1,823 research outputs found
Study of excitation transfer in laser dye mixtures by direct measurement of fluorescence lifetime
By directly measuring the donor fluorescence lifetime as a function of acceptor concentration in the laser dye mixture Rhodamine 6G-Cresyl violet, we found that the Stern-Volmer relation is obeyed, from which the rate of excitation transfer is determined. The experimental results indicate that the dominant mechanism responsible for the efficient excitation transfer is that of resonance transfer due to long range dipole-dipole interaction
Application of the ex-Gaussian function to the effect of the word blindness suggestion on Stroop task performance suggests no word blindness
The aim of the present paper was to apply the ex-Gaussian function to data reported by Parris et al. (2012) given its utility in studies involving the Stroop task. Parris et al. showed an effect of the word blindness suggestion when Response-Stimulus Interval (RSI) was 500 ms but not when it was 3500 ms. Analysis revealed that: (1) The effect of the suggestion on interference is observed in μ, supporting converging evidence indicating the suggestion operates over response competition mechanisms; and, (2) Contrary to Parris et al. an effect of the suggestion was observed in μ when RSI was 3500 ms. The reanalysis of the data from Parris et al. (2012) supports the utility of ex-Gaussian analysis in revealing effects that might otherwise be thought of as absent. We suggest that word reading itself is not suppressed by the suggestion but instead that response conflict is dealt with more effectively. © 2013 Parris, Dienes and Hodgson
Modularity and 4D-2D spectral equivalences for large-N gauge theories with adjoint matter
In recent work, we demonstrated that the confined-phase spectrum of
non-supersymmetric pure Yang-Mills theory coincides with the spectrum of the
chiral sector of a two-dimensional conformal field theory in the large-
limit. This was done within the tractable setting in which the gauge theory is
compactified on a three-sphere whose radius is small compared to the strong
length scale. In this paper, we generalize these observations by demonstrating
that similar results continue to hold even when massless adjoint matter fields
are introduced. These results hold for both thermal and -twisted
partition functions, and collectively suggest that the spectra of large-
confining gauge theories are organized by the symmetries of two-dimensional
conformal field theories.Comment: 51 pages, LaTeX, 3 figure
Dark Matter and Dark Forces from a supersymmetric hidden sector
We show that supersymmetric "Dark Force" models with gravity mediation are
viable. To this end, we analyse a simple string-inspired supersymmetric hidden
sector model that interacts with the visible sector via kinetic mixing of a
light Abelian gauge boson with the hypercharge. We include all induced
interactions with the visible sector such as neutralino mass mixing and the
Higgs portal term. We perform a detailed parameter space scan comparing the
produced dark matter relic abundance and direct detection cross sections to
current experiments.Comment: 40 pages, 11 figures comprising 21 plots. 4Mb total size. v2: figures
and references updated; typos removed; some extra explanations added. Matches
version published in PR
Adventures in Thermal Duality (II): Towards a Duality-Covariant String Thermodynamics
In a recent companion paper, we observed that the rules of ordinary
thermodynamics generally fail to respect thermal duality, a symmetry of string
theory under which the physics at temperature T is related to the physics at
the inverse temperature 1/T. Even when the free energy and internal energy
exhibit the thermal duality symmetry, the entropy and specific heat are defined
in such a way that this symmetry is destroyed. In this paper, we propose a
modification of the traditional definitions of these quantities, yielding a
manifestly duality-covariant thermodynamics. At low temperatures, these
modifications produce "corrections" to the standard definitions of entropy and
specific heat which are suppressed by powers of the string scale. These
corrections may nevertheless be important for the full development of a
consistent string thermodynamics. We find, for example, that the
string-corrected entropy can be smaller than the usual entropy at high
temperatures, suggesting a possible connection with the holographic principle.
We also discuss some outstanding theoretical issues prompted by our approach.Comment: 31 pages, 6 figures, 1 conversatio
Bulk Higgs with 4D Gauge Interactions
We consider a model with an extra compact dimension in which the Higgs is a
bulk field while all other Standard Model fields are confined on a brane. We
find that four-dimensional gauge invariance can still be achieved by
appropriate modification of the brane action. This changes accordingly the
Higgs propagator so that, the Higgs, in all its interactions with Standard
Model fields, behaves as an ordinary 4D field, although it has a bulk kinetic
term and bulk self-interactions. In addition, it cannot propagate from the
brane to the bulk and, thus, no charge can escape into the bulk but it remains
confined on the brane. Moreover, the photon remains massless, while the
dependence of the Higgs vacuum on the extra dimension induces a mixing between
the graviphoton and the Z-boson.
This results in a modification of the sensitive \rho-parameter.Comment: 16 page
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