Bulletin of the American Physical Society
2012 Annual Meeting of the California-Nevada Section of the APS
Volume 57, Number 13
Friday–Saturday, November 2–3, 2012; San Luis Obispo, California
Session H3: Atomic and Molecular Physics |
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Chair: Peter Beiersdorfer, Lawrence Livermore National Laboratory Room: Business 003 0209 |
Saturday, November 3, 2012 2:00PM - 2:12PM |
H3.00001: Search for an anomalous spin-mass coupling with a dual isotope rubidium comagnetometer Cesar Rios, Julian Valdez, Jerlyn Swiatlowski, Jackie Kremer, Derek Kimball We discuss progress in our search for a hypothetical long-range coupling between rubidium (Rb) nuclear spins and the mass of the Earth. The experiment employs a dual-isotope Rb comagnetometer: the valence electron dominates magnetic interactions and serves as a precise magnetic field monitor for the nuclei in a simultaneous measurement of Rb-85 and Rb-87 spin precession frequencies, enabling accurate subtraction of magnetic perturbations. The nuclear structure of Rb makes the experiment particularly sensitive to non-magnetic, spin-dependent interactions of the proton. The majority of recent searches for similar effects limit anomalous couplings of either the neutron or electron spin, so the proposed experiment searches a parameter space to some degree, depending on the theoretical model, orthogonal to that constrained by previous experiments. We have begun to collect data and carry out in-depth analysis of systematic effects. The optimized dual-isotope Rb magnetometer has the sensitivity to improve experimental limits on long-range spin-mass couplings by an order of magnitude in general and by three orders of magnitude for the proton spin in particular. [Preview Abstract] |
Saturday, November 3, 2012 2:12PM - 2:24PM |
H3.00002: Two-photon direct frequency comb spectroscopy of alkali atoms Christopher Palm, Trinity Pradhananga, Khoa Nguyen, Caitlin Montcrieffe, Derek Kimball We have studied transition frequencies and excited state hyperfine structure in rubidium using 2-photon transitions excited directly with the frequency-doubled output of a erbium fiber optical frequency comb. The frequency comb output is directed in two counterpropagating directions through a vapor cell containing the rubidium vapor. A pair of optical filters is used to select teeth of the comb in order to identify the transition wavelengths. A photomultiplier tube (PMT) measures fluorescence from a decay channel wavelength selected with another optical filter. Using different combinations of filters enables a wide range of transitions to be investigated. By scanning the repetition rate, a Doppler-free spectrum can be obtained enabling kHz-resolution spectral measurements. An interesting dependence of the 2-photon spectrum on the energy of the intermediate state of the 2-photon transition is discussed. Our investigations are laying the groundwork for a long-term research program to use direct frequency comb spectroscopy to understand the complex spectra of rare-earth atoms. [Preview Abstract] |
Saturday, November 3, 2012 2:24PM - 2:36PM |
H3.00003: Application of electric fields to alkene-coated cesium vapor cells Li Wang, Brandon Guidl, Cheng-Kai Chen, Maryna Longnickel, Derek Kimball Recently, a new alkene-based antirelaxation coating has been discovered [Balabas et al., Phys. Rev. Lett. 105, 070801 (2010)] which enables spin-polarized alkali atoms to bounce off vapor cell walls more than a million times before the spin polarization relaxes, yielding electron spin relaxation times on the order of a minute. This remarkable new technology may open the possibility of conducting a new search for the parity- and time-reversal violating permanent electric dipole moment (EDM) of the electron using a cesium vapor contained in an alkene-coated cell. Previous antirelaxation coatings have demonstrated dramatic vapor density variations upon application and reversal of the large electric fields required for an EDM experiment [Jackson Kimball et al., Phys. Rev. A 79, 032901 (2009)]. We have found that in the new alkene-coated cells these electric-field-induced vapor density variations can be mitigated for particular choices of cell and alkali metal reservoir temperatures. Future work will involve demonstrating the long spin-relaxation times during application and reversal of electric fields and direct measurement of the electric field using the Stark shift of excited states in Cs. [Preview Abstract] |
Saturday, November 3, 2012 2:36PM - 2:48PM |
