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 Chaos theory (1)
 Mean field approximation (1)
 Approximation theory (1)
 Atmospheric Chemistry (1)
 Horizontal Transport (1)

 Magnetic fields (1)
 Effective field theory (1)
 Contrail (1)
 Air Pollution (1)
 Boundary Layer Air (1)
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 Enhanced Efficiency (1)
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 Acetone (1)
 Aircraft Fuel (1)
 Observation (1)
 Glauber Ising model (1)
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 Damage spreading (1)
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 Aerosol Formation (1)
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Articles 1  13 of 13
FullText Articles in Physical Sciences and Mathematics
NearField Measurements On Contrail Properties From Fuels With Different Sulfur Content, Andreas Petzold, Reinhold Busen, Franz Peter Schroder, Robert Baumann, Markus Kuhn, Johan Strom, Donald E. Hagen, Philip D. Whitefield, Darrel G. Baumgardner, Frank Arnold, Stephan Borrmann, Ulrich Schumann
NearField Measurements On Contrail Properties From Fuels With Different Sulfur Content, Andreas Petzold, Reinhold Busen, Franz Peter Schroder, Robert Baumann, Markus Kuhn, Johan Strom, Donald E. Hagen, Philip D. Whitefield, Darrel G. Baumgardner, Frank Arnold, Stephan Borrmann, Ulrich Schumann
Physics Faculty Research & Creative Works
Microphysical properties of jet exhaust aerosol and contrails were studied in the near field of the emitting aircraft for different fuel sulfur contents. Measurements were performed behind two different aircraft (ATTAS test aircraft of type VFW 614 and Airbus A310300) using fuels with sulfur contents of 6 ppm and 2700 ppm, respectively. At closest approach (plume age < 1 s), the total number concentrations exceeded the measuring range of the condensation particle counter, i.e., N > 10^{5} cm^{3}. The concentration of the dry accumulation mode aerosol, i.e., predominantly soot particles, was not affected by the fuel sulfur content. At a plume age of 10 s, an increase in total number concentration (Dp > 0.01 μm) by ...
Bound Μ⁺Μˉ System, Ulrich D. Jentschura, Gerhard Soff, Vladimir G. Ivanov, Savely Karshenboim
Bound Μ⁺Μˉ System, Ulrich D. Jentschura, Gerhard Soff, Vladimir G. Ivanov, Savely Karshenboim
Physics Faculty Research & Creative Works
We consider the hyperfine structure, the atomic spectrum, and the decay channels of the bound μ^{+}μ^{} system (dimuonium). The annihilation lifetimes of lowlying atomic states of the system lie in the 10^{12} s range. The decay rates could be measured by detection of the decay products (highenergy photons or electronpositron pairs). The hyperfinestructure splitting of the dimuonic system and its decay rate are influenced by electronic vacuum polarization effects in the far timelike asymptotic region. This constitutes a previously unexplored kinematic regime. We evaluate nexttoleadingorder radiative corrections to the decay rate of lowlying atomic states. We also obtain ...
Nonlinear Response Theory: Transport Coefficients For Driving Fields Of Arbitrary Magnitude, Paul Ernest Parris, Marek Kus, David H. Dunlap, Vasudev M. Kenkre
Nonlinear Response Theory: Transport Coefficients For Driving Fields Of Arbitrary Magnitude, Paul Ernest Parris, Marek Kus, David H. Dunlap, Vasudev M. Kenkre
Physics Faculty Research & Creative Works
A theory of nonlinear response is developed for driving fields of arbitrary magnitude. Exact and usable expressions are provided for electrical and thermal mobility, and related transport coefficients, in terms of correlation functions of the system. A generalization into the nonlinear domain is provided of the WiedemannFranz law connecting electrical and thermal response and of the Einstein relation relating the diffusion constant and the mobility.
Quantum Coulomb Glass Within A HartreeFock Approximation, Frank Epperlein, Michael Schreiber, Thomas Vojta
Quantum Coulomb Glass Within A HartreeFock Approximation, Frank Epperlein, Michael Schreiber, Thomas Vojta
Physics Faculty Research & Creative Works
We study the influence of electronelectron interactions on the electronic properties of disordered materials. In particular, we consider the insulating side of a metalinsulator transition where screening breaks down and the electronelectron interaction remains long ranged. The investigations are based on the quantum Coulomb glass, a generalization of the classical Coulomb glass model of disordered insulators. The quantum Coulomb glass is studied by decoupling the Coulomb interaction by means of a HartreeFock approximation and exactly diagonalizing the remaining localization problem. We investigate the behavior of the Coulomb gap in the density of states when approaching the metalinsulator transition and study ...
