Regensburg 2007 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 13: Spinstructures and magnetic Phase Transitions

MA 13.7: Vortrag

Dienstag, 27. März 2007, 11:45–12:00, H5

Low temperature formalism for glassy order — •Manuel Joachim Schmidt and Reinhold Oppermann — Institut für Theoretische Physik und Astrophysik, Am Hubland, 97074 Würzburg

While the low temperature limit usually simplifies the description of physical systems in a very obvious way, this limit can remain complicated in case of disordered systems like spin- or structural glasses. The reason for this is the appearance of replica-symmetry-breaking (RSB), which complicates the analysis even of the simplest models. The mean-field theory of systems which exhibit RSB needs an infinite number of order parameters which are conveniently described as an order function. For temperatures well below the spin-glass transition temperature, only numerical solutions are available. The approach to T=0, however, is plagued by singularities within the traditional formalism. The proper T=0 limit of the order function and its implications is the objective of our work.

We have developed a novel formalism, free of singularities, which allows for the treatment of RSB in spin glasses and other random systems at low temperatures and directly at T=0. Physical observables like the ground state energy or susceptibilities have been obtained with unprecedented accuracy.