6,367 research outputs found
Living with the user: Design drama for dementia care through responsive scripted experiences in the home
Participation in forms of drama and narrative can provoke empathy and creativity in user-centred design processes. In this paper, we expand upon existing methods to explore the potential for responsive scripted experiences that are delivered through the combination of sensors and output devices placed in a home. The approach is being developed in the context of Dementia care, where the capacity for rich user participation in design activities is limited. In this case, a system can act as a proxy for a person with Dementia, allowing designers to gain experiences and insight as to what it is like to provide care for, and live with, this person. We describe the rationale behind the approach, a prototype system architecture, and our current work to explore the creation of scripted experiences for design, played out though UbiComp technologies.This research is funded by the Arts and Humanities Research Council UK, (AH/K00266X/1) and Horizon Digital Economy Research (RCUK grant EP/G065802/1)
Cosmology with a TeV mass GUT Higgs
The most natural way to break the GUT gauge symmetry is with a Higgs field
whose vacuum expectation value is of order 10^{16}\,\mbox{GeV} but whose mass
is of order to 10^3\,\mbox{GeV}. This can lead to a cosmological
history radically different from what is usually assumed to have occurred
between the standard inflationary and nucleosynthesis epochs, which may solve
the gravitino and Polonyi/moduli problems in a natural way.Comment: 4 pages, revte
Thermal Inflation and the Moduli Problem
In supersymmetric theories a field can develop a vacuum expectation value , even though its mass is of order to
. The finite temperature in the early Universe can hold such a
field at zero, corresponding to a false vacuum with energy density . When the temperature falls below , the thermal energy
density becomes negligible and an era of thermal inflation begins. It ends when
the field rolls away from zero at a temperature of order , corresponding to
of order 10 -folds of inflation which does not affect the density
perturbation generated during ordinary inflation. Thermal inflation can solve
the Polonyi/moduli problem if is within one or two orders of magnitude of
.Comment: Revised version to appear in Phys Rev D. Improved discussion of the
possible effect of parametric resonance. Latex, 31 page
On the Moduli Problem and Baryogenesis in Gauge-mediated SUSY Breaking Models
We investigate whether the Affleck-Dine mechanism can produce sufficient
baryon number of the universe in the gauge-mediated SUSY breaking models, while
evading the cosmological moduli problem by late-time entropy production. We
find that the Q-ball formation renders the scenario very difficult to work,
irrespective of the detail mechanism of the entropy production.Comment: 11 pages, RevTeX, 5 postscript figures include
Naturally Large Cosmological Neutrino Asymmetries in the MSSM
A large neutrino asymmetry is an interesting possibility for cosmology, which
can have significant observable consequences for nucleosynthesis and the cosmic
microwave background. However, although it is a possibility, there is no
obvious reason to expect the neutrino asymmetry to be observably large. Here we
note that if the baryon asymmetry originates via the Affleck-Dine mechanism
along a d=4 flat direction of the MSSM scalar potential and if the lepton
asymmetry originates via Affleck-Dine leptogenesis along a d=6 direction,
corresponding to the lowest dimension directions conserving R-parity, then the
ratio n_{L}/n_{B} is naturally in the range 10^{8}-10^{9}. As a result, a
potentially observable neutrino asymmetry is correlated with a baryon asymmetry
of the order of 10^{-10}.Comment: 10 pages LaTeX. Final version to be published in Physical Review
Letter
A Model of Direct Gauge Mediation
We present a simple model of gauge mediation (GM) which does not have a
messenger sector or gauge singlet fields. The standard model gauge groups
couple directly to the sector which breaks supersymmetry dynamically. This is
the first phenomenologically viable example of this type in the literature.
