Bulletin of the American Physical Society
80th Annual Meeting of the APS Southeastern Section
Volume 58, Number 17
Wednesday–Saturday, November 20–23, 2013; Bowling Green, Kentucky
Session CC: Invited Session on Atomic, Molecular, Optical |
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Chair: John Yukich, Davidson College Room: 3/4 |
Thursday, November 21, 2013 11:00AM - 11:36AM |
CC.00001: Out-of-plane (e,2e) experiments on helium autoionizing levels Invited Speaker: N.L.S. Martin An (e,2e) experiment investigates the electron impact ionization by observing both the scattered and ejected electrons in (delayed) coincidence. Up to a decade ago, all experiments were of the coplanar type where the ejected electrons were detected in the scattering plane formed by the incident and scattered electron trajectories. Theory was in quite good agreement with experiment for such experiments. About 10 years ago, so called out-of-plane experiments, where the ejected electron was observed out of the scattering plane, found results for direct (non-resonant) ionization that could not be explained by existing theories. I shall describe an out-of-plane experiment and calculations carried out for ionization that involved autoionizing levels in helium.\footnote{B.A. deHarak, K. Bartschat, and N.L.S. Martin, {\em Phys. Rev. Lett.}, {\bf 100}, 063201 (2008).} [Preview Abstract] |
Thursday, November 21, 2013 11:36AM - 12:12PM |
CC.00002: Generation, manipulations and applications of squeezed vacuum in optically dense Rb vapor Invited Speaker: Irina Novikova Harnessing quantum mechanical properties of light opens up exciting possibilities for quantum information and precision metrology. In this talk I will discuss the generation of non-classical ``squeezed'' optical vacuum field using a rubidium vapor cell as a nonlinear medium, and the polarization self-rotation effect as the squeezing nonlinearity. I will also describe some methods for squeezed vacuum manipulations based on coherent optical effects, as well as possible applications for quantum-enhanced measurements and information technologies. [Preview Abstract] |
Thursday, November 21, 2013 12:12PM - 12:48PM |
CC.00003: Investigations of quantum pendulum dynamics in a spin-1 Bose-Einstein condensate Invited Speaker: Michael Chapman An inverted pendulum at rest is a prototype of unstable equilibrium and corresponds to a hyperbolic fixed point in the dynamical phase space. While mechanical pendulums operating at the quantum limit are currently unavailable in the lab, it is possible to study ultracold atomic many-body systems that have similar dynamical behavior. In this talk, I will describe our recent measurements of the non-equilibrium dynamics of a spin-1 Bose-Einstein condensate ``pendulum'' initialized to the hyperbolic fixed point of the phase space by quenching the system. Subsequent evolution of the quantum fluctuations lead to spin squeezing and non-Gaussian probability distributions that are in good agreement with exact quantum calculations. Additionally, we have demonstrated stabilization of the non-equilibrium dynamics by periodic application of phase shifts to the collective states of the system. These experiments demonstrate new methods of manipulating out-of-equilibrium quantum many-body systems, drawing together ideas from classical Hamiltonian dynamics and quantum squeezing of collective states. [Preview Abstract] |
Thursday, November 21, 2013 12:48PM - 1:24PM |
CC.00004: Filamentation of Laser Light in Air Invited Speaker: Martin Richardson Studies of filamentation are now entering a new phase of investigation. As we consolidate more our understanding of the dynamics of the creation and propagation of single stabilized filaments in air, we can begin to deploy new modalities in filamentation, and to consider how they may be used in specific applications. In this review we consider our current understand of single filament formation in air by conventional high intensity femtosecond lasers, describing in particular new investigations of the continuum emission and the impact molecular alignment can have on filament propagation. We describe the use of multiple filaments to both investigate the phase characteristics of filaments, and through multi-color filaments to generate remote coherent THz emission. This opens the scenario of remote detection of organic materials including explosives through THz REEF spectroscopy. By manipulating the initial phase of the originating laser beam, we describe how multiple organized arrays of filaments can be generated, and illustrate this with the recent demonstration of double helical rotating filaments. Structured arrays of filaments open the pathway to many air filament scenarios, including the guiding and manipulation of microwaves, and potentially electric discharges. Air filaments can project to significant distances, instantaneous intensities that are well above the ablation thresholds of all materials. We have a multi-component research program to characterize the ablation and plasmas created from several types of materials. These studies include determining the energy balance and plasma characteristics, and examining the emissions that emanate from the plasma. [Preview Abstract] |
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