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Full-Text Articles in Physical Sciences and Mathematics

Analysis Of Drift Effects On The Tokamak Power Scrape-Off Width Using Solps-Iter, E. T. Meier, R. J. Goldston, E. G. Kaveeva, M. A. Makowski, Saskia Mordijck, V. A. Rozhansky, I. Yu Senichenkov, S. P. Voskoboynikov Dec 2016

Analysis Of Drift Effects On The Tokamak Power Scrape-Off Width Using Solps-Iter, E. T. Meier, R. J. Goldston, E. G. Kaveeva, M. A. Makowski, Saskia Mordijck, V. A. Rozhansky, I. Yu Senichenkov, S. P. Voskoboynikov

Arts & Sciences Articles

SOLPS-ITER, a comprehensive 2D scrape-off layer modeling package, is used to examine the physical mechanisms that set the scrape-off width (lambda(q)) for inter-ELM power exhaust. Guided by Goldston's heuristic drift (HD) model, which shows remarkable quantitative agreement with experimental data, this research examines drift effects on lambda(q) in a DIII-D H-mode magnetic equilibrium. As a numerical expedient, a low target recycling coefficient of 0.9 is used in the simulations, resulting in outer target plasma that is sheath limited instead of conduction limited as in the experiment. Scrape-off layer (SOL) particle diffusivity (D-SOL) is scanned from 1 to 0.1 m(2) s(-1). …


Ac Zeeman Force With Ultracold Atoms, Charles Fancher Nov 2016

Ac Zeeman Force With Ultracold Atoms, Charles Fancher

Dissertations, Theses, and Masters Projects

Ultracold atom experiments use a gas of neutral atoms with temperatures less than 100 µK above absolute zero and offer unmatched experimental control of quantum states and coherence, which has allowed ultracold atom-based measurements to be some of the most precise to date. While ultracold atom experiments can control almost all atomic degrees of freedom, spin-dependent trapping and spatial manipulation has remained difficult if not inaccessible. We are developing a method of spin-dependent trapping and spatial manipulation for ultracold neutral atoms using the AC Zeeman force produced by a microwave magnetic near-field gradient generated by an atom chip. We measure …


An Improved Measurement Of The Muon Neutrino Charged Current Quasi-Elastic Cross-Section On Hydrocarbon At Minerva, Dun Zhang Nov 2016

An Improved Measurement Of The Muon Neutrino Charged Current Quasi-Elastic Cross-Section On Hydrocarbon At Minerva, Dun Zhang

Dissertations, Theses, and Masters Projects

Neutrino interactions in the detectors of long baseline oscillation experiments are analyzed to determine the neutrino flavor and energy spectrum, allowing the neutrino mass ordering and mixing parameters to be determined. For neutrino interactions below the pion production threshold, the dominant reaction is charged current quasi-elastic (CCQE) scattering. Oscillation experiments are made of heavy nuclei so the QE process occurs on nucleons that are embedded in the nuclear environment. Predictions of the QE cross-section suffer from significant uncertainties due to our understanding of that nuclear environment and the way it is probed by the weak interaction. I have developed a …


Electron Neutrino Appearance In The Nova Experiment, Ji Liu Nov 2016

Electron Neutrino Appearance In The Nova Experiment, Ji Liu

Dissertations, Theses, and Masters Projects

The NuMI off-Axis $\nu_e$ Appearance (NO$\nu$A) experiment is a long baseline, off-axis neutrino oscillation experiment. It is designed to search for oscillations of $\nu_\mu$ to $\nu_e$ by comparing measurements of the NuMI beam composition in two detectors. These two detectors are functionally identical, nearly fully-active liquid-scintillator tracking calorimeters and located at two points along the beam line to observe the neutrinos. The Near Detector (ND), situated \unit[1]{km} away from the proton target at Fermilab, measures neutrinos prior to oscillation. Then the Far Detector (FD), located 810 km away at Ash River, Minnesota, measures the neutrinos after they have traveled and …


