UScholar Works
 
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276 - 300 of 924
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CreatorTitleDescriptionSubjectDate
276 Mishchenko, EugeneFrequency dependence of the photonic noise spectrum in an absorbing or amplifying diffusive mediumA theory is presented for the frequency dependence of the power spectrum of photon current fluctuations originating from a disordered medium. Both the cases of an absorbing medium ("grey body") and of an amplifying medium ("random laser") are considered in a waveguide geometry. The semiclassical ap...Random laser; Noise power spectrum; Frequency dependence; Waveguide geometry2001-01
277 Ailion, David CharlesFrequency modulation method for performing adiabatic demagnetization in the rotating reference frameA 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; NMR1970
278 Lupton, John MarkFrequency up-conversion as a temperature probe of organic opto-electronic devicesFrequency up-conversion is demonstrated in a polyfluorene-based conjugated polymer. Up-converted emission is observed upon excitation to the red of the 0-0 luminescence band. The emission intensity depends strongly on temperature and provides an accurate probe of the operating temperature of organic...Frequency up-conversion; Organic opto-electronic devices2002
279 Mishchenko, EugeneFull counting statistics of a charge pump in the Coulomb blockade regimeWe study full charge counting statistics (FCCS) of a charge pump based on a nearly open single electron transistor. The problem is mapped onto an exactly soluble problem of a nonequilibrium g=1/2 Luttinger liquid with an impurity. We obtain an analytic expression for the generating function of the...Counting statistics; Luttinger liquid2001-11
280 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
281 Kieda, David B.; Binks, Joshua ThomasGamma-ray emission by the BL Lac Markarian 501Optical astronomy is the study of the heavens as they emit light, or the visible portion of the electromagnetic spectrum. Gamma-ray astronomy is the study of astrophysical sources that emit the most energetic form of electromagnetic radiation (ie: gamma-rays). High Energy gamma-rays are much too f...Markarian 501; Gamma-ray emission; Trapeze Interactive Poster2010-03-15
282 Gondolo, PaoloGamma-ray summary reportThis paper reviews the field of gamma-ray astronomy and describes future experiments and prospects for advances in fundamental physics and high-energy astrophysics through gamma-ray measurements. We concentrate on recent progress in the understanding of active galaxies, and the use of these sources ...EGRET; GLAST; VERITAS2001
283 Mishchenko, EugeneGapless surfaces in anisotropic superfluidsWe demonstrate when p-wave pairing occurs between species whose free Fermi surfaces are mismatched the gap generally vanishes over a two-dimensional surface. We present detailed calculations of condensation energy, superfluid density (Meissner mass) and specific heat for such states. We also consi...Anisotropic superfluids; Meissner mass2006-11
284 Saam, Brian; Pugmire, Ronald J.Gas-phase spin relaxation of 129XeWe have completed an extensive study of 129Xe longitudinal spin relaxation in the gas phase, involving both intrinsic and extrinsic mechanisms. The dominant intrinsic relaxation is mediated by the formation of persistent Xe2 van der Waals dimers. The dependence of this relaxation on applied magnetic...129Xe; Gas-phase spin relaxation2008-10
285 Wu, Yong-ShiGauge invariance of fractionally charged quasiparticles and hidden topological Zn symmetryUsing the braid-group formalism we study the consequences of gauge invariance for fractionally charged anyonic quasiparticles in a two-dimensional multiply connected system. It is shown that gauge invariance requires multicomponent wave functions, and leads to the emergence of a hidden topological...Gauge invariance; Topological Zn symmetry; Braid-group representation1991-02
286 Wu, Yong-ShiGeneral theorem relating the bulk topological number to edge states in two-dimensional insulatorsWe prove a general theorem on the relation between the bulk topological quantum number and the edge states in two-dimensional insulators. It is shown that whenever there is a topological order in bulk, characterized by a nonvanishing Chern number, even if it is defined for a nonconserved quantity s...Edge states; Bulk topology; Chern number2006-07
287 Wu, Yong-ShiGeneral theory for quantum statistics in two dimensionsBecause of complicated topology of the configuration space for indistinguishable particles in two dimensions, Feynman's path-integral formulation allows exotic statistics. All possible quantum statistics in two-space are characterized by an angle parameter 9 which interpolates between bosons and fe...Homotopy classes1984-06
