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Creator | Title | Description | Subject | Date |
| 151 |
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Wu, Yong-Shi | Multiparticle quantum mechanics obeying fractional statistics | We obtain the rule governing many-body wave functions for particles obeying fractional statistics in two (space) dimensions. It generalizes and continuously interpolates the usual symmetrization and antisymmetrization. Quantum mechanics of more than two particles is discussed and some new features a... | Multiparticle quantum mechanics; Fractional statistics | 1984-07 |
| 152 |
 |
Vardeny, Zeev Valentine | Photoinduced absorption spectra in α-GeH and α-Si:H | Measurements of steady-state photoinduced absorption in α-Ge:H and α-Si:H were extended to cover the energy range from 0.25 to 1.9 eV. The subgap photoinduced-absorption bands in both materials are interpreted in terms of four kinds of optical transitions of photogenerated carriers from traps in ... | Photoinduced absorption; in a-GeH; a-Si:H; Amorphous germanium; Amorphous silicon | 1984-07 |
| 153 |
 |
Vardeny, Zeev Valentine | Mechanism for photogeneration of charge carriers in polyacetylene | In light of new experimental observations, a mechanism for the photogeneration of charge carriers in trans-polyacetylene is presented. By way of introduction, we discuss the qualitative changes in the picture of charged-soliton photogeneration that are expected due to the inclusion of electron corre... | Photogeneration; Charge carriers; Photocarriers | 1984-07 |
| 154 |
 |
Vardeny, Zeev Valentine | Coherent phonon generation and detection by picosecond light pulses | Using the picosecond pump and probe technique we have detected oscillations of photoinduced transmission and reflection in thin films of α-As2Te3 and cis-polyacetylene. These oscillations are due to the generation and propagation of coherent acoustic phonons in the film. We discuss the generation ... | a-As2Te3; Cis-polyacetylene; Pump and probe technique | 1984-09 |
| 155 |
 |
Williams, Clayton C. | High-resolution photothermal laser probe | An advance in photothermal imaging is described. A photothermal laser probe is presented that operates at a frequency of 1 GHz. At this frequency the spacial resolution is limited only by the optical spot size of the probe beam. The photothermal sensitivity of the probe is 1.2 X 10-4 degrees Celsiu... | Laser probes | 1985 |
| 156 |
 |
Ailion, David Charles; Morris, Alan H. | Asymmetric spin echo sequences. a simple new method for obtaining NMR 1H spectral images | The nuclear magnetic resonance (NMR) signal decay produced by reversible tissue-induced dephasing of the magnetization components in the transverse plane (reversible tissue-induced dephasing) was measured and expressed as a function of a new transverse relaxation time T'2 (T2 prime) for samples of ... | Asymmetric spin echo; Signal decay; Chemical shift; Tissue characterization; Lung aeration; Fatty liver | 1985 |
| 157 |
 |
Mattis, Daniel C. | Tricritical point in random-field Ising model | The numerical investigation of the random-field Ising model by Houghton, Khurana, and Seco1 has revealed a number of interesting features concerning the three-dimensional Ising model in a random external field Bt. Earlier, Aharony2 had already found that even in a mean-field approximation the b... | Random external field; Tricritical points; Gaussian distribution | 1985 |
| 158 |
 |
Symko, Orest George | Spin glass behavior of Cd1-xMnxTe below the nearest-neighbor percolation limit | Magnetization measurements down to 10 mK of Cd, _ x Mn, Te for Mn concentrations 0.01<x<0.15 show spin glass behavior. Such behavior is attributed to short-range exchange and dipolar interactions. Both interactions are used to explain the concentration dependence of the spin freezing temperatures fo... | Spin glass behavior; Cd1-xMnxTe | 1985 |
| 159 |
 |
