Bulletin of the American Physical Society
2015 Annual Meeting of the Far West Section of the APS
Thursday–Saturday, October 29–31, 2015; Long Beach, California
Session F1: AMO and Plasma Physics |
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Chair: Alla Safronova, University of Nevada, Reno Room: CBA-122 |
Friday, October 30, 2015 2:00PM - 2:12PM |
F1.00001: \begin{center} Measuring the Internal Energies of Asymmetrical Diatomic Molecular Ions using a Three-Dimensional Imaging Technique \end{center} D. A. Rivas, C. I. Guillen, J. B. Sauza, V. M. Andrianarijaona Our goal is to measure the vibrational state of a small asymmetrical~diatomic molecular ion~by observing the kinetic energy release through a resonant dissociative charge transfer. We will use an imaging~technique similar to the one used for symmetrical diatomic ions (PRL 92 163004, 2004), which gives a direct access to the vibrational state distribution of the mother molecular ion. The two fragments hit two detectors which sense the positions and their time difference of impact. In the case of a symmetrical ion, the two daughter particles have the same velocity in the center of mass frame of reference and there is no reason to distinguish which particle hits the detector first and which one stops the stopwatch. The asymmetrical case is not the same because for a~diatomic molecular~ion such as HeH$^{\mathrm{+}}$, the lighter fragment has a higher recoil velocity than~the heavier fragment and goes~transversely~further away from the center of mass direction.~Thus,~the two fragments are naturally selected as the lighter~cannot hit the first detector if the beam is judicially misaligned. Once we obtain the computed kinetic energy release then we may relate it to the vibrational excitation level of the initial asymmetrical ion. In addition details of this particular technique will be presented. [Preview Abstract] |
Friday, October 30, 2015 2:12PM - 2:24PM |
F1.00002: Hypothetical model of the electron from E$^{\mathrm{\mathbf{2}}}\textbf{ }=\textbf{p}^{\mathrm{\mathbf{2}}}\textbf{c}^{\mathrm{\mathbf{2}}}\textbf{ }+\textbf{ (mc}^{\mathrm{\mathbf{2}}}\textbf{)}^{\mathrm{\mathbf{2}}}$ and the Dirac equation S. Moses, D. Panchenko, D. Rivas, J. Lyu, J. Tobar, E. Vargas, V. Andrianarijaona This scientific inquiry serves to study the relationship between relativistic energy, momentum, and the rest energy,~E$^{\mathrm{2}}=$p$^{\mathrm{2}}$c$^{\mathrm{2}}+$(mc$^{\mathrm{2}})^{\mathrm{2}}$, while using underlying geometric parallels to understand each portion of the equation. The aforementioned equation invites recognition that quantities, pc and~mc$^{\mathrm{2}}$, could be viewed as axes on a plane. With the consideration of de Broglie's hypothesis $\lambda =$h/p, it follows that the pc-axis is tied to the wave properties of a moving object, and subsequently, the~mc$^{\mathrm{2}}$-axis is connected with the particle properties of the same object. These two axes could simultaneously represent both the particle and wave properties of the moving object. We will apply these considerations to the particular case of an electron, suggesting alternative shapes by making use of the Dirac equation ([1] Dirac, P.A.M., Nobel Prize Lecture, Dec. 12, 1933, http://www.nobelprize.org/nobel\textunderscore prizes/physics/laureates/1933/dirac--lecture.pdf ). We hope to shed new light on these ideas by presenting possible models and meaningful interpretations. [Preview Abstract] |
Friday, October 30, 2015 2:24PM - 2:36PM |
F1.00003: Structure of Resonances in Atomic Three Body Systems Daniel Diaz, Chi-Yu Hu, Zoltan Papp Atomic resonances are short-lived quantum states. They can be modeled as the complex-energy solutions of the Schr\"{o}dinger equation. A three-particle system may have several genuinely different asymptotics, which are difficult to fulfill with one wave function. Therefore, we adopted the Faddeev method, which amounts to splitting the wave function into components such that each component is responsible only for one kind of asymptotics. To incorporate the long-range Coulomb interactions we also needed to cut the interactions in the three-body configuration space a' la Merkuriev. We solved the Faddeev-Merkuriev integral equations by approximating the potential kernels in the three-body configuration space on