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Creator | Title | Description | Subject | Date |
| 551 |
 |
Mattis, Daniel C. | Ordering energy levels of interacting spin systems | The total spin S is a good quantum number in problems of interacting spins. We have shown that for rather general antiferromagnetic or ferrimagnetic Hamiltonians, which need not exhibit translational invariance, the lowest energy eigenvalue for each value of S [denoted E(S) ] is ordered in a natural... | Interacting spin; Energy levels; Ferrimagnetic arrays | 1962 |
| 552 |
 |
Vardeny, Zeev Valentine | Organic random lasers in the weak-scattering regime | We used the ensemble-averaged power Fourier transform (PFT) of random laser emission spectra over the illuminated area to study random lasers with coherent feedback in four different disordered organic gain media in the weak scattering regime, where the light mean free path, ℓ* is much larger tha... | Organic random lasers; Gain media; pi-conjugated polymers; Opal photonic crystal; RG6; Optical gain; Chicken breast | 2005-01 |
| 553 |
 |
Vardeny, Zeev Valentine | Organic spin-valves: physics and applications | Spin-valve devices of organic semiconductors in the vertical configuration using a variety of exotic and regular ferromagnetic electrodes were fabricated and studied as a function of applied magnetic field, temperature and applied bias voltage. These devices show that spin polarized carriers can be ... | Organic spin-valves; Spin-polarized transport; Spin-polarized carrier injection; Spin polarization | 2005 |
| 554 |
 |
Lupton, John Mark | Origin of spectral broadening in amorphous π-conjugated amorphous semiconductors | We present a study of the picosecond fluorescence dynamics of p-conjugated semiconducting organic dendrimers in the solid state. By varying the degree of branching within the dendrons, referred to as the dendrimer generation, a control of intermolecular spacing of the emissive core and therefore o... | pi-conjugated polymers; pi-conjugated semiconductors; Spectral broadening; Solid state; Picosecond fluorescence dynamics | 2002-10 |
| 555 |
 |
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 |
| 556 |
 |
Kieda, David B. | Overview of the ANITA project | The ANITA project is designed to investigate ultra-high energy (>1017 eV) cosmic ray interactions throughout the universe by detecting the neutrinos created in those interactions. These high energy neutrinos are detectable through their interactions within the Antarctic ice sheet, which ANITA will u... | ANITA; Antarctic Impulsive Transient Antenna; High energy neutrinos; Antarctica; Balloon | 2003 |
| 557 |
 |
Wu, Yong-Shi | P-p′ strings in M(atrix) theory | We 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 |
| 558 |
 |
Mattis, Daniel C. | Partially frustrated Ising models in two dimensions | We examine ordered, periodic, Ising models on a sq lattice at varying levels x of frustration. The thermodynamic singularity of the fully frustrated model (x=1) is at T=0 while those of partially frustrated lattices (0<x<1) occur at finite Tc . The critical indices in the partially frustrated latti... | Antiferromagnets; Frustration; Ising chain | 2003-06 |
| 559 |
 |
Mishchenko, Eugene; Raikh, Mikhail E. | Penetration of external field into regular and random arrays of nanotubes: implications for field emission | We develop an analytical theory of polarization of a vertically aligned array of carbon nanotubes (NTs) in external electric field. Such arrays are commonly utilized in field-emission devices, due to the known electrostatic effect of strong field enhancement near the tip of an individual NT. A sma... | Field-emission current; Fowler-Nordheim law | 2006-06 |
| 560 |
 |
Bromley, Benjamin C. | Periodic standing-wave approximation: nonlinear scalar fields, adapted corrdinates, and the eigenspectral method | The periodic standing wave (PSW) method for the binary inspiral of black holes and neutron stars computes exact numerical solutions for periodic standing-wave spacetimes and then extracts approximate solutions of the physical problem, with outgoing waves. The method requires solution of a boundary-... | Periodic standing wave method; Black holes; Neutron stars | 2005 |
| 561 |
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Bromley, Benjamin C. | Periodic standing-wave approximation: overview and three dimensional scalar models | The periodic standing-wave method for binary inspiral computes the exact numerical solution for periodic binary motion with standing gravitational waves, and uses it as an approximation to slow binary inspiral with outgoing waves. Important features of this method presented here are: (i) the mathe... | Periodic standing wave method; Black holes; Neutron stars | 2004 |
| 562 |
 |
Bromley, Benjamin C. | Periodic standing-wave approzimation: post-Minkowski computations | The periodic standing-wave method studies circular orbits of compact objects coupled to helically symmetric standing-wave gravitational fields. From this solution an approximation is extracted for the strong field, slowly inspiralling motion of black holes and binary stars. Previous work on this m... | Black holes; Binary stars; Gravitational waves | 2007 |
| 563 |
 |