Despite the direct coupling, the model can preserve perturbative gauge
unification. This is achieved by the inverted hierarchy mechanism which
generates a large scalar expectation value compared to the size of
supersymmetry breaking. There is no dangerous negative contribution to the
squark, slepton masses due to two-loop renormalization group equation. The
potentially non-universal supergravity contribution to the scalar masses can be
suppressed enough to maintain the virtue of the gauge mediation. The model is
completely chiral, and one does not need to forbid mass terms for the messenger
fields by hand. Beyond the simplicity of the model, it possesses cosmologically
desirable features compared to the original models of GM: an improved gravitino
and string moduli cosmology. The Polonyi problem is back unlike in the original
GM models, but is still much less serious than in hidden sector models.Comment: LaTeX, 12 page
Cosmological consequences of particle creation during inflation
Particle creation during inflation is considered. It could be important for
species whose interaction is of gravitational strength or weaker. A complete
but economical formalism is given for spin-zero and spin-half particles, and
the particle abundance is estimated on the assumption that the particle mass in
the early universe is of order the Hubble parameter . It is roughly the same
for both spins, and it is argued that the same estimate should hold for higher
spin particles in particular the gravitino. The abundance is bigger than that
from the usual particle collision mechanism if the inflationary energy scale is
of order , but not if it is much lower.Comment: 17 pages, no Figure
Inflationary models with a flat potential enforced by non-abelian discrete gauge symmetries
Non-abelian discrete gauge symmetries can provide the inflaton with a flat
potential even when one takes into account gravitational strength effects. The
discreteness of the symmetries also provide special field values where
inflation can end via a hybrid type mechanism. An interesting feature of this
method is that it can naturally lead to extremely flat potentials and so, in
principle, to inflation at unusually low energy scales. Two examples of
effective field theories with this mechanism are given, one with a hybrid exit
and one with a mutated hybrid exit. They include an explicit example in which
the single field consistency condition is violated.Comment: 24 pages, uses revtex.sty, submitted to PRD (Nov. 1999) Final version
to appear in PRD. Background information on supergravity expande
Monitoring the CMS strip tracker readout system
The CMS Silicon Strip Tracker at the LHC comprises a sensitive area of approximately 200 m2 and 10 million readout channels. Its data acquisition system is based around a custom analogue front-end chip. Both the control and the readout of the front-end electronics are performed by off-detector VME boards in the counting room, which digitise the raw event data and perform zero-suppression and formatting. The data acquisition system uses the CMS online software framework to configure, control and monitor the hardware components and steer the data acquisition. The first data analysis is performed online within the official CMS reconstruction framework, which provides many services, such as distributed analysis, access to geometry and conditions data, and a Data Quality Monitoring tool based on the online physics reconstruction. The data acquisition monitoring of the Strip Tracker uses both the data acquisition and the reconstruction software frameworks in order to provide real-time feedback to shifters on the operational state of the detector, archiving for later analysis and possibly trigger automatic recovery actions in case of errors. Here we review the proposed architecture of the monitoring system and we describe its software components, which are already in place, the various monitoring streams available, and our experiences of operating and monitoring a large-scale system
Quantum System under Periodic Perturbation: Effect of Environment
In many physical situations the behavior of a quantum system is affected by
interaction with a larger environment. We develop, using the method of
influence functional, how to deduce the density matrix of the quantum system
incorporating the effect of environment. After introducing characterization of
the environment by spectral weight, we first devise schemes to approximate the
spectral weight, and then a perturbation method in field theory models, in
order to approximately describe the environment. All of these approximate
models may be classified as extended Ohmic models of dissipation whose
differences are in the high frequency part.
The quantum system we deal with in the present work is a general class of
harmonic oscillators with arbitrary time dependent frequency. The late time
behavior of the system is well described by an approximation that employs a
localized friction in the dissipative part of the correlation function
appearing in the influence functional. The density matrix of the quantum system
is then determined in terms of a single classical solution obtained with the
time dependent frequency. With this one can compute the entropy, the energy
distribution function, and other physical quantities of the system in a closed
form.
Specific application is made to the case of periodically varying frequency.
This dynamical system has a remarkable property when the environmental
interaction is switched off: Effect of the parametric resonance gives rise to
an exponential growth of the populated number in higher excitation levels, or
particle production in field theory models. The effect of the environment is
investigated for this dynamical system and it is demonstrated that there existsComment: 55 pages, LATEX file plus 13 PS figures. A few calculational
mistatkes and corresponding figure 1 in field theory model corrected and some
changes made for publication in Phys. Rev.D (in press
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