully reveal information about the anomaly transition observed in the H-P phase diagram of CeIn$_{3}$ at t $\sim $400mK. [Preview Abstract] |
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DA.00002: Study of Effects of Scratch and Shadow Defects on Superconducting Niobium Thin films David Myers, Phillip Broussard Using niobium thin films approximately 47 nm thick made by magnetron sputtering, we attempted to produce a superconducting sample exhibiting Josephson junction behavior. We began by studying resistance vs. temperature plots of unpatterned niobium thin film samples without defects in order to characterize the films that our deposition techniques were producing. We then studied patterned samples that consisted of narrow bridges between 200 $\mu$m and 400 $\mu$m wide and between 3 mm and 5 mm long. We measured resistance vs. temperature and voltage vs. current traces on patterned samples both with and without defects and with and without an applied magnetic field. The defects were produced on some samples by lightly scratching the Si substrates before deposition, and on other samples by using a thin wire to shadow the substrate during deposition. We were able to produce multiple scratched samples that had voltage vs. current traces characterized by a voltage jump, and one sample that exhibited clear hysteresis below a reduced temperature (t=$T/T_{c}$) of 0.9. [Preview Abstract] |
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DA.00003: Electronic Transport Properties of Pd-substituted (Zr,Hf)NiSn Half Heusler Alloys Westly Nolting, Rumana Yaqub, Sanshrut Sapkota, Kevin Stokes ZrNiSn-based alloys which crystallize in the half-Heusler structure are currently being investigated as potential thermoelectric materials due to their relatively large Seebeck coefficient. Here, we present measurements of the electronic transport properties of Zr$_{0.5}$Hf$_{0.5}$Ni$_{1{\-}x}$Pd$_{x}$Sn$_{0.99}$Sb$_{0.01 }$semiconducting half-Heusler compounds with Pd concentrations range from x=0 to1. The compounds are synthesized by solid-state chemical reaction at 900\r{ }C. The compounds are densified into 10~mm pellets by uniaxial hot pressing. Measured electrical conductivity, thermoelectric power, and Hall coefficient data are analyzed to extract carrier concentration and carrier mobility. All compounds in the series are n-type. The magnitude of the Seebeck coefficient is found to decreases with increasing Pd concentration. The electrical conductivity and carrier mobility are found to be dependent on the materials processing conditions as well as the Pd concentration. [Preview Abstract] |
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DA.00004: Effects of the interior static polarization in photoionization of ``regular'' ($A$@C$_{60}$) and ``giant'' ($A$@C$_{240}$) endohedral atoms: A comparative study Takehiro Akiyama, Valeriy Dolmatov Recently, photoionization of an atom $A$ confined inside the C$_ {60}$ fullerene ($A$@C$_{60}$) has come under a novel theoretical scrutiny by accounting for static relaxation of the system in response to ionization of the atom $A$, termed the interior static polarization effect [1]. In the present work, we explore how the impact might get altered with increasing size of the fullerene cage. ``Regular'' C$_{60}$ and ``giant'' C$_{240}$ cages with the Ne atom sitting at the center of a cage, i.e., Ne@C$_{60}$ and Ne@C$_{240}$, are chosen for the study. Both carbon cages are regarded as conducting spheres. They are simulated by the corresponding potentials of given inner radii, depths, and thickness [2]. The impact's significance is found to be about the same in both systems. It strongly alters the photoionization of the encaged atom near threshold as well as changes phases of associated confinement resonances. However, the photoionization spectrum of the encaged atom differs much stronger from that of the free atom with increasing size of the cage. [1] V. K. Dolmatov and S. T. Manson, Phys. Rev. A (in print). [2] V. K. Dolmatov, Adv. Quant. Chem., \textbf{58}, 13 (2009). [Preview Abstract] |
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DA.00005: Molecular dynamics simulations on mid-linked polymer matrix Adam Dillon, Hye-Young Kim, Devesh Misra We utilize molecular dynamics simulations to probe the dependence of thermodynamic properties on the structure of polymer molecules. We study four different polymer materials: (1) Long chain polymers of $\sim $50 united atoms, (2) short chain polymers of $\sim $10 united atoms, (3) mixture of long and short chain polymers with varied mixing ratio, and (4) polymer matrix of Long chains cross-linked by short chains. Here the cross-linking sites are not at the end of the chain (end-linked) of which most previous studies were done, but in the middle of the chain (mid-linked). We will discuss the difference in thermodynamic properties, such as glass transition temperature, among these four structures. [Preview Abstract] |
