UScholar Works
 
Filters: Department: "Physics" Collection: "ir_uspace"
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CreatorTitleDescriptionSubjectDate
1 Saam, BrianPhase relationship between the long-time beats of free induction decays and spin echoes in solidsRecent theoretical work on the role of microscopic chaos in the dynamics and relaxation of many-body quantum systems has made several experimentally confirmed predictions about the systems of interacting nuclear spins in solids, focusing in particular on the shapes of spin echo responses measured by...2012-01-01
2 Vardeny, Zeev ValentinePhotoexcitation dynamics in polythiophene/fullerene blends for photovoltaic applicationsWe used the transient and steady state photomodulation spectroscopies for studying the photoexcitations dynamics in blends of regio-regular poly(3-hexylthiophene) (RR-P3HT) and fullerene in a broad spectral range from 0.15 to 2.25 eV. We found that both localized polarons and singlet excitons are in...2012-01-01
3 Mishchenko, EugeneResonant finite-size impurities in graphene, unitary limit, and Friedel oscillationsA unitary limit for model point scatterers in graphene is known to reveal low-energy resonances. The same limit could be achieved from hybridization of band electrons with the localized impurity level positioned in the vicinity of the Fermi level. The finite-size defects represent an easier realizat...2012-01-01
4 Gondolo, PaoloSimple renormalizable flavor symmetry for neutrino oscillationsThe recent measurement of a nonzero neutrino mixing angle θ13 requires a modification of the tri-bimaximal mixing pattern that predicts a zero value for it. We propose a new neutrino mixing pattern based on a spontaneously broken A4 flavor symmetry and a type-I seesaw mechanism. Our model allows fo...2012-01-01
5 Mattis, Daniel C.PrefaceIt was the early 1960s. Elliott H. Lieb and the present author were colleagues at the IBM Research Laboratories in Yorktown Heights, occupying neighboring cubicles. We collaborated in the study, creation and solution of mathematical models of many-body phenomena. In the course of this work we ultima...2012-01-01
6 Symko, Orest GeorgeUltrasonic thermoacoustic energy converterThermoacoustic prime movers have been developed for operation in the low ultrasonic frequency range by scaling down the device size. The developed engines operate at frequencies up to 23 kHz. They are self-sustained oscillators whose dimensions scale inversely with operating frequency. The smallest ...2012-01-01
7 Wu, Yong-ShiEmergent exclusion statistics of quasiparticles in two-dimensional topological phasesWe demonstrate how the generalized Pauli exclusion principle emerges for quasiparticle excitations in 2D topological phases. As an example, we examine the Levin-Wen model with the Fibonacci data (specified in the text), and construct the number operator for fluxons living on plaquettes. By numerical...2014-01-01
8 Gondolo, PaoloHalo independent comparison of direct dark matter detection dataWe extend the halo-independent method of Fox, Liu, and Weiner to include energy resolution and efficiency with arbitrary energy dependence, making it more suitable for experiments to use in pre-senting their results. Then we compare measurements and upper limits on the direct detection of low mass (...2012-01-01
9 Rogachev, AndreyMagnetic-field dependent differential capacitance of polymer diodesUsing admittance spectroscopy, we found that bipolar organic diodes based on pi-conjugated polymer, 2-methoxy-5-(20-ethylhexyloxy), MEH-PPV, have strong divergent contribution to the device differential capacitance. It is positive at low bias voltages, turns negative at intermediate biases, and beco...2012-01-01
10 Gondolo, PaoloThe effect of quark interactions on dark matter kinetic decoupling and the mass of the smallest dark halosThe kinetic decoupling of dark matter (DM) from the primordial plasma sets the size of the first and smallest DM halos. Studies of the DM kinetic decoupling have hitherto mostly neglected interactions between the DM and the quarks in the plasma. Here we illustrate their importance using two framewor...2012-01-01
11 Gerton, JordanEffect of magnetic Gd impurities on the superconducting state of amorphous Mo-Ge thin films with different thickness and morphologyWe studied the effect of magnetic doping with Gd atoms on the superconducting properties of amorphous Mo70Ge30 films. We observed that in uniform films deposited on amorphous Ge, the pair-breaking strength per impurity strongly decreases with film thickness initially and saturates at a finite value ...2012-01-01
12 Gondolo, PaoloDark stars: BegynnelsenThe 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; Annihilations2009
13 Ailion, David CharlesNuclear magnetic resonance study of diffusion of bound and free fluorine interstitials in alkaline earth fluorides doped with trivalent impuritiesWhen alkaline-earth fluorides are doped with trivalent impurities, interstitial fluorines are created to maintain charge neutrality. We have performed NMR dipolar-energy relaxation measurements over a wide temperature range and have observed the diffusion of both free and locally bound fluorine inte...Diffusion; Motion; Crystals; NMR; Fluorine1979