H3.00004: On the Non-Pauli Electronic States of Atoms and Molecules Peter Langhoff, Jeffrey Mills Schr\"odinger's equation for atoms and molecules supports solutions that are not totally antisymmetric under electron coordinate permutations. These non-Pauli eigenstates are generally regarded as unphysical, with interest in them centered largely on their role as possible ``contaminants'' in physical solutions constructed by methods that provide only approximate antisymmetry, such as exchange perturbation theories, many-body diagrammatic approaches, and variational methods in the absence of precise prior enforcement of basis-state antisymmetry. Here we report atomic and molecular non-Pauli Schr\"odinger solutions employing largely pedestrian methods as an alternative to the more complicated Wigner-Weyl approach based on theory of the symmetric group. Using the non-relativistic Hamiltonian operator and spin-orbital product representations in variational calculations, we show that every antisymmetric Schr\"odinger eigenstate of an $n$ electron atom or molecule is accompanied by 2$^{n}$-1 degenerate non-Pauli ``ghost'' solutions. As a consequence of this degeneracy, admixtures of non-Pauli states are always present in Pauli solutions having only approximate antisymmetry. These can significantly affect calculated expectation values, even in the face of precise energy predictions. [Preview Abstract] |
Saturday, November 3, 2012 2:48PM - 3:00PM |
H3.00005: ABSTRACT WITHDRAWN |
Saturday, November 3, 2012 3:00PM - 3:12PM |
H3.00006: Thermodynamic description of cellulose chain collapse using coarse grain modeling Ritankar Das, Jhih-Wei Chu Biomass contains abundant amounts of cellulose as crystalline microfibrils. A limiting step to using cellulose as an alternative energy source, however, is the hydrolysis of the biomass and subsequent transformation into fuels. Cellulose is insoluble in most solvents including organic solvents and water, but it is soluble in some ionic liquids like BMIM-Cl. This project aims to find alternative solvents that are less expensive and are more environmentally benign than the ionic liquids. All-atom molecular dynamics simulations were performed on dissociated glucan chains separated by multiple (4-5) solvation shells, in the presence of several novel solvents and solvent mixtures. The solubility of the chains in each solvent was indicated by contacts calculations after the equilibration of the molecular dynamics. It was discovered that pyridine and imidazole acted as the best solvents because their aromatic electronic structure was able to effectively disrupt the inter-sheet interactions among the glucan chains in the axial direction, and because perturbation of the solvent interactions in the presence of glucan chains was minimal. [Preview Abstract] |
Saturday, November 3, 2012 3:12PM - 3:24PM |
H3.00007: Path-Integral Foundations Ken Wharton Research in the field of Quantum Foundations often aims to interpret the standard quantum wavefunction (including its dynamics and its probabilistic relationship to observations). However, it is known that all of the predictions of quantum theory can also be recovered using the Feynman Path Integral (FPI), in which the wavefunction need not play any role at all. This raises the possibility of an alternate approach to quantum foundations -- ``path-integral foundations" -- in which it is the FPI that needs an interpretation, not the wavefunction. This talk will summarize the efforts that have already been made in this regard, and will present indications that this is a promising research direction -- especially if one is concerned with time-symmetry and/or ``realistic" approaches to quantum phenomena. [Preview Abstract] |
Saturday, November 3, 2012 3:24PM - 3:36PM |
H3.00008: Capillary Action may be used in feeding Particles and as calorimeters in Accelerators Richard Kriske Capillary Action was first proposed to be a Quantum Mechanical Effect by this Author. In plants it takes no work for water to travel up a tree, a flow of fluid begins when a thermal photon causes the water at the top of the column to evaporate. When the molecule evaporates a ``hole'' is transfered down the water column to the roots where apparently the ``hole'' establishes a ``current'' of ``holes'' in the manner of theory which is superior to the theory of ``solid-state'' physics. The ``hole'' can also be used in a ``path-integral'' formulation as is done in particle physics. A particle (a thermal photon) would strike the surface at the top of the column in through some ``spring'' method cause the whole column to rise--which is an interesting variation of the ``spring-in-mattress'' model used in Quantum Field Theory. Obviously a proper size tube- say a nanotube could be coupled to an Accelerator and the Quantum Field Theory Calculation of the Beam could be used to couple with the ``spring'' field available in the Tube. For the right sized tube, a Calorimeter would be the result. For other sized tubes, the beam could be fed with molecules and particles that have similar characteristics to water. Capillary Action is an example of Particle Physics seen in directly in the Classical world. [Preview Abstract] |
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