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The essay will focus on three of the "many faces of irreversibility", sketching a history of irreversibility in 20th-century Russian thought: The abstract irreversibility of time in physics, the 'embodied' irreversibility of biological evolution and, finally, the irreversibility of cultural processes. The first part will trace the history of irreversibility in 19th-century physics and biology. The second part will discuss Vladimir Vernadsky's theory of biological time as an attempt to synthesize physical and biological irreversible processes ('neobratimye protsessy') as phenomena of asymmetry in space-time. The third part will look at the migration of scientific ideas of irreversibility into the theory of culture, i.e., Juri Lotman's semiotic theory of irreversibility as unpredictable and unrepeatable processes of culture. In this three-step sketch, the history of irreversibility will be outlined as one of spatialization (from an abstract law to the image of 'time's arrow') and of specialization (from the law of entropy to the case of the generation of meaning).
Energie und Katalyse sind Schlüsselbegriffe zum Werk von Wilhelm Ostwald. Seine Naturphilosophie nannte er selber "Energetik". Für seinen Katalysebegriff erhielt er den Chemie-Nobelpreis. Nach ersten Vorlesungen in Leipzig über Naturphilosophie erschien 1908 sein Werk 'Grundriss der Naturphilosophie', in dem er ein modernes Konzept der Naturphilosophie im Rahmen der Naturwissenschaft entwirft.Im Folgenden wird dieses Programm geprüft, und Ostwalds allgemeine Gesetze sowie Prinzipien werden mit heutigen Weiterentwicklungen konfrontiert. Dabei zeigt sich, dass seine naturphilosophischen Konzepte von großer Aktualität sind.
Lattice simulation of a center symmetric three dimensional effective theory for SU(2) Yang-Mills
(2010)
We present lattice simulations of a center symmetric dimensionally reduced effective field theory for SU(2) Yang Mills which employ thermal Wilson lines and three-dimensional magnetic fields as fundamental degrees of freedom. The action is composed of a gauge invariant kinetic term, spatial gauge fields and a potential for the Wilson line which includes a "fuzzy" bag term to generate non-perturbative fluctuations between Z(2) degenerate ground states. The model is studied in the limit where the gauge fields are set to zero as well as the full model with gauge fields. We confirm that, at moderately weak coupling, the "fuzzy" bag term leads to eigenvalue repulsion in a finite region above the deconfining phase transition which shrinks in the extreme weak-coupling limit. A non-trivial Z(N) symmetric vacuum arises in the confined phase. The effective potential for the Polyakov loop in the theory with gauge fields is extracted from the simulations including all modes of the loop as well as for cooled configurations where the hard modes have been averaged out. The former is found to exhibit a non-analytic contribution while the latter can be described by a mean-field like ansatz with quadratic and quartic terms, plus a Vandermonde potential which depends upon the location within the phase diagram. Other results include the exact location of the phase boundary in the plane spanned by the coupling parameters, correlation lengths of several operators in the magnetic and electric sectors and the spatial string tension. We also present results from simulations of the full 4D Yang-Mills theory and attempt to make a qualitative comparison to the 3D effective theory.