A General Approach to Welfare Measurement through National Income Accounting

We develop a framework for analyzing national income accounting using a revealed welfare approach that is sufficiently general to cover, e.g., both the standard discounted utilitarian and maximin criteria as special cases. We show that the basic welfare properties of comprehensive national income accounting, which were previously ascribed only to the discounted utilitarian case, in fact extend to this more general framework. In particular, it holds under a wide range of circumstances that real NNP growth (or equivalently, a positive value of net investments) indicates welfare improvement. We illustrate the applicability of our approach by considering resource allocation mechanisms in the Dasgupta-Heal-Solow model of capital accumulation and resource depletion.national income accounting, dynamic welfare

The Hartwick Rule: Myths and Facts

We consider the Hartwick rule for capital accumulation and resource depletion, provide semantic clarifications and investigate whether this rule indicates sustainability and requires substitutability between manmade and natural capital. In addition to shedding light on the meaning of the Hartwick rule by reviewing established results, we establish the following novel finding: The value of net investments being negative does not imply that utility is unsustainable. Throughout we make the assumption of a constant technology, without which the Hartwick rule does not apply.Hartwick rule, natural resources, sustainability

The Malleability of Undiscounted Utilitarianism as a Criterion of Intergenerational Justice

Undiscounted utilitarianism as a criterion of intergeneration justice has been questioned for different reasons: It has been argued (1) that any complete ordering of allocations with an infinite number of generations guaranteeing an optimal allocation must involve discounting, and (2) that undiscounted utilitarianism subjects the present generation to heavy demands and leads to outcomes that do not appeal to our ethical intuitions. In a previous work (Asheim, Buchholz & Tungodden, forthcoming in J. Env. Econ. Man.) we have shown that equal treatment of different generations is not incompatible with the existence of maximal allocations, given that one considers technologies that are productive (in a given sense). In this paper we consider the second argument. We show within three classes of technologies (linear, Ramsey and Dasgupta-Heal-Solow tech-nologies) that undiscounted utilitarianism is so malleable that any efficient and non-decreasing allocation can be the unique optimum given the utilitarian criterion, provided that the utility function is appropriately chosen. Hence, undiscounted utilitarianism allows for optimal allocations and need not lead to unequal distributions imposing a too heavy burden on the present generation.Utilitarianism, intergenerational justice

Nuclearity and Thermal States in Conformal Field Theory

We introduce a new type of spectral density condition, that we call L^2-nuclearity. One formulation concerns lowest weight unitary representations of SL(2,R) and turns out to be equivalent to the existence of characters. A second formulation concerns inclusions of local observable von Neumann algebras in Quantum Field Theory. We show the two formulations to agree in chiral Conformal QFT and, starting from the trace class condition for the semigroup generated by the conformal Hamiltonian L_0, we infer and naturally estimate the Buchholz-Wichmann nuclearity condition and the (distal) split property. As a corollary, if L_0 is log-elliptic, the Buchholz-Junglas set up is realized and so there exists a beta-KMS state for the translation dynamics on the net of C*-algebras for every inverse temperature beta>0. We include further discussions on higher dimensional spacetimes. In particular, we verify that L^2-nuclearity is satisfied for the scalar, massless Klein-Gordon field.Comment: 37 pages, minor correction

Warped Convolutions, Rieffel Deformations and the Construction of Quantum Field Theories

Warped convolutions of operators were recently introduced in the algebraic framework of quantum physics as a new constructive tool. It is shown here that these convolutions provide isometric representations of Rieffel's strict deformations of C*-dynamical systems with automorphic actions of R^n, whenever the latter are presented in a covariant representation. Moreover, the device can be used for the deformation of relativistic quantum field theories by adjusting the convolutions to the geometry of Minkowski space. The resulting deformed theories still comply with pertinent physical principles and their Tomita-Takesaki modular data coincide with those of the undeformed theory; but they are in general inequivalent to the undeformed theory and exhibit different physical interpretations.Comment: 34 page

Stable quantum systems in anti-de Sitter space: Causality, independence and spectral properties

If a state is passive for uniformly accelerated observers in n-dimensional anti-de Sitter space-time (i.e. cannot be used by them to operate a perpetuum mobile), they will (a) register a universal value of the Unruh temperature, (b) discover a PCT symmetry, and (c) find that observables in complementary wedge-shaped regions necessarily commute with each other in this state. The stability properties of such a passive state induce a "geodesic causal structure" on AdS and concommitant locality relations. It is shown that observables in these complementary wedge-shaped regions fulfill strong additional independence conditions. In two-dimensional AdS these even suffice to enable the derivation of a nontrivial, local, covariant net indexed by bounded spacetime regions. All these results are model-independent and hold in any theory which is compatible with a weak notion of space-time localization. Examples are provided of models satisfying the hypotheses of these theorems.Comment: 27 pages, 1 figure: dedicated to Jacques Bros on the occasion of his 70th birthday. Revised version: typos corrected; as to appear in J. Math. Phy

Deformations of Fermionic Quantum Field Theories and Integrable Models

Considering the model of a scalar massive Fermion, it is shown that by means of deformation techniques it is possible to obtain all integrable quantum field theoretic models on two-dimensional Minkowski space which have factorizing S-matrices corresponding to two-particle scattering functions S_2 satisfying S_2(0) = -1. Among these models there is for example the Sinh-Gordon model. Our analysis provides a complement to recent developments regarding deformations of quantum field theories. The deformed model is investigated also in higher dimensions. In particular, locality and covariance properties are analyzed.Comment: 20 page

Family as challenge: Contexts of adequate counselling

Das familiäre Standardmodell – zwei Erwachsene verschiedenen Geschlechts mit zwei Kindern verschiedenen Geschlechts – hat längst Konkurrenzen bekommen. Neben diesem soziologischen Kontext konzentriert sich der Aufsatz auf die inneren Kontexte der familientherapeutischen Gesprächssituation und hebt hier insbesondere die Prozessphantasien hervor. Weiter wird auf die Rolle der Metapher hingewiesen, für die sich zu sensibilisieren eine Voraussetzung guter therapeutischer Gesprächsführung wird. Hinweise, wie mit Metaphern in Familien gearbeitet werden kann, werden gegeben. Drei ausführliche Transkripte familientherapeutischer Sitzungen werden präsentiert.(DIPF/Orig.)We live in a world of competing family models of which the standard model – two adults of different sex with two children of different sex – is only one among many others. Besides this sociocultural context this article focusses on the inner contexts of familytherapeutic dialogues. Processphantasies and the role of metaphor are underlined. This articles gives clinical advice how to carefully listen to the use of metaphors by family members and how to deal with them. Three extended transkripts of family sessions are presented.(DIPF/Orig.

On the Existence of Local Observables in Theories With a Factorizing S-Matrix

A recently proposed criterion for the existence of local quantum fields with a prescribed factorizing scattering matrix is verified in a non-trivial model, thereby establishing a new constructive approach to quantum field theory in a particular example. The existence proof is accomplished by analyzing nuclearity properties of certain specific subsets of Fermionic Fock spaces.Comment: 13 pages, no figures, comment in sect. 3 adde