Publikationer från Karlstads Universitet
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An analytical framework for welfare analysis of trade
No full textThe purpose of this note is to develop a general model of trade between countries in which benefits and costs of free trade and restrictions to trade can be analysed. The model assumes a linear relationship in all of its components and the existence of a general equilibrium in prices in the post-trade markets determined by the world market price. Though the following situations are not examined in the note, the derived framework can be used to examine changes in social welfare from trade restrictions in the two countries, such as from a tariff or a quantity restriction on exports and imports and reciprocity, as well as industry subsidies, favourable production laws, lowering of environmental standards, and favourable corporate taxation
Quantum Measurement as a Stochastic Entanglement Race
No full textThe thesis of this paper is that quantum measurement can be analyzed and understood within quantum mechanics itself. The statistics of the measurement process comes from the unknown details of the macroscopic measurement device. Quantum measurement is analyzed within the framework of scattering theory of quantum field theory with the aim of finding a physical rather than a metaphysical understanding. The measurement interaction is treated together with the quantum process to be measured. The evaluation of a Feynman diagram for the total process leads to one factor from the measurement interaction for each channel multiplying the basic scattering amplitudes. With increasing entanglement taken into account, these factors compete for dominance. They depend on unknown details of the measurement apparatus. The statistics of this competition is studied under the assumption that the measurement interaction does not introduce any bias. A binary quantum system is analyzed and after that the n-channel case. As a background, a couple of classical examples are shown, leading to the same selective mechanisms. The result of this analysis is that the quantum measurement process can be understood, whether a single measurement or an ensemble of measurements, as a result of an ordinary unitary time development, based on the interaction beteen the system subjet to measurement and the measurement apparatus. This result makes it possible to view the quantum-mechanical state as describing reality rather than merely a potentiality. This opens again for an ontology of physics, and hence for science in general
