Future capacity growth of energy technologies: are scenarios consistent with historical evidence?

Future scenarios of the energy system under greenhouse gas emission constraints depict dramatic growth in a range of energy technologies. Technological growth dynamics observed historically provide a useful comparator for these future trajectories. We find that historical time series data reveal a consistent relationship between how much a technology’s cumulative installed capacity grows, and how long this growth takes. This relationship between extent (how much) and duration (for how long) is consistent across both energy supply and end-use technologies, and both established and emerging technologies. We then develop and test an approach for using this historical relationship to assess technological trajectories in future scenarios. Our approach for “learning from the past” contributes to the assessment and verification of integrated assessment and energy-economic models used to generate quantitative scenarios. Using data on power generation technologies from two such models, we also find a consistent extent - duration relationship across both technologies and scenarios. This relationship describes future low carbon technological growth in the power sector which appears to be conservative relative to what has been evidenced historically. Specifically, future extents of capacity growth are comparatively low given the lengthy time duration of that growth. We treat this finding with caution due to the low number of data points. Yet it remains counter-intuitive given the extremely rapid growth rates of certain low carbon technologies under stringent emission constraints. We explore possible reasons for the apparent scenario conservatism, and find parametric or structural conservatism in the underlying models to be one possible explanation

Exact renormalization group equation in presence of rescaling anomaly II - The local potential approximation

Exact renormalization group techniques are applied to mass deformed N=4 supersymmetric Yang-Mills theory, viewed as a regularised N=2 model. The solution of the flow equation, in the local potential approximation, reproduces the one-loop (perturbatively exact) expression for the effective action of N=2 supersymmetric Yang-Mills theory, when the regularising mass, M, reaches the value of the dynamical cutoff. One speculates about the way in which further non-perturbative contributions (instanton effects) may be accounted for.Comment: 13 pages, no figures, uses JHEP3.cl

Synthetic magnetism for photon fluids

We develop a theory of artificial gauge fields in photon fluids for the cases of both second-order and third-order optical nonlinearities. This applies to weak excitations in the presence of pump fields carrying orbital angular momentum, and is thus a type of Bogoliubov theory. The resulting artificial gauge fields experienced by the weak excitations are an interesting generalization of previous cases and reflect the PT-symmetry properties of the underlying non-Hermitian Hamiltonian. We illustrate the observable consequences of the resulting synthetic magnetic fields for examples involving both second-order and third-order nonlinearities

Two Phases of Supersymmetric Gluodynamics

We argue that supersymmetric gluodynamics has two phases with equivalent infrared behavior, one of which is asymptotically free and another one is superstrongly coupled in the ultraviolet domain.Comment: Plain LaTeX, 6 pages, 2 figures in a uuencoded file Final version which appeared in Phys. Rev. Let.75;2085-2087,1995 Corrected references and some Comments with no effect on conclusion

Polio survivors’ perceptions of the meaning of quality of life and strategies used to promote participation in everyday activities

This article is made available through the Brunel Open Access Publishing Fund.Introduction: The term ‘post-polio syndrome’ (PPS) is used to describe new and late manifestations of poliomyelitis that occur later in life. Research in this area has focused upon health status rather than its effect on quality of life. Aim: To gain an in-depth understanding of the meaning of quality of life for polio survivors and to determine the type of strategies that are used by people with PPS and the support that they consider as important to facilitate participation in everyday life activities that have an impact on their quality of life. Method: Six focus groups were conducted with 51 participants from two regions in England. Data were audio-taped and analysed using thematic analysis. Results: Our research found that polio survivors used terms used to describe quality of life which could be associated with that of happiness. Our research has identified resolvable factors that influence quality of life namely inaccessible environments, attitudes of health-care professionals and societal attitudes. Polio survivors have tried alternative therapies, chiefly acupuncture and massage, and found them to be effective in enhancing their quality of life. Conclusion: It is suggested that health-care professionals should consider factors which influence happiness and implement a person-centred approach with the views of the polio survivor being listened to. The three factors that influenced quality of life could be resolved by health-care professionals and by society. With regard to strategies used, we suggest that polio survivors should have access to the treatments that they perceive as important, although further research is required to design optimal interventions for this client group

Wilsonian Proof for Renormalizability of N=1/2 Supersymmetric Field Theories

We provide Wilsonian proof for renormalizability of four-dimensional quantum field theories with ${\cal N}=1/2$ supersymmetry. We argue that the non-hermiticity inherent to these theories permits assigning noncanonical scaling dimension both for the Grassman coordinates and superfields. This reassignment can be done in such a way that the non(anti)commutativity parameter is dimensionless, and then the rest of the proof ammounts to power counting. The renormalizability is also stable against adding standard four-dimensional soft-breaking terms to the theory. However, with the new scaling dimension assignments, some of these terms are not just relevant deformations of the theory but become marginal.Comment: 10 pages, no figure, v2: minor correctio

Theoretical studies of the phase transition in the anisotropic 2-D square spin lattice

The phase transition occurring in a square 2-D spin lattice governed by an anisotropic Heisenberg Hamiltonian has been studied according to two recently proposed methods. The first one, the Dressed Cluster Method, provides excellent evaluations of the cohesive energy, the discontinuity of its derivative around the critical (isotropic) value of the anisotropy parameter confirms the first-order character of the phase transition. Nevertheless the method introduces two distinct reference functions (either N\'eel or XY) which may in principle force the discontinuity. The Real Space Renormalization Group with Effective Interactions does not reach the same numerical accuracy but it does not introduce a reference function and the phase transition appears qualitatively as due to the existence of two domains, with specific fixed points. The method confirms the dependence of the spin gap on the anisotropy parameter occurring in the Heisenberg-Ising domain

Gap Domain Wall Fermions

I demonstrate that the chiral properties of Domain Wall Fermions (DWF) in the large to intermediate lattice spacing regime of QCD, 1 to 2 GeV, are significantly improved by adding to the action two standard Wilson fermions with supercritical mass equal to the negative DWF five dimensional mass. Using quenched DWF simulations I show that the eigenvalue spectrum of the transfer matrix Hamiltonian develops a substantial gap and that the residual mass decreases appreciatively. Furthermore, I confirm that topology changing remains active and that the hadron spectrum of the added Wilson fermions is above the lattice cutoff and therefore is irrelevant. I argue that this result should also hold for dynamical DWF and furthermore that it should improve the chiral properties of related fermion methods.Comment: 12 pages of text, 14 figures, added sect.6 on topology and reference

Renormalization in Quantum Mechanics

We implement the concept of Wilson renormalization in the context of simple quantum mechanical systems. The attractive inverse square potential leads to a \b function with a nontrivial ultraviolet stable fixed point and the Hulthen potential exhibits the crossover phenomenon. We also discuss the implementation of the Wilson scheme in the broader context of one dimensional potential problems. The possibility of an analogue of Zamolodchikov's $C$ function in these systems is also discussed.Comment: 16 pages, UR-1310, ER-40685-760. (Additional references included.