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DA.00006: Patterned Polymer-Metal Ion Complexes Jonathan Hoffpauir, Naga Korivi, Pratul Ajmera The doping of polymers with metal ions has been of interest due to the possibility of tailoring their electrical, optical and mechanical properties. Such tailored polymers have potential applications in a variety of areas including flexible electronic devices and systems, optical systems such as those for holography, data storage, and mechanical systems. To extend the applications of metal doped polymers to novel micro-devices and systems, it is pertinent to develop methodologies to pattern or structure such polymers in small dimensions, often in the micro-scale. We report on the development of micro-patterned thin films of polyvinyl alcohol (PVA) doped with copper (Cu$^{2+})$ ions. The films were patterned in the micro-scale dimensions and larger by contact printing onto a substrate. Patterned Cu$^{2+}$ doped PVA films were also made by combining solution casting with micro-molding. Raman spectroscopic analysis of the developed Cu$^{2+}$ doped PVA films revealed the presence of PVA-Cu$^{2+}$ complexes. Further characterization of the Cu$^{2+}$ doped PVA films for electrical conductivity and x-ray diffraction is in progress and will be presented. The doping of PVA by other metal ions is also being explored and initial results will be presented. [Preview Abstract] |
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DA.00007: ABSTRACT WITHDRAWN |
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DA.00008: Magnetic bead microrheology in \textit{Drosophila} embryos Maria Paula Angarita In this project, we developed the materials and methods that will be used to investigate the germ band retraction and dorsal closure stages of development in fruit fly embryos (about seven to eleven hours after fertilization) using the microinjection of superparamagnetic beads. As a first step, we calibrate the electromagnet by tracking bead displacement with the magnetic field on and off and use the bead velocity to estimate the magnetic force applied to the beads. This gives us an approximation of the magnetic field gradient around the pole tip, which will contribute to the \textit{in vivo }calculations of the magnetic force exerted on the beads. We can thus extract the viscoelastic properties of the embryonic tissues during different stages of development by using Stokes' Law. [Preview Abstract] |
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DA.00009: Characterization of a Grazing-Incidence Dye laser R. Seth Smith The grazing-incidence dye laser remains a versatile device for generating tunable laser radiation for a variety of scientific applications. A homebuilt grazing incidence dye laser was constructed at Francis Marion University. This laser is pumped by the second harmonic output from a Continuum Surelite I YAG laser. A small percentage of the pump radiation is coupled into the dye laser. A cylinder lens brings this light to a tight focus on the laser dye. The resulting fluorescence is dispersed by a diffraction grating that is held at grazing-incidence. A portion of this light is reflected by a tuning mirror and is directed back into the active medium for amplification. The output wavelength is controlled by scanning the tuning mirror. The performance of this dye laser was analyzed. The results will be presented and discussed. [Preview Abstract] |
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DA.00010: Implementing the Landau-Pomeranchuk-Migdal (LPM) effect in a parton cascade Christopher Coleman-Smith Recent data from the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven have provided strong evidence for the existence of a transient Quark-Gluon-Plasma (QGP), where partons become freed from their non-perturbative confined states. Among these exciting findings is the suppression of particles with high transverse momentum (jet quenching). Parton Cascade Models (PCM [1]), which describe the full time-evolution of a system of quarks and gluons using pQCD interactions are ideally suited for the description of jet production, including the emission, evolution and energy-loss of the full parton shower in a hot and dense QCD medium. The Landau-Pomeranchuk-Migdal (LPM) effect, where quantum interference of parton wave functions due to repeated scatterings against the background medium, is likely the dominant mechanism for jet suppression. We have developed a probabilistic implementation within the PCM which can be validated against previously derived analytical calculations (BDMPS [2]), producing the expected length dependance of the lead parton energy loss. \\[4pt] [1] Geiger K and Muller B, Nucl Phys B369 (1992)\\[0pt] [2] Baier.R, et al, Nucl Phys B483 (1997) [Preview Abstract] |
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DA.00011: N-16 Capture to Differentiate Between Neutrinos and Antineutrinos in SK Ashley Jones Super-Kamiokande is a large water Cherenkov neutrino detector in Japan. Without a magnetic field, the difference between neutrinos and antineutrinos is not apparent. But when negative muons capture on oxygen nuclei, oxygen-16 becomes nitrogen-16, which beta decays. Looking for this beta decay after low energy events within detector samples can signify neutrino events. [Preview Abstract] |
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DA.00012: Water Cherenkov Simulation Tuning and Comparison Farzan Beroz This study compared SKdetsim and WCSim, two Monte Carlo simulations of Water Cherenkov detectors used mainly to investigate neutrino oscillation physics. SKdetsim is used for the Super-Kamiokande experiment while WCSim is for the Long Baseline Neutrino Experiment. Using the well-accepted SKdetsim as a standard, parameters of WCSim were adjusted to obtain a stronger agreement between the output of the two programs. Simulations of particles at high and low energies were then examined and compared to further understand the behavior of WCSim at extreme conditions. Although the outputs of the simulations were found to agree closely, additional parameters must be considered to allow for a finer tune. [Preview Abstract] |