Evaluation Of The Potential Impact On Flow And Sediment Transport From Proposed James River Crossings, Yinglong J. Zhang, Harry V. Wang, Zhuo Liu, Mac Sisson, Jian Shen Oct 2016

Evaluation Of The Potential Impact On Flow And Sediment Transport From Proposed James River Crossings, Yinglong J. Zhang, Harry V. Wang, Zhuo Liu, Mac Sisson, Jian Shen

Reports

The purpose of this study is to evaluate the potential impact on flow and sedimentation potential due to the proposed new crossings on the lower James River by VDOT. This project was built upon previous effort in the same area (Boon et al. 1999); the latter used VIMS’ 3D Hydrodynamic-Sedimentation Model (HYSED) to study the impact of the bridge-tunnel infrastructure on the physical characteristics (including tides, currents, circulation, salinity and sedimentation) under the existing and alternative scenarios. Due to various limitations at that time, smaller bridge pilings were not resolved but instead parameterized. In this update study, we used an …


Study Of Variations Of The Dynamics Of The Metal-Insulator Transition Of Thin Films Of Vanadium Dioxide With An Ultra-Fast Laser, Elizabeth Lee Radue Oct 2016

Study Of Variations Of The Dynamics Of The Metal-Insulator Transition Of Thin Films Of Vanadium Dioxide With An Ultra-Fast Laser, Elizabeth Lee Radue

Dissertations, Theses, and Masters Projects

Vanadium dioxide is an intensely studied material, since it goes through an insulator-metal transition at a critical temperature just above room temperature at 340~K. The dramatic change in conductivity and the easily accessible transition temperature makes it an attractive material for novel technologies. Thin films of VO2 have a reversible transition without any significant degradation in contrast, and depending on the microstructure of the films, the properties of the transition are tunable. In this work, I study the dynamics of the insulator-transition in thin films grown on different substrates using a pump-probe configuration. The energy needed to trigger the transition, …


Applications Of High Energy Theory To Superconductivity And Cosmic Inflation, Zhen Wang Oct 2016

Applications Of High Energy Theory To Superconductivity And Cosmic Inflation, Zhen Wang

Dissertations, Theses, and Masters Projects

This dissertation examines applications of methods of high-energy theory to other physical systems: unconventional superconductors on the one hand, and cosmology on the other. Extra-dimensional models of superconductors, motivated by gauge/gravity duality in string theory, have proven remarkably successful in reproducing qualitative, and sometimes quantitative, aspects of unconventional superconductors. We analyze the universality of some of these predictions, and discover a universal relation between certain superconducting observables. The second part of this dissertation is about cosmic inflation. The evolution of the universe is sensitive to the fundamental particles and their interactions. We investigate models of cosmic inflation which involve the …


A Measurement Of The Parity-Violating Asymmetry In Aluminum And Its Contribution To A Measurement Of The Proton's Weak Charge, Joshua Allen Magee Oct 2016

A Measurement Of The Parity-Violating Asymmetry In Aluminum And Its Contribution To A Measurement Of The Proton's Weak Charge, Joshua Allen Magee

Dissertations, Theses, and Masters Projects

The Qweak experiment, which ran at the Thomas Je↵erson National Accelerator Facility, made a precision measurement of the proton’s weak charge, Q_p^W . The weak charge is extracted via a measurement of the parity-violating asymmetry in elastic electron-proton scattering from hydrogen at low momentum transfer (Q^2=0.025 GeV^2). This result is directly related to the electroweak mixing angle, sin2 (theta_W ), a fundamental parameter in the Standard Model of particle physics. This provides a precision test sensitive to new, as yet unknown, fundamental physics. This dissertation focuses on two central corrections to the Qweak measurement: the target window contribution and sub-percent …