Vardeny, Zeev Valentine | Effect of bias illumination on photoinduced absorption decay in ?-Si:H | Zeldov and Weiser1 proposed a model to explain the influence of optical biasing on the decay of photoinduced absorption (PA) in ?-Si:H at high temperatures observed by Pfost, Vardeny, and Tauc.2 This model differs from the model originally used2 for interpreting the experimental data at temperatures... | Optical biasing; Bias illumination; Photoinduced absorption decay; a-Si:H; Amorphous silicon | 1985 |
| 160 |
 |
Ailion, David Charles | Commensurability and defect-induced phason gaps in incommensurate systems | The phason energy gap has been observed to increase on going from the incommensurate to higher-order commensurate phases in the "devil's staircase" compound [N(CH3)4]2ZnCl4. The gap was determined via the phason-induced 1 4N spin-lattice relaxation contribution, which was obtained from the variati... | Phasons; Commensurate; Incommensurate; Lattices; Modulation | 1985 |
| 161 |
 |
Ailion, David Charles | NMR spectra and relaxation in incommensurate systems in the presence of a devil's staircase | The possibility of discriminating true incommensurate phases from long period commensurate phases via NMR lineshape and spin-lattice relaxation measurements is discussed. The theoretical results are compared with experimental data in Rb2ZnCl4, Rb2ZnBr4, and [N(CH3)4]2ZnCl4. Devil's staircase effects... | Incommensurate phases; Commensurate phases; Phason gap; Spin-lattice relaxation | 1985 |
| 162 |
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Wu, Yong-Shi | Remarks on fractional statistics | Some issues in the theory of fractional (or intermediate) statistics are discussed with an eye on possible applications to the quantum Hall effect: spins and statistics of clusters, invariant characterization of statistics, and the effect of space topology. | Fractional statistics | 1985-01 |
| 163 |
 |
Vardeny, Zeev Valentine; Ehrenfreund, Eitan A. | Classification of disorder and extrinsic order in polymers by resonant Raman scattering | Resonant Raman scattering is used to quantify the effect of disorder and extrinsic order on Peierls systems such as (CH)X . We introduce "X plots" in which the phonon and gap distribution are related and characterize the system by the functional dependence of the gap 2 A on the coupling X. For c/s-r... | Peierls systems | 1985-01 |
| 164 |
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Wu, Yong-Shi | Quantized Hall conductance as a topological invariant | Whenever the Fermi level lies in a gap (or mobility gap) the bulk Hall conductance can be expressed in a topologically invariant form showing the quantization explicitly. The new formulation generalizes the earlier result by Thouless, Kohmoto, Nightingale, and den Nijs to the situation where many-bo... | Hall conductance; Fermi gap; Degeneracy | 1985-03 |
| 165 |
 |
Vardeny, Zeev Valentine | Method for direct determination of the effective correlation energy of defects in semiconductors: optical modulation spectroscopy of dangling bonds | The optical modulation technique is used for direct determination of energy levels and the effective correlation energy U/eff of dangling-bond defects. With an accuracy of 0.1 eV we found for the dangling-bond defect in α-Si:H, f/e f f=0.5 eV; in α-As2S3, £/e f f= - 1.0 eV; in As2Se3, Ueff = -0.7... | Dangling bonds; Correlation energy | 1985-04 |
| 166 |
 |
Mattis, Daniel C. | Comment on "Ground-state properties of a spin-1 antiferromagnetic chain | Botet and Jullien [Phys. Rev. B 27, 613 (1983)] and Botet, Jullien, and Kolb [Phys. Rev. B 28, 3914 (1983)] performed a finite-size scaling analysis of the spin-1 antiferromagnetic Heisenberg-Ising chain. Their work was criticized by Bonner and Mtiller [Phys. Rev. B 29, 5216 (1984)] on the grounds... | Antiferromagnets; Ground-state; Ising chain; Energy gap | 1985-04 |
| 167 |
