1,274 research outputs found
Critical behavior of disordered systems with replica symmetry breaking
A field-theoretic description of the critical behavior of weakly disordered
systems with a -component order parameter is given. For systems of an
arbitrary dimension in the range from three to four, a renormalization group
analysis of the effective replica Hamiltonian of the model with an interaction
potential without replica symmetry is given in the two-loop approximation. For
the case of the one-step replica symmetry breaking, fixed points of the
renormalization group equations are found using the Pade-Borel summing
technique. For every value , the threshold dimensions of the system that
separate the regions of different types of the critical behavior are found by
analyzing those fixed points. Specific features of the critical behavior
determined by the replica symmetry breaking are described. The results are
compared with those obtained by the -expansion and the scope of the
method applicability is determined.Comment: 18 pages, 2 figure
Patterned and Disordered Continuous Abelian Sandpile Model
We study critical properties of the continuous Abelian sandpile model with
anisotropies in toppling rules that produce ordered patterns on it. Also we
consider the continuous directed sandpile model perturbed by a weak quenched
randomness and study critical behavior of the model using perturbative
conformal field theory and show the model has a new random fixed point.Comment: 11 Pages, 6 figure
Privacy Management as Unfinished Business: Shifting Boundaries in the Context of Infertility
Privacy dilemmas are prevalent for women who experience a fertility problem. In this study, we use communication privacy management (CPM) theory to explore how privacy boundaries shift over time as women cope with infertility. Based on interviews with 23 women, we found that women described distinctive patterns of shifting privacy boundaries, including situations in which the experience of infertility served as a change agent, patterns in which women became more or less open over time, and patterns that indicated a continuous oscillation of boundaries. These ever-changing patterns of talk indicate that managing private information about infertility is unfinished business
Stability of critical behaviour of weakly disordered systems with respect to the replica symmetry breaking
A field-theoretic description of the critical behaviour of the weakly
disordered systems is given. Directly, for three- and two-dimensional systems a
renormalization analysis of the effective Hamiltonian of model with replica
symmetry breaking (RSB) potentials is carried out in the two-loop
approximation. For case with 1-step RSB the fixed points (FP's) corresponding
to stability of the various types of critical behaviour are identified with the
use of the Pade-Borel summation technique. Analysis of FP's has shown a
stability of the critical behaviour of the weakly disordered systems with
respect to RSB effects and realization of former scenario of disorder influence
on critical behaviour.Comment: 10 pages, RevTeX. Version 3 adds the functions for arbitrary
dimension of syste
Electron beam induced damage in PECVD Si3N4 and SiO2 films on InP
Phosphorus rich plasma enhanced chemical vapor deposition (PECVD) of silicon nitride and silicon dioxide films on n-type indium phosphide (InP) substrates were exposed to electron beam irradiation in the 5 to 40 keV range for the purpose of characterizing the damage induced in the dielectic. The electron beam exposure was on the range of 10(exp -7) to 10(exp -3) C/sq cm. The damage to the devices was characterized by capacitance-voltage (C-V) measurements of the metal insulator semiconductor (MIS) capacitors. These results were compared to results obtained for radiation damage of thermal silicon dioxide on silicon (Si) MOS capacitors with similar exposures. The radiation induced damage in the PECVD silicon nitride films on InP was successfully annealed out in an hydrogen/nitrogen (H2/N2) ambient at 400 C for 15 min. The PECVD silicon dioxide films on InP had the least radiation damage, while the thermal silicon dioxide films on Si had the most radiation damage
Submicron gate InP power MISFET's with improved output power density at 18 and 20 GHz
The microwave characteristics are presented at 18 and 20 GHz of submicron gate indium phosphide (InP) metal-insulator-semiconductor field-effect transistors (MISFET's) for high output power density applications. InP power MISFET's were fabricated and the output power density was investigated as a function of drain-source spacing. The best output power density and gain were obtained for drain-source spacing of 3 microns. The output power density is 2.7 times greater than was previously measured for InP MISFET's at 18 and 20 GHz, and the power-added efficiency also increased
Investigation of Field Emitter Array Vacuum Microtriodes for Space Electronics Applications
Research into processing techniques for fabrication of vacuum microelectronic devices has been carried out, with special emphasis being given to the growth of silicon dioxide thin films. Oxide films ranging from 30 nm to approximately 2 micrometers have been grown on single crystal silicon wafers. Metal-oxide-semiconductor capacitor test structures have been made from some of these oxide films, and current-versus-voltage plots for these structures have been measured. It has been observed that the rate of applied voltage across the oxide films produces marked differences in measured leakage current. Breakdown fields across two of the thinnest oxide films have been measured and are comparable with highest values reported in literature. Several silicon wafers were processed to make field- emitter array diodes, and were delivered to collaborators at NASA-Lewis Research Center for final fabrication steps and testing
Numerical Results For The 2D Random Bond 3-state Potts Model
We present results of a numerical simulation of the 3-state Potts model with
random bond, in two dimension. In particular, we measure the critical exponent
associated to the magnetization and the specific heat. We also compare these
exponents with recent analytical computations.Comment: 9 pages, latex, 3 Postscript figure
White Light Flare Continuum Observations with ULTRACAM
We present sub-second, continuous-coverage photometry of three flares on the
dM3.5e star, EQ Peg A, using custom continuum filters with WHT/ULTRACAM. These
data provide a new view of flare continuum emission, with each flare exhibiting
a very distinct light curve morphology. The spectral shape of flare emission
for the two large-amplitude flares is compared with synthetic ULTRACAM
measurements taken from the spectra during the large 'megaflare' event on a
similar type flare star. The white light shape during the impulsive phase of
the EQ Peg flares is consistent with the range of colors derived from the
megaflare continuum, which is known to contain a Hydrogen recombination
component and compact, blackbody-like components. Tentative evidence in the
ULTRACAM photometry is found for an anti-correlation between the emission of
these components.Comment: 8 pages, 3 figures. Proceedings of the 16th Workshop on Cool Stars,
Stellar Systems, and the Sun (PASP conference series, in press
Scaling Analysis of the Site-Diluted Ising Model in Two Dimensions
A combination of recent numerical and theoretical advances are applied to
analyze the scaling behaviour of the site-diluted Ising model in two
dimensions, paying special attention to the implications for multiplicative
logarithmic corrections. The analysis focuses primarily on the odd sector of
the model (i.e., that associated with magnetic exponents), and in particular on
its Lee-Yang zeros, which are determined to high accuracy. Scaling relations
are used to connect to the even (thermal) sector, and a first analysis of the
density of zeros yields information on the specific heat and its corrections.
The analysis is fully supportive of the strong scaling hypothesis and of the
scaling relations for logarithmic corrections.Comment: 15 pages, 3 figures. Published versio
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