Solving Problems Of The Standard Model Through Scale Invariance, Dark Matter, Inflation And Flavor Symmetry, Raymundo Alberto Ramos Oct 2016

Solving Problems Of The Standard Model Through Scale Invariance, Dark Matter, Inflation And Flavor Symmetry, Raymundo Alberto Ramos

Dissertations, Theses, and Masters Projects

Through beyond standard model formulations we are able to suggest solutions to some of the current shortcomings of the standard model. In this thesis we focus in particular on inflation, the hierarchy of fermion masses, scale invariant extensions and dark matter candidates. First we present a model of hybrid natural inflation based on the discrete group S_3, the smallest non-Abelian group. The S_3 potential has an accidental symmetry whose breaking results in a pseudo-Goldstone boson with the appropriate potential for a slow-rolling inflaton. The hybrid adjective comes from the fact that inflation is ended by additional scalar fields interacting with …


Compton Scattering Polarimetry For The Determination Of The Proton’S Weak Charge Through Measurements Of The Parity-Violating Asymmetry Of 1h(E,E')P, Juan Carlos Cornejo Oct 2016

Compton Scattering Polarimetry For The Determination Of The Proton’S Weak Charge Through Measurements Of The Parity-Violating Asymmetry Of 1h(E,E')P, Juan Carlos Cornejo

Dissertations, Theses, and Masters Projects

The Standard Model has been a theory with the greatest success in describing the fundamental interactions of particles. as of the writing of this dissertation, the Standard Model has not been shown to make a false prediction. However, the limitations of the Standard Model have long been suspected by its lack of a description of gravity, nor dark matter. its largest challenge to date, has been the observation of neutrino oscillations, and the implication that they may not be massless, as required by the Standard Model. The growing consensus is that the Standard Model is simply a lower energy effective …


Neutrino Flux Prediction For The Numi Beamline, Leonidas Aliaga Soplin Oct 2016

Neutrino Flux Prediction For The Numi Beamline, Leonidas Aliaga Soplin

Dissertations, Theses, and Masters Projects

The determination of the neutrino flux in any conventional neutrino beam presents a challenge for the current and future short and long baseline neutrino experiments. The uncertainties associated with the production and attenuation of the hadrons in the beamline materials along with those associated with the beam optics have a big effect in the flux spectrum knowledge. For experiments like MINERvA, understanding the flux is crucial since it enters directly into every neutrino-nucleus cross-section measurements. The foundation of this work is predicting the neutrino flux at MINERvA using dedicated measurements of hadron production in hadron-nucleus collisions and incorporating in-situ MINERvA …


Turbulent Particle Transport In H-Mode Plasmas On Diii-D, Xin Wang Oct 2016

Turbulent Particle Transport In H-Mode Plasmas On Diii-D, Xin Wang

Dissertations, Theses, and Masters Projects

Particle transport is an important topic in plasma physics. It determines the density profile of a burning plasma within a tokamak – a magnetic confinement device. Microscopic turbulent particle transport is two orders of magnitude larger than other transport mechanisms for electrons and small ions. In order to confine a plasma in a tokamak with a core density that exceeds the fusion criteria, it is essential to study turbulent particle transport. This thesis investigates how different plasma parameters such as the toroidal rotation and microscopic instabilities affect turbulent particle transport in the DIII-D tokamak. First, we show how toroidal rotation …


Investigating Proton Spin Structure: A Measurement Of G_2^P At Low Q^2, Melissa Ann Cummings Oct 2016

Investigating Proton Spin Structure: A Measurement Of G_2^P At Low Q^2, Melissa Ann Cummings