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Sokolsky, Pierre; Cassiday, George L. | Evidence for a high-energy cosmic-ray spectrum cutoff | We report a measurement of the ultrahigh-energy cosmic-ray spectrum using an atmospheric fluorescence technique for extensive-air-shower detection. The differential spectrum between 0.1 and 10 EeV (1 EeV = 10^18 eV) is well fitted by a power law with slope 2.94 ±0.02. Above 10 EeV evidence is prese... | Energy spectrum; Extensive air showers; Spectral cutoff | 1985-04 |
| 168 |
 |
Sokolsky, Pierre; Cassiday, George L. | Limits on deeply penetrating particles in the >10^17 eV cosmic-ray flux | We report on a search for deeply penetrating particles in the > 10^17 eV cosmic-ray flux using the University of Utah Fly's Eye detector. No such events have been found in 6 x 106 sec of running time. We consequently set limits on the following: quark matter in the primary cosmic-ray flux, high-ener... | | 1985-05 |
| 169 |
 |
Wu, Yong-Shi | Fractional statistics and fractional quantized Hall effect | We suggest that the origin of the odd-denominator rule observed in the fractional quantized Hall effect (FQHE) may lie in fractional statistics which govern quasiparticles in FQHE. A theorem concerning statistics of clusters of quasiparticles implies that fractional statistics do not allow coexist... | Fractional statistics; Quasielectrons; Quasiholes | 1985-05 |
| 170 |
 |
Mattis, Daniel C. | Ground state of the Kondo model | The single-impurity Kondo problem is investigated with the use of the nonperturbative Lanczos (tridiagonalization) method. We are able to obtain an explicit expression for the ground-state energy in terms of the Kondo coupling constant J. The method places no restrictions on the range of J. | Kondo model; Ground-state energy; Coupling constant | 1985-06 |
| 171 |
 |
DeTar, Carleton | Conjecture concerning the modes of excitation of the quark-gluon plasma | It is a widely held belief that at temperatures much higher than the confinement scale of quantumchromodynamics (QCD), quarks and gluons become free, giving rise to a new form of matter, called the quark-gluon plasma. It is conjectured here that the characterization of the plasma as a free or weakl... | Polyakov loops; Excitation | 1985-07 |
| 172 |
 |
Mattis, Daniel C. | Effect of exciton hopping upon the mass of an exciton | A plausible formula derived in a previous paper for the mass Mn* of an exciton in an nth bound state of the electron-hole binding potential is extended so as to include the effect of an exciton-hopping (or Heller-Marcus) mechanism upon Mn*. | Frenkel excitons; Exciton-hopping; Heller-Marcus energy; Binding potential | 1985-10 |
| 173 |
 |
Wu, Yong-Shi | Quantum dynamics and statistics of vortices in two-dimensional superfluids | The phase change of the wave function of a superfluid film as a vortex moves around a closed path counts the number of superfluid particles enclosed by that path. This result is used to investigate whether such vortices obey "fractional statistics." We conclude that this is not the case in compress... | Superfluid films; Vortices; Fractional statistics | 1985-12 |
| 174 |
 |
Ailion, David Charles | Nuclear magnetic resonance in random fields: cluster formation and local dynamics of a deuteron glass | NMR data show that the deuteron "pseudo spin-glass" transition in Rbi- X(ND4)*D2P04 is not just a simple kinetic slowing down process but is characterized by a gradual condensation of randomly polarized clusters as expected if we deal with a percolation transition in eigenstate space. The results pr... | NMR; Nuclear magnetic resonance; Random fields; Spin lattice | 1986 |
| 175 |
 |
Vardeny, Zeev Valentine | Picosecond dynamics of photoexcitations in amorphous multilayer structures | We report on measurements of ultrafast relaxation processes in transmission and reflection in amorphous multilayer structures consisting of a-Si:H, a-SiNx:H, a-SiOx:H, and a-Ge:H. The decays recorded in transmission in the a-Si:H/a-SiNx :H and a-Si:H/a-SiOx :H multilayers depend strongly on the sili... | Photoexcitations | 1986 |