Lamb Shift Of 3p And 4p States And The Determination Of Α, Ulrich D. Jentschura, Gerhard Soff, Peter J. Mohr
Lamb Shift Of 3p And 4p States And The Determination Of Α, Ulrich D. Jentschura, Gerhard Soff, Peter J. Mohr
Physics Faculty Research & Creative Works
The finestructure interval of P states in hydrogenlike systems can be determined theoretically with high precision, because the energy levels of P states are only slightly influenced by the structure of the nucleus. Therefore a measurement of the fine structure may serve as an excellent test of QED in bound systems, or alternatively as a means of determining the finestructure constant a with very high precision. In this paper an improved analytic calculation of higherorder binding corrections to the oneloop selfenergy of 3P and 4P states in hydrogenlike systems with a low nuclear charge number Z is presented. The method ...
Small Angle Neutron Scattering From Nanodroplet Aerosols, Barbara Ellen Wyslouzil, Janice L. Cheung, Gerald Wilemski, Reinhard Strey
Small Angle Neutron Scattering From Nanodroplet Aerosols, Barbara Ellen Wyslouzil, Janice L. Cheung, Gerald Wilemski, Reinhard Strey
Physics Faculty Research & Creative Works
We report the first measurements of small angle neutron scattering from an aerosol. The aerosol was produced by expanding a D_{2}ON_{2} vapor mixture in a supersonic Laval nozzle. The neutron wavelength (0.5 nm) is less than the typical particle size, and we can therefore derive the average particle size (58 nm), number density (~10^{12} cm^{3}), and polydispersity of the size distribution directly from the experimental data rather than by inferring them from complex models of particle formation and growth. We also predict and observe a Doppler shiftinduced anisotropy in the scattering pattern due to ...
In Situ Observations Of Air Traffic Emission Signatures In The North Atlantic Flight Corridor, Hans Schlager, Paul Konopka, P. Schulte, U. Schumann, H. Ziereis, F. Arnold, M. Klemm, Donald E. Hagen, Philip D. Whitefield, J. Ovarlez
In Situ Observations Of Air Traffic Emission Signatures In The North Atlantic Flight Corridor, Hans Schlager, Paul Konopka, P. Schulte, U. Schumann, H. Ziereis, F. Arnold, M. Klemm, Donald E. Hagen, Philip D. Whitefield, J. Ovarlez
Physics Faculty Research & Creative Works
Focussed aircraft measurements have been carried out over the eastern North Atlantic to search for signals of air traffic emissions in the flight corridor region. Observations include NO, NO_{2}, HNO_{3}, SO_{2}, O_{3}, H_{2}O, total condensation nuclei (CN), and meteorological parameters. A flight pattern with constantaltitude northsouth legs across the major North Atlantic air traffic tracks was flown. Signatures of air traffic emissions were clearly detected for NO_{x}, SO_{2}, and CN with peak concentrations of 2 ppbv, 0.25 ppbv, and 500 cm^{3}, respectively, exceeding background values by factors of 30 (NO ...
Chaotic Behavior And Damage Spreading In The Glauber Ising Model: A Master Equation Approach, Thomas Vojta
Chaotic Behavior And Damage Spreading In The Glauber Ising Model: A Master Equation Approach, Thomas Vojta
Physics Faculty Research & Creative Works
We investigate the sensitivity of the time evolution of a kinetic Ising model with Glauber dynamics against the initial conditions. To do so we apply the "damage spreading" method, i.e., we study the simultaneous evolution of two identical systems subjected to the same thermal noise. We derive a master equation for the joint probability distribution of the two systems. We then solve this master equation within an effectivefield approximation which goes beyond the usual meanfield approximation by retaining the fluctuations though in a quite simplistic manner. The resulting effectivefield theory is applied to different physical situations. It is used ...
Studies Of V, Nb, Cr, And Zr Substituted 2:17 Compounds And Their Carbides Using Neutron Diffraction, H. Luo, Z. Hu, Muguo Chen, William B. Yelon, G. K. Marasinghe, Peter C. Ezekwenna, William Joseph James, W. C. Chang, S. H. Tsai
Studies Of V, Nb, Cr, And Zr Substituted 2:17 Compounds And Their Carbides Using Neutron Diffraction, H. Luo, Z. Hu, Muguo Chen, William B. Yelon, G. K. Marasinghe, Peter C. Ezekwenna, William Joseph James, W. C. Chang, S. H. Tsai
Physics Faculty Research & Creative Works
Samples of Nd_{2}Fe_{17x}T_{x}C_{y} with T=V, Nb, Cr, and Zr were prepared by melting of the constituent elements including C and studied by neutron diffraction. Comparing with their uncarbided counterparts, we found that the substituents transfer, more or less, from the 6c site to the 18f and 18h sites with the introduction of C atoms. This behavior appears to relate to the electronegativities between the C atoms and the early transition series elements because the 18f and 18h sites are near neighbors of the interstitial C site. However, the C effects in the ...