Dissertations, Theses, and Masters Projects

The $g_2^p$ collaboration performed the first measurement of the reaction $\vec{p}(\vec{e},e')X$ in the kinematic range 0.02 $ < $ Q$^2$ $ < $ 0.2 GeV$^2$ in the resonance region. Experiment E08-027 took place in Hall A at the Thomas Jefferson National Accelerator Facility from March-May of 2012. Data was taken with a longitudinally polarized electron beam, using an NH$_3$ target polarized in both parallel and perpendicular configurations. Very preliminary results for $g_1^p$ and $g_2^p$ are shown in this thesis. to extract the spin structure functions, asymmetries are calculated from data taken with a 2.2 GeV electron beam and a 5 T target field, and combined with the Bosted model proton cross section. Preliminary dilution factors and preliminary radiative corrections are included in the asymmetry analysis. Sum rules and $\chi$PT allow us to test the Burkhardtt-Cottingham (BC) sum rule and obtain the spin polarizability quantities $\gamma_0$ and $\delta_{LT}$. The BC sum rule, valid for all values of $Q^2$, says that the integral of $g_2$ over all Bjorken $x$ vanishes. The very preliminary result presented here shows the contribution to the integral from the measured kinematic region. Although the contribution from the resonance region is not consistent with the expected result of zero, an extrapolation to high and low $x$ must be included to test whether the BC sum rule is satisfied. The difficulty in $\chi$PT calculations of $\gamma_0$ and $\delta_{LT}$ is how to include the resonance contributions, particularly the $\Delta$-resonance, which dominates. Recent developments have found better agreement with neutron experimental results, however this is little proton data to compare with the calculations, particularly at low $Q^2$. The very preliminary results shown here do not show agreement with any of the current $\chi$PT predictions. However, as this is only the contribution from the measured kinematic region, it is necessary to include the extrapolation outside the resonance region to draw a stronger conclusion. Further analysis is ongoing, and preliminary results, including a cross section extracted from data instead of a model prediction, are expected within the next year.


Study Of Spatial Structure Of Squeezed Vacuum Field, Mi Zhang Sep 2016

Study Of Spatial Structure Of Squeezed Vacuum Field, Mi Zhang

Dissertations, Theses, and Masters Projects

Squeezed states of light, with field fluctuations smaller than the coherent state fluctuations (or shot noise), are used for improving accuracy of quantum-noise limited measurements, like the detection of gravitational waves. They are also essential resources for quantum information transfer protocols. We studied a squeezed vacuum field generated in hot Rb vapor via the polarization self-rotation effect. We studied the mode structure of the squeezed field by spatially-masking the laser beam after its interaction with the Rb atomic vapor. From analysis of the data we developed a multi-mode theory to simulate the mode composition of the squeezed vacuum field. Our …


Thin Film Approaches To The Srf Cavity Problem: Fabrication And Characterization Of Superconducting Thin Films, Douglas Beringer Sep 2016

Thin Film Approaches To The Srf Cavity Problem: Fabrication And Characterization Of Superconducting Thin Films, Douglas Beringer

Dissertations, Theses, and Masters Projects

Superconducting Radio Frequency (SRF) cavities are responsible for the acceleration of charged particles to relativistic velocities in most modern linear accelerators, such as those employed at high-energy research facilities like Thomas Jefferson National Laboratory’s CEBAF and the LHC at CERN. Recognizing SRF as primarily a surface phenomenon enables the possibility of applying thin films to the interior surface of SRF cavities, opening a formidable tool chest of opportunities by combining and designing materials that offer greater benefit. Thus, while improvements in radio frequency cavity design and refinements in cavity processing techniques have improved accelerator performance and efficiency – 1.5 GHz …


Enhanced Superconductivity In Aluminum-Based Hyperbolic Metamaterials, Vera N. Smolyaninova, Christopher Jensen, William Zimmerman, (...), M. M. Qazilbash, Et Al. Sep 2016

Enhanced Superconductivity In Aluminum-Based Hyperbolic Metamaterials, Vera N. Smolyaninova, Christopher Jensen, William Zimmerman, (...), M. M. Qazilbash, Et Al.