a Coulomb-Sturmian basis. The Coulomb-Sturmian matrix elements of the three-body Coulomb Green's operator have been evaluated as a complex contour integral of the two-body Green's operators. In this study we reinvestigated the resonances of the e-Ps system. Our particular focus was the broad resonances found earlier by us. We reestablished their existence and propose a mechanism that creates those broad resonances lined up to the thresholds. We now aim to look for similar resonances in other three-body systems and different spin states of the e-Ps system. We specifically look at the resonances of H-e$^{\mathrm{+}}$ and H-e systems. [Preview Abstract] |
Friday, October 30, 2015 2:36PM - 2:48PM |
F1.00004: Anatomy of a Spin: The Information-Theoretic Structure of Classical Spin Systems Ryan James It is well known that classical spin systems store information in statistical deviations from independence, such as clustering in the Ising model. Drawing on recent results in the study of stochastic processes, we study the way this information in stored in a variety of lattices. In particular, we decompose the thermodynamic entropy density into two components: the \emph{emphemeral information}, measuring the amount of independent information in the lattice, and the \emph{bound information}, measuring intrinsically collective behavior. We then demonstrate the behavior of these two measures, as well as related ones, as a function of temperature for the ferromagnetic nearest-neighbor Ising model on the 1- and 2-dimensional square lattices, as well as the Bethe lattice with branching factor 3. [Preview Abstract] |
Friday, October 30, 2015 2:48PM - 3:00PM |
F1.00005: Thermal Corrections to Density Functional Simulations of Warm Dense Matter Justin Smith, Aurora Pribram-Jones, Kieron Burke Present density functional calculations of warm dense matter often use the Mermin-Kohn-Sham (MKS) scheme at finite temperature, but employ ground-state approximations to the exchange-correlation (XC) free energy. In the simplest solvable non-trivial model, an asymmetric Hubbard dimer, we calculate the exact many-body energies, the exact Mermin-Kohn-Sham functionals for this system, and extract the exact XC free energy. For moderate temperatures and weak correlation, we show this approximation is excellent, but fails for stronger correlations. Additionally, we use this system to test various conditions that must be satisfied. [Preview Abstract] |
Friday, October 30, 2015 3:00PM - 3:12PM |
F1.00006: Investigation of Quality Factors in Multistage Photolithography Cody Johnson This experiment was conducted to identify factors in the photolithography process that cause either a vertical or slumped undercut, thus providing a lower yield of usable features due to poor lift off of coating. Five parameters were altered to survey their individual effect on the profile of the undercut. Each parameter: developer time, exposure dose, spin speed, hard bake temperature and time; is representative of an integral step in the photolithography process. The wafers, after being processed, were then diced using a scribe and break machine and analyzed using a Nikon Nexiv microscope to identify the profile of the undercut and calculate its angle [Preview Abstract] |
Friday, October 30, 2015 3:12PM - 3:24PM |
F1.00007: Stability Conditions for Trapping of Low Index Contrast Particles Dual Beam Optical Trap Alison Huff, Charles Melton, Linda Hirst, Jay Sharping The use of radiation pressure to hold and manipulate microscopic dielectric particles is driving fundamental advancements in our understanding of the machinery that makes up living cells. The dual-beam fiber-optical trapping configuration is particularly useful due to its diverging beams, allowing larger particles to be trapped with little photodamage. Most such studies are conducted using particles in a medium where the refractive index contrast between the particle and surrounding medium is relatively large: $m \, = \, (n_{\text{particle}}/n_{\text{medium}})\, > \, 1.1$. However, the low-$m$ case is of practical interest because it often applies to cells in vivo and artificially-synthesized vesicles where the internal and external media are similar to one another. We find experimentally and theoretically that there are regimes of fiber separation, particle size and refractive index contrast where the magnitudes of the gradient forces are nearly the same as the scattering forces, leading to multiple stable trapping locations. Besides being important for understanding the unusual behavior such a system may display, it raises the possibility of using a single-fiber trap for manipulating lipid vesicles. [Preview Abstract] |
