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Identification of drivers, benefits, and challenges of ISO 50001 through case study content analysis
An expanding body of research is defining drivers, benefits, and challenges of adopting ISO 50001 energy management systems. The Clean Energy Ministerial's Energy Management Leadership Awards program requires ISO 50001-certified organizations to develop case studies of their implementation experience. 72 recent case studies spanning multiple economic sectors provide a unique global look at implementation from certified organizations' perspectives. This dataset was investigated through content analysis of phrases related to motivations and goals, the role of management and the organization, benefits achieved, keys to success, and challenges. This paper presents findings from this quantitative analysis of “codes” assigned to phrases that capture their meaning. While organizations adopted ISO 50001 for different motives and saw myriad benefits beyond energy savings and associated greenhouse gas emissions reductions, commonalities exist. The most frequently identified drivers are existing values and goals, environmental sustainability, and government incentives or regulations. Findings also include: obtaining and sustaining top management support is critical; top benefits mentioned are cost savings, productivity, and operational improvements; and the primary barrier is lacking a culture of energy management. Policymakers and others looking to accelerate ISO 50001 uptake can use these findings to highlight benefits and incentives that will resonate with corporate decisionmakers worldwide
Criteria for Continuous-Variable Quantum Teleportation
We derive an experimentally testable criterion for the teleportation of
quantum states of continuous variables. This criterion is especially relevant
to the recent experiment of Furusawa et al. [Science 282, 706-709 (1998)] where
an input-output fidelity of was achieved for optical coherent
states. Our derivation demonstrates that fidelities greater than 1/2 could not
have been achieved through the use of a classical channel alone; quantum
entanglement was a crucial ingredient in the experiment.Comment: 12 pages, to appear in Journal of Modern Optic
Quantum versus classical domains for teleportation with continuous variables
By considering the utilization of a classical channel without quantum entanglement, fidelity Fclassical=1/2 has been established as setting the boundary between classical and quantum domains in the teleportation of coherent states of the electromagnetic field [S. L. Braunstein, C. A. Fuchs, and H. J. Kimble, J. Mod. Opt. 47, 267 (2000)]. We further examine the quantum-classical boundary by investigating questions of entanglement and Bell-inequality violations for the Einstein-Podolsky-Rosen states relevant to continuous variable teleportation. The threshold fidelity for employing entanglement as a quantum resource in teleportation of coherent states is again found to be Fclassical=1/2. Likewise, violations of local realism onset at this same threshold, with the added requirement of overall efficiency η>2/3 in the unconditional case. By contrast, recently proposed criteria adapted from the literature on quantum-nondemolition detection are shown to be largely unrelated to the questions of entanglement and Bell-inequality violations
Optimal Universal and State-Dependent Quantum Cloning
We establish the best possible approximation to a perfect quantum cloning
machine which produces two clones out of a single input. We analyze both
universal and state-dependent cloners. The maximal fidelity of cloning is shown
to be 5/6 for universal cloners. It can be achieved either by a special unitary
evolution or by a novel teleportation scheme. We construct the optimal
state-dependent cloners operating on any prescribed two non-orthogonal states,
discuss their fidelities and the use of auxiliary physical resources in the
process of cloning. The optimal universal cloners permit us to derive a new
upper bound on the quantum capacity of the depolarizing quantum channel.Comment: 30 pages (RevTeX), 2 figures (epsf), further results and further
authors added, to appear in Physical Review
Interactions and magnetic moments near vacancies and resonant impurities in graphene
The effect of electronic interactions in graphene with vacancies or resonant
scatterers is investigated. We apply dynamical mean-field theory in combination
with quantum Monte Carlo simulations, which allow us to treat
non-perturbatively quantum fluctuations beyond Hartree-Fock approximations. The
interactions narrow the width of the resonance and induce a Curie magnetic
susceptibility, signaling the formation of local moments. The absence of
saturation of the susceptibility at low temperatures suggests that the coupling
between the local moment and the conduction electrons is ferromagnetic
The absoption refrigerator as a thermal transformer
The absorption refrigerator can be considered a thermal transformer, i.e. a
device that is analogous to the electric transformer. The analogy is based on a
correspondence between the extensive quantities entropy and electric charge and
that of the intensive variables temperature and electric potential
Lectures on conformal field theory and Kac-Moody algebras
This is an introduction to the basic ideas and to a few further selected
topics in conformal quantum field theory and in the theory of Kac-Moody
algebras.Comment: 59 pages, LaTeX2e, extended version of lectures given at the Graduate
Course on Conformal Field Theory and Integrable Models (Budapest, August
1996), to appear in Springer Lecture Notes in Physic
Spectral properties of the three-dimensional Hubbard model
We present momentum resolved single-particle spectra for the
three-dimensional Hubbard model for the paramagnetic and antiferromagnetically
ordered phase obtained within the dynamical cluster approximation. The
effective cluster problem is solved by continuous-time Quantum Monte Carlo
simulations. The absence of a time discretization error and the ability to
perform Monte Carlo measurements directly in Matsubara frequencies enable us to
analytically continue the self-energies by maximum entropy, which is essential
to obtain momentum resolved spectral functions for the N'eel state. We
investigate the dependence on temperature and interaction strength and the
effect of magnetic frustration introduced by a next-nearest neighbor hopping.
One particular question we address here is the influence of the frustrating
interaction on the metal insulator transition of the three-dimensional Hubbard
model.Comment: 16 pages, 14 figure
Scalar and vector decomposition of the nucleon self-energy in the relativistic Brueckner approach
We investigate the momentum dependence of the nucleon self-energy in nuclear
matter. We apply the relativistic Brueckner-Hartree-Fock approach and adopt the
Bonn A potential. A strong momentum dependence of the scalar and vector
self-energy components can be observed when a commonly used pseudo-vector
choice for the covariant representation of the T-matrix is applied. This
momentum dependence is dominated by the pion exchange. We discuss the problems
of this choice and its relations to on-shell ambiguities of the T-matrix
representation. Starting from a complete pseudo-vector representation of the
T-matrix, which reproduces correctly the pseudo-vector pion-exchange
contributions at the Hartree-Fock level, we observe a much weaker momentum
dependence of the self-energy. This fixes the range of the inherent uncertainty
in the determination of the scalar and vector self-energy components. Comparing
to other work, we find that extracting the self-energy components by a fit to
the single particle potential leads to even more ambiguous results.Comment: 35 pages RevTex, 7 PS figures, replaced by a revised and extended
versio
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