2,852 research outputs found
Repetition of contaminating question types when children and youths with intellectual disabilities are interviewed
Background The present study examined the effects of repeating questions in interviews investigating the possible sexual abuse of children and youths who had a variety of intellectual disabilities. We predicted that the repetition of option-posing and suggestive questions would lead the suspected victims to change their responses, making it difficult to understand what actually happened. Inconsistency can be a key factor when assessing the reliability of witnesses. Materials Case files and transcripts of investigative interviews with 33 children and youths who had a variety of intellectual disabilities were obtained from prosecutors in Sweden. The interviews involved 25 females and 9 males whose chronological ages were between 5.4 and 23.7 years when interviewed (M = 13.2 years). Results Six per cent of the questions were repeated at least once. The repetition of focused questions raised doubts about the reports because the interviewees changed their answers 40% of the time. Conclusions Regardless of the witnesses' abilities, it is important to obtain reports that are as accurate and complete as possible in investigative interviews. Because this was a field study, we did not know which responses were accurate, but repetitions of potentially contaminating questions frequently led the interviewees to contradict their earlier answers. This means that the interviewers' behaviour diminished the usefulness of the witnesses' testimony
Constraining dark energy
In this paper we propose a mechanism that protects theories violating a
holographic bound suggested in arXiv:1203.5476 from developing accelerated
expansion. The mechanism builts on work on transplanckian physics, and a
non-trivial choice of vacuum states. If correct, it lends further support for
detectable signatures in the CMBR signalling new physics.Comment: 8 pages. arXiv admin note: text overlap with arXiv:astro-ph/0606474.
Minor misprints correcte
Transplanckian energy production and slow roll inflation
In this paper we investigate how the energy density due to a non-standard
choice of initial vacuum affects the expansion of the universe during
inflation. To do this we introduce source terms in the Friedmann equations
making sure that we respect the relation between gravity and thermodynamics. We
find that the energy production automatically implies a slow rolling
cosmological constant. Hence we also conclude that there is no well defined
value for the cosmological constant in the presence of sources. We speculate
that a non-standard vacuum can provide slow roll inflation on its own.Comment: 16 pages, 2 figures, version 2: minor corrections to section 4 and
references adde
Quasi-normal modes of AdS black holes : A superpotential approach
A novel method, based on superpotentials is proposed for obtaining the
quasi-normal modes of anti-de Sitter black holes. This is inspired by the case
of the three-dimensional BTZ black hole, where the quasi-normal modes can be
obtained exactly and are proportional to the surface gravity. Using this
approach, the quasi-normal modes of the five dimensional Schwarzschild
anti-deSitter black hole are computed numerically. The modes again seem to be
proportional to the surface gravity for very small and very large black holes.
They reflect the well-known instability of small black holes in anti-deSitter
space.Comment: LaTeX, 17 pages, 5 eps figures, 1 eepic figure, minor typos correcte
Holographic Superconductors with Lifshitz Scaling
Black holes in asymptotically Lifshitz spacetime provide a window onto finite
temperature effects in strongly coupled Lifshitz models. We add a Maxwell gauge
field and charged matter to a recently proposed gravity dual of 2+1 dimensional
Lifshitz theory. This gives rise to charged black holes with scalar hair, which
correspond to the superconducting phase of holographic superconductors with z >
1 Lifshitz scaling. Along the way we analyze the global geometry of static,
asymptotically Lifshitz black holes at arbitrary critical exponent z > 1. In
all known exact solutions there is a null curvature singularity in the black
hole region, and, by a general argument, the same applies to generic Lifshitz
black holes.Comment: 23 pages, 4 figures; v2: added references; v3: matches published
versio
Scalar Synchrotron Radiation in the Schwarzschild-anti-de Sitter Geometry
We present a complete relativistic analysis for the scalar radiation emitted
by a particle in circular orbit around a Schwarzschild-anti-de Sitter black
hole. If the black hole is large, then the radiation is concentrated in narrow
angles- high multipolar distribution- i.e., the radiation is synchrotronic.