14 Vardeny, Zeev Valentine; Nahata, AjayResonantly-enhanced transmission through a periodic array of subwavelength apertures in heavily-doped conducting polymer filmsWe observed resonantly-enhanced terahertz transmission through two-dimensional (2D) periodic arrays of subwavelength apertures with various periodicities fabricated on metallic organic conducting polymer films of polypyrrole heavily doped with PF6 molecules [PPy(PF6)]. The"anomalous transmission" s...Resonantly enhanced transmission; Subwavelength apertures; Polypyrrole; PPy(PF6)2006
15 Mattis, Daniel C.Extinction of antiferromagnetism by holes in CuO2The introduction of a sufficient number of holes into antiferromagnetic planes of Cu02 in La-Cu-O and Y-Ba-Cu-O causes antiferromagnetism to disappear at a critical density xc, beyond which superconductivity occurs. We investigate two competing tendencies, which determine the dependence of xc on the...Antiferromagnets1991-08
16 Vardeny, Zeev Valentine; Ehrenfreund, Eitan A.Linear and nonlinear photoexcitation dynamics in ∏-conjugated polymersLinear and nonlinear recombination kinetics with various lifetime distributions were identified for long-lived photoexcitations in a series of rr-conjugated polymer films using modulation frequency and excitation intensity dependencies of the photoinduced absorption. This includes monomolecular, bim...Linear photoexcitation; Nonlinear photoexcitation; pi-conjugated polymers; Recombination kinetics2003-01
17 DeTar, CarletonPotts flux tube model at nonzero chemical potentialWe model the deconfinement phase transition in quantum chromodynamics at nonzero baryon number density and large quark mass by extending the flux tube model ~three-state, three-dimensional Potts model! to nonzero chemical potential. In a direct numerical simulation we confirm mean-field-theory pre...Phase transitions; Quark-gluon plasma; Chemical potential; Potts model2000-03
18 Vardeny, Zeev ValentinePolarization memory decay spectroscopy of photoexcitations in ∏-conjugated polymers: evidence for excimersWe used the technique of ultrafast transient polarized photomodulation in the visible/near-infrared range and polarization memory decay (PMD) spectroscopy to study the primary photoexcitations in films and solutions of two poly(phenylene-vinylene) (PPV) derivatives, namely, 2-methoxy-5-(2'-ethylhex...Photoexcitations; pi-conjugated polymers; Polarization memory decay spectroscopy; PMD; DOO-PPV; MEH-PPV; Ultrafast transient polarized photomodulation; Intrachain singlet excitons; Excimers; Interchain charge transfer exciton2008-05
19 Gondolo, PaoloImproved constraints on supersymmetric dark matter from muon g-2The new measurement of the anomalous magnetic moment of the muon by the Brookhaven AGS experiment 821 again shows a discrepancy with the standard model value. We investigate the consequences of these new data for neutralino dark matter, updating and extending our previous work [E. A. Baltz and P. ...Magnetic moment; Neutralinos2003-03
20 Wu, Yong-ShiOpen spin chain and open spinning stringIn this letter, we study the open spinning strings and their SYM duals. A new class of folded open spinning strings is found. At planar one-loop level in SYM, by solving the thermodynamic limit of the Bethe ansatz equations for an integrable open spin chain, we find good agreement with string theory...2004-07
21 Kieda, David B.; Bergman, Douglas R.; Sokolsky, PierreMeasurement of the flux of ultrahigh energy cosmic rays from monocular observations by the high resolution fly's eye experimentWe have measured the cosmic ray spectrum above 10^172 eV using the two air-fluorescence detectors of the High Resolution Fly's Eye observatory operating in monocular mode.We describe the detector, phototube, and atmospheric calibrations, as well as the analysis techniques for the two detectors.We ...High Resolution Fly's Eye; Ultrahigh energy cosmic rays2004-04
22 Wu, Yong-ShiAlgebraic and geometric aspects of generalized quantum dynamicsWe briefly discuss some algebraic and geometric aspects of the generalized Poisson bracket and noncommutative phase space for generalized quantum dynamics, which are analogous to properties of the classical Poisson bracket and ordinary symplectic structure.Quantum dynamics; Jacobi identity1994-06
23 Wu, Yong-ShiGround-state degeneracy in the Levin-Wen model for topological phasesWe study the properties of topological phases by calculating the ground-state degeneracy (GSD) of the two-dimensional Levin-Wen (LW) model. Here it is explicitly shown that the GSD depends only on the spatial topology of the system. Then we show that the ground state on a sphere is always nondegener...2012-01-01
24 Lupton, John MarkMechanisms of spin-dependent dark conductivity in films of a soluble fullerene derivative under bipolar injectionWe report room-temperature pulsed electrically detected magnetic resonance measurements of the dark conductivity of films of the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) under bipolar (electron-hole) and unipolar (electron-rich) injection conditions. Directly after mate...2014-01-01
25 Vardeny, Zeev ValentineMechanically stretchable and reversibly deformable liquid metal-based plasmonicsWe demonstrate that liquid metals are attractive materials for active plasmonic devices at terahertz frequencies. Using a liquid metal injected into an elastomeric mold, we measure the static and stretched transmission properties of aperture arrays.2012-01-01
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