1,311 research outputs found
Approaches used to evaluate the social Impacts of protected areas
Protected areas are a key strategy in conserving biodiversity, and there is a pressing need to evaluate their social impacts. Though the social impacts of development interventions are widely assessed, the conservation literature is limited and methodological guidance is lacking. Using a systematic literature search, which found 95 relevant studies, we assessed the methods used to evaluate the social impacts of protected areas. Mixed methods were used by more than half of the studies. Almost all studies reported material aspects of wellbeing, particularly income; other aspects were included in around half of studies. The majority of studies provided a snapshot, with only one employing a before-after-control-intervention design. Half of studies reported respondent perceptions of impacts, while impact was attributed from researcher inference in 1/3 of cases. Although the number of such studies is increasing rapidly, there has been little change in the approaches used over the last 15 years, or in the authorship of studies, which is predominantly academics. Recent improvements in understanding of best practice in social impact evaluation need to be translated into practice if a true picture of the effects of conservation on local people is to be obtained
Topological field theory and the quantum double of SU(2)
We study the quantum mechanics of a system of topologically interacting
particles in 2+1 dimensions, which is described by coupling the particles to a
Chern-Simons gauge field of an inhomogeneous group. Analysis of the phase space
shows that for the particular case of ISO(3) Chern-Simons theory the underlying
symmetry is that of the quantum double D(SU(2)), based on the homogeneous part
of the gauge group. This in contrast to the usual q-deformed gauge group
itself, which occurs in the case of a homogeneous gauge group. Subsequently, we
describe the structure of the quantum double of a continuous group and the
classification of its unitary irreducible representations. The comultiplication
and the R-element of the quantum double allow for a natural description of the
fusion properties and the nonabelian braid statistics of the particles. These
typically manifest themselves in generalised Aharonov-Bohm scattering
processes, for which we compute the differential cross sections. Finally, we
briefly describe the structure of D(SO(2,1)), the underlying quantum double
symmetry of (2+1)-dimensional quantum gravity.Comment: 48 pages, 3 figures, LaTeX2e; two remarks and a reference added,
typos corrected; to appear in Nucl.Phys.
Geometric quantization of completely integrable Hamiltonian systems in the action-angle variables
We provide geometric quantization of a completely integrable Hamiltonian
system in the action-angle variables around an invariant torus with respect to
polarization spanned by almost-Hamiltonian vector fields of angle variables.
The associated quantum algebra consists of functions affine in action
coordinates. We obtain a set of its nonequivalent representations in the
separable pre-Hilbert space of smooth complex functions on the torus where
action operators and a Hamiltonian are diagonal and have countable spectra.Comment: 8 page
Non-linear finite -symmetries and applications in elementary systems
In this paper it is stressed that there is no {\em physical} reason for
symmetries to be linear and that Lie group theory is therefore too restrictive.
We illustrate this with some simple examples. Then we give a readable review on
the theory finite -algebras, which is an important class of non-linear
symmetries. In particular, we discuss both the classical and quantum theory and
elaborate on several aspects of their representation theory. Some new results
are presented. These include finite coadjoint orbits, real forms and
unitary representation of finite -algebras and Poincare-Birkhoff-Witt
theorems for finite -algebras. Also we present some new finite -algebras
that are not related to embeddings. At the end of the paper we
investigate how one could construct physical theories, for example gauge field
theories, that are based on non-linear algebras.Comment: 88 pages, LaTe
QUANTIZATION OF A CLASS OF PIECEWISE AFFINE TRANSFORMATIONS ON THE TORUS
We present a unified framework for the quantization of a family of discrete
dynamical systems of varying degrees of "chaoticity". The systems to be
quantized are piecewise affine maps on the two-torus, viewed as phase space,
and include the automorphisms, translations and skew translations. We then
treat some discontinuous transformations such as the Baker map and the
sawtooth-like maps. Our approach extends some ideas from geometric quantization
and it is both conceptually and calculationally simple.Comment: no. 28 pages in AMSTE
Geometric Dequantization
Dequantization is a set of rules which turn quantum mechanics (QM) into
classical mechanics (CM). It is not the WKB limit of QM. In this paper we show
that, by extending time to a 3-dimensional "supertime", we can dequantize the
system in the sense of turning the Feynman path integral version of QM into the
functional counterpart of the Koopman-von Neumann operatorial approach to CM.
Somehow this procedure is the inverse of geometric quantization and we present
it in three different polarizations: the Schroedinger, the momentum and the
coherent states ones.Comment: 50+1 pages, Late
Mechanical similarity as a generalization of scale symmetry
In this paper we study the symmetry known as mechanical similarity (LMS) and
present for any monomial potential. We analyze it in the framework of the
Koopman-von Neumann formulation of classical mechanics and prove that in this
framework the LMS can be given a canonical implementation. We also show that
the LMS is a generalization of the scale symmetry which is present only for the
inverse square potential. Finally we study the main obstructions which one
encounters in implementing the LMS at the quantum mechanical level.Comment: 9 pages, Latex, a new section adde
The "Symplectic Camel Principle" and Semiclassical Mechanics
Gromov's nonsqueezing theorem, aka the property of the symplectic camel,
leads to a very simple semiclassical quantiuzation scheme by imposing that the
only "physically admissible" semiclassical phase space states are those whose
symplectic capacity (in a sense to be precised) is nh + (1/2)h where h is
Planck's constant. We the construct semiclassical waveforms on Lagrangian
submanifolds using the properties of the Leray-Maslov index, which allows us to
define the argument of the square root of a de Rham form.Comment: no figures. to appear in J. Phys. Math A. (2002
(2+1)D Exotic Newton-Hooke Symmetry, Duality and Projective Phase
A particle system with a (2+1)D exotic Newton-Hooke symmetry is constructed
by the method of nonlinear realization. It has three essentially different
phases depending on the values of the two central charges. The subcritical and
supercritical phases (describing 2D isotropic ordinary and exotic oscillators)
are separated by the critical phase (one-mode oscillator), and are related by a
duality transformation. In the flat limit, the system transforms into a free
Galilean exotic particle on the noncommutative plane. The wave equations
carrying projective representations of the exotic Newton-Hooke symmetry are
constructed.Comment: 30 pages, 2 figures; typos correcte
Toeplitz Quantization of K\"ahler Manifolds and
For general compact K\"ahler manifolds it is shown that both Toeplitz
quantization and geometric quantization lead to a well-defined (by operator
norm estimates) classical limit. This generalizes earlier results of the
authors and Klimek and Lesniewski obtained for the torus and higher genus
Riemann surfaces, respectively. We thereby arrive at an approximation of the
Poisson algebra by a sequence of finite-dimensional matrix algebras ,
.Comment: 17 pages, AmsTeX 2.1, Sept. 93 (rev: only typos are corrected
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