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Creator | Title | Description | Subject | Date |
226 |
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DeTar, Carleton | Nature of the thermal phase transition with Wilson quarks | We describe a series of simulations of high temperature QCD with two flavors of Wilson quarks aimed at clarifying the nature of the high temperature phase found in current simulations. Most of our work is with four time slices, although we include some runs with six and eight time slices for compar... | Wilson quarks; Landau gauge; Polyakov loop; Phase transitions | 1994-04 |
227 |
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Vardeny, Zeev Valentine | Transient and steady-state photoconductivity of a solid C60 film | We report the experimental results of the subnanosecond time-resolved transient photoconductivity (PC) of solid C60 film at various photon energies, and the spectral response of the steady-state PC in the energy range between 1.5 and 4.5 eV. The initial fast transient PC response decays exponenti... | Transient photoconductivity; Steady-state photoconductivity; Solid C60 film | 1993-09 |
228 |
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Vardeny, Zeev Valentine | Spatially mapping random lasing cavities | A mapping technique is developed to spatially resolve random laser emission spectra from disorder solid media with optical gain above the threshold excitation intensity for lasing; the technique is applied to rr-conjugated polymer lms. By mapping the spatial extent of emission peaks in the random la... | | 2010 |
229 |
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Vardeny, Zeev Valentine | Film morphology and photophysics of polyfluorene | We have studied the interplay between photophysics and film morphology of poly(9,9-dioctyl)fluorene (PFO) using a variety of optical probes. Upon slowly warming a spin-cast PFO film from 80 to 300 K, a fraction of the sample is transformed into a different solid phase, the ß phase. Absorption and e... | Polyfluorene; Photophysics; Film morphology | 2000-12 |
230 |
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Vardeny, Zeev Valentine | Phonon polariton study of CuCl1-x Brx | The optical-phonon spectrum of CuCI-x Brx at low temperature is very unusual in regard to many of its properties. Despite the apparent two-mode behavior our measurements illustrate anomalies in the Raman intensity and temperature-induced frequency shift, as well as in the oscillator strengths yiel... | Cuprous halides; CuCl1-x Brx | 1981-08 |
231 |
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Williams, Clayton C. | Instability induced tunneling and repeatable charge injection to SiO2 surfaces by electrostatic force microscopy | The dynamic response and stability of a voltage biased oscillating cantilever in the proximity of an insulating sample surface is investigated. As the tip approaches the sample surface, the cantilever can jump between two different oscillation modes. The jump is detected as an abrupt increase in t... | Electrostatic force microscopy; EFM; Dielectric films | 2004 |
232 |
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Dawson, Kyle | The effects of charge transfer inefficiency (CTI) on galaxy shape measurements | We examine the effects of charge transfer inefficiency (CTI) during CCD readout on the demanding galaxy shape measurements required by studies of weak gravitational lensing. We simulate a CCD readout with CTI such as that caused by charged particle radiation damage in space-based detectors. We verif... | | 2010 |
233 |
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Vardeny, Zeev Valentine | Optical probes of ∏-conjugated polymer blends with strong acceptor molecules | We used a variety of optical probes to study the primary and long-lived photoexcitations in blends of polyphenylene-vinylene derivative poly(2-methoxy-5(2'-ethyl)hexoxy-phenylenevinylene) (MEH-PPV) with various concentrations of a strong electron-acceptor molecule 2,4,7-trinitro-9-fluorenone (TNF... | pi-conjugated polymers; pi-conjugated polymer blends; Acceptor molecules; Optical probes; Photoexcitations; MEH-PPV; Electron acceptors; Organic solar cells | 2009-05 |
234 |
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Sokolsky, Pierre | Evidence for 10^18-eV neutral particles from the direction of Cygnus X-3 | Analysis of the cumulative Fly's Eye data reveals an excess of air showers from the direction of Cygnus X-3 at energies above 0.5 x 10^18 eV. No point source has previously been identified at such high energies. The probability of this excess arising as a chance clustering of isotropic cosmic rays i... | Cygnus X-3; Extensive air showers; Neutral particles | 1989-01 |
235 |
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Wu, Yong-Shi | High-precision quasienergies for a driven two-level atom at the two-photon preresonance | A computation with unprecedented precision is presented for quasienergies of a two-level atom in a monochromatic radiation on the basis of a recently obtained exact expression [D.-S. Guo et al., Phys. Rev. A 73,023419 (2006)]. We start with the proof of an expression theorem. With this theorem the ... | Quasienergies; Preresonance; Floquet periodicity | 2008-02 |
236 |
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Gondolo, Paolo | Directional recoil rates for WIMP direct detection | New techniques for the laboratory direct detection of dark matter weakly interacting massive particles (WIMPs) are sensitive to the recoil direction of the struck nuclei.We compute and compare the directional recoil rates dR/d cosθ, (where θ is the angle measured from a reference direction in th... | WIMP; Weakly interacting massive particles; WMAP 3; Directional recoil; Halo models | 2008-02 |
237 |
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Bromley, Benjamin C. | Eigenspectral computtations for linear gravity and nonlinear toy models | The periodic standing-wave approach to binary inspiral assumes rigid rotation of gravitational fields and hence helically symmetric solutions. To exploit the symmetry, numerical computations must solve for "helical scalars," fields that are functions only of corotating coordinates, the labels on the... | Binary black holes; General relativity; Standing wave | 2006 |
238 |
