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CreatorTitleDescriptionSubjectDate
76 Vardeny, Zeev ValentineUniversal properties of quasi-one-dimensional excitons in semiconducting single-walled carbon nanotubes and ∏-conjugated polymersThe 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 spectr...Carbon nanotubes; pi-conjugated polymers; SWCNT; Photoexcitation; Optoelectronic properties; Quasi-one-dimensional2006
77 Gondolo, PaoloClumpy neutralino dark matterWe investigate the possibility to detect neutralino dark matter in a scenario in which the galactic dark halo is clumpy. We find that under customary assumptions on various astrophysical parameters, the antiproton and continuum γ-ray signals from neutralino annihilation in the halo put the strong...Neutralinos; Clumpiness1999-01
78 Vardeny, Zeev ValentineOptical probes of excited states in poly (p-phenylenevinylene)We have studied electronic excited states in films of poly(p-phenylenevinylene) using picosecond transient and cw photomodulation, photoluminescence, and their excitation spectra, as well as electroabsorption spectroscopy. We have determined all the important energy levels of singlet excitons with...Poly (p-phenylenevinylene); Photoexcitation1994-01
79 Symko, Orest GeorgeSpatial Fourier transform method for evaluating SQUID gradiometersA simple method of measuring the spatial transfer function of a gradiometer, consisting of a flux transformer coupled to a SQUID, is presented and it is compared with theoretical predictions. Based, on this approach, a new method of reporting a gradiometer's performance is proposed; the rejection fa...Spatial Fourier transform; SQUID gradiometers; Evaluation; Spatial transfer function1987
80 DeTar, CarletonUpdate on the hadron spectrum with two flavors of staggered quarksWe present an update on the MILC Collaboration's light hadron spectrum calculation with two flavors of dynamical, staggered quarks. Results are presented for gauge couplings 5.30, 5.415, 5.50 and 5.60, with a range of quark masses for each value of the coupling. We present extrapolations of mN/mp ...Staggered quarks; Hadron spectrum1998-04
81 Lupton, John MarkEnergetic disorder limits energy transfer in semiconductor nanocrystal-DNA-dye conjugatesWe demonstrate the influence of spectral linewidths of individual donor-acceptor couples on energy transfer efficiency in semiconductor nanocrystal-DNA-organic dye conjugates. Temperature-dependent single molecule and ensemble spectroscopy data are analyzed using the Förster theory within the mac...2009
82 Mattis, Daniel C.Mattis and Pan replyAfter several independent calculations failed to confirm our published1 numbers on the ground-state energy of the s = 1/2 antiferromagnet in two dimensions, we checked our computer programs and found some deplorable errors introduced in proceeding from one dimension to two.Ground-state energy; Antiferromagnets; Long-range order1988
83 Gerton, JordanTriplet s-wave resonance in 6Li collisions and scattering lengths of 6Li and 7LiThe triplet s-wave scattering length of 6Li is determined using two-photon photoassociative spectroscopy of the diatomic α 3Σu+ state of 6Li2. The measured binding energy of the highest-lying bound state, combined with knowledge of the potential, determines the s-wave scattering length to be -21...1997-05
84 Mattis, Daniel C.Eigenfunction localization in dilute lattices of various dimensionalitiesAs a fraction of bonds p is removed from a lattice, we find a threshold PQ above which all eigenstates are nonpropagating (Anderson localized). This occurs well before the classical percolation threshold. For example, in two dimensions where the classical threshold is pc = 1/2 , we find PQ = 0.Eigenstates; Dilute lattices1981-05
85 DeTar, CarletonThermal phase transition in mixed action SU(3) lattice gauge theory and Wilson fermion thermodynamicsWe study the thermal phase diagram of pure SU(3) lattice gauge theory with fundamental and adjoint couplings. We improve previous estimates of the position of the bulk transition line and determine the thermal deconfinement transition lines for Nt = 2, 4, 6, and 8. The endpoint of the bulk transitio...Wilson fermions; Wilson quarks; Phase transitions; Demon algorithms1995-05
86 Dawson, KyleIntensive HST survey for z > 1 type Ia supernovae by targeting galaxy clustersWe present a new survey strategy to discover and study high redshift Type Ia supernovae (SNe Ia) using the Hubble Space Telescope (HST). By targeting massive galaxy clusters at 0.9 < z < 1.5, we obtain a twofold improvement in the efficiency of finding SNe compared to an HST field survey and a facto...Cosmological parameters2009-11-01
87 Wu, Yong-ShiAnalyzing powers for ∏±-13C scattering at T∏=100 MeVMeasurements of the analyzing power for the nC(rr±,rr±) reaction at Trr = 100 MeV have been made at TRIUMF using a polarized target consisting of 99% 1 3C enriched butanol. Data were obtained for the ground and 3.68 MeV excited states at angles from 110° to 150° in 10° steps. The data are con...1992-02
88 Wu, Yong-ShiP-p′ strings in M(atrix) theoryWe study the off-diagonal blocks in the M(atrix) model that are supposed to correspond to open strings stretched between a Dp-brane and a Dp′-brane. It is shown that the spectrum, including the quantum numbers, of the zero modes in the off-diagonal blocks can be determined from the index theorem a...1998-08