Arts & Sciences Articles

One of the most important goals of condensed matter physics is materials by design, i.e. the ability to reliably predict and design materials with a set of desired properties. A striking example is the deterministic enhancement of the superconducting properties of materials. Recent experiments have demonstrated that the metamaterial approach is capable of achieving this goal, such as tripling the critical temperature T-C in Al-Al2O3 epsilon near zero (ENZ) core-shell metamaterial superconductors. Here, we demonstrate that an Al/Al2O3 hyperbolic metamaterial geometry is capable of a similar T-C enhancement, while having superior transport and magnetic properties compared to the core-shell metamaterial …


Role Of Electron-Electron Interactions In The Charge Dynamics Of Rare-Earth-Doped Cafe2as2, Zhen Xing, T. J. Huffman, Peng Xu, (...), M. M. Qazilbash, Et Al. Aug 2016

Role Of Electron-Electron Interactions In The Charge Dynamics Of Rare-Earth-Doped Cafe2as2, Zhen Xing, T. J. Huffman, Peng Xu, (...), M. M. Qazilbash, Et Al.

Arts & Sciences Articles

We have investigated the charge dynamics and the nature of many-body interactions in La- and Pr-doped CaFe2As2. From the infrared part of the optical conductivity, we discover that the scattering rate of mobile carriers above 200 K exhibits saturation at the Mott-Ioffe-Regel limit of metallic transport. However, the dc resistivity continues to increase with temperature above 200 K due to the loss of Drude spectral weight. The loss of Drude spectral weight with increasing temperature is seen in a wide temperature range in the uncollapsed tetragonal phase, and this spectral weight is recovered at energy scales about one order of …


Line Parameters Including Temperature Dependences Of Air- And Self-Broadened Line Shapes Of (Co2)-C-12-O-16: 2.06-Mu M Region, D. Chris Benner, V. Malathy Devi, Keeyoon Sung, Linda R. Brown, Et Al. Aug 2016

Line Parameters Including Temperature Dependences Of Air- And Self-Broadened Line Shapes Of (Co2)-C-12-O-16: 2.06-Mu M Region, D. Chris Benner, V. Malathy Devi, Keeyoon Sung, Linda R. Brown, Et Al.

Arts & Sciences Articles

This study reports the results from analyzing a number of high resolution, high signal-to-noise ratio (S/N) spectra in the 2.06-μm spectral region for pure CO2 and mixtures of CO2 in dry air. A multispectrum nonlinear least squares curve fitting technique has been used to retrieve the various spectral line parameters. The dataset includes 27 spectra: ten pure CO2, two 99% 13C-enriched CO2 and fifteen spectra of mixtures of 12C-enriched CO2 in dry air. The spectra were recorded at various gas sample temperatures between 170 and 297 K. The absorption path lengths range from 0.347 to 49 m. The sample pressures …


Controlling Excited-State Contamination In Nucleon Matrix Elements, Boram Yoon, Rajan Gupta, (...), Kostas Orginos, Et Al. Jun 2016

Controlling Excited-State Contamination In Nucleon Matrix Elements, Boram Yoon, Rajan Gupta, (...), Kostas Orginos, Et Al.

Arts & Sciences Articles

We present a detailed analysis of methods to reduce statistical errors and excited-state contamination in the calculation of matrix elements of quark bilinear operators in nucleon states. All the calculations were done on a 2 + 1-flavor ensemble with lattices of size 32(3) x 64 generated using the rational hybrid Monte Carlo algorithm at a = 0.081 fm and with M-pi = 312 MeV. The statistical precision of the data is improved using the all-mode-averaging method. We compare two methods for reducing excited-state contamination: a variational analysis and a 2-state fit to data at multiple values of the source-sink separation …


Turbulent Particle Transport As A Function Of Toroidal Rotation In Diii-D H-Mode Plasmas, X. Wang, Saskia Mordijck, L. Zeng, L. Schmitz, Et Al. Apr 2016

Turbulent Particle Transport As A Function Of Toroidal Rotation In Diii-D H-Mode Plasmas, X. Wang, Saskia Mordijck, L. Zeng, L. Schmitz, Et Al.