However, small black holes exhibit a totally different behavior: in the small
black hole regime, the radiation is concentrated in low multipoles. There is a
transition mass at , where is the AdS radius. This behavior is
new, it is not present in asymptotically flat spacetimes.Comment: 13 pages, 6 figures, published version. References adde
CMB quadrupole suppression: II. The early fast roll stage
Within the effective field theory of inflation, an initialization of the
classical dynamics of the inflaton with approximate equipartition between the
kinetic and potential energy of the inflaton leads to a brief fast roll stage
that precedes the slow roll regime. The fast roll stage leads to an attractive
potential in the wave equations for the mode functions of curvature and tensor
perturbations. The evolution of the inflationary perturbations is equivalent to
the scattering by this potential and a useful dictionary between the scattering
data and observables is established.Implementing methods from scattering theory
we prove that this attractive potential leads to a suppression of the
quadrupole moment for CMB and B-mode angular power spectra. The scale of the
potential is determined by the Hubble parameter during slow roll. Within the
effective field theory of inflation at the grand unification (GUT) energy scale
we find that if inflation lasts a total number of efolds N_{tot} ~ 59, there is
a 10-20% suppression of the CMB quadrupole and about 2-4% suppression of the
tensor quadrupole. The suppression of higher multipoles is smaller, falling off
as 1/l^2. The suppression is much smaller for N_{tot} > 59, therefore if the
observable suppression originates in the fast roll stage, there is the upper
bound N_{tot} ~ 59.Comment: Some comments and references adde
Dissipation from a heavy quark moving through N=4 super-Yang-Mills plasma
Using AdS/CFT, we compute the Fourier space profile of generated by
a heavy quark moving through a thermal plasma of strongly coupled N=4
super-Yang-Mills theory. We find evidence of a wake whose description includes
gauge fields with large momenta. We comment on the possible relevance of our
results to relativistic heavy ion collisions.Comment: 17 pages, 2 figures. v2: reference added, other minor improvements.
v3: improved the phrasing describing directional structure
Unruh Radiation, Holography and Boundary Cosmology
A uniformly acclerated observer in anti-deSitter space-time is known to
detect thermal radiation when the acceleration exceeds a critical value. We
investigate the holographic interpretation of this phenomenon. For uniformly
accelerated trajectories transverse to the boundary of the AdS space, the
hologram is a blob which expands along the boundary. Observers on the boundary
co-moving with the hologram become observers in cosmological space-times. For
supercritical accelerations one gets a Milne universe when the holographic
screen is the boundary in Poincare coordinates, while for the boundary in
hyperspherical coordinates one gets deSitter spacetimes. The presence or
absence of thermality is then interpreted in terms of specific classes of
observers in these cosmologies.Comment: LaTeX, 35 pages, 3 figures. A reference is added and typos are
correcte
Signatures of very high energy physics in the squeezed limit of the bispectrum (violation of Maldacena's condition)
We investigate the signatures in the squeezed limit of the primordial scalar
bispectrum due to modifications of the standard theory at high energy. In
particular, we consider the cases of modified dispersion relations and/or
modified initial quantum state (both in the Boundary Effective Field Theory and
in the New Physics Hyper-Surface formulations). Using the in-in formalism we
study in details the squeezed limit of the contributions to the bispectrum from
all possible cubic couplings in the effective theory of single-field inflation.
We find general features such as enhancements and/or non-local shape of the
non-Gaussianities, which are relevant, for example, for measurements of the
halo bias and which distinguish these scenarios from the standard one (with
Bunch-Davies vacuum as initial state and standard kinetic terms). We find that
the signatures change according to the magnitude of the scale of new physics,
and therefore several pieces of information regarding high energy physics could
be obtained in case of detection of these signals, especially bounds on the
scales of new physics.Comment: 37 pages plus bibliography, version matching the one accepted for
publication by JCAP. Increased pedagogical comments, improved presentation
and text, added reference
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