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[en] Due to the fact that the precise relations between the two major phenomenological approaches to nonequilibrium thermodynamics and statistics have hardly been studied we try to develop a general theory from which both the Onsager-Machlup theory and the Prigogine-Glansdorff theory may be obtained as special cases. The relation to Schloegl's statistical formulation and to the generalization of the Prigogine-Glansdorff theory is also considered. We start by considering the basic postulates and equations that apply to macroscopic systems and show that the description can be based on a Fokker-Planck equation. We then consider the path-integral formulation for small fluctuations in steady states, and its relation to various variational principles. We continue by relaxing the linearity assumption and formulate the path-integral description of the nonlinear theory, followed by a discussion of the relation of probability-density functionals to dissipative potentials. Finally we study the variational principles for the nonlinear case and point out the relations of our theory to Schloegl's statistical formulation of the Prigogine-Glansdorff theory. The only application that we consider in the last section of our lectures is to the well-studied system of the Benard convection cell. An appendix contains a derivation of the probability-density functional from the maximum-entropy principle. (HJ)

[en] To reach maximum sensitivity, any method used to search for orphan sources must be insensitive to local variations of the background. Using imaging and non-imaging techniques, we analyzed the same data acquired by a search instrument deployed as a large-area, coded-mask imager. Data from many passes past a 1 mCi source at 65 m from the instrument were used to construct a model of the instrument response. We then used the model to ''hide'' the source in data taken in a light urban environment. We compared the success of detecting the hidden sources using imaging coded-mask methods, pseudo-imaging based on a zero-area matched filter, and non-imaging using simple thresholding. The results clearly indicate the superiority of imaging with the coded-mask techniques returning the best results

[en] The time evolution of the density matrix generated by a quantum map which corresponds to the classical dissipative standard map is studied numerically. The system approaches a steady state which is the quantum analogue of a classical ensemble on an attractor. The quantum-statistical steady state is represented both as Wigner quasi-probability density and as the diagonal elements of the density matrix in coherent states. It is compared with the corresponding results for a stochastic classical map that is equivalent to the semi-classical limit of the quantum map

[en] The quantum Langevin force of a parametrically driven damped harmonic oscillator is determined from the condition of the preservation of the canonical commutation relations. The arguments are independent of the microscopic modelling of the heat reservoir. For damping with and without retardation the Langevin force is found to be independent of the time-dependent parametric driving force and determined by the damping rate alone

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[en] The linearized hydrodynamic theory of ³He-B is derived from thermodynamics by symmetry arguments alone. Spin waves are obtained as Goldstone modes of the broken spin-orbit symmetry. Their spectrum ω(k) is analysed and found to be isotropic, phonon-like with a damping approximately k². Effects of the weak magnetic dipole interaction and an applied external magnetic field are calculated. The former leads to a mixing of one transverse mode and the longitudinal mode and a gap in the spectrum of one of the Goldstone modes which is the large longitudinal NMR shift characteristic of ³He-B. (author)

[en] The linearized hydrodynamics of ³He-B is derived from the eight global conservation laws ( mass (1), momentum (3), energy (1), spin (3) ) and the four broken symmetries ( gauge invariance (1), rotational invariance of spins against real space (3) ). These broken symmetries are present, if ³He-B is, indeed, a Balian Werthamer state, as assumed. The method of derivation is analogous to earlier hydrodynamic spin wave theories. (Auth.)