Nonanalytic Behavior Of The Spin Susceptibility In Clean Fermi Systems, Dietrich Belitz, Theodore R. Kirkpatrick, Thomas Vojta
Nonanalytic Behavior Of The Spin Susceptibility In Clean Fermi Systems, Dietrich Belitz, Theodore R. Kirkpatrick, Thomas Vojta
Physics Faculty Research & Creative Works
The wave vector and temperaturedependent static spin susceptibility, X_{s}(Q, T), of clean interacting Fermi systems is considered in dimensions 1 ≤ d ≤ 3. We show that at zero temperature X_{s} is a nonanalytic function of Q, with the leading nonanalyticity being Q^{d1} for 1 < d < 3, and Q^{2}lnQ for d = 3. For the homogeneous spin susceptibility we find a nonanalytic temperature dependence T^{d1} for 1 < d < 3. We give qualitative modemode coupling arguments to that effect, and corroborate these arguments by a perturbative calculation to second order in the electronelectron interaction amplitude. The implications of this, in particular for itinerant ferromagnetism, are discussed. We also point out the relation between our findings and established perturbative results for onedimensional systems, as well as for the temperature dependence of X_{s}(Q = 0) in d = 3.
Monte Carlo Simulations Of The Dynamical Behavior Of The Coulomb Glass, Torsten Wappler, Thomas Vojta, Michael Schreiber
Monte Carlo Simulations Of The Dynamical Behavior Of The Coulomb Glass, Torsten Wappler, Thomas Vojta, Michael Schreiber
Physics Faculty Research & Creative Works
We study the dynamical behavior of disordered manyparticle systems with longrange Coulomb interactions by means of damagespreading simulations. In this type of Monte Carlo simulation one investigates the time evolution of the damage, i.e., the difference of the occupation numbers of two systems, subjected to the same thermal noise. We analyze the dependence of the damage on temperature and disorder strength. For zero disorder the spreading transition coincides with the equilibrium phase transition, whereas for finite disorder we find evidence for a dynamical phase transition well below the transition temperature of the pure system.
ThreeBody Models Of ElectronHydrogen Ionization, Stephenie J. Jones, Don H. Madison, Dmitry A. Konovalov
ThreeBody Models Of ElectronHydrogen Ionization, Stephenie J. Jones, Don H. Madison, Dmitry A. Konovalov
Physics Faculty Research & Creative Works
In this paper, we report calculations of electronhydrogen ionization whereby the finalstate wave Function is approximated by recently reported analytical threebody wave functions. In a first model we use the wave function of Alt and Mukhamedzhanov [Phys. Rev. A 47, 2004 (1993)], and in a second model we use the wave function of Berakdar [Phys. Rev. A 53, 2314 (1996)].
Observation Of Upper Tropospheric Sulfur Dioxide And AcetonePollution: Potential Implications For Hydroxyl Radical And Aerosol Formation, F. Arnold, J. Schneider, K. Gollinger, H. Schlager, P. Schulte, Donald E. Hagen, Philip D. Whitefield, Peter F. J. Van Velthoven
Observation Of Upper Tropospheric Sulfur Dioxide And AcetonePollution: Potential Implications For Hydroxyl Radical And Aerosol Formation, F. Arnold, J. Schneider, K. Gollinger, H. Schlager, P. Schulte, Donald E. Hagen, Philip D. Whitefield, Peter F. J. Van Velthoven
Physics Faculty Research & Creative Works
Aircraftbased measurements of sulfur dioxide, acetone, carbon dioxide, and condensation nuclei (CN) were made over the northeastern Atlantic at upper tropospheric altitudes, around 9000 m. On October 14, 1993, strong SO _{2} and acetonepollution (both up to 3 ppbv) were observed, which were accompanied by a CO _{2}enhancement of up to 6 ppmv, and large CNconcentrations of up to about 1500 cm ^{3} (for radii ≥ 6 nm). CN, excess CO _{2}, and to a lesser degree also acetone, were positively correlated with SO _{2}. Air mass trajectory analyses indicate, that most of the air masses encountered by our aircraft ...