Arts & Sciences Articles

In this paper we show how changes in toroidal rotation, by controlling the injected torque, affect particle transport and confinement. The toroidal rotation is altered using the co- and counter neutral beam injection (NBI) in low collisionality H-mode plasmas on DIII-D (Luxon 2002 Nucl. Fusion 42 614) with dominant electron cyclotron heating (ECH). We find that there is no correlation between the toroidal rotation shear and the inverse density gradient, which is observed on AUG when T-e/T-i is varied using ECH (Angioni et al 2011 Phys. Rev. Lett. 107 215003). In DIII-D, we find that in a discharge with balanced …


Resolution Limits Of Time-Of-Flight Mass Spectrometry With Pulsed Source, Guangzhi Qu Apr 2016

Resolution Limits Of Time-Of-Flight Mass Spectrometry With Pulsed Source, Guangzhi Qu

Dissertations, Theses, and Masters Projects

Matrix Assisted Laser Desorption/Ionization (MALDI) is a time-of-flight mass spectrometry commonly used to detect a wide mass range of biomarkers. However, MALDI requires a high laser pulse energy to create ions with a mass higher than 50,000 Daltons. That high laser energy increases the net ion production but it also degrades the instrument's mass resolution. This project uses a Room Temperature Ionization Liquid (RTIL) as a liquid matrix with a self healing surface instead of a standard crystal matrix to increase shot to shot reproducibility, enabling a systematic study of the origin of the resolution degradation. This study shows that …


A Sonic Net Excludes Birds From An Airfield: Implications For Reducing Bird Strike And Crop Losses, John P. Swaddle, Dana L. Moseley, Mark H. Hinders, Elizabeth P. Smith Mar 2016

A Sonic Net Excludes Birds From An Airfield: Implications For Reducing Bird Strike And Crop Losses, John P. Swaddle, Dana L. Moseley, Mark H. Hinders, Elizabeth P. Smith

Arts & Sciences Articles

Collisions between birds and aircraft cause billions of dollars of damages annually to civil, commercial, and military aviation. Yet technology to reduce bird strike is not generally effective, especially over longer time periods. Previous information from our lab indicated that filling an area with acoustic noise, which masks important communication channels for birds, can displace European Starlings (Sturnus vulgaris) from food sources. Here we deployed a spatially controlled noise (termed a “sonic net”), designed to overlap with the frequency range of bird vocalizations, at an airfield. By conducting point counts, we monitored the presence of birds for four …


Unitary Limit Of Two-Nucleon Interactions In Strong Magnetic Fields, William Detmold, Kostas Orginos, Assumpta Parreño, Martin J. Savage, Et Al. Mar 2016

Unitary Limit Of Two-Nucleon Interactions In Strong Magnetic Fields, William Detmold, Kostas Orginos, Assumpta Parreño, Martin J. Savage, Et Al.

Arts & Sciences Articles

Two-nucleon systems are shown to exhibit large scattering lengths in strong magnetic fields at unphysical quark masses, and the trends toward the physical values indicate that such features may exist in nature. Lattice QCD calculations of the energies of one and two nucleons systems are performed at pion masses of mπ∼450 and 806 MeV in uniform, time-independent magnetic fields of strength |B|∼1019–1020  G to determine the response of these hadronic systems to large magnetic fields. Fields of this strength may exist inside magnetars and in peripheral relativistic heavy ion collisions, and the unitary behavior at large scattering lengths may have …


Disorder Effects In Dirac Heterostructures, Martin Alexander Rodriguez-Vega Jan 2016

