UScholar Works
 
Filters: Department: "Physics" Collection: "ir_uspace"
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CreatorTitleDescriptionSubjectDate
1 Wu, Yong-ShiTime variation of Newton's gravitational constant in superstring theoriesThe present time variation of coupling constants in superstring theories with currently favorable internal backgrounds critically depends on the shape of the potential for the size of the internal space. If the potential is almost flat, as in perturbation theory to all orders, the value of G/G for N...Gravitational constant; Time variation1986-10
2 Mattis, Daniel C.Theory of glass dynamics: the low-lying modes of anharmonic materialsWe study the lowest-lying excited states of arbitrary anharmonic solids (crystalline, glassy, or amorphous). Defining the harmonic ("skeleton") lattice underlying any such anharmonic medium, we find that its spectrum of elementary excitations provides a rigorous upper bound to that of the anharmonic...Spectrum; Arbitrary; Lattices1987
3 Kieda, David B.Status of the VERITAS observatoryAbstract. VERITAS, an Imaging Atmospheric Cherenkov Telescope (IACT) system for gammma-ray astronomy in the GeV-TeV range, has recently completed its first season of observations with a full array of four telescopes. A number of astrophysical gamma-ray sources have been detected, both galactic and e...2008
4 Gondolo, PaoloWanted! Nuclear data for dark matter astrophysicsAstronomical observations from small galaxies to the largest scales in the universe can be consistently explained by the simple idea of dark matter. The nature of dark matter is however still unknown. Empirically it cannot be any of the known particles, and many theories postulate it as a new elemen...2014-01-01
5 Efros, Alexei L.Sensor-based distributed control scheme for mobile robotsIn this paper we present a sensor-based distributed control scheme for mobile robots. This scheme combines centralized and decentralized control strategies. A server-client model is used to implement this scheme where the server is a process that caries out the commands to be executed, and each clie...Sensor-based; Distributed control scheme1995
6 Sokolsky, Pierre; Cassiday, George L.Evidence for a high-energy cosmic-ray spectrum cutoffWe 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 cutoff1985-04
7 DeTar, CarletonSemileptonic decays of heavy mesons with the fat clover actionWe are studying a variety of semileptonic decays of heavy-light mesons in an effort to improve the determination of the heavy-quark Standard-Model CKM matrix elements. Our fermion action is a novel, improved "fat" clover action that promises to reduce problems with exceptional configurations. Dynami...Semileptonic decay; Decay constants; Staggered quarks; Fat-clover valence quarks2000-04
8 Gondolo, PaoloAnnual modulation of dark matter in the presence of streamsIn addition to a smooth component of weakly interacting massive particle (WIMP) dark matter in galaxies, there may be streams of material; the effects of WIMP streams on direct detection experiments is examined in this paper. The contribution to the count rate due to the stream cuts off at some char...WIMP streams; Weakly interacting massive particles; Cutoff energy; Halo models; Sagittarius dwarf galaxy; Recoil energy; Sgr stream2006-08
9 Mattis, Daniel C.Molecular-field theory with correlationsWe derive an improved molecular-field theory for spins 1/2 from first principles. Formulas are obtained for use in cases when the fields, bonds, or occupation of the sites are random variables.Molecular-field theory; Spin glasses1979-05
10 Vardeny, Zeev ValentinePicosecond dynamics of carriers in amorphous semiconductorsUsing time resolved photoinduced absorption with subpicosecond resolution we studied hot carrier thermalization followed by deep trapping and recombination in a-Si, a-Si:H, a-Si:F, a-Si:H:F and a-As2Se3. In a-Se and a-As2S3_xSex (0.25 < x < 0.75) the observed relaxations were attributed to geminat...Excess carriers; Thermalization1981-10
11 Gondolo, PaoloMeasurement of the gluon parton distribution function at small x with neutrino telescopesWe analyze the possibility that neutrino telescopes may provide an experimental determination of the slope λ of the gluon distribution in the proton at momentum fractions x smaller than the accelerator reach. The method is based on a linear relation between λ and the spectral index (slope) of th...Neutrino telescopes; Charm2001-01
12 Gondolo, PaoloStellar orbit constraints on neutralino annihilation at the galactic centerDark matter annihilation has been proposed to explain the TeV gamma rays observed from the Galactic Center. We study constraints on this hypothesis coming from the mass profile around the Galactic Center measured by observing stellar dynamics. We show that for several proposed WIMP candidates, the...Neutralinos; Annihilation2006-09