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DA.00013: Analysis of the CDHSW Neutrino Oscillation Experiment Jocelyn Mandalou, David Ernst Analysis of the world's neutrino oscillation data in terms of a phenomenology that employs the three known neutrinos allows extraction of the five parameters that determine the model, three mixing angles and two mass-squared differences. However, two existing experiments, LSND and MiniBooNE do not fit within this model. These experiments lead to the suggestion that the addition of a fourth neutrino, called a sterile neutrino, might accommodate them. Two publications which use various approximations say that this suggestion does not work. The group with which I worked will do a full four neutrino analysis to further investigate this hypothesis. An additional experiment, CERN Dortmund Heidelberg Saclay Warsaw (CDHSW) will impact this investigation in the region of a larger mass-squared difference, the region where a fourth neutrino is expected to lie. I constructed a computational tool that analyzes the CDHSW experiment by calculating the probability for mu neutrinos to not oscillate in the CDHSW experiment. It was calibrated to reproduce the two-neutrino results given by the experimentalists and then will be generalized to four neutrinos. It will be used in the larger analysis which will include all of the world's data. [Preview Abstract] |
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DA.00014: Prospects for a Low Threshold Neutrino Experiment at the SNS Taritree Wongjirad A low-threshold neutrino scattering experiment at a high intensity stopped-pion neutrino source has the potential to measure coherent neutral current neutrino- nucleus elastic scattering. A promising prospect for the measurement of this process is a noble-liquid-based experiment at the Spallation Neutron Source: an example is the proposed CLEAR (Coherent Low Energy Nuclear Recoils) experiment. This poster will present the design of this experiment and its physics reach. [Preview Abstract] |
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DA.00015: Monte Carlo Simulations for Future Geoneutrino Detectors Morgan Askins The main contribution of heat in the earth's mantle is thought to be the radioactive decays of 238U, 232Th, and 40K. A precise measurement of the levels of 238U and 232Th can be determined by measuring the flux of electron anti-neutrinos (geoneutrinos) emitted from their decay chains. Although detectors such as kamLAND and Borexino have detected few geoneutrinos, a new cost effective geoneutrino detector is proposed which takes advantage of the total internal reflection within a long rectangular prism acrylic container of liquid scintillator having a single photomultiplier tube (PMT) on each end. An array of these containers would allow for a large scintillator volume relative to the number of PMTs, but could have a lower radio-purity. The event signatures of these decays were compared to those from neutrino interactions using Monte Carlo simulation software based upon GEANT4. In this poster I will discuss the limitations which arise from this design such as, the thickness of the acrylic container which causes high loss of optical photons due to scattering and absorption, rod length which results in higher scattering rates within the scintillator, and size of the array. [Preview Abstract] |
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DA.00016: Investigations of Data Quality in LIGO Data, Techniques Brooke Rankins The existing data quality (DQ) flag veto pipeline procedure used to categorize DQ flag channels and calculate their associated metric attributes relies heavily on MATLAB scripts. The scripts have been built upon each other ad-hoc as users have required new information, sometimes with limited documentation. We are restructuring the calculation process in an object-oriented language, Python, for two primary purposes. The first is to allow users to retrieve specific isolated information without having to run the entire pipeline. The second is to calculate additional summary statistics regarding DQ flag interaction, which may prove useful in evaluating the effectiveness of the categorization process. The nature of the Python vetopipeline code allows the addition of such new features with greater simplicity. The presentation will detail the framework of the Python vetopipeline, and introduce the DQ flag interaction statistics. [Preview Abstract] |
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DA.00017: Parallel Phase Modulation for Advanced LIGO Michael T. Hartman, Benjamin Wu, Volker Quetschke, Muzammil Arain, David Reitze, David Tanner, Guido Mueller LIGO is a ground based interferometer gravitational wave observatory which attempts to detect gravitational waves by measuring the length changes between its two arms. To operate the interferometer it is necessary to control several longitudinal and angular degrees of freedom of the interferometer. These signals are formed by phase modulation and demodulation of the laser field. Phase modulation introduces frequency sidebands to the carrier laser beam; LIGO requires multiple sidebands to disentangle all the longitudinal and angular signals. The modulation is usually applied by a series of modulators which also generate sidebands around sidebands. Current length and alignment sensing schemes don't require parallel phase modulation, however, if there needed to be a change in the sensing schemes, sidebands of sidebands could limit the performance of LIGO. This talk covers the results of an experiment whose goal is to avoid sidebands of sidebands by modulating the laser in parallel within two arms of a Mach-Zehnder interferometer. In this system, the Mach-Zehnder's arm lengths must be stabilized to meet Advanced LIGO requirements. I will report on the status of this risk reduction activity. [Preview Abstract] |