Disorder Effects In Dirac Heterostructures, Martin Alexander Rodriguez-Vega

Dissertations, Theses, and Masters Projects

In this dissertation, we study theoretically heterostructures based on Dirac mate- rials, i.e. materials, such as graphene in which the electrons behave as massless Dirac fermions at low energies. We first examine how the presence of long-range disorder affects the electronic ground state of a double layer graphene heterostruc- ture formed by two graphene layers separated by a thin dielectric film. We then identify the necessary conditions for the formation of an interlayer exciton conden- sate in such a system. We also comment on the effect of long-range disorder on the broken symmetry ground state induced by electron-electron interactions in …


A Precision Measurement Of The Weak Charge Of Proton At Low Q^2: Kinematics And Tracking, Siyuan Yang Jan 2016

A Precision Measurement Of The Weak Charge Of Proton At Low Q^2: Kinematics And Tracking, Siyuan Yang

Dissertations, Theses, and Masters Projects

The Standard Model of particle physics represents our present best understanding of the elementary particles and three of the four fundamental forces. One of the most important and challenging tasks of modern particle physics is to test, and perhaps, to find the evidence for new physics not contained in the Standard Model. One such test, the $Q_{weak}$ experiment, was conducted at JLab in Newport News, VA, from 2010 to 2012. The goal of the experiment is to measure the value of the weak charge of proton, $Q_{weak}$ to a 4\% precision, which, if it confirms the Standard Model prediction, will …


Effects Of Resonant Magnetic Perturbations On Turbulence And Transport In Diii-D L-Mode Plasmas, Saskia Mordijck, T. L. Rhodes, L. Zeng, E. J. Doyle, Et Al. Jan 2016

Effects Of Resonant Magnetic Perturbations On Turbulence And Transport In Diii-D L-Mode Plasmas, Saskia Mordijck, T. L. Rhodes, L. Zeng, E. J. Doyle, Et Al.

Arts & Sciences Articles

In this paper we show that resonant magnetic perturbations (RMPs) affect the L- to H-mode power threshold. We find that during the L-mode phase, RMPs cause the particle pinch to reverse from traditionally inward to outward. As a result, the density at the plasma edge increases, while the density in the plasma core is reduced. Linear stability calculations indicate that the plasma transitions from an ion temperature gradient (ITG) to trapped electron mode (TEM) regime at the plasma edge. If the applied RMP current is below the threshold for penetration and island formation, we find that the changes in the …


Local, Global, And Nonlinear Screening In Twisted Double-Layer Graphene, Chih-Pin Lu, Martin Rodriguez-Vega, (...), Enrico Rossi, Et Al. Jan 2016

Local, Global, And Nonlinear Screening In Twisted Double-Layer Graphene, Chih-Pin Lu, Martin Rodriguez-Vega, (...), Enrico Rossi, Et Al.

Arts & Sciences Articles

One-atom-thick crystalline layers and their vertical heterostructures carry the promise of designer electronic materials that are unattainable by standard growth techniques. To realize their potential it is necessary to isolate them from environmental disturbances, in particular those introduced by the substrate. However, finding and characterizing suitable substrates, and minimizing the random potential fluctuations they introduce, has been a persistent challenge in this emerging field. Here we show that Landau-level (LL) spectroscopy offers the unique capability to quantify both the reduction of the quasiparticles' lifetime and the long-range inhomogeneity due to random potential fluctuations. Harnessing this technique together with direct scanning …


Quantitative Analysis Of Periodic Breathing And Very Long Apnea In Preterm Infants., Mary A. Mohr Jan 2016

Quantitative Analysis Of Periodic Breathing And Very Long Apnea In Preterm Infants., Mary A. Mohr

Dissertations, Theses, and Masters Projects

No abstract provided.


Experimental Apparatus For Quantum Pumping With A Bose-Einstein Condensate., Megan K. Ivory Jan 2016

Experimental Apparatus For Quantum Pumping With A Bose-Einstein Condensate., Megan K. Ivory

Dissertations, Theses, and Masters Projects

No abstract provided.