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Ailion, David Charles | Nature of Ag+ self-diffusion in AgF | Measurements of the nuclear magnetic resonance (NMR) dipolar relaxation times T w and T i (51°) have been made on the 1 9 F resonance in AgF powder over the temperature range 60-300 K. Also the technique of Stokes and Ailion for detecting the diffusion of weakly magnetic spins has been verified f... | NMR; Nuclear magnetic resonance; Diffusion; Ionic conductivity | 1981 |
239 |
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Sokolsky, Pierre | Measurement of the flux of ultra high energy cosmic rays by the stereo technique | The High Resolution Fly's Eye (HiRes) experiment has measured the flux of ultrahigh energy cosmic rays using the stereoscopic air fluorescence technique. The HiRes experiment consists of two detectors that observe cosmic ray showers via the fluorescence light they emit. HiRes data can be analyzed i... | Ultrahigh energy cosmic rays; Fluorescence; Energy spectrum; GZK cutoff | 2009-08 |
240 |
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Vardeny, Zeev Valentine | Transient photomodulation spectroscopy of nanocrystalline hydrogenated silicon | Transient photomodulation spectra were measured on nanocrystalline Si:H films in the time domain from 10-7 to 10-2 s, spectral range from 0.25 to 1.25 eV, and temperature range from 80 to 300 K. The properties of the spectra are compatible with the presence of two phases, amorphous and crystalline. ... | Transient photomodulation spectroscopy; Nanocrystalline silicon | 1989-03 |
241 |
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Symko, Orest George; Vardeny, Zeev Valentine | Quasiparticle relaxation in a high-Tc superconductor | Recent measurements by Eesley et al. [1] of transient reflectivity in superconducting Tl2Ba2Ca2Cu30io were interpreted as evidence for order-parameter relaxation in the vicinity of Tc, which was analyzed in terms of BCS weak coupling for A(r)/A(0). In this Comment we question this interpretation ... | Quasiparticle relaxation; High-tc | 1991 |
242 |
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Mattis, Daniel C. | Mobility gap and anomalous dispersion | It is shown that anomalous dispersion of quasiparticles leads to nonpropagating states. Therefore regions of anomalous dispersion define a sort of "mobility gap." Using the coherent-potential approximation, we calculate the conditions for obtaining such a mobility gap in a disordered binary alloy. J... | Mobility gap; Disordered media; Quasiparticles | 1973-09 |
243 |
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Mishchenko, Eugene | Transport equations for a two-dimensional electron gas with spin-orbit interaction | The transport equations for a two-dimensional electron gas with spin-orbit interaction are presented. The distribution function is a 232-matrix in the spin space. Particle and energy conservation laws determine the expressions for the electric current and the energy flow. The derived transport equ... | Spin-orbit coupling | 2003-07 |
244 |
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Boehme, Christoph | Effect of exchange coupling on coherently controlled spin-dependent transition rates | The effect of exchange interactions within spin pairs on spin-dependent transport and recombination rates through localized states in semiconductors during coherent electron-spin resonant excitation is studied theoretically. It is shown that for identical spin systems, significant quantitative diff... | Spin coherence; Electron spin nutations | 2008-06 |
245 |
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Ailion, David Charles | Observation of ultraslow translational diffusion in metallic lithium by magnetic resonance | The theory of a new magnetic-resonance technique for studying the ultra slow motion of atoms was presented in a previous paper. In this paper, we present its experimental confirmation for the case of translational diffusion in lithium metal. By this technique the mean time between atomic jumps r can... | Ultraslow atomic motion; Magnetic resonance | 1965 |
246 |
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Gerton, Jordan | Laser-free slow atom source | A slow atom source, which does not rely on lasers, has been developed and characterized. The device, acting as an atomic low-pass velocity filter, utilizes permanent magnets to passively select the slow atoms present in a thermal atomic beam. Slow atoms are guided along a curved, conduction-limite... | | 1999-11 |
247 |
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Vardeny, Zeev Valentine | Picosecond photomodulation spectroscopy in amorphous semiconductors | Picosecond trapping of photogenerated carriers in gap states of doped, compensated and undoped amorphous hydrogenated silicon (a-Si:H) and of a-Si:H based superlattices was studied by the pump and probe photomodulation technique. In undoped a-Si:H the photogenerated carries are trapped in band-tail ... | Picosecond spectroscopy | 1987 |
248 |
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Boehme, Christoph | Room temperature electrical detection of spin coherence in C60 | An experimental demonstration of electrical detection of coherent spin motion of weakly coupled, localized electron spins in thin fullerene C60 films at room temperature is presented. Pulsed electrically detected magnetic resonance experiments on vertical photocurrents through Al/C60/ZnO samples sh... | Spin coherence | 2007-05 |
249 |
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Vardeny, Zeev Valentine | Coherent umklapp scattering of light from disordered photonic crystals | A theoretical study of the coherent light scattering from disordered photonic crystals is presented. In addition to the conventional enhancement of the reflected light intensity into the backscattering direction, the so-called coherent backscattering (CBS), the periodic modulation of the dielectri... | Coherent umklapp scattering; Disordered photonic crystals; Coherent backscattering; Bragg | 2001-05 |
250 |
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Mattis, Daniel C. | Nonlinear lattice dynamics in two dimensions | In general, dynamical and quantum-mechanical properties of anharmonic lattices are best expressed in terms of bond variables. A transformation from atomic (site) to bond coordinates is generated in two dimensions, with the help of a number of subsidiary conditions expressed on plaquettes. It is sho... | Phonons; Plaquettes; Harmonic oscillators; Ferromagnets | 1983-04 |