15,963 research outputs found
The shape of equality: discourses around the Section 28 repeal in Scotland
This article focuses on conceptualizations of equality in the discourses deployed in the campaign to repeal Section 28 in Scotland. I use the parliamentary debates and two newspapers: the Daily Record, which supported the campaign to Keep the Clause, and The Guardian, which supported repeal, to exemplify the different discursive articulations around equality and citizenship. I suggest that the Scottish example provides further evidence of the ways in which liberalism naturalizes heterosexuality as the standard for citizenship and thus bequeaths a hierarchy of 'equality' and citizenship in the realm of sexuality, wherein lesbian and gay citizenship is either rendered invalid or characterized as 'special rights'. However, within the narrow confines of the parliamentary debates, more expansive and differentiated notions of citizenship and equality are evident. Whilst I conclude that the 'shape' of equality achieved through the repeal has been moulded to support institutionalized heterosexuality - with Section 28 replaced by statutory guidelines on sex education which advocate marriage - I also suggest equality is contested, both through the recognition of transformations in heterosexual family forms and the appeal to non-discrimination as a democratic principle. It is possible, therefore, that current destabilizations of the heterosexual social order simultaneously destabilize the precepts of liberal democracy
Implications of a Quantum Mechanical Treatment of the Universe
We attempt to treat the very early Universe according to quantum mechanics.
Identifying the scale factor of the Universe with the width of the wave packet
associated with it, we show that there cannot be an initial singularity and
that the Universe expands. Invoking the correspondence principle, we obtain the
scale factor of the Universe and demonstrate that the causality problem of the
standard model is solved.Comment: LaTex, 5 pages, 1 figure, to be published in Mod. Phys. Lett.
Flat Cosmology with Coupled Matter and Dark Energies
Three models of a flat universe of coupled matter and dark energies with
different low-redshift parameterizations of the dark energy equation of state
are considered. The dark energy is assumed to vary with time like the trace of
the energy-momentum tensor of cosmic matter. In the radiation-dominated era the
models reduce to standard cosmology. In the matter-dominated era they are, for
modern values of the cosmological parameters, consistent with data from SNe Ia
searches and with the data of Gurvits et al.(1999)for angular sizes of ultra
compact radio sources. We find that the angular size-redshift tests for our
models offer a higher statistical confidence than that based on SNe Ia data. A
comparison of our results with a recent revised analysis of angular
size-redshift legacy data is made,and the implications of our models with
optimized relativistic beaming in the radio sources is discussed. In particular
we find that relativistic beaming implies a Lorentz factor less than 6,in
agreement with its values for powerful Active Galactic Nuclei.Comment: Version to appear in The Astronomical Journal, with a modified name-
Flat Cosmology with Coupled Matter and Dark Energies. Expanded and Modified
conten
Thermodynamics of Decaying Vacuum Cosmologies
The thermodynamic behavior of vacuum decaying cosmologies is investigated
within a manifestly covariant formulation. Such a process corresponds to a
continuous irreversible energy flow from the vacuum component to the created
matter constituents. It is shown that if the specific entropy per particle
remains constant during the process, the equilibrium relations are preserved.
In particular, if the vacuum decays into photons, the energy density and
average number density of photons scale with the temperature as and . The temperature law is determined and a generalized
Planckian type form of the spectrum, which is preserved in the course of the
evolution, is also proposed. Some consequences of these results for decaying
vacuum FRW type cosmologies as well as for models with ``adiabatic'' photon
creation are discussed.Comment: 21 pages, uses LATE
Interface-induced heavy-hole/light-hole splitting of acceptors in silicon
The energy spectrum of spin-orbit coupled states of individual sub-surface
boron acceptor dopants in silicon have been investigated using scanning
tunneling spectroscopy (STS) at cryogenic temperatures. The spatially resolved
tunnel spectra show two resonances which we ascribe to the heavy- and
light-hole Kramers doublets. This type of broken degeneracy has recently been
argued to be advantageous for the lifetime of acceptor-based qubits [Phys. Rev.
