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Creator | Title | Description | Subject | Date |
| 251 |
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Wu, Yong-Shi | On gauge invariance of noncommutative Chern-Simons theories | Motivated by possible applications to condensed matter systems, in this paper we construct U(N) noncommutative Chern-Simons (NCCS) action for a disc and for a double-layer geometry, respectively. In both cases, gauge invariance severely constrains the form of the NCCS action. In the first case, it ... | | 2002-05 |
| 252 |
 |
Ailion, David Charles | Frequency modulation method for performing adiabatic demagnetization in the rotating reference frame | A new method for preforming adiabatic demagnetization in the rotating reference frame in NMR experiments is presented in this paper. In this new method the frequency of a crystal oscillator rather than the actual magnetic field is pulsed off resonance. Using simple circuits which are described in th... | Demagnetization; Physics experiments; NMR | 1970 |
| 253 |
 |
Vardeny, Zeev Valentine | Exciton dynamics in single-walled nanotubes: transient photoinduced dichroism and polarized emission | Ultrafast relaxation of photoexcitations in semiconducting single-walled carbon nanotubes (S-NTs) were investigated using polarized pump-probe photomodulation (with 150 fs time resolution) and cw polarized photoluminescence (PL). Both annealed and unannealed thin NT films and D2O solutions of isola... | Exciton dynamics; Single-walled carbon nanotubes; SWNT; Transient photoinduced dichroism; Polarized emission; Ultrafast relaxation; Photoexcitations | 2005-03 |
| 254 |
 |
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 |
| 255 |
 |
Mattis, Daniel C. | Phase transition of model interacting chains | The partition function of n interacting chains having a phase transition at Tc(n) is reduced, by the transfer-matrix formalism, to the determination of an w-body bound state in one dimension. Subject to mild restrictions on the potentials, this w-body problem can be analyzed in terms of a two-body p... | Phase transition; Interacting chains | 1981-12 |
| 256 |
 |
Gondolo, Paolo | Solar neutrino limit on axions and keV-mass bosons | The all-flavor solar neutrino flux measured by the Sudbury Neutrino Observatory constrains nonstandard energy losses to less than about 10% of the Sun's photon luminosity, superseding a helioseismological argument and providing new limits on the interaction strength of low-mass particles. For the ... | Interaction strength; keV-mass | 2009-05 |
| 257 |
 |
Vardeny, Zeev Valentine | Ultrafast spectroscopy of even-parity states in ∏-conjugated polymers | Relaxation dynamics of even parity (Ag) states in poly(p-phenylene vinylene) derivatives are studied using a novel fsec transient spectroscopy, in which two different excitation pulses successively generate odd parity (1 1Bµ) excitons at 2.2 eV and then reexcite them to higher Ag states. For reexci... | pi-conjugated polymers; Ultrafast spectroscopy; PPV; Relaxation dynamics | 2000-09 |
| 258 |
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Vardeny, Zeev Valentine | Photophysics of excitons in quasi-one-dimensional organic semiconductors: single-walled carbon nanotubes and ∏-conjugated polymers | The nature of the primary photoexcitations in semiconducting single-walled carbon nanotubes (S-SWCNTs) is of strong current interest. We have studied the emission spectra of S-SWCNTs and two different rr-conjugated polymers in solutions and films, and have also performed ultrafast pump-probe spectro... | Photophysics; Excitons; Quasi-one-dimensional; Single-walled carbon nanotubes; pi-conjugated polymers | 2006-02 |
| 259 |
 |
Vardeny, Zeev Valentine | Interchain photogeneration of charged solitons in trans-(CH)x | In a recent Letter1 Rothberg, Jedju, Etemad, and Baker (RJEB) used a novel photoinduced-absorption (PA) technique to study charged-soliton (S ?) dynamics in trans-(CH)X with picosecond resolution by measuring transient PA at 0.45 eV. Both intrachain and interchain photogeneration of S ? are rep... | Interchain photogeneration; Charged solitons; Trans-(CH)x | 1987 |
| 260 |
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DeTar, Carleton | Critical behavior at the chiral phase transition | It is generally expected that two-flavor QCD undergoes a high temperature chiral symmetry restoring phase transition at zero quark mass, with O(4) critical behavior[1]. Verifying this expectation is important for understanding the phenomenology of the transition and for facilitating an extrapolation... | Phase transitions; Staggered fermions | 1998-04 |
| 261 |
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Gondolo, Paolo | Dark Stars: Död och Återuppståndelse | The first phase of stellar evolution in the history of the universe may be Dark Stars, powered by dark matter heating rather than by fusion. Weakly interacting massive particles, which are their own antiparticles, can annihilate and provide an important heat source for the first stars in the univers... | Dark stars; WIMP; Weakly interacting massive particles | 2009 |
| 262 |
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DeTar, Carleton | Static screening lengths in the gluon plasma | We report results of an extensive numerical simulation in lattice gauge theory to study various static screening lengths in a finite-temperature pure gluon plasma. Measurements are made for fixed triplet charges (Wilson lines) and a variety of local operators near and above the phase transition for ... | Gluon plasma; Phase transitions; Deconfinement; Strange quarks | 1986-10 |
| 263 |
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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 |