Friday, October 30, 2015 3:24PM - 3:36PM |
F1.00008: An analysis of x-rays emitted from laser-produced noble gas jet plasmas and a comparison of gas jet nozzles K.A. Schultz, V.L. Kantsyrev, V.V. Shlyaptseva, I.K. Shrestha, E.E. Petkov, A.S. Safronova, J.J. Moschella, A. Stafford, M.C. Cooper The study of fs laser interaction with underdense gas jet plasmas is important for understanding the mechanisms of x-ray (1-20keV) emission. Clusterized gas jets produced by a linear supersonic nozzle were irradiated with a high-intensity laser pulse generated by the UNR Leopard laser (at 1-2x10$^{\mathrm{19}}$W/cm$^{\mathrm{2}})$. Jets of Ar, Kr, and Xe were studied as well as triple mixtures with different percentages of each of the noble gases. Absolute x-ray outputs of the laser-gas jet interactions measured by PCDs are presented and show a strong anisotropy of x-ray radiation with respect to laser beam polarization direction. The triple mixtures each exhibited a higher x-ray yield compared to pure gases and a factor of 10$^{\mathrm{-3}}$ of laser energy was converted into x-rays. Characterization of gas jets was also performed at the Radiation Physics Laboratory at UNR using interferometry and Rayleigh scattering. The combination of density and cluster measurements results in the calculation of the cluster parameter $\eta $N$_{\mathrm{c}}$. The characterization was performed for the linear supersonic nozzle and a new, complex conical nozzle with applications in Z-pinch and laser-produced plasma research. The linear nozzle has a larger line-integrated density. [Preview Abstract] |
Friday, October 30, 2015 3:36PM - 3:48PM |
F1.00009: Spectroscopic Analysis and Optimization of Krypton X-ray Emission from a Dense Plasma Focus Device in Singapore. E.E. Petkov, R.S. Rawat, K.S. Tan, V.L. Kantsyrev, V.V. Shlyapsteva, K.A. Schultz, A.S. Safronova The study of x-ray emission from a dense plasma focus (DPF) device is of significant interest due to its wide range of applications (scientific, industrial, medical, etc). In the past, extensive research has been conducted on x-ray emission from noble gases such as Neon and Argon from a DPF device, but almost no investigation has been done on higher Z molecular gases. Winning the National Science Foundation's EAPSI award has allowed for the opportunity of international scientific collaboration on this topic, and thus we present, for the first time, a comprehensive analysis of L-shell Krypton radiation including optimization of Krypton x-ray emission from a 3 kJ DPF device in Singapore. The advantages of using Krypton as the operating gas are also discussed. [Preview Abstract] |
Friday, October 30, 2015 3:48PM - 4:00PM |
F1.00010: The Uncertainty Principle v wave mechanics - conflict seen via the stable wave packet. antony bourdillon The traveling wave group that is defined on conserved physical values is the vehicle of transmission for a unidirectional photon or free particle having a wide wave front. As a stable wave packet, it expresses internal periodicity combined with group localization. Heisenberg's Uncertainty Principle is precisely derived from it, though significant conflict between the Principle and wave mechanics is apparent. Also derived is the phase velocity beyond the horizon set by the speed of light. In this space occurs the reduction of the wave packet which occurs in measurement and which is represented by comparing phase velocities in the direction of propagation with the transverse plane. The new description of the wavefunction for the stable free particle or antiparticle contains variables that were previously ignored. Deterministic physics must always appear probabilistic when hidden variables are bypassed. Secondary hidden variables always occur in measurement. The wave group turns out to be probabilistic. It is ubiquitous in physics and has many consequences. [Preview Abstract] |
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