89 Vardeny, Zeev ValentinePhotoconductivity and photoinduced absorption in a-Si:F and a-Si:HThe photoconductivity (PC) and photoinduced absorption (PA) of RF glow discharge a-Si:F and a-Si:H samples is reported. The value of the room temperature PC of a-Si:F is lower by some four orders of magnitude relative to that of a-Si:H, but the PA of a-Si:F is found to be significantly higher than t...Photoinduced absorption; a-Si:F; a-Si:H; RF glow discharge; Spin densities1984
90 Wu, Yong-ShiIntegrable open spin chain in super Yang-Mills and the plane-wave/SYM dualityWe investigate the integrable structures in an N = 2 superconformal Sp(N) Yang-Mills theory with matter, which is dual to an open+closed string system. We restrict ourselves to the BMN operators that correspond to free string states. In the closed string sector, an integrable structure is inherited ...2004-02-01
91 Boehme, ChristophFast nuclear spin hyperpolarization of phosphorus in siliconWe experimentally demonstrate a method for obtaining nuclear spin hyperpolarization, that is, polarization significantly in excess of that expected at thermal equilibrium. By exploiting a nonequilibrium Overhauser process, driven by white light irradiation, we obtain more than 68% negative nuclear p...Hyperpolarization; Spin coherence; Electrical readout2009-01
92 Ailion, David CharlesNature of the incommensurate-paraelectric transition: a two dimensional exchange-difference NMR study87Rb two-dimensional exchange-difference NMR was used to study collective motions in the incommensurate (I) and paraelectric (P) phases of Rb2ZnCl4, which elucidate the nature of the I-P transition. We measured the cross-peak frequency displacement vs mixing time and observed a gradual increase towa...Incommensurate systems; NMR; Paraelectric phase2000
93 Ailion, David CharlesGallium and thallium NMR study of phase transitions and incomemensurability in the layered semiconductor TlGaSe2We report on the first NMR study of phase transitions and incommensurability in the layered semiconductor TlGaSe2. 69,71Ga and 205Tl NMR data from a powder sample show phase transitions at 118, 108 and around 69 K. The 69Ga and 71Ga spin-lattice relaxation times T1 are short and nearly temperature i...NMR; Atomic motion; Phase transitions; Spin-lattice; Relaxation-time2004
94 Wu, Yong-ShiWave function describing superfluidity in a perfect crystalWe propose a many-body wave function that exhibits both diagonal and off-diagonal long-range order. Incorporating short-range correlations due to interatomic repulsion, this wave function is shown to allow condensation of zero-point lattice vibrations and phase rigidity. In the presence of an exter...2005-07-01
95 Wu, Yong-ShiFast tracking detector with fiber scintillators and a position sensitive photomultiplierWe have studied the properties of a tracking detector composed of 32 fiber scintillators coupled to a multianode photo-multiplier placed in a pion beam at TRIUMF. We measured the efficiency of the detector, as well as its tracking capabilities and double hit resolution.Fast tracking detector; Fiber scintillators; Position sensitive photomultiplier1989-02
96 Kieda, David B.High statistics search for ultrahigh energy gamma-ray emission from Cygnus X-3 and Hercules X-1We have carried out a high statistics (2 X 10 9 events) search for ultrahigh energy g-ray emission from the x-ray binary sources Cygnus X-3 and Hercules X-1. Using data taken with the CASA-MIA detector over a five year period (1990-1995), we find no evidence for steady emission from either source. T...Cygnus X-3; Hercules X-1; Ultrahigh energy; X-rays1997
97 Gondolo, PaoloDark stars: dark matter in the first stars leads to a new phase of stellar evolutionThe _x000C_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 fi_x000C_rst stars...Dark stars; WIMP; Weakly interacting massive particles2008-06
98 Vardeny, Zeev Valentine; Ehrenfreund, Eitan A.Optically detected magnetic resonance study of recombination mechanisms in polythiopheneFrom detailed optically detected magnetic resonance measurements in polythiophene, we show that the g=2.003 signal is luminescence enhancing, and that the signal comes from a broad photoluminescence band peaking near 1.65 eV. This band is tentatively assigned to the radiative recombination of polaro...Recombination mechanisms1988
99 Mattis, Daniel C.Switching in magnetite: a thermally driven magnetic phase transitionWe have performed a variety of experiments on switching phenomena in a metal oxide, magnetite. Our findings are consistent with Joule microheating which drives the Verwey transition occurring at 119 K. We conclude that considerations of band structure, direct electric-field-induced transitions, tunn...Negative resistance; Electrical switching; Verwey transition; Joule heating1969-12
100 Sokolsky, PierreCosmic-ray composition around 10^18 eVWe use the depth of maximum distribution as measured by the stereo Fly's Eye detector to study the chemical composition of the primary cosmic radiation between 3 x 10^17 eV and 10^19 eV. The analysis depends on the use of simulations to study the response of the detector as well as sensitivity to as...Energy spectrum; Extensive air showers; Inelasticity; Hadronic interactions1993-03
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