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DA.00018: Quantum Evolution of Scalar Fields in Spherically Symmetric Gravity Brajesh Gupt, Jorge Pullin We present progress of our first step towards theoretical and numerical study of the quantum evolution of mass(less) scalar field in gravity. We utilise the framework of loop quantum gravity and calculate the Classical Hamilton's equation of motion for scaler field $\phi$ and gravitational variables (connection variable $K_\varphi$ and triads $E^\varphi$), equations are then quantised through LQG approach. The scalar field evolves as a spherical wave when weakly coupled to flat space time. Numerical results are presented and its importance in study of quantum collapse is discussed. [Preview Abstract] |
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DA.00019: Varying-G Cosmology with Type Ia Supernovae Rutger Dungan, Harrison Prosper The observation that Type Ia supernovae (SNe Ia) are fainter than expected given their red shifts has led to the conclusion that the expansion of the universe is accelerating. The widely accepted hypothesis is that this acceleration is caused by a cosmological constant or, more generally, some dark energy field that pervades the universe. This hypothesis presents a challenge to physics so severe that one is motivated to explore alternative explanations. We explore whether the data from Type Ia supernovae can be explained with an idea that is almost as old as that of the cosmological constant, namely, that the strength of gravity varies on a cosmic timescale. [Preview Abstract] |
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DA.00020: LBNE Supernova Study: Distance Sensitivity for An Early Supernova Alert Wes Johnson The aim of this study is to compare the distance sensitivity to supernova burst events of various possible neutrino detector masses. We examine distance sensitivity at various background rates. [Preview Abstract] |
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DA.00021: ABSTRACT WITHDRAWN |
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DA.00022: Ideas on How to Improve the Inertial Navigation Systems Argenis Da Silva Inertial navigation systems (INS) present some difficulties. For example, the drifting. Part of the problem is the integration. The readings of the system give the acceleration, this acceleration must be integrated over some time interval to get the velocity. And the velocity must be integrated to get the position. This double integration introduces much of the errors. Here we present an idea to get the position using only one integration and we show how to use the acceleration as a measure of the errors. The scheme make it possible to extend the autonomy and accuracy of the INS beyond the today values. [Preview Abstract] |
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DA.00023: E = (f.d) + G Peter Schick Energy equals work plus gravity. In vacuum, work is attracted to gravity, which creates energy. Gravity and work are attracted to each other which create energy. [Preview Abstract] |
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DA.00024: POST-DEADLINE POSTERS |
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DA.00025: Entanglement-enhanced BB-84 Scheme for Quantum Key Distribution Carl Sabottke, Bhaskar Roy Bardhan, Chris Richardson We develop a novel enhancement to the traditional BB-84 scheme for quantum key distribution using entanglement To improve the security of the scheme and its resilience to the photon number splitting attack. The potential benefits and shortcomings of this scheme are then compared to the popular decoy states solution to the photon number splitting attack. [Preview Abstract] |
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DA.00026: The mass, energy, space and time systemic theory-MEST change the orbit of earth and dark comet to avoid their impaction each other Dayong Cao Things have their own system of mass, energy, space and time of themself. (The MEST for short there in after). The time is from the frequency of wave, the spac is from the amplitude square of wave. There is the transmutation (and interaction) between the space-time and mass-energy. There is the balance system between the space-time and mass-energy. Sun and its companion dark hole make up of MEST. Because there is the ``transmutation'' and the ``balance system'' between sun and its companion dark hole. So the ``pseudo'' dark mass-energy go into sun, control and ignite its nuclear fission-fusion (of sun of mass-energy); the ``pseudo'' light go into the dark hole, control and ignite its nuclear fission-fusion (of dark hole of space-time). The dark mass-energy make up of the negative proton and the negative neutron. And the dark atom of the dark comet make up of the dark photon, the dark neutrino and the dark muon. The companion dark hole will go near sun and take the dark comet to impact our earth. We need study their ``transmutation'' and their ``balance system,'' and need find a new energy both of the nuclear fission-fusion of sun and the ``nuclear fission-fusion'' of dark hole. We will use them to change the orbit of earth and dark comet, and will avoid the dark comet to impact our earth-a astronomic orbital engineering. Not only we need change the mass-energy to the space-time, but also we need change the space-time to the mass-energy. [Preview Abstract] |