Wu, Yong-Shi | Perturbative formulation and nonadiabatic corrections in adiabatic quantum-computing schemes | Adiabatic limit is the presumption of the adiabatic geometric quantum computation and of the adiabatic quantum algorithm. But in reality, the variation speed of the Hamiltonian is finite. Here we develop a general formulation of adiabatic quantum computing, which accurately describes the evolution... | Perturbative formulation; Nonadiabatic corrections; Adiabatic | 2004-02 |
| 564 |
 |
DeTar, Carleton | Phase diagram of high temperature QCD with three flavors of improved staggered quarks | We report on progress in our study of high temperature QCD with three flavors of improved staggered quarks. Simulations are being carried out with three degenerate quarks with masses less than or equal to the strange quark mass, ms, and with degenerate up and down quarks with masses in the range 0... | Staggered quarks | 2004-03 |
| 565 |
 |
Saam, Brian | Phase relationship between the long-time beats of free induction decays and spin echoes in solids | Recent 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 |
| 566 |
 |
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 |
| 567 |
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Gerton, Jordan | Phase-contrast imaging of atomic superfluid state in degenerate gas of 6Li atoms | The recent experimental realizations of Bose-Einstein condensation in trapped ultracold atomic gases composed of bosonic alkali atoms has generated a broad interest in studying different properties of these degenerate atomic Bose systems. Although the degenerate atomic gas composed of fermionic atom... | | 1998 |
| 568 |
 |
Gondolo, Paolo | Phase-space distribution of unbound dark matter near the sun | We resolve discrepancies in previous analyses of the flow of collisionless dark matter particles in the Sun's gravitational field. We determine the phase-space distribution of the flow both numerically, tracing particle trajectories back in time, and analytically, providing a simple correct relati... | Phase-space distribution; Gravitational field; Velocity functions | 2006-10 |
| 569 |
 |
DeTar, Carleton | Phenomenological lattice model of the high-temperature phase transition in quantum chromodynamics | We propose a simple phenomenological lattice model for the high-temperature phase transition in a quark-gluon plasma, in which the elementary dynamical variables are Wilson lines and SU(iV) chiral spins. A mean-field analysis of the model shows a second-order chiral phase transition for N=2 and a fi... | Quark plasma; Gluon plasma; Chiral symmetry; Phase transitions | 1987-06 |
| 570 |
 |
Vardeny, Zeev Valentine | Phonon anomalies in Cu halides | A great number of the observed phonon anomalies in the zinc-blende phase of Cu-halide crystals are explained by means of a dynamical model. It is assumed that a Cu ion populates four equivalent off-center sites or its ideal position. The off-center Cu+ population is temperature and pressure dependen... | Phonon anomalies; Cu-halide crystals; Cuprous halides | 1979-03 |
| 571 |
 |
Mattis, Daniel C. | Phonon free path in an isotopic mixture | A time-dependent perturbation theory is developed for the classical laws of motion of a crystal lattice. This is applied to the case of a cubic crystal which is chemically pure but contains various isotopic constituents. The random variations in the masses of neighboring atoms scatter plane wave p... | Crystal lattice; Thermal conductivity | 1957-05 |
| 572 |
 |
Mattis, Daniel C. | Phonon model of vacancy-interstitial pair formation in solids | Bonds between neighboring atoms in a solid are imperfect harmonic oscillators. Through consideration of the nonlinearities, it is shown that vacancy-interstitial defect pairs can be described in terms of phonon dynamical variables. The effective spring constants are determined by self-consistency... | Harmonic; Potential; Homogeneous | 1984 |
| 573 |
 |
Vardeny, Zeev Valentine | Phonon polariton study of CuCl1-x Brx | The optical-phonon spectrum of CuCI-x Brx at low temperature is very unusual in regard to many of its properties. Despite the apparent two-mode behavior our measurements illustrate anomalies in the Raman intensity and temperature-induced frequency shift, as well as in the oscillator strengths yiel... | Cuprous halides; CuCl1-x Brx | 1981-08 |
| 574 |
 |
Vardeny, Zeev Valentine; Ehrenfreund, Eitan A. | Phonon spectroscopy in π-conjugated polymers; the role of the excited electronic states | The Raman active vibrational modes in 7r-conjugated polymers are known to have different frequencies in different types of experiments. The best known examples are the resonant Raman scattering (RRS) and doping or photoinduced absorption infrared active vibrations (IRAV) measurements, in which the s... | pi-conjugated polymers; Phonon spectroscopy; Resonant Raman scattering; ir-active phonons | 1997 |
| 575 |
 |
Vardeny, Zeev Valentine | Phonon-polaritons in Cu halides: anomalies and their temperature dependence | The polariton Raman spectra of CuCl, CuBr, and Cul crystals are studied at various temperatures of their zinc-blende phase. Two polar modes are proven to exist in CuCl at room temperature and below; their oscillator-strength ratio changes with temperature and follows the temperature dependence of ... | Cuprous halides; CuBr; CuCl; CuI; Phonon anomalies; Temperature dependence; Zinc blende phase | 1980-03 |
