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CreatorTitleDescriptionSubjectDate
226 DeTar, CarletonNature of the thermal phase transition with Wilson quarksWe 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 transitions1994-04
227 Vardeny, Zeev ValentineTransient and steady-state photoconductivity of a solid C60 filmWe 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 film1993-09
228 Vardeny, Zeev ValentineSpatially mapping random lasing cavitiesA 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 Vardeny, Zeev ValentineFilm morphology and photophysics of polyfluoreneWe 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 morphology2000-12
230 Vardeny, Zeev ValentinePhonon polariton study of CuCl1-x BrxThe 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 Brx1981-08
231 Williams, Clayton C.Instability induced tunneling and repeatable charge injection to SiO2 surfaces by electrostatic force microscopyThe 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 films2004
232 Dawson, KyleThe effects of charge transfer inefficiency (CTI) on galaxy shape measurementsWe 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 Vardeny, Zeev ValentineOptical probes of ∏-conjugated polymer blends with strong acceptor moleculesWe 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 cells2009-05
234 Sokolsky, PierreEvidence for 10^18-eV neutral particles from the direction of Cygnus X-3Analysis 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 particles1989-01
235 Wu, Yong-ShiHigh-precision quasienergies for a driven two-level atom at the two-photon preresonanceA 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 periodicity2008-02
236 Gondolo, PaoloDirectional recoil rates for WIMP direct detectionNew 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 models2008-02
237 Bromley, Benjamin C.Eigenspectral computtations for linear gravity and nonlinear toy modelsThe 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 wave2006
238 Ailion, David CharlesNature of Ag+ self-diffusion in AgFMeasurements 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 conductivity1981
239 Sokolsky, PierreMeasurement of the flux of ultra high energy cosmic rays by the stereo techniqueThe 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 cutoff2009-08
240 Vardeny, Zeev ValentineTransient photomodulation spectroscopy of nanocrystalline hydrogenated siliconTransient 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 silicon1989-03
241 Symko, Orest George; Vardeny, Zeev ValentineQuasiparticle relaxation in a high-Tc superconductorRecent 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-tc1991
242 Mattis, Daniel C.Mobility gap and anomalous dispersionIt 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; Quasiparticles1973-09
243 Mishchenko, EugeneTransport equations for a two-dimensional electron gas with spin-orbit interactionThe 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 coupling2003-07
244 Boehme, ChristophEffect of exchange coupling on coherently controlled spin-dependent transition ratesThe 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 nutations2008-06
245 Ailion, David CharlesObservation of ultraslow translational diffusion in metallic lithium by magnetic resonanceThe 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 resonance1965
246 Gerton, JordanLaser-free slow atom sourceA 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 Vardeny, Zeev ValentinePicosecond photomodulation spectroscopy in amorphous semiconductorsPicosecond 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 spectroscopy1987
248 Boehme, ChristophRoom temperature electrical detection of spin coherence in C60An 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 coherence2007-05
249 Vardeny, Zeev ValentineCoherent umklapp scattering of light from disordered photonic crystalsA 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; Bragg2001-05
250 Mattis, Daniel C.Nonlinear lattice dynamics in two dimensionsIn 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; Ferromagnets1983-04
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