7,582 research outputs found
A modular methodology for converting large, complex books into usable, accessible and standards-compliant ebooks
This report describes the methodology used for ebook creation for the Glasgow Digital Library (GDL), and provides detailed instructions on how the same methodology could be used elsewhere. The document includes a description and explanation of the processes for ebook creation followed by a tutorial
Subject searching requirements : the HILT II experience
The HILT Phase II project aimed to develop a pilot terminologies server with a view to improving cross-sectoral information retrieval. In order to inform this process, it was first necessary to examine how a representative group of users approached a range of information-related tasks. This paper focuses on exploratory interviews conducted to investigate the proposed ideal and actual strategies of a group of 30 users in relation to eight separate information tasks. In addition, users were asked to give examples of search terms they may employ and to describe how they would formulate search queries in each scenario. The interview process undertaken and the results compiled are outlined, and associated implications for the development of a pilot terminologies server are discussed
Testing quantised inertia on galactic scales
Galaxies and galaxy clusters have rotational velocities apparently too fast
to allow them to be gravitationally bound by their visible matter. This has
been attributed to the presence of invisible (dark) matter, but so far this has
not been directly detected. Here, it is shown that a new model that modifies
inertial mass by assuming it is caused by Unruh radiation, which is subject to
a Hubble-scale (Theta) Casimir effect predicts the rotational velocity (v) to
be: v^4=2GMc^2/Theta (the Tully-Fisher relation) where G is the gravitational
constant, M is the baryonic mass and c is the speed of light. The model
predicts the outer rotational velocity of dwarf and disk galaxies, and galaxy
clusters, within error bars, without dark matter or adjustable parameters, and
makes a prediction that local accelerations should remain above 2c^2/Theta at a
galaxy's edge.Comment: 7 pages, 1 figure. Accepted for publication in Astrophysics and Space
Science on 27/7/201
Greening information management: final report
As the recent JISC report on âthe âgreeningâ of ICT in education [1] highlights, the increasing reliance on ICT to underpin the business functions of higher education institutions has a heavy environmental impact, due mainly to the consumption of electricity to run computers and to cool data centres. While work is already under way to investigate how more energy efficient ICT can be introduced, to date there has been much less focus on the potential environmental benefits to be accrued from reducing the demand âat sourceâ through better data and information management. JISC thus commissioned the University of Strathclyde to undertake a study to gather evidence that establishes the efficacy of using information management options as components of Green ICT strategies within UK Higher Education environments, and to highlight existing practices which have the potential for wider replication
Particle number conservation in quantum many-body simulations with matrix product operators
Incorporating conservation laws explicitly into matrix product states (MPS)
has proven to make numerical simulations of quantum many-body systems much less
resources consuming. We will discuss here, to what extent this concept can be
used in simulation where the dynamically evolving entities are matrix product
operators (MPO). Quite counter-intuitively the expectation of gaining in speed
by sacrificing information about all but a single symmetry sector is not in all
cases fulfilled. It turns out that in this case often the entanglement imposed
by the global constraint of fixed particle number is the limiting factor.Comment: minor changes, 18 pages, 5 figure
Phase Diagram of the 1D Kondo Lattice Model
We determine the boundary of the fully polarized ferromagnetic ground state
in the one dimensional Kondo lattice model at partial conduction electron band
filling by using a newly developed infinite size DMRG method which conserves
the total spin quantum number. The obtained paramagnetic to ferromagnetic phase
boundary is below for the whole range of band filling. By this
we solve the controversy in the phase diagram over the extent of the
ferromagnetic region close to half filling.Comment: 6 pages, 4 EPS figures. Presented at MOS9
Edge singularities in high-energy spectra of gapped one-dimensional magnets in strong magnetic fields
We use the dynamical density matrix renormalization group technique to show
that the high-energy part of the spectrum of a S=1 Haldane chain, placed in a
strong external magnetic field exceeding the Haldane gap , contains
edge singularities, similar to those known to exist in the low-energy spectral
response. It is demonstrated that in the frequency range
the longitudinal (with respect to the applied field) dynamical structure factor
is dominated by the power-law singularity
. We study
the behavior of the high-energy edge exponent and the edge
as functions of the magnetic field. The existence of edge
singularities at high energies is directly related to the Tomonaga-Luttinger
liquid character of the ground state at and is expected to be a
general feature of one-dimensional gapped spin systems in high magnetic fields.Comment: (v2) error in Eq.(11) correcte
Symmetry between repulsive and attractive interactions in driven-dissipative Bose-Hubbard systems
The driven-dissipative Bose-Hubbard model can be experimentally realized with
either negative or positive onsite detunings, inter-site hopping energies, and
onsite interaction energies. Here we use one-dimensional matrix product density
operators to perform a fully quantum investigation of the dependence of the
non-equilibrium steady states of this model on the signs of these parameters.
Due to a symmetry in the Lindblad master equation, we find that simultaneously
changing the sign of the interaction energies, hopping energies, and chemical
potentials leaves the local boson number distribution and inter-site number
correlations invariant, and the steady-state complex conjugated. This shows
that all driven-dissipative phenomena of interacting bosons described by the
Lindblad master equation, such as "fermionization" and "superbunching", can
equivalently occur with attractive or repulsive interactions.Comment: single column 12 pages, 4 figures, 1 tabl
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