13 Gondolo, PaoloIndirect detection of dark matter in km-size neutrino telescopesNeutrino telescopes of kilometer size are currently being planned. They will be two or three orders of magnitude larger than presently operating detectors, but they will have a much higher muon energy threshold. We discuss the trade-off between area and energy threshold for indirect detection of ne...Neutrino telescopes; Energy threshold; Neutralino annihilations; Supersymmetric models1999
14 Gondolo, PaoloNeutralinos as dark matter in the minimal supergravity modelA new approach to the phenomenological study of the minimal supergravity model is presented in which the model is effectively parametrized in terms of five low energy observables. Radiative corrections due to large Yukawa couplings and particle-sparticle mass splitting are included into the analysis...Neutralinos1992
15 Wu, Yong-ShiChiral bosonization and local Lorentz-invariant actions for chiral bosonsWe formulate a geometrical theory of self-dual scalar fields in two dimensions with a local Lorentz-invariant action. Path-integral quantization is used to derive chiral bosonization by demonstrating equivalence of correlation functions of currents and energy-momentum tensors in our theory with thos...Bosonization; String theory; Weyl fermions1988-06
16 Ailion, David CharlesFloating of the modulation wave and phase pinning in incommensurate Rb2ZnBr4Nuclear-magnetic-resonance measurements in incommensurate Rb2ZnBr4 show the existence of regions where the modulation wave is floating. The floating regions coexist with other regions where the modulation wave is static. Impurity phase pinning and a roughening of the modulation wave at higher temper...Floating; Incommensurate phase; Phason mode; Lattices1983
17 Gondolo, PaoloSolar neutrino limit on axions and keV-mass bosonsThe 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-mass2009-05
18 Mattis, Daniel C.Symmetry of ground state in a dilute magnetic metal alloyIt is proved that the spin of the ground state of a magnetic atom having exchange interaction with a nonmagnetic host metal is s ± ½, where s =spin of noninteracting magnetic atom, the upper sign is appropriate to antiferromagnetic coupling, and the lower, to ferromagnetic coupling. This result is...Magnetic impurity1967-12
19 Gondolo, PaoloAGAPE: a search for dark matter in M31 by microlensing effects on unresolved starsM 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 lensing1997
20 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
21 Gondolo, PaoloDark Stars: the first stars in the universe may be powered by dark matter healingA new line of research on Dark Stars is reviewed, which suggests that the first stars to exist in the universe were powered by dark matter heating rather than by fusion. Weakly Interacting Massive Particles, which may be there own antipartmers, collect inside the first stars and annihilate to produc...Dark stars; WIMP; Weakly interacting massive particles2009
22 Gondolo, PaoloAxion cold dark matter in view of BICEP2 resultsThe properties of axions that constitute 100% of cold dark matter (CDM) depend on the tensor-to-scalar ratio r at the end of inflation. If r ¼ 0.20 þ0.07 −0.05 as reported by the BICEP2 Collaboration, then "half" of the CDM axion parameter space is ruled out. Namely, in the context of single-fie...2014-01-01
23 Rogachev, AndreyInfluence of high magnetic fields on the superconducting transition of one-dimensional Nb and MoGe nanowiresThe effects of a strong magnetic field on superconducting Nb and MoGe nanowires with diameter ~10 nm have been studied. We have found that the Langer-Ambegaokar-McCumber-Halperin (LAMH) theory of thermally activated phase slips is applicable in a wide range of magnetic fields and describes well the ...Nb; MoGe; Superconducting transition; Langer-Ambegaokar-McCumber-Halperin; LAMH; Phase slips2005-01
24 Lupton, John MarkLinewidth-limited energy transfer in single conjugated polymer moleculesUsing low temperature single molecule spectroscopy on rigid-rod conjugated polymers we are able to identify homogeneously broadened, strongly polarized emission from individual chromophore units on a single chain. Gated fluorescence spectroscopy allows real time imaging of intramolecular energy tran...Linewidth-limited; Energy transfer; Rigid-rod; Single molecule spectroscopy; Gated fluorescence spectroscopy; Chromophores; Intramolecular energy transfer; Spectral linewidth2003-12
25 Mishchenko, EugeneNonlinear voltage dependence of the shot noise in mesoscopic degenerate conductors with strong electron-electron scatteringIt is shown that measurements of zero-frequency shot noise can provide information on electron-electron interaction, because the strong interaction results in the nonlinear voltage dependence of the shot noise in metallic wires. This is due to the fact that the Wiedemann-Franz law is no longer vali...Shot noise; Degenerate conductors2000-11
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