4,155 research outputs found
Post‐traumatic stress disorder\u27s relation with positive and negative emotional avoidance: The moderating role of gender
Post‐traumatic stress disorder (PTSD) is characterized by avoidance of trauma‐related emotions. Research indicates that this avoidance may extend to any emotional experience that elicits distress, including those that are unrelated to the trauma. Literature in this area has been limited in its exclusive focus on negative emotions. Despite evidence of gender differences in PTSD and emotional avoidance separately, no studies to date have examined gender as a moderator of their association. The goal of the current study was to extend research by exploring the moderating role of gender in the relation between PTSD symptom severity and positive and negative emotional avoidance. Participants were 276 trauma‐exposed individuals (65.9% female, 65.6% White, Mage = 19.24) from a university in the north‐eastern United States. Moderation results indicated a main effect for PTSD symptom severity on both positive (b = 0.07, p \u3c .001) and negative (b = 0.04, p = .03) emotional avoidance. The interaction of gender and PTSD symptom severity was significant for positive emotion avoidance (b = 0.97, p = .01). Analysis of simple slopes revealed that PTSD symptom severity was significantly associated with positive emotional avoidance for males (b = 0.13, p \u3c .001) but not females (b = 0.03, p = .08). Results suggest the importance of gender‐sensitive recommendations for assessment and treatment of emotional avoidance in PTSD
Biorthogonal quantum mechanics
The Hermiticity condition in quantum mechanics required for the characterization of (a) physical observables and (b) generators of unitary motions can be relaxed into a wider class of operators whose eigenvalues are real and whose eigenstates are complete. In this case, the orthogonality of eigenstates is replaced by the notion of biorthogonality that defines the relation between the Hilbert space of states and its dual space. The resulting quantum theory, which might appropriately be called 'biorthogonal quantum mechanics', is developed here in some detail in the case for which the Hilbert-space dimensionality is finite. Specifically, characterizations of probability assignment rules, observable properties, pure and mixed states, spin particles, measurements, combined systems and entanglements, perturbations, and dynamical aspects of the theory are developed. The paper concludes with a brief discussion on infinite-dimensional systems. © 2014 IOP Publishing Ltd
Asymptotics of Universal Probability of Neighboring Level Spacings at the Anderson Transition
The nearest-neighbor level spacing distribution is numerically investigated
by directly diagonalizing disordered Anderson Hamiltonians for systems of sizes
up to 100 x 100 x 100 lattice sites. The scaling behavior of the level
statistics is examined for large spacings near the delocalization-localization
transition and the correlation length exponent is found. By using
high-precision calculations we conjecture a new interpolation of the critical
cumulative probability, which has size-independent asymptotic form \ln I(s)
\propto -s^{\alpha} with \alpha = 1.0 \pm 0.1.Comment: 5 pages, RevTex, 4 figures, to appear in Physical Review Letter
Shape Analysis of the Level Spacing Distribution around the Metal Insulator Transition in the Three Dimensional Anderson Model
We present a new method for the numerical treatment of second order phase
transitions using the level spacing distribution function . We show that
the quantities introduced originally for the shape analysis of eigenvectors can
be properly applied for the description of the eigenvalues as well. The
position of the metal--insulator transition (MIT) of the three dimensional
Anderson model and the critical exponent are evaluated. The shape analysis of
obtained numerically shows that near the MIT is clearly different
from both the Brody distribution and from Izrailev's formula, and the best
description is of the form , with
. This is in good agreement with recent analytical results.Comment: 14 pages in plain TeX, 6 figures upon reques
Mean Free Path and Energy Fluctuations in Quantum Chaotic Billiards
The elastic mean free path of carriers in a recently introduced model of
quantum chaotic billiards in two and three dimensions is calculated. The model
incorporates surface roughness at a microscopic scale by randomly choosing the
atomic levels at the surface sites between -W/2 and W/2. Surface roughness
yields a mean free path l that decreases as L/W^2 as W increases, L being the
linear size of the system. But this diminution ceases when the surface layer
begins to decouple from the bulk for large enough values of W, leaving more or
less unperturbed states on the bulk. Consequently, the mean free path shows a
minimum of about L/2 for W of the order of the band width. Energy fluctuations
reflect the behavior of the mean free path. At small energy scales, strong
level correlations manifest themselves by small values of the number of levels
variance Sigma^2(E) that are close to Random Matrix Theory (RMT) in all cases.
At larger energy scales, fluctuations are below the logarithmic behavior of RMT
for l > L, and above RMT value when l < L.Comment: 8 twocolumn pages, seven figures, revtex and epsf macros. To be
published in Physical Review B
Statistical Theory of Parity Nonconservation in Compound Nuclei
We present the first application of statistical spectroscopy to study the
root-mean-square value of the parity nonconserving (PNC) interaction matrix
element M determined experimentally by scattering longitudinally polarized
neutrons from compound nuclei. Our effective PNC interaction consists of a
standard two-body meson-exchange piece and a doorway term to account for
spin-flip excitations. Strength functions are calculated using realistic
single-particle energies and a residual strong interaction adjusted to fit the
experimental density of states for the targets, ^{238} U for A\sim 230 and
^{104,105,106,108} Pd for A\sim 100. Using the standard Desplanques, Donoghue,
and Holstein estimates of the weak PNC meson-nucleon coupling constants, we
find that M is about a factor of 3 smaller than the experimental value for
^{238} U and about a factor of 1.7 smaller for Pd. The significance of this
result for refining the empirical determination of the weak coupling constants
is discussed.Comment: Latex file, no Fig
Spatial Correlation in Quantum Chaotic Systems with Time-reversal Symmetry: Theory and Experiment
The correlation between the values of wavefunctions at two different spatial
points is examined for chaotic systems with time-reversal symmetry. Employing a
supermatrix method, we find that there exist long-range Friedel oscillations of
the wave function density for a given eigenstate, although the background
wavefunction density fluctuates strongly. We show that for large fluctuations,
once the value of the wave function at one point is known, its spatial
dependence becomes highly predictable for increasingly large space around this
point. These results are compared with the experimental wave functions obtained
from billiard-shaped microwave cavities and very good agreement is
demonstrated.Comment: 12 pages, REVTeX3+epsf, two EPS figures. Minor modification
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