B 88 064308 (2013)]. The depth dependent energy splitting between the heavy-
and light-hole Kramers doublets is consistent with tight binding calculations,
and is in excess of 1 meV for all acceptors within the experimentally
accessible depth range (< 2 nm from the surface). These results will aid the
development of tunable acceptor-based qubits in silicon with long coherence
times and the possibility for electrical manipulation
Valley filtering and spatial maps of coupling between silicon donors and quantum dots
Exchange coupling is a key ingredient for spin-based quantum technologies
since it can be used to entangle spin qubits and create logical spin qubits.
However, the influence of the electronic valley degree of freedom in silicon on
exchange interactions is presently the subject of important open questions.
Here we investigate the influence of valleys on exchange in a coupled
donor/quantum dot system, a basic building block of recently proposed schemes
for robust quantum information processing. Using a scanning tunneling
microscope tip to position the quantum dot with sub-nm precision, we find a
near monotonic exchange characteristic where lattice-aperiodic modulations
associated with valley degrees of freedom comprise less than 2~\% of exchange.
From this we conclude that intravalley tunneling processes that preserve the
donor's and valley index are filtered out of the interaction
with the valley quantum dot, and that the and
intervalley processes where the electron valley index changes are weak.
Complemented by tight-binding calculations of exchange versus donor depth, the
demonstrated electrostatic tunability of donor/QD exchange can be used to
compensate the remaining intravalley oscillations to realise uniform
interactions in an array of highly coherent donor spins.Comment: 6 pages, 4 figures, 6 pages Supplemental Materia
Causal Bulk Viscous Dissipative Isotropic Cosmologies with Variable Gravitational and Cosmological Constants
We consider the evolution of a flat Friedmann-Robertson-Walker Universe,
filled with a causal bulk viscous cosmological fluid, in the presence of
variable gravitational and cosmological constants. The basic equation for the
Hubble parameter, generalizing the evolution equation in the case of constant
gravitational coupling and cosmological term, is derived, under the
supplementary assumption that the total energy of the Universe is conserved. By
assuming that the cosmological constant is proportional to the square of the
Hubble parameter and a power law dependence of the bulk viscosity coefficient,
temperature and relaxation time on the energy density of the cosmological
fluid, two classes of exact solutions of the field equations are obtained. In
the first class of solutions the Universe ends in an inflationary era, while in
the second class of solutions the expansion of the Universe is non-inflationary
for all times. In both models the cosmological "constant" is a decreasing
function of time, while the gravitational "constant" increases in the early
period of evolution of the Universe, tending in the large time limit to a
constant value.Comment: 14 pages, 15 figure
The q-harmonic oscillator and an analog of the Charlier polynomials
A model of a q-harmonic oscillator based on q-Charlier polynomials of
Al-Salam and Carlitz is discussed. Simple explicit realization of q-creation
and q-annihilation operators, q-coherent states and an analog of the Fourier
transformation are found. A connection of the kernel of this transform with
biorthogonal rational functions is observed
Cosmic Acceleration With A Positive Cosmological Constant
We have considered a cosmological model with a phenomenological model for the
cosmological constant of the form \Lambda=\bt\fr{\ddot R}{R}, \bt is a
constant. For age parameter consistent with observational data the Universe
must be accelerating in the presence of a positive cosmological constant. The
minimum age of the Universe is , where is the present Hubble
constant. The cosmological constant is found to decrease as . Allowing
the gravitational constant to change with time leads to an ever increasing
gravitational constant at the present epoch. In the presence of a viscous fluid
this decay law for is equivalent to the one with () provided \alpha=\fr{\bt}{3(\bt-2)}. The
inflationary solution obtained from this model is that of the de-Sitter type.Comment: a more revised versio
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