288 Mishchenko, EugeneGeneration of spin current by Coulomb dragCoulomb drag between two quantum wires is exponentially sensitive to the mismatch of their electronic densities. The application of a magnetic field can compensate this mismatch for electrons of opposite spin directions in different wires. The resulting enhanced momentum transfer leads to the conv...Spin current; Coulomb drag; Quantum wires2006-12
289 Mattis, Daniel C.Ground state of interacting spinsThe question is posed of how the ground state of the Heisenberg Hamiltonian H= - ΣFij Si-Sj depends on the magnitude s of N interacting spins, particularly in the case of long-ranged oscillatory interactions Fij. It is discussed whether fixing the geometry and the bond strengths Fij suffices to d...Ground states; Interacting spin; Ruderman-Kittel interaction1963-04
290 Mattis, Daniel C.Ground state of the Kondo modelThe 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 constant1985-06
291 Wu, Yong-ShiGround states and thermal states of the random field Ising modelThe random field Ising model is studied numerically at both zero and positive temperature. Ground states are mapped out in a region of random field and external field strength. Thermal states and thermodynamic properties are obtained for all temperatures using the Wang-Landau algorithm. The specific...Ground states; Thermal states2005-09
292 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
293 Mattis, Daniel C.Ground-state energy of Heisenberg antiferromagnet for spins s=1/2 and s=1 in d=1 and 2 dimensionsA simple real-space renormalization method yields the ground-state energy of the Heisenberg antiferromagnet. We find the ground-state energy per spin for s=1/2 (-0.4438 in ID , -0.6723 in 2D ) and s = 1 (-1.388 in ID and -1.907 in 2D) to three-figure accuracy, using properties of relatively small o...Ground-state energy; Heisenberg antiferromagnet; Long-range order1988-07
294 Mattis, Daniel C.Ground-state symmetry in XY model of magnetismNumerical studies by Betts and Oitmaa have led those authors to conjecture that in the XY model the ground-state magnetization Mz is zero. This is a model of spins on a lattice with interactions - J(SnxSmx+SnySmy), that can also describe a hard-sphere boson fluid. In the present note I prove the c...Ground state; Magnetization; Bipartite lattice1979-06
295 Gondolo, PaoloGroups of galaxies in the local supercluster: some hypotheses on the evolutionary stageWe present a method capable of determining the evolutionary stage of bound, isolated systems of galaxies. In particular, we apply it to a sample of groups, belonging to the Local Supercluster, taken from the Geller and Huchra's (1983) catalogue. We find that most of them are still in the phase of c...Evolution of galaxy clusters1988
296 Boehme, ChristophH loss mechanism during anneal of silicon nitride: chemical dissociationRemote plasma enhanced chemical vapor deposited silicon nitride (SixNyHz), produced at high ammonia to silane flow rates (ammonia rich) shows a reduction of hydrogen during rapid thermal anneal at temperatures that exceed the deposition temperature. This H release could be either due to a ‘‘slow...Anneal2000
297 Dawson, KyleHST discovery of a z=3.9 multiply imaged galaxy behind the complex cluster lens WARPS J1415.1+36 at z=1.026We report the discovery of a multiply lensed Lyα_x000B_ emitter at z=3.90 behind the massive galaxy cluster WARPS J1415.1+3612 at z=1.026. Images taken by the Hubble Space Telescope (HST) using ACS reveal a complex lensing system that produces a prominent, highly magnified arc and a triplet of smal...2009-12-10
298 DeTar, CarletonHadronic deformation energy. I. Quark-antiquark separationThe MIT bag model for hadrons is treated in the static cavity approximation in three dimensions with a definite quark number. The energy of the system is computed to second order in the gluon coupling. A constrained variational method is described which permits the calculation of the energy as a f...Bag models; Quark bag; Deformation energy; Antiquarks; Gluon coupling; Quark energies; Gluon energies1978-01
299 DeTar, CarletonHadronic deformation energy. II. Two-nucleon interactionThe MIT bag model for hadrons is treated in the static cavity approximation. The adiabatic deformation of a six-quark hadron with quantum numbers of the deuteron is studied in a configuration which permits the separation of two triplets with quantum numbers of the neutron and proton. The energy of...Bag models; Quark bag; Deformation energy; Gluon coupling; Two-nucleon problem; Nucleons; Self-energy1978-01
300 DeTar, CarletonHadronic spectrum of the quark plasmaWe have carried out a numerical simulation in SU(3) lattice gauge theory with four flavors of low-mass staggered fermions at zero baryon-number density in the vicinity of the high-temperature phase transition on 6x 103 and 6x 102x20 lattices. Static screening masses (static susceptibilities) were m...Hadronic matter; Quark plasma; Chiral symmetry; Phase transitions1987-07
276 - 300 of 924