| 264 |
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Wu, Yong-Shi | Absence of (1,0) supersymmetry anomaly in world-sheet gauge theories: a purely cohomological proof | A purely cohomological proof is given for the absence of the (1,0) supersymmetry anomaly in gauge theories on a world sheet. In particular, it is shown that generalized cohomological approaches to anomalies in supersymmetric gauge theory, either formulated in whole superconnection space or only in t... | World sheet; String theory; Superfields; Superspace | 1989-01 |
| 265 |
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Gondolo, Paolo | AGAPE: a search for dark matter in M31 by microlensing effects on unresolved stars | M 31 is a very tempting target for a microlensing search of compact objects in galactic haloes. It is the nearest large galaxy, it probably has its own dark halo, and its tilted position with respect to the line of sight provides an unmistakable signature of microlensing. However most stars of M 31... | M31; AGAPE; Pixel method; Galaxy; Halo; Cosmology; Gravitational lensing | 1997 |
| 266 |
 |
Gerton, Jordan | Nanoscale fluorescence microscopy using carbon nanotubes | We demonstrate the use of single-walled carbon nanotubes as nano-optical probes in apertureless near-field fluorescence microscopy. The carbon nanotubes strongly quench fluorescence leading to near-field contrast with spatial resolution of ~20 nm. | | 2008-07 |
| 267 |
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Mattis, Daniel C. | Eigenstates of N excitons and one hole | We solve for the eigenstates and energy eigenvalues of N immobile Frenkel excitons (a relatively trivial proposition) and of N such excitons plus one hole (which for large N can only be done in one dimension). We also guess that a charged globule, consisting of N excitons and O(N) holes, can be stab... | Eigenstates; Frenkel excitons; Many-body problem | 1983-04 |
| 268 |
 |
Vardeny, Zeev Valentine | Nonlinear optical spectroscopy of excited states in disubstituted polyacetylene | We used a variety of nonlinear optical (NLO) spectroscopies for studying the excited states order and primary photoexcitations in disubstituted polyacetylene (DPA). The NLO spectroscopies include ultrafast pump-probe photomodulation in a broad spectral range of 0.2-2.5 eV, two-photon absorption in... | | 2010-05 |
| 269 |
 |
Vardeny, Zeev Valentine | Recombination kinetics in ?-Si:H | Mort et al.1 reinterpreted our data on the relaxation of photoinduced absorption (PA) in a-Si:H. 2 We want to show that the proposed interpretation contradicts one basic feature of the data while our original interpretation is in good agreement with experiment. | Hydrogenated amorphous silicon; a-Si:H; Recombination kinetics; Photoinduced absorption; Decay; Relaxation | 1981 |
| 270 |
 |
DeTar, Carleton | Exotic hybrid mesons with light quarks | Hybrid mesons, made from a quark, an antiquark and gluons, can have quantum numbers inaccessible to conventional quark-antiquark states. Confirmation of such states would give information on the role of "dynamical" color in low energy QCD. We present preliminary results for hybrid meson masses using... | Hybrid mesons; Kogut-Susskind quarks; Wilson quarks | 1997-02 |
| 271 |
 |
Vardeny, Zeev Valentine | Resonant Raman-scattering spectroscopy of polydiacetylene films at high pressure | We studied the electronic energies and phonon frequencies of polydiacetylene 4-BCMU thin films at high pressures up to 50 kbar using Raman scattering under preresonant and resonant conditions. Pressure-induced changes in the resonant Raman scattering (RRS) include (1) hardening of the most strongly... | Resonant raman scattering spectroscopy; Polydiacetylene films; Pi-conjugated polymers | 1993-02 |
| 272 |
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Wu, Yong-Shi | Overcoming the slowing down of flat-histogram Monte Carlo simulations: cluster updates and optimized broad-histogram ensembles | We study the performance of Monte Carlo simulations that sample a broad histogram in energy by determining the mean first-passage time to span the entire energy space of d-dimensional ferromagnetic Ising/Potts models. We first show that flat-histogram Monte Carlo methods with single-spin flip upda... | Energy space; Spin dynamics; Density of states; Cluster dynamics | 2005-10 |
| 273 |
 |
Symko, Orest George | Superconducting microphone for photoacoustic spectroscopy | A superconducting microphone has been developed for photoacoustic spectroscopy at low temperatures. The microphone consists of a thin mylar membrane coated with a film of lead whose motion is detected by SQUID magnetometer. For the simple set-up presented here, the limiting pressure sensitivity is ... | Superconducting microphone; Photoacoustic spectroscopy; Low temperatures | 1982 |
| 274 |
 |
Williams, Clayton C. | Atomic force microscope-force mapping and profiling on a sub 100-Å scale | A modified version of the atomic force microscope is introduced that enables a precise measurement of the force between a tip and a sample over a tip-sample distance range of 30-150Å. As an application, the force signal is used to maintain the tip-sample spacing constant, so that profiling can be ... | Attractive force; Silicon wafer | 1987 |
| 275 |
 |
Mishchenko, Eugene | Electronic Raman scattering in a magnetic field | Raman scattering in a magnetic field is proposed as a possible method to solve the problem of whether the light scattering in high-Tc superconductors comes from conduction electrons or not. The electronic Raman light scattering in a magnetic field is studied theoretically. The semiclassical approa... | Raman scattering | 1996-01 |