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DA.00027: Nondestructive Analysis of Telescope Surfaces and Coatings Julie Scott, Edward Kintzel, Louis Strolger, Schuyler Wolff The Department of Physics and Astronomy at Western Kentucky University has a Large Chamber Scanning Electron Microscope (LCSEM) available for materials analysis. As one of 10 in the world, the capability exists for nondestructive analysis of large samples. Currently we are investigating using the LCSEM to quantify reflectivity and long-term integrity for large segments of optical elements and detectors for ground and space-based environments. Comparisons of reflectance ratios as a function of surface roughness for Al-Coated optical mirrors may be confirmed with the LCSEM. Long-term structural integrity of Al-coated thinned mirror segments at ground-based facilities due to weather (oxidation) and spaced-based high-radiation environments can be investigated. Fatigue behavior of these metallic films from active/adaptive actuation will be simulated using the LCSEM. New research possibilities across a broad multidisciplinary spectrum will be key to the success of the LCSEM facility. These partnerships will lead to the development of new and existing technologies. [Preview Abstract] |
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DA.00028: Development of a Portable Automated Gas Environment System (PAGES2) Jacob Baxley, Nathan Campbell, Edward Kintzel, Bruce Hill, Louis Santodonato, Kenneth Herwig For the user community at the Spallation Neutron Source (SNS), a portable automated gas environment system (PAGES2), capable of remote operation at pressures up to 100 bar has been built and programmed. The function of this system will be to characterize a variety of high surface area materials and allow studies of energy significant gases such as methane on these surfaces to be carried out. Understanding the fundamental physics of interaction at the gas-surface interface is key for the generation of application-minded products such as fuel cells. PAGES2 can generate adsorption isotherms to determine surface area of the material as well as the number of gas molecules required for a specific surface coverage. This system will not only produce new science, but also allow for better experimental design. PAGES2 system testing is currently underway, and initial results indicate the system is operating as designed. Future tests will be done prior to use at the SNS. [Preview Abstract] |
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DA.00029: High Performance Quantum Cascade Lasers Matthew Escarra, Peter Liu, Yu Yao, Richard Cendejas, Loan Le, Claire Gmachl Quantum cascade (QC) lasers have shown great promise for use in applications ranging from trace chemical detection to infrared countermeasures. Since light is generated through intersubband transitions in coupled quantum wells, as opposed to interband transitions that are restricted by available materials, QC lasers have an enormous amount of flexibility in their design space. This flexibility allows for lasing across the mid- infrared and even in the terahertz portions of the spectrum. We report on our recent work to improve the performance of these devices, by discussing the results of low voltage defect, strong coupling, and broad gain approaches to QC laser design. One of these laser designs will be put into context through discussion of our latest work to use QC lasers for detecting CO2 isotopic concentrations in the atmosphere. [Preview Abstract] |
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DA.00030: Investigation of multiplexed plasmonic structure metamaterials with equivalent transmission line model Boyang Zhang, Junpeng Guo, Stuart Yin We report our investigation of multiplexed structure metamaterials with the equivalent coupled transmission line model. In this metamaterials, two plasmon resonance elements are multiplexed in each unit cell of the periodic structures. Symmetrically multiplexed structures give increased spectral bandwidth and the non-symmetrically multiplexed structures give the band splitting property. By varying the gap size between the multiplexed elements, we find the plasmonic coupling affects the spectral property of the multiplexed structure metamaterials. We have developed a coupled transmission line model that can successfully model the multiplexed structure metamaterials when far-field coupling dominates, but the coupled transmission line model cannot describe the multiplexed plasmonic structures when the strong near-field coupling occurs. [Preview Abstract] |
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DA.00031: Nonlinear Cosmological Predictability Time Keith Andrew, John Wilson We examine time scales for phase space orbits in a FRW cosmological model coupled to a scalar field. The cosmological model from the Einstein field equations are coupled to the Klein-Gordon equation for a spin zero scalar field with an interaction potential V($\phi )$. The resulting cosmological equations are nonlinear in the scale cosmic parameter and scalar field. The equations can be linearized in the neighborhood of equilibrium points and then diagonalized to yield a classification of solutions. Some of the solutions exhibit a sensitive dependence on initial conditions and an exponential deviation or orbits in phase space. Such deviations can be characterized by a predictability time beyond which all information about the initial state of the system is lost. We calculate the predictability time in terms of the scalar field potential function for this system and compare it to the cosmic spacetime big rip time scale for a scalar field source term. [Preview Abstract] |
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