30,661 research outputs found
Why can't every year be a National Year of Reading? An evaluation of the NYR in Yorkshire
An evaluation of the National Year of Reading in Yorkshire was conducted by Leeds Metropolitan University in response to a brief from Museums, Libraries and Archives, Yorkshire. This paper outlines the development and planning of phase one of this small scale qualitative research project and the analysis of the initial results which looks at the impact of NYR on the organisations that delivered the campaign and their work with target groups. The Generic Social Outcomes and the National Indicators were used to develop a theoretical framework. Data were gathered via in depth interviews and focus groups with NYR steering group partners in Calderdale and North Lincolnshire, selected as the two case study authorities. The use of MAXQDA computer-assisted qualitative data analysis software (CAQDAS) enabled data and coding structures to be stored and will facilitate comparison in this longitudinal study. This evaluation will provide material that local library authorities can use for advocacy with a range of audiences including local and central government
Effect of topology on dynamics of knots in polymers under tension
We use computer simulations to compare the dynamical behaviour of torus and
even-twist knots in polymers under tension. The knots diffuse through a
mechanism similar to reptation. Their friction coefficients grow linearly with
average knot length for both knot types. For similar complexity, however, the
torus knots diffuse faster than the even twist knots. The knot-length
auto-correlation function exhibits a slow relaxation time that can be linked to
a breathing mode. Its timescale depends on knot type, being typically longer
for torus than for even-twist knots. These differences in dynamical behaviour
are interpreted in terms of topological features of the knots.Comment: 6 pages, 8 figure
Complex dynamics of knotted filaments in shear flow
Coarse-grained simulations are used to demonstrate that knotted filaments in
shear flow at zero Reynolds number exhibit remarkably rich dynamic behaviour.
For stiff filaments that are weakly deformed by the shear forces, the knotted
filaments rotate like rigid objects in the flow. But away from this regime the
interplay between between shear forces and the flexibility of the filament
leads to intricate regular and chaotic modes of motion that can be divided into
distinct families. The set of accessible mode families depends to first order
on a dimensionless number that relates the filament length, the elastic
modulus, the friction per unit length and the shear rate.Comment: 6 pages, 6 figure
Localization and its consequences for quantum walk algorithms and quantum communication
The exponential speed-up of quantum walks on certain graphs, relative to
classical particles diffusing on the same graph, is a striking observation. It
has suggested the possibility of new fast quantum algorithms. We point out here
that quantum mechanics can also lead, through the phenomenon of localization,
to exponential suppression of motion on these graphs (even in the absence of
decoherence). In fact, for physical embodiments of graphs, this will be the
generic behaviour. It also has implications for proposals for using spin
networks, including spin chains, as quantum communication channels.Comment: 4 pages, 1 eps figure. Updated references and cosmetic changes for v
Coherent Time Evolution and Boundary Conditions of Two-Photon Quantum Walks
Multi-photon quantum walks in integrated optics are an attractive controlled
quantum system, that can mimic less readily accessible quantum systems and
exhibit behavior that cannot in general be accurately replicated by classical
light without an exponential overhead in resources. The ability to observe time
evolution of such systems is important for characterising multi-particle
quantum dynamics---notably this includes the effects of boundary conditions for
walks in spaces of finite size. Here we demonstrate the coherent evolution of
quantum walks of two indistinguishable photons using planar arrays of 21
evanescently coupled waveguides fabricated in silicon oxynitride technology. We
compare three time evolutions, that follow closely a model assuming unitary
evolution, corresponding to three different lengths of the array---in each case
we observe quantum interference features that violate classical predictions.
The longest array includes reflecting boundary conditions.Comment: 7 pages,7 figure
Shor's quantum factoring algorithm on a photonic chip
Shor's quantum factoring algorithm finds the prime factors of a large number
exponentially faster than any other known method a task that lies at the heart
of modern information security, particularly on the internet. This algorithm
requires a quantum computer a device which harnesses the `massive parallelism'
afforded by quantum superposition and entanglement of quantum bits (or qubits).
We report the demonstration of a compiled version of Shor's algorithm on an
integrated waveguide silica-on-silicon chip that guides four single-photon
qubits through the computation to factor 15.Comment: 2 pages, 1 figur
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