11,643 research outputs found
Circuit analysis of quantum measurement
We develop a circuit theory that enables us to analyze quantum measurements
on a two-level system and on a continuous-variable system on an equal footing.
As a measurement scheme applicable to both systems, we discuss a swapping state
measurement which exchanges quantum states between the system and the measuring
apparatus before the apparatus meter is read out. This swapping state
measurement has an advantage in gravitational-wave detection over contractive
state measurement in that the postmeasurement state of the system can be set to
a prescribed one, regardless of the outcome of the measurement.Comment: 11pages, 7figure
Ab-initio shell model with a core
We construct effective 2- and 3-body Hamiltonians for the p-shell by
performing 12\hbar\Omega ab initio no-core shell model (NCSM) calculations for
A=6 and 7 nuclei and explicitly projecting the many-body Hamiltonians onto the
0\hbar\Omega space. We then separate these effective Hamiltonians into 0-, 1-
and 2-body contributions (also 3-body for A=7) and analyze the systematic
behavior of these different parts as a function of the mass number A and size
of the NCSM basis space. The role of effective 3- and higher-body interactions
for A>6 is investigated and discussed
Chameleon fields and solar physics
In this article we discuss some aspects of solar physics from the standpoint
of the so-called chameleon fields (i.e. quantum fields, typically scalar, where
the mass is an increasing function of the matter density of the environment).
Firstly, we analyze the effects of a chameleon-induced deviation from standard
gravity just below the surface of the Sun. In particular, we develop solar
models which take into account the presence of the chameleon and we show that
they are inconsistent with the helioseismic data. This inconsistency presents
itself not only with the typical chameleon set-up discussed in the literature
(where the mass scale of the potential is fine-tuned to the meV), but also if
we remove the fine-tuning on the scale of the potential. Secondly, we point out
that, in a model recently considered in the literature (we call this model
"Modified Fujii's Model"), a conceivable interpretation of the solar
oscillations is given by quantum vacuum fluctuations of a chameleon.Comment: 17 pages including figure
Conceptual models of urban environmental information systems - toward improved information provision
Cities are the hub of European society - for over a millennium, they are the locus of social, political
and economic development. As the core of intensive and creative human activity, they are also the
place where the environmental externalities that accompany rapid development are most visible.
The environmental consequences of urban development have been recognised long ago, as in the
case of London, where in 1388 legislation was introduced to control pollutant emissions
(Lowenthal, 1990). Similar historical environmental regulations can be demonstrated for many
cities in Europe. However, while for most of history those who govern the city (be it the sovereign,
city elders or local government) where responsible for the control, mitigation and management of
the common environment in the city, the last 30 years are a period of profound change. This is due
to the trend toward improved participation in environmental decision making . a more inclusive and
open approach to decisions that deal with the city commons. This change did not occurre overnight
but rather gradually. For example, in the United Kingdom, it was the Town and Country Planning
Act of 1947 which introduced public scrutiny to changes in the urban form (Rydin, 1998), or the
development of public involvement in environmental impact assessment of urban projects as
developed in many countries throughout the developed world during the 1970s and 1980s (Gilpin
1995). These changes accelerate within the last three decades, and especially since the publication
of .Our Common Future. (WCED and Brundtland 1987), the acceptance of the .Sustainable
Development. principles and the Rio conference. A quiet (mini) revolution happened in Europe not
long ago, toward the end of 1998 when the members of the United Nations Economic Commission
for Europe (UN/ECE) signed the .Convention on Access to Information, Public Participation in
Decision Making and Access to Justice in Environmental Matters. - the Aarhus Convention
(UN/ECE 1998). The convention is expected to come into force by the end of 2001, and calls the
governments and public authorities to open up access to environmental information as a means to
improve public participation in environmental decision making and awareness of environmental
issues (UN/ECE, 1998).
However, these declarations on the value and importance of environmental information do not
match our level of understanding on the role of environmental information in decision making
processes, and especially on the role of information in improving awareness and participation.
Therefore, it is useful to take a step back, and to try and evaluate how environmental information
and access to it and its use support public involvement in such processes.
This paper is aimed to offer a framework that can assist us in the analytical process of
understanding environmental information use. It focuses on public access and assumes that
environmental information will be delivered to the public through the Internet. Such assumption is
based on the current trend within public authorities is to use Information and Communication
Technology (ICT) as a major delivery medium and it seems that it will become more so in the near
future (OECD 2000).
The framework which this paper presents, is based on Soft Systems Methodology (SSM) study
which unpacked some of the core issues relating to public access and use of environmental
information (Haklay, 2001). Although the aim here is not to discuss the merits of SSM, but to focus
on the conceptual models, some introduction to the techniques that are used here is needed.
Therefore, the following section opens with introduction to SSM and its techniques. The core of the
paper is dedicated to the development of conceptual models. After presenting the conceptual
models, some conclusions about these models and their applications are drown
Basic principles of SSM modelling: an examination of CATWOE from a soft perspective
This paper examines the SSM technique CATWOE, which focuses on defining necessary elements that together constitute a human activity system from a certain perspective. Despite its recognition within the literature and its numerous uses, there are few studies on how the technique can be improved. This research reflects on each of the elements both from a theoretical and a practical perspective. Findings point to the fact that some of the terms have a meaning in everyday language that differs from its definition within CATWOE. Other concepts are not well-defined. This is unfortunate and may both lead to misunderstandings and limit analysis. The paper points to a number of ways in which the use of CATWOE can be developed in order to further support the process of eliciting novel ideas for future actions. Hence, the overall conclusion is that the elements need to be rethought and some of them renamed
On the extended Kolmogorov-Nagumo information-entropy theory, the q -> 1/q duality and its possible implications for a non-extensive two dimensional Ising model
The aim of this paper is to investigate the q -> 1/q duality in an
information-entropy theory of all q-generalized entropy functionals (Tsallis,
Renyi and Sharma-Mittal measures) in the light of a representation based on
generalized exponential and logarithm functions subjected to Kolmogorov's and
Nagumo's averaging. We show that it is precisely in this representation that
the form invariance of all entropy functionals is maintained under the action
of this duality. The generalized partition function also results to be a scalar
invariant under the q -> 1/q transformation which can be interpreted as a
non-extensive two dimensional Ising model duality between systems governed by
two different power law long-range interactions and temperatures. This does not
hold only for Tsallis statistics, but is a characteristic feature of all
stationary distributions described by q-exponential Boltzmann factors.Comment: 13 pages, accepted for publication in Physica
Goldstini
Supersymmetric phenomenology has been largely bound to the hypothesis that
supersymmetry breaking originates from a single source. In this paper, we relax
this underlying assumption and consider a multiplicity of sectors which
independently break supersymmetry, thus yielding a corresponding multiplicity
of goldstini. While one linear combination of goldstini is eaten via the
super-Higgs mechanism, the orthogonal combinations remain in the spectrum as
physical degrees of freedom. Interestingly, supergravity effects induce a
universal tree-level mass for the goldstini which is exactly twice the
gravitino mass. Since visible sector fields can couple dominantly to the
goldstini rather than the gravitino, this framework allows for substantial
departures from conventional supersymmetric phenomenology. In fact, this even
occurs when a conventional mediation scheme is augmented by additional
supersymmetry breaking sectors which are fully sequestered. We discuss a number
of striking collider signatures, including various novel decay modes for the
lightest observable-sector supersymmetric particle, gravitinoless
gauge-mediated spectra, and events with multiple displaced vertices. We also
describe goldstini cosmology and the possibility of goldstini dark matter.Comment: 14 pages, 7 figures; references adde
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