Bulletin of the American Physical Society
79th Annual Meeting of the APS Southeastern Section
Volume 57, Number 16
Wednesday–Saturday, November 14–17, 2012; Tallahassee, Florida
Session HB: Atomic, Molecular, and Optical Physics II |
Hide Abstracts |
Chair: John Yukich, Davidson College Room: DoubleTree Salon AB |
Friday, November 16, 2012 10:45AM - 11:15AM |
HB.00001: Perfect Fluidity: From Strongly-Interacting Fermi Gases to Quark-Gluon Plasmas Invited Speaker: John Thomas Strongly interacting atomic Fermi gases and quark-gluon plasmas share a common feature: They exhibit nearly ideal, minimum viscosity hydrodynamic expansion, which is a characteristic of a ``perfect'' fluid. A perfect fluid is defined to be a normal fluid (not a superfluid) with the minimum ratio of shear viscosity to entropy density permitted by the laws of quantum physics, $\hbar /(4\pi k_B )$, as derived recently using string-theory methods. We measure both the shear viscosity and the entropy of an optically-trapped, strongly-interacting gas of spin $\raise.5ex\hbox{$\scriptstyle 1$}\kern-.1em/ \kern-.15em\lower.25ex\hbox{$\scriptstyle 2$} $-up and spin $\raise.5ex\hbox{$\scriptstyle 1$}\kern-.1em/ \kern-.15em\lower.25ex\hbox{$\scriptstyle 2$} $-down $^{6}$Li atoms. A bias magnetic field tunes the gas to a collisional (Feshbach) resonance, where the s-wave scattering length, for collisions between atoms of opposite spin, diverges. At resonance, the system is universal and scale-invariant, so that the thermodynamic and hydrodynamic properties are universal functions of the density and temperature. Even though it is dilute, such an atomic Fermi is the most strongly interacting non-relativistic system known, enabling tests of recent theories in diverse disciplines from high temperature superconductors to nuclear matter, and even string- theory, via the minimum viscosity conjecture. [Preview Abstract] |
Friday, November 16, 2012 11:15AM - 11:27AM |
HB.00002: Time Resolved Analysis of the C, (C$_{2})$ Swan and (CN) Violet Systems from Dicarboxylic Acids from Laser Induced Breakdown Spectroscopy Staci Brown, Charlemagne Akpovo, Jorge Martinez, Dawn Lewis, Lewis Johnson Laser Induced Breakdown Spectroscopy (LIBS) was used as a method for the detection of carbon, carbon-carbon and carbon- nitrogen molecular bonds from atmospheric recombination. Ablated samples were comprised of a series of dicarboxylic acids with an increasing number of carbon in their molecular structure from 2 to 7 (ex. Oxalic Acid, Malonic acid, Succinic Acid, etc). Accumulated pulses of a focused Nd:YAG q-switched laser beam operated at 532nm and an energy of approximately 5mJ at a repetition rate of 20 Hz were used to generate a plasma. The LIBS spectra were acquired using a high-resolution Czerny-Turner image spectrometer with an intensified charge-coupled device. Through a time resolved analysis of the emission spectra, we demonstrate the effects of the change in gate delay on the emission of the vibrational headbands for the Swan (C$_{2})$ and Violet (CN) spectroscopic systems. We also, illustrate the effects that these constraints have on the peak intensities of the individual headbands in relation to each other and those of ionic Carbon and Nitrogen. [Preview Abstract] |
Friday, November 16, 2012 11:27AM - 11:57AM |
HB.00003: Atomic and Molecular Collisions using a Time-Dependent Close-Coupling Method Invited Speaker: M.S. Pindzola A non-perturbative time-dependent close-coupling method has been developed to handle quantal many-body Coulomb breakups found in photon-impact, electron-impact, and ion-impact ionization of atoms, molecules, and their ions. For atoms the time-dependent Schrodinger equation is solved using a 2D or 3D numerical lattice and an expansion in coupled spherical harmonics. For molecules the time-dependent Schrodinger equation is solved using a 4D numerical lattice and an expansion in rotational functions. For highly charged atomic ions the time-dependent Dirac equation is solved using a 2D numerical lattice and an expansion in coupled spin-orbit eigenfunctions. Theoretical cross sections are compared to experiment for a variety of atomic and molecular collisions, including the triple photoionization of the Li atom. [Preview Abstract] |
Friday, November 16, 2012 11:57AM - 12:09PM |
HB.00004: ABSTRACT